"Everything went quite well as long as a mechanic from Augsburg and an engineering school professor were permanently on hand.”

—a note from an early diesel engine owner to Rudolph Diesel, 1898

Canada was showing great initiative, independence, and creativity in their evolving quest for nuclear power at Chalk River in the 1950s, but whatever they were doing, the United States was doing it larger, faster, and in dazzling variety. Experimental projects, trying new and previously unheard-of ways to build atomic piles, were underway in Illinois and New Mexico, while plutonium and enriched uranium were being produced by the ton in Washington State and Tennessee. Europe was behind but gathering speed in England, France, and the Soviet Union.

In a rare fit of post-war brilliance, the government of the United States decided to relieve the military services of research, development, manufacturing, testing, and ownership of any nuclear weapons or power systems, beginning January 1, 1947. Everything having to do with nuclear reactions, including facilities, access roads, employees, and waste dumps, was transferred from the Army Corps of Engineers to a new federal agency, the Atomic Energy Commission, or the AEC. The Navy would own the nuclear submarine Nautilus, but the engine and the fuel would belong to the AEC. If you kicked up a rock in your back yard and it was carnotite, a uranium ore, it belonged to the AEC. David Lilienthal was appointed chairman. Lilienthal had proven his mettle by keeping both hands around the throat of the Tennessee Valley Authority as it evolved from a make-work project under President Franklin Roosevelt into a major source of electrical power. Piloting this new agency was no easier than controlling the TVA. The AEC was tasked with promoting world peace and improving the public welfare while developing weapons that could return civilization to low-population Stone Age conditions in a few seconds.

In 1949 the AEC decided that the public welfare could be improved by moving all of the experimental nuclear reactor developments to the middle of nowhere in Idaho. Montana had been considered for the site, but there was plant life and some animals scattered around in it. Roughly in the middle of Idaho, between Arco and Idaho Falls, was a flat desert resembling the surface of the moon. It even had craters, left over from its tenure as the Naval Proving Ground

during the war.92 Frankly, if a reactor experiment happened to go rogue and self-destruct, there was not much there to be harmed, and it was good practice to concentrate all the dangerous stuff in one place. The new facility was named the National Reactor Testing Station, or the NRTS, and its headquarters was built in Idaho Falls.

With more than 50 prototype reactors and some large-scale chemistry experiments, personal safety at the NRTS was not bad. There were a couple of meltdowns and three steam explosions that were considered to be accidents. Two of the blow-ups were staged events that happened to have larger effects than were expected, but one, the infamous SL-1 incident, was the strangest and most tragic reactor accident in American history. Lessons were learned and stringently applied in most cases. The causes of these unfortunate incidents were all over the map, and their listing does not necessarily help us pin down anything we saw in Canada as the universal reason for problems using nuclear fission.

The first accident at the NRTS involved the Experimental Breeder Reactor One, or the EBR-I, in 1955. EBR-I was an odd piece of atomic enthusiasm. It was designed in 1949 at the Argonne National Laboratory in suburban Chicago with the encouragement of Dr. Enrico Fermi, the Italian who conceived the CP-1 pile back in ’42 and the pontifex maximus of reactor physics. The design team was led by Walter Zinn, a nuclear physics Ph. D. from Canada. When the CP-1 was started up at the University of Chicago on December 2, 1942, Zinn was responsible for withdrawing the safety control rod, called the “zip.” By 1946 he was the head of the Argonne Lab, in charge of all the nuclear reactor research in the United States.

The importance and omnipotence of Walter Zinn’s monopoly was felt by the other labs still standing after the war. The Singing Oak Ridge Physicists expressed their feelings with this song at the 1947 Christmas party, to the tune of Deck the Halls:

Pile research is not for us’uns.

Fa la la la la, la la la la.

Leave it to our Argonne cousins.

Fa la la la la, la la la la.

Engineering is for we’uns.

Fa la la la la, la la la la.

We’re a bunch of dirty peons.

Fa la la la la, la la la la.

Zinn was comfortable at Argonne, but just as the breeder reactor design started to gel, this and every other reactor construction project was moved to Idaho, which some people came to know as “Argonne West.”

At the time, there was not a single electrical-power-producing reactor in the entire world. All the piles were used either for plutonium production or as neutron sources for research. Uranium mining out west was a small enterprise, usually involving old vanadium mines, and the thought of relying on Canada or the Belgian Congo for the fuel to run the industrial economy of the United States was not attractive. There simply was no promise of enough uranium to do anything but make bombs and run a few submarines. Rickover’s nuclear sub fuel was expensive, exotic 50- percent enriched U-235 from the still-top-secret gas diffusion plant at Oak Ridge, and there was no way that commercially competitive power could be produced by burning it in a privately owned pile.

Backing up at Oak Ridge by the hundreds of tons was an inventory of depleted uranium-238, the waste exhaust from the uranium enrichment process. In theory, this useless stuff could be converted to fissile plutonium-239 by fast neutron capture. This was possible in the graphite­moderated converter reactors, because the fissioning U-235 was co-located with the U-238 in the natural uranium fuel. Before it had a chance to escape the fuel rod and be moderated down to thermal energy, a freshly born neutron running at ramming speed had a chance of being captured by a nearby U-238 nucleus. The uranium nucleus, heavier by one captured neutron, would then be U-239, which would beta-minus decay into neptunium-239 with a 23.47-minute half-life. The neptunium would beta-minus decay in its own sweet time with a half-life of 2.365 days into almost-stable plutonium-239, a very useful nuclide. Once it made it out of a fuel rod and into the graphite, a neutron’s value changed from being able to convert U-238 to being able to cause fission in another U-235 nucleus as it slowed down to thermal speed. Walter Zinn postulated a reactor that could run without a moderator. All the neutrons would be fast, causing fissions at top speed rather than slowed down, and therefore neutrons not used for fission would be able to convert the wasted U-238 into useful plutonium. Each fission released more

than two hot-running neutrons, and only one was required to trigger another fission.93

Zinn’s concept was a reactor that burned the artificial nuclide Pu-239 to make power. Manufactured plutonium was almost 100 percent pure, containing no worthless isotopes, and it did not need the advantage of thermalized neutrons to fission efficiently in a fast-neutron environment. The fission process in pure Pu-239 was not marginal and barely able to make it, as was the natural uranium fission scheme. The plutonium reactor core, bleeding fast neutrons from every external surface, would be surrounded by a blanket of pure U-238. Wasted fast neutrons escaping the fission process would be captured in the uranium shield, converting in a few days into more Pu-239. Calculations showed that such a pile would produce more Pu-239 than it burned in the fission process. It seemed utopian. It was a power source that produced more fuel than it consumed. There was enough U-238 piling up from the weapons production to provide the total energy needs of civilization for thousands of years into the future, without drawing down the weapons material or the submarine fuel. This gorgeous concept would be known forevermore as the “fast breeder reactor.” There were some minor complications to be

worked out.94

A power reactor must have some means of transferring energy from the fission process to the power-generation process. In Rickover’s submarine reactor, being assembled for testing just over the horizon from the EBR-I site, the medium of transfer was water. The water absorbed heat from the fission by direct contact with the fission neutrons, which were born going 44 million miles per hour. Zinn’s breeder had to be different. There would be no neutron moderation, no slowing them down to thermal speed. The coolant in the breeder had to be heavy, metallic, and liquefied, so that it could absorb heat from the reaction by conduction to metal surfaces in the reactor structure without slowing anything down. Neutrons hitting heavy metal nuclei would simply bounce off and retain their speed. Both transfer methods, water and metal, kept energy from accumulating in the machine and causing it to melt. The fluid medium would flow into the bottom of the reactor core, picking up heat and exiting through a pipe at the top. For the EBR-I, the logical choice of coolant was a mixture of sodium and potassium metals, pronounced “nack.”

By mixing sodium with potassium, the melting point of the metal could be brought down to about room temperature. It was a very sluggish fluid, but it would flow, particularly when heated to 900 degrees Fahrenheit with the reactor at full power. Unlike water it was, of course, completely opaque. There was no way to visually inspect the reactor internal structures with the coolant in it, the way it was possible using water moderator. The sodium tended to activate under the neutron bombardment of fission, becoming sodium-24, throwing beta and gamma radiation with a 15-hour half-life. The potassium was a lesser activation risk, but it would contribute some to the induced radioactivity. The worst characteristic of nack is that it would react vigorously with air, water vapor, or particularly liquid water, becoming sodium and potassium hydroxides. In their undiluted form, these are nasty chemicals. Step in a puddle of it, and it will first dissolve your heavy leather boot followed by the foot inside the boot. Anything aluminum touched by it, like an airplane or a Pullman railway car, turns to white powder. There were entire reactors made of aluminum, but this one would have to be stainless steel.

Zinn found that plutonium-239 was impossible to obtain for reactor experiments. By 1951 the AEC was turning out plutonium-based implosion bombs on an industrial scale, and surplus material was simply unavailable at the time. It was easier to obtain 97-percent enriched

uranium-235 for the EBR-I fuel, and it was an adequate substitute for the plutonium.95 At Argonne, the 52 kilograms of bomb-grade uranium was fabricated into 179 stainless steel-clad fuel rods with some spares, made pencil-thin for good heat conductivity to the nack. The rods were mounted vertically in a steel tank, separated from each other in the preferred “hexagonal pitch” configuration so that the coolant could flow through them from bottom to top.

Control of a fast reactor is a bit touchy, because a smaller percentage of the fission neutrons are delayed than in the usual thermal reactors. With most of the neutrons born instantly upon fission and no slowing-down time allowed, the smoothness of the controls is diminished. The fission in EBR-I was managed using boron neutron-absorption rods, moved up and down into the reactor core by electric motors. To shut it down quickly, you could bring your palm down on the red scram button and operate the motors at maximum in-speed, or you could hit the reflector release button. Under this condition, the bottom half of the breeding blanket would unlatch and fall away by gravity with a floor-shaking CLUMP. Just losing the blanket and its tendency to reflect some neutrons back into the core was enough to kill the fission process and make the reactor quickly subcritical. In the middle of the control room there was also an alternate scram control. It was a triangular metal handle, hanging by a chain. Anyone in the room could pull that handle at any time and shut down the pile instantly.

In late May 1951, the experiment was ready for a power-up, and dignified guests and visitors, having endured a dreary ride out to the site, were eagerly anticipating success. With all the controls carefully pulled out, the reactor remained serene and subcritical. Zinn remained calm and estimated that the core was so completely dead, he would need another 7.5 kilograms of fuel to make it work. With a hint of reluctance the AEC granted him some more U-235 from military stockpiles, and it took three months to get it fabricated into fuel.

On August 24, 1951, the world’s first fast breeder reactor was the first reactor at NRTS to go critical. At zero power it worked fine, but measurements indicated that the fuel assemblies would have to be modified if the thing was going to boil water and make steam, as was necessary for a power reactor. Two thirds of the fuel rods were shipped back to Argonne, where they were made shorter and wider by a hydraulic press. Arriving back in Idaho, they were arranged as a belt-line around the thinner fuel tubes.

On December 20, the reactor was run up to about 45 kilowatts. The hot metal coolant was pumped continuously through a heat exchanger with water on the other side of the heat transfer process. At 1:23 in the afternoon, an operator opened a steam valve connected to the heat exchanger, and steam ran through the power turbine. Four 200-watt light bulbs on the turbine deck began to glow white-hot. At that instant, electrical power was first generated by a nuclear

reactor.96 Zinn took a piece of chalk, wrote his name on the concrete wall of the building, and invited his entire team to do the same. Those names remain on that wall to this day.

Success followed success with EBR-I. Three days later, the crew was able to connect the entire facility to the generator and run everything off reactor power. They ran it at power until early in 1953, when they shut it down for a fuel and breeding blanket evaluation. Representative samples were sent back to Argonne for chemical analysis, and the results came back positive. There was more plutonium made in the blanket than there was uranium lost in the fuel. The breeder concept was verified, and the electrical power future of the world could now be moved beyond the point where the coal runs out. Zinn believed that in the short run, breeders would be the only type of reactor that could compete commercially with fossil-fuel power plants. He pressed on vigorously and started the plans for EBR-II.

Experiments continued, revealing the subtle unknowns in breeder reactor behavior. One characteristic was a particular nag. The breeder had a positive temperature coefficient of reactivity. That is, when the temperature increased, the thing went supercritical, and the operator would have to pull it back down by inserting control rods until it was back to the desired power level. Zinn had a theory that if he pushed the temperature to beyond 852°F, then the effect would reverse, pulling the power down. The logical way to run the temperature up and test this idea was to stop the coolant pump and see what happened. The scram channel for core temperature that would normally shut the reactor down if the core was hot beyond a threshold was disconnected.

On November 29, 1955, the EBR-I was ready for the experiment. It was kept at a low power of 50 watts, so that things would not get out of hand. The coolant flow was stopped with the controls set for a period of 60 seconds, meaning that the power level was multiplying by about

2.7 every minute.97 The pile immediately started acting crazy. In three seconds the power had climbed from 50 watts to one million watts, and the period was at 0.9 seconds and dropping. The thin, unsupported fuel rods had buckled under the high heat at the center of the reactor core, bending inward, getting closer together, and improving the reactivity of the non­moderated pile. As the heat increased, the fuel bent farther inward, becoming less like a metal — cooled reactor and more like a Godiva assembly, a touchy, dangerous ball of fissile metal. Harold Lichtenberger, the reactivity specialist on hand, yelled to the operator “Take it down!” The assistant operator at the controls, not knowing exactly how to respond to such a request, reached for the button to initiate a slow control drive-in. It took two seconds for this error to sink in, with the power rising faster and faster. Operating on instinct, the senior operator lunged for the scram button, and the power excursion ended immediately.

The crew resumed breathing. One strong advantage of a liquid-metal-cooled breeder reactor over a water-cooled reactor was immediately obvious. If they had been running a water reactor in that kind of runaway condition, the steam explosion would have wiped out the building. In this case, there was not a sound, not a whisper out of the pile as it went wild. The only way they could tell that anything was wrong was by the instruments on the control panel. Nobody had been exposed to any unusual radiation, and the reactor looked just as it had that morning before the startup. Fifteen minutes passed and they were feeling very good about their design concept when the building radiation alarms started going off.

It is an ear-damaging, hair follicle-killing sound that penetrates down to your center of mass. It sounds like a pterodactyl screaming into the side of your head, as if we knew what a pterodactyl sounds like. BRAK. You can almost feel his hot, nasty breath condensing on your temple and rolling down your cheek. BRAK. BRAK. Your nerves unravel at the urgency of the signal. BRAK. BRAK. BRAK. It means “make for the door,” or, as they say in the accident reports, “all personnel evacuated the building.” You unconsciously drop whatever you were holding and swivel to face the exit.

Careful analysis of the incident revealed that the core was completely trashed and the primary cooling loop was contaminated with fission products. The United States had experienced its first meltdown, with the top half of the core liquefied and running south into the bottom half. Nack in the center had vaporized and forced its way into the breeding blanket as the power reached 10 megawatts, or 7 times the pile’s designed capacity if the coolant were running. No personnel were harmed, and the accident was undetectable outside the building. If the senior operator had not hit the scram button, the reactor would have shut itself down anyway. At the time of the scram, the melted fuel was foaming in the metallic coolant, diluting in the nack and beginning to lose its supercritical configuration.

The AEC kept the incident secret out of fear that news of a nuclear reactor accident would affect public opinion in a negative way, which it did a year later when an account was leaked into the journal Nucleonics. The editor was merciless. Keeping such incidents secret deprived the engineering community of experience, and it was incorrect to keep information concerning a system that was meant to be handed over to the public out of the public view, particularly if it indicated something bad. The AEC agreed in principle and resumed doing what it was doing. The public, watching movies about giant insects mutated by A-bomb tests and digging backyard bomb shelters, was considered incapable of handling routine nuclear news. They were too saturated with Hiroshima, Nagasaki, deaths by radium, and Japanese fishing boats to think rationally.

The EBR-I core was redesigned and reinstalled in 1957. The new U-235 core had zirconium spacers between fuel rods, developed in Rickover’s S1W program 10.47 miles northeast of the site, and this embellishment seemed to prevent further power excursions due to mechanical effects. In 1962 EBR-I finally got a plutonium core, and it ran with good performance until 1964 when the old pile was shut down permanently. It was time to move on to a bigger, more advanced power plant, the EBR-II. The improved plant ran without incident until it was finally shut down in 1994. In its lifetime it made over two billion kilowatt-hours of electricity and, with the production of direct space heating, kept the workers at Argonne West, which had become an official installation at NRTS, from freezing in the Idaho winters.

By some opinions, the most bizarre adventure in fission development in the 1950s was not the nuclear-powered tractor wheel hub, the plutonium-fueled coffee maker, or even the atomic land mine. No, the prize for the most money thrown at the least likely application probably belongs to the Aircraft Nuclear Propulsion program, or the ANP.

The ANP program began in 1947. There was talk in the Defense Department about a possible nuclear submarine project for the Navy, and the Air Force wanted its own counterweight, a strategic bomber that could stay in the air for months on nuclear jet engines. The working slogan was “Fly early!”, and an unrealistic development period of five years was estimated.

Some reactor physicists knew better and expressed doubt as to the practicality of the plan. Putting a light-weight reactor operating at 2,000°F in an airplane and running it without killing everyone within a few hundred feet was not as easy as it sounded. Airplanes had to be made of thin, lightweight materials, like aluminum or magnesium. Reactors were set in concrete, with a lot of lead and steel involved. The two design concepts, fission power and airplanes, were working at opposite ends of the materials spectrum. There were many unknowns for building such an engine, and a lot of piecemeal experimentation would be necessary before the concept could be called possible.

In 1948 a report was commissioned at MIT for studying the feasibility of developing a nuclear — powered airplane. The final document, called the “Lexington Report,” contained some good news and some bad news. The good news was that building a nuclear-powered vehicle that could lift off the ground and fly on its own looked possible. The bad news was that it would take a billion dollars and 15 years to work out the details, and if the thing crashed somewhere, the debris field would be uninhabitable for thousands of years. The Air Force pounced on the good news. Together with the Joint Committee on Atomic Energy and a cadre of aircraft manufacturers, they overruled the nay-saying nuclear scientists, President Eisenhower, the Bureau of Budget, and the Secretary of Defense. The ANP got a green light to proceed in

1952.—

The project spread out all over the country, from Pratt & Whitney in Massachusetts to Lockheed in Georgia, from Convair in Texas to General Electric in Ohio. In July the largest chunk of the work went to the NRTS in Idaho, where the engines would be hot-tested out in the desert. There was jubilant celebration in every quarter.

A jet engine is basically a large metal tube, mounted with one open end pointing toward the front of the aircraft and the other end at the back. With the plane moving forward, air blows into the front of the tube. An axial compressor spinning at high speed at the front acts as a one-way door, encouraging air to come into the tube while preventing anything from escaping out. In the center of the tube is a continuous explosion of jet fuel mixed with the compressed incoming air. The mixture, burned and heated to the point of violence in the explosion, instead of blowing the airplane to pieces finds a clear path out through the back of the tube. The escaping explosion products create a reactive force, just as would be made by a rocket engine, pushing the engine and the vehicle to which it is attached forward. On its way out, the expanding gases spin a turbine, like a windmill, and it is connected forward to the spinning compressor wheel. The nuclear aircraft engine was to operate in this way, except that the continuously exploding jet fuel would be replaced by a nuclear reactor running perilously close to fiery destruction.

General Electric got the contract for the engines, to be tested at the NRTS.99

A piece of desert about 30 miles north of the center of the NRTS was picked out and named Test Area North, or TAN. It was the farthest point from anyone else’s reactor experiment. A large assembly building was erected, the control room was buried for safety reasons, and the test stand was built a mile and a half away, with a four-track railway connecting back to the main site. The engine was put together in the assembly building, and then it was rolled out to the test stand using a lead-shielded locomotive. The engine weighed a hefty eight tons.

The first test engine was called “HTRE-1,” High Temperature Reactor Experiment One, or “Heater-One.” The two jets were modified GE J-47s, and the reactor having enough power to superheat the intake air turned out to be too large to fit in the space normally occupied by the fuel burners. The reactor used enriched uranium clad in nickel chromium, with water as the moderator. The airstream was taken from the jet engine tube immediately after the compressor stage at the intake opening. Using a large conduit, this compressed air was fed through a honeycomb of passages in the reactor, where it was heated and expanded as it would have been in the fuel burner in a normal engine. The air was then piped back into the engine in front of the turbine and out the exhaust nozzle. On November 4, 1955, the reactor was tested at criticality by itself, and on December 30, it was ready for a hot test in the fully assembled engine. The reactor was unrealistically large, meant to test the concept and not to be mounted in an airframe, and it heated the air for both tandem-mounted jet engines.

The assembly was rolled out to the test stand, bolted down to the concrete apron so it wouldn’t fly away, and hooked up to a long, horizontal pipe used to direct the exhaust into a filter bank. This would prevent disintegrating fuel rods from being blown all over NRTS. The pipe ended in a 150-foot vertical smokestack staring right up into the big Idaho sky. The operation crew, hunkered down in the control room, spun up the two compressors using electric starter motors, lit the flames in the burners, and powered up the reactor. When both engines reached operating temperature, the jet fuel automatically shut off, and the jets spooled up to screaming speed on pure atomic power. It performed as predicted, but the gamma radiation was far greater than had been anticipated. Operational plans for the bomber would have to be modified, and perhaps more crew shielding would be needed.

Testing of Heater One continued, and work began on the world’s first fully shielded bomber hangar. A special tracked vehicle, heavy with lead shielding, was built with robotic arms and a thick, lead-glass viewing port for the driver. It would be used by the mechanic to work on a radiologically dirty airplane, blazing with fission product contamination and neutron-activated metal parts. A 23,000-foot-long runway was surveyed, and test missions were scripted. An electric incinerator toilet was invented for use by the flight crew, and pre-packaged meals were planned. Money flowed.

There were problems with the extremely high temperature necessary in the reactor. Fuel and reactor internal components evolved into exotic ceramics. HTRE-1 was modified and renamed HTRE-2, changed into a high-temperature-materials test reactor by cutting a hexagonal, 11-inch hole in the middle of the reactor. Newly designed fuel elements were mounted in the hole and run up to 2,800°F. Progress was encouraging, and it was time for HTRE-3.

HTRE-3 was a complete redesign. One smaller, horizontally mounted reactor ran two tandem J-47 jet engines, mounted as they would be in the proposed airplane, with the reactor located

at the center of balance of the airframe.100 The reactor was sized realistically, such as would fit in the finished airplane, but it still dwarfed the big General Electric jets. The fuel pins and control rods took up a lot of space, but there still had to be enough air passageway to spin the turbines in two J-47s. The core diameter was 51 inches, and the length 43.5 inches. The moderator was a solid ceramic, zirconium hydride, and that also took up room in the reactor core. The whole thing was encased in a solid beryllium neutron reflector. The reactor would still be considered highly advanced 54 years later.

By November of 1958 Heater-Three was on the test stand and ready to show what it could do.101 On the morning of November 18 the crew started the engine compressors and made the reactor supercritical by manual control. Power was increased slowly to 60 kilowatts and leveled off, just to “check for leaks.” Everything seemed fine. The crew shut it down and went

to lunch.102 Feeling fed and frisky, the crew decided to proceed with the experiment program and run it up to 120 kilowatts. The engines started smoothly, with power increasing by a factor of 2.7 every 20 seconds. When the power reached 12 kilowatts, they switched to automatic, released the control handles, and sat back to watch it happen.

The automatic control used an ion chamber to detect gamma rays originating in fission. The number of gamma rays detected per second was perfectly proportional to the power level of the reactor, and it was read out as kilowatts on a meter at the control panel. The same signal was fed to a pen-chart recorder, giving a permanent record of power history of the engines. The current from this same detector was also fed to an amplifier, and this enhanced signal controlled a set of electric motors connected to the reactor control rods, running them in or out of the reactor core to satisfy a pre-set level of gamma-ray production rate. The high-voltage line feeding electricity to the ion chamber had been modified as an improvement to the circuit. A filter had been installed to prevent clicks and hums originating in the electric motors from contaminating the gamma ray signal.

If the power got out of hand for some unforeseen reason, the reactor would scram automatically on the gamma-ray level signal at a pre-set point, below the level where any harm could come to the machinery. As a backup, a set of thermocouples in the core monitored the reactor temperature continuously, feeding another scram channel. There was no steam to explode, so the worst thing that could happen would be too much power making too much temperature and causing the thing to melt.

The power level passed the 60-kilowatt level. No problems. They were now in untested territory, but the engines were accelerating smoothly. 80 kilowatts. No problem. 90 kilowatts. Still increasing power. 96 kilowatts. The power level started to fall rapidly, as if the bottom had dropped out. The crew, watching the instruments, found this curious, and the reactor operators cocked forward in their seats. The automatic control, sensing that the power was dropping quickly, pulled out the controls, trying to bring it back up. The power seemed to keep going south, and the needle on the meter fell to the left. Twenty agonizing seconds passed and WHAP! The scram circuit, detecting that the thermocouples in the reactor core had all melted, shut her down automatically, throwing in all the controls at once. In those 20 seconds, every piece of fuel in the reactor had lapsed into the liquid state. The fact that it overheated had not disassembled the reactor, as it was made of some very rugged ceramic materials, and the reactivity had actually increased as the nickel-chromium-uranium-oxide fuel turned to fluid. When the indication had been that the power was falling, it was actually increasing very quickly. Although the fuel was designed to be very tolerant of extreme temperature, the power level had spiked beyond the capacity of the two jet engine air-intakes to keep the reactor core from melting. Only a few of the zirconium-hydride moderator sections were damaged.

A slight increase in background radioactivity was detected downwind of the smokestack as some few fission products, evaporated off the white-hot fuel, made it through the filter bank. Aside from that and the pen-chart recording, there was no outside indication that anything had gone wrong, and no humans were harmed.

The steel annulus surrounding the reactor was pumped full of mercury from a holding tank.

Mercury is a high-density metal, liquid at room temperature, and it makes an excellent gamma — ray shield. With it in place, the crew could approach the Heater-Three to disconnect it without

danger from the decaying fission products built up in the damaged fuel.103 The engine was then dragged back to the hot-lab in the assembly building, where the core was rebuilt and the source of the problem was analyzed.

That filter in the high-voltage cable had unfortunately limited the number of electrons per second that could travel through the wire. That was fine, as long as not too many electrons were needed to register the number of gamma rays per second that were traversing the ion chamber. At the higher power level, at which the equipment had never been tested, the gamma flux overwhelmed the ability of the power supply to keep up. The current demand from the chamber was so high, the voltage dropped, and the detector stopped detecting. The automatic system interpreted this as a power loss, and it tried to compensate for it by pulling the controls. The power climb accelerated until the engine was, as we say, outside its operating envelope. This incident went down as the first time in history a reactor was melted because of an instrumentation error. Human error was a fault only indirectly.

In December the AEC told the Air Force that the nuclear bomber could not be flown over the United States. The only way it could be flown was out over the Pacific Ocean, presumably taking off from the beach. The 8-million-dollar shielded hangar, recently finished, could no longer be used to house a nuclear bomber, and grading the runway would not be productive. On January 20, 1961, John F. Kennedy was sworn in as President of the United States. On March 28, he signed a paper canceling the ANP project, and that was that. The much disappointed staff at the NRTS knew that they were very close to a working atomic aircraft engine, but for the good fortune of nuclear power we will never know if it would have flown.

A cluster of three reactor accidents involved the explosive conversion of water into steam by nuclear means. Two of the incidents were accidents only by procedural technicalities, and the other one was a complete surprise. We know exactly how it happened, down to the millisecond, but we have no answer as to why.

Among the gifted reactor physicists at Zinn’s Argonne lab was Samuel Untermyer II, grandchild of Samuel Untermyer I. Sam the First was a Jewish-American born in Lynchburg, Virginia, who became the most famous New York lawyer of all time. He was responsible for, among other things, maintenance of the 5-cent subway fare. His grandson, a graduate from MIT in 1934, did not believe that the revered pressurized water reactor, in which the coolant is kept at such a high pressure it cannot boil, was the only way to build a water-moderated pile. In those early days of reactor development in the late 1940s, the general opinion was that if the water in the reactor vessel were allowed to boil, then the neutron production would become erratic and unpredictable. The coolant voids caused by steam bubble formation were predicted to cause fuel melts, chemical explosions, unchecked power excursions, and probably boils on the reactor operators and tension headaches.

Untermyer proposed a contrary prediction. If the coolant, which is also the moderator, in the reactor vessel were allowed to boil into steam, it would simplify the power production mechanism. There would be no need for a complicated, expensive, failure-prone steam generator and a second cooling loop. The reactor vessel would become a boiler, like the boiler in a coal-fired power plant but simpler, without any boiler tubes. No pressurizer to maintain the lack of boiling would be necessary, and several pumps and valves could be eliminated. Instead of running wild and unpredictable, the neutron flux would be controlled. A great deal of boiling would result in moderator voids, which would degrade the fission process and lower the power level. If the boiling were quenched, the density of the moderator would increase, and the power level would rise to a threshold cutoff, floating between too much power and too little power. Such a boiling-water pile would control itself and follow the load demand. There would be a lesser need for an electronic feedback-control system, such as would cause the HTRE-3 to melt in ’58. In the event of an uncontrolled upward power excursion, the moderator would boil away, and this would automatically turn off the fission process without the need for an electronically controlled scram system. These seemed like desirable qualities in a power reactor, but it would all have to be proven with physical experiments.

Untermyer convinced his boss, Walter Zinn, of the importance of the boiling-water-reactor concept, and together they petitioned the AEC for a contract to prove the principles. In 1952 he was given enough money to make a modest stab at it and a spot of desert at the NRTS. The test reactor would be laid out on the ground, without so much as a tin roof over it, and the control room was a small trailer parked half a mile away. Television cameras gave the experimenters views of the reactor, including one using a large mirror to show the top of the core. The reactor vessel was a steel tank, half an inch thick, 13 feet high and 4 feet in diameter, halfway sunk in the ground. The 28 aluminum-clad enriched-uranium fuel elements were surplus from the big-budget Materials Test Reactor being erected elsewhere on the desert. The total fuel loading was 4.16 kilograms of uranium. The control rods were inserted through the open top of the vessel, adjusted in and out of the core with electric motors and wired back to the control trailer. Pipes, cables, and tanks were all over the ground. The steam made by the reactor heat was simply vented into the air. Dirt was mounded around the exposed portion of the reactor to give it some gamma-ray shielding. Untermyer, expecting this

to be the first in a glorious series of experimental reactors, named it BORAX-I.104

By May 1953 BORAX-I was loaded with fuel, filled with water, and ready to go. Over the next 14 months, Untermyer and his operating crew would afflict this frail collection of scrounged parts with every torture imaginable. Over 200 experiments were performed, subjecting the system to all the operator errors and component failures they could think of. Tourists riding by on Highway 20/26 would report a geyser to the authorities. That would be Untermyer seeing how far he could throw a plume of water if the thing went uncontrollably supercritical. The record, I think, was 150 feet straight up. Under all conditions, the system performed exactly as predicted, shutting itself down automatically while allowing no harm to the machinery. The self­regulating feature worked right on the money.

By July 21, 1954, they had done everything to the reactor that their fertile minds could conjure, and it was time to shut her down and vacate the site. As one last experiment, Untermyer wanted to blow out the control with compressed air and see how the thing would react in a fast transient, with the reactivity taken from stable criticality to prompt supercriticality

as quickly as possible.105 Although there was no conceivable physical situation in which this would normally occur, it would give them an upper boundary of reactor mayhem to work with. It would also be a fine spectacle to watch, a steam explosion in keeping with the Bill Crush trainwreck spectacle in Waco, 1896, only without the public being able to watch. They would,

however, film it in slow motion, so that it could be watched and studied, over and over. Extra fuel was loaded, and the central control rod was beefed up.

The wind was blowing in the wrong direction. Thinking that it could waft fission products over someone else’s reactor experiment, the site meteorologist canceled the test. The crowd of important guests, expecting a train-wreck, went away disappointed. The next day at 7:50 a. m., the smoke bombs ringing the site were sending fumes straight up. It was time. The drivers cranked up the emergency evacuation buses, and the State Patrol stood prepared to close down the highway. The visitors, having returned with renewed anticipation of a good show, were standing in rapt attention at the official Observation Post, growing quiet, spitting out gum, and polishing the dust off eyeglasses.

The crew was worried. Would the explosion be big enough to excite the crowd? Would the

control rod hang in the guides and spoil the transient?106 Harold Lichtenberger, the physicist sitting at the controls, promised to give it his all.

Lichtenberger hit the EJECT CONTROLS button. KABOOM! Up she went with the force equivalent of 70 pounds of high explosive in the reactor vessel. A total energy release of 80 megajoules had been expected. They got 135 megajoules instead, and this inaccurate prediction instantly qualified the test as a nuclear accident. The little reactor that usually shed energy at the rate of 1 watt ramped up to 19 billion watts with a minimum period of 2.6 milliseconds. In all other tests of explosive steaming, the thing would send up a geyser of water droplets, sparkling in the western sun. This time the core melted instantly and homogenized into a vertical column of black smoke. A shock wave rippled through the floor of the control trailer.

Walter Zinn, standing in the control trailer, shouted “Harold, you’d better put the rods back in!”

“I don’t think it will do any good,” Lichtenberger shouted back. “There’s one flying through the air!”

In fact, the entire control mechanism, bolted to the top of the reactor vessel and weighing 2,200 pounds, was thrown 30 feet up in the air. Zinn watched as a sheet of plywood flew spinning across the desert like a Frisbee. BORAX-I was totally destroyed. Pieces were found 200 feet away, and all that was left of the reactor was the bottom plate of the vessel with some twisted fuel remnants lying on top of it. The slow-motion movies were fogged by unexpectedly high radiation, and the power to the cameras failed as the wiring was carried away in the blast, but there was enough footage to show the plume of debris as it shot upward. Pieces of fuel were shown catching fire in the air as they tumbled upward. A control rod could be seen rocketing away at the upper left and eventually the control chassis re-entered the frame from above. In the first few seconds of the film they watched something that always seemed a feature of a prompt fission runaway: the blue flash. It lasted only two milliseconds, but it lit up the top of the reactor assembly as if it had been struck with a bolt of lightning.

You could not have asked for a better show, and a fine time was had by all. Untermyer had pushed a boiling-water reactor as far over the brink of disaster as was possible, and there were no radiation exposures or physical injuries. With this one staged spectacle, Untermyer had brought the AEC, the Argonne Laboratory, the military services, and the NRTS face to face with their collective fear, that a nuclear power reactor out of control could wreak havoc with a nineteenth-century steam explosion. Instead of frightening everybody, it calmed them down to have seen it. The maximum disaster seemed finite and manageable, and it was clear that this accident could never happen again. No normal power reactor control panel would ever be built to pull out the rods at explosive speed, and nobody was crazy enough to jerk out the central control by hand.

The debris was buried on the spot, and plans for BORAX-II were implemented on the same site. In the next few years, BORAX-III, BORAX-IV, and finally BORAX-V, a full fledged commercial-grade power reactor, were built and tested, with further experimentation justifying Untermyer’s dream of an inherently safe, self-controlling nuclear reactor. The good feelings, however, would barely make it into the next decade.

The United States Department of Defense was forming strategies for winning the Cold War, the global stand-off with the Soviet Union in which each side threatened to blow the other to kingdom come. These preparations were forward-looking yet practical, and they seemed somewhat less like science-fiction than the Air Force’s ANP program. Among the plans were the Distant Early Warning System, or “DEW Line,” and Camp Century. The DEW Line would be a set of remote, long-distance radar stations along an arc inside the Arctic Circle, in Alaska and Canada, intended to give a heads-up of several minutes if Soviet nuclear missiles were bearing down on the United States. Camp Century would be an under-ice city in Greenland supporting a hidden array of mobile, medium-range guided missiles, capable of pounding Moscow down to

bedrock with thermonuclear warheads.107 The mission was code-named “Project Iceworm.”

Each of these proposed measures would require electricity for lighting in the months of total darkness and operation of the radars plus space-heating to keep the soldiers from freezing to death. These types of installation, such as outposts in the Antarctic, were usually powered with diesel generators running 24 hours a day, but to give life to a base as large as the proposed Camp Century would take a million barrels of diesel fuel per year, which seemed impractical. Camp Century supported 200 soldiers, one dog, and—brace yourself—two Boy Scouts: Kent Goering of Neldesha, Kansas, and Soren Gregerson of Korsor, Denmark, all existing on a sheet of glacial ice 6,000 feet thick. The base commander, Captain Andre G. Brouma, is credited with the motto, “Another day in which to excel!”

The Army Corps of Engineers was assigned, on April 9, 1954, to develop a range of small reactors to provide electrical power and space heating for remote conditions in the Arctic and the Antarctic. The U. S. Army Engineer Reactors Group, headquartered in Ft. Belvoir, Virginia, was in charge, and their observers had been very impressed with Untermyer’s BORAX-I experiments.

The list of specifications for the army reactors was interesting, and the boiling-water reactors being developed at NRTS were closer to meeting the requirements than were Rickover’s submarine plant or Zinn’s breeder. The reactors had to be small, relatively inexpensive, and as simple as possible, with a minimum number of moving parts. Nuclear reactors at this young stage were notorious for needing nuclear physicists, highly specialized engineers, and all manner of Ph. D. scientists on hand for normal operation. These reactors would need no such specialists at the plant site. Operators would be given a few months of training and a couple of weeks experience on a training reactor at Ft. Belvoir, but keeping a staff of thoughtful academics alive at a remote army base was out of the question. Moreover, the entire plant would have to be able to be pulled on a sled over ice, lowered into place, and hooked up with a minimum of effort. It could be broken down into sections, but they would have to screw together easily under hard conditions. Nothing could be welded together on site, and certainly no concrete, the basis of all nuclear construction, could be poured in temperatures far below freezing. There would be no calling the factory for replacement parts. They would have to be foolproof, such that an inexperienced operator or one deprived of sleep for three days would not be capable of pushing the wrong button and destroying anything.

The reactor design shop at Argonne took the challenge eagerly, and they came up with the Argonne Low Power Reactor. The name was changed to SL-1, meaning Stationary Low-power reactor, version one, and the small demonstration plant was built in a remote spot at the NRTS in Idaho. Construction and management of the project was transferred to Combustion Engineering in Stamford, Connecticut.

It was everything that the Army had asked for. It was a small boiling-water reactor, making three megawatts of heat. Of this, 200 kilowatts would be converted into electricity using a combined steam turbine-generator, 400 kilowatts would be hot air to be piped into living and working quarters, and the rest would be exhausted into the environment using an air-cooled heat exchanger. All the machinery was housed in a simple, cylindrical building made of quarter — inch steel, 38 feet in diameter and 48 feet high. In the ceiling was the “fan room,” containing the heat exchanger and electrically powered blowers. The lower section was filled in with a combination of loose gravel and steel punchings, with the reactor buried in the middle and flush with the floor. The punchings, left over from making rivet holes in bridge girders, and gravel acted as a bio-shield to absorb all radiation made during and after fission in the reactor vessel. The mid-section of the building was an open space containing the turbogenerator, transformer, tanks, valves, and equipment that could be accessed by workers.

The reactor vessel was 14 feet 6 inches tall, filled with water to the 9-foot level, leaving 5 feet 6 inches of clear space at the top where the steam could collect.

A covered walkway led to the sheet-metal control building sitting on the ground next to the reactor building. Security was provided by a high chain-link fence surrounding the site, with a guard stationed during the day shift. It was functional and as simple as it could be, and the entire facility was built for about $1.5 million. As an Arctic power source, it would cost less to buy and run than the shipping charges alone for the fuel that it was to replace.

The SL-1 plant was started up on August 11, 1958. Its Argonne design had been slightly modified to extend the operating time between fuelings to five years. The fuel assemblies had been lengthened by a few inches so that more highly enriched uranium could be included. This increased the reactivity of the core considerably, and to bring it down to a controllable level some metallic boron was added to the lower ends of the flat, aluminum-covered fuel strips. The boron would soak up neutrons and negate the extended reactivity, but as the fuel in the upper core fissioned away, the boron’s ability to absorb neutrons would also wane. Every time a boron-11 nucleus soaked up a neutron and took it out of the fission process, it would decay in multiple steps to carbon-14, which had no affinity for neutrons. Gradually, over five years, the active region of the reactor core would migrate down while maintaining the designed power level. There were better ways to do this, but for the SL-1 thin sheets of boron were riveted to the ends of the fuel assemblies.

The controls, like everything else in the plant, were designed to be as simple and foolproof as it was possible to make them. There was one main control, made as crossed cadmium-filled blades that would fit between the fuel assemblies, inserted down through the middle of the core. It was moved up and down in the reactor to control the neutron population by a rack-and — pinion mechanism, driven by a DC electric motor and gearbox bolted to the floor off to the side. The control rack penetrated the top of the reactor through a watertight seal called the “shield plug.”

In its operating configuration, the SL-1 reactor was radiation-shielded on top by large concrete blocks and a stack of steel plates. All this shielding had to be removed for servicing the inside of the reactor vessel. The control "rods” were actually cross-shaped, and only the large control in the center of the core was used to regulate the fission. The smaller rods were used to smooth out the neutron flux so that the fuel would be consumed evenly across the diameter of the reactor core.

Having one big, master control was fine, but for the fuel to last for more than a few years the flux profile would have to be flattened. In theory, the number of fission neutrons in the reactor at a given time would tend to peak at the center of the core. A plot of neutron population across the diameter of the reactor, or the “flux profile,” would be bell-shaped, and for this reason the fuel would fission unevenly, with center fuel burning out first. That one big control distorted the profile, actually improving it by discouraging the peak in the center. To further enhance the profile, there were eight minor controls spaced around the periphery of the core. They were shorter than the main control, with lesser loading of neutron-absorbing cadmium. The purpose of these controls was to flatten the flux, and they could be adjusted by moving them in and out with motors, just like the main control. As the fuel fissioned away over the years, the operators were expected to have to inch these controls out of the core to allow more fuel to be exposed to neutrons while trying to maintain a flat profile. Under all conditions the master control had sufficient heft to take the reactor from cold shutdown to supercriticality without any help from the peripheral devices.

There were no active control-room instruments that could evaluate the flatness of the flux profile. That was accomplished for this extended experiment using flux wires. Flux wires are aluminum with cobalt-59 pellets imbedded at one-inch intervals. Station flux wires around the core in specified locations, and the cobalt-59 was to be activated into radioactive cobalt-60 to an extent dependent on the density of neutrons. After having stayed in the core a while, these wires are retrieved and cut into one-inch lengths. The gamma rays emitted by each section of each wire are then counted, and from these measurements a map of the neutron flux in the reactor is drawn, evaluating the flux-flattening efforts. Unfortunately, to retrieve the flux wires and put in a new set, you have to take the reactor apart. It takes at least three men per shift working for a couple of days, and the reactor, of course, has to be completely shut down.

By January 3, 1961, the SL-1 had been producing power for over two years, and the experiment was going well. This was more than just a test to see if a small boiling-water reactor would produce power. There was not really anything to learn on this point. The purpose of the test was to see if such a plant could be run and managed by minimally trained soldiers without the advantage of expert scientists looking over their shoulders. Could the inhabitants of a remote station, even more cut off from civilization than the NRTS, maintain a power reactor no matter what happened?

There had been a few problems. Water seals and gaskets were leaking, but it was nothing fatal. Those boron strips tacked onto the fuel turned out to be a bad idea. The boron, when it was changed into carbon-14, would curl up and crack. Pieces of it were falling into the bottom of the vessel, and what was left on the fuel was binding up the controls. Under any normal reactor operating conditions, the words “binding up the controls” would result in a quick shutdown, a study, a redesign, assignment of blame, papers written, operating rules changed, and so on. In this case the problem was treated as an interesting perturbation thrown into the exercise. It was just the sort of unexpected problem that could show up on the glacier in Greenland. The Army said “Let’s see how it plays out,” while the AEC and Combustion Engineering kept a detached, mildly interested stance. Any time the reactor was down and apart for maintenance, the peripheral rods had to be jacked up and down by hand to clear out the bent boron at the bottom of the core, or the motors would not be strong enough to move them against the resistance. The main rod, weighing a hefty 100 pounds, was big enough to take care of itself, crashing its way through the twisted metal and having no particular trouble moving with the motor.

It was a clear night and bitterly cold. The graveyard shift consisted of Senior Reactor Operator Jack Byrnes, an Army private; Assistant Operator Dick Legg, a Navy Seabee; and trainee Richard McKinley, Air Force. Byrnes was going through a marriage crisis, he wasn’t making enough money, and he had problems with being managed. Legg was sensitive to comments about his stature and enjoyed playing tricks on his colleagues to pass the time. McKinley was there to learn how to run a reactor plant.

It was time to change out the flux wires, and the previous shifts had done all the heavy lifting. The reactor was basically put back together, with the vessel filled to 9 feet with water and the head screwed down. All the night shift had to do was reconnect the controls and put the big concrete blocks that shielded the top back into place. It was a three-man job. Byrnes and Legg would reconnect the rack to the main control while McKinley would stand off and act like a health physicist, pointing a “cutie pie” ionization chamber at Byrnes and Legg while they worked. The day shift would actually have an “HP” on the staff, monitoring all the activities in the reactor building to constantly check for abnormal radiation, but the night shift was a minimum crew.

The rack that engaged the pinion for up-down motion was screwed to the top of the control, which was at its lowest position in the core, keeping the reactor at cold shutdown status. A C — clamp had been tightened on the rack to hold it in a slightly raised condition, just above the top of the shield plug. This position allowed a three-foot metal rod to be temporarily screwed into the top of the rack so that a man could handle it with the motor disconnected.

The instructions were clearly mimeographed. Byrnes would take hold of the handling rod with all ten digits and lift the 100-pound center control by one inch. With the load off the C-clamp, Legg, crouching over the shield plug, would unscrew it and lay it aside, and then Byrnes would gently lower the control until it rested on the bottom of the core structure. McKinley was standing off the reactor top, in front of one of the man-sized concrete shield blocks, idly watching the show and pointing his radiation detector.

All that we know for sure is that at 9:01 P. M., Byrnes, against the written directions and everything that the instructors had drilled into his head, with one massive heave jerked the master control clean out of the core as fast as he could. If it were lifted four inches, the reactor would go critical, blasting the three workers with unshielded fission radiation. Byrnes managed a full 23-inch pull, and the reactor went prompt critical with a 2-millisecond period, producing a steam explosion in the reactor such as has never been seen before or since. The water

covering the reactor core instantly became superheated steam.108 The four-foot slug of still water over the core, not becoming steam, was pushed with incredible speed to the top of the reactor vessel, through the 4 feet 6 inches of clear space, until it hit the screwed-down top like a very big hammer. The force of the hammer-hit picked up the 13-ton steel vessel and shot it nine feet out of the floor, shearing away its feed-water and steam pipes. The nine shield plugs on top of the vessel shot off like cannon shells, burying control-rod fragments in the ceiling.

Byrnes and Legg were killed instantly, not by the intense radiation surge, but by the explosive shock of two billion billion fissions, 15 megawatt seconds of energy, and an air pressure wave of 500 pounds per square inch. McKinley died two hours later of a massive head wound, inflicted by the concrete shield block as he was thrown backwards. All three men had fission products, built up by the reactor running at full power for two years and turned to nascent vapor in the sudden heat of prompt fission, buried deep in their bodies. There was no way to simply wash away the contamination. It seemed embedded in every tissue.

Legg was pinned to the ceiling with a piece of the master control. The reactor internals were an unrecognizable tangle of twisted parts, and water, gravel, and steel punchings were scattered all over the reactor building floor. The crude steel building, which was meant only to house the equipment and keep the rain off, managed to prevent a scattering of radioactive debris, and outside it was hard to tell that anything had happened. The plant was a total loss, and everything would have to be carefully disposed of, leaving not a trace of radioactive contamination or subjecting any worker to an abnormal dose. The three bodies were so deeply and severely contaminated, they would have to be treated as high-level radioactive waste. Autopsies were performed quickly, behind lead shields with instruments on 10-foot poles.

A commendable job was done analyzing the accident and cleansing the site of any trace of it. It required a great deal of skill and planning to decontaminate the site, as the inside of the reactor building was too radioactive for normal work. A full-scale mock-up of the building was constructed for decontamination practice and to figure out the actions of Byrnes and Legg before and during the accident. Television cameras were inserted into the reactor core using remote manipulators, and a Minox subminiature camera was used on the end of a pole to take photographs through small openings. A seldom-mentioned technique called the “gamma camera” was used to spot where highly radioactive fragments of the reactor had landed in the ceiling and on the floor of the building.

The gamma camera is a variation of the old “pinhole” camera. It is possible to make a picture on a piece of photographic film by mounting it on one inside face of a light-proof, square box. On the opposite face of the box is a tiny pinhole. Light enters the box through the hole, very dimly, and it forms an image on the film without the use of a lens. Light can only travel in a straight line, so individual rays of light from the scene outside the box are organized into an image simply because they all have to come through at the same point, the pinhole. If the box is made of lead, through which radiation cannot pass, then the pinhole on the front face of the box will image gamma rays onto the film the same way it uses visible light. Gamma rays are photons, just like visible light but at a much higher oscillatory frequency and energy. To use the camera, the investigators first made a light image of the ceiling in the reactor building using the open pinhole, then covered the pinhole with a light-tight but gamma-transparent shutter. The gamma ray image was allowed to expose the film for 24 hours through the same pinhole, superimposing a gamma-ray image atop the light image. When the film was developed, it identified radioactive objects in the picture as shining brightly, like points of light.

The reactor building and its contents were buried in a trench 1,600 feet away from the original SL-1 building site. The cleanup took 13 months and $2.5 million. Much was learned about managing power reactor disasters, and the question of what had happened was answered in great detail, down to the millisecond.

What was never answered by detailed forensic analysis was: Why did Byrnes pull that control out? He knew good and well what it would do if it came up to four inches. Why jerk it out all the way? There are, to this day, a few conflicting opinions, ranging from it was a murder-suicide to he was exercising the rod to clear the bent boron. In my opinion, Byrnes was showing off for McKinley, the new guy from the almighty Air Force. The Air Force was running the dangerous, super high-tech HTRE experiments down the road at Test Area North, and the Army was stuck with this cheap, low-power rig that was just sitting here making a slight turbine-hum. Byrnes wanted to give McKinley a thrilling blip on the cutie-pie radiation detector he was holding by bouncing the main rod. He knew that if he could bring it up to supercritical for just a split second, the power would drop again quickly as the control went back down. No harm done, but he bet himself that he could make Air Force lose control of his bladder. The thing was heavier than it looked. He wiped his sweaty palms on his pants, braced, and put both arms into it. Up she came. They never knew what hit them. Their nervous systems were destroyed before the senses had time to register the violent event.

It was a tragic loss of life, and the general attitude toward small, simple, cheap nuclear power was affected. The Army went on to deploy the PM-2A portable medium-power reactor in Greenland, the PM-3A at McMurdo Station in Antarctica, the MH-1A mobile high-power reactor at the Panama Canal, the SM-1A stationary medium-power reactor at Ft. Greely, Alaska, and the PM-1 at Sundance, Wyoming. They even developed the ML-1 at the NRTS, the first nuclear power plant that would fit on the back of a truck. It all ground to a stop in 1977 when the need for remote power and the money to support it both drifted away. It was not at all a bad idea, but commercial nuclear power production moved off in the opposite direction, toward bigger, more complicated, more expensive installations, and the SL-1 incident was a reminder of the dangers of making it too simple. The accident had proven that there was no such thing as foolproof.

The snowcap over Greenland into which Project Iceworm was dug turned out to be one big, slow-moving glacier. The rooms and tunnels so carefully carved out of the ice deformed and shrank with time. Every month, 120 tons of ice had to be shaved off the inside walls, and by the summer of 1962 the ceiling in the reactor room had come down five feet. In July 1963 it was clear that this bold step in missile positioning was not going to work, and the PM-2A reactor was shut down and shipped back home. By 1966, Camp Century was unlivable, and it was given back to nature. When last visited in 1969, it was completely wrecked and buried under a great deal of new snow.

The deep snow cores taken at Camp Century are still in use today. These long cylinders of snow cut from the glacier are a record of the climate and atmospheric conditions for the last 100,000 years, and they have been used to map the carbon dioxide history on Earth since the emergence of mankind.

The last steam explosion in Idaho was the final in a series of experiments with the SPERT-I, or the Special Power Excursion Reactor Test One, on November 5, 1962. One would think that enough was learned in the BORAX-I and the SL-1 blow-ups to pretty much give us what there was to know about water boiling too fast in a reactor tank, but this odd experiment was funded by the AEC. It, like BORAX, gave a bit more of a show than was anticipated, and it went down in history as another accidental power excursion at the NRTS. The incident was all recorded as

a movie in slow-motion at 650 frames per second.109

The reason for the SPERT experiments had to do with the expanding need for nuclear specialists in the 1950s. The AEC was aware of a projected shortage of nuclear engineering and health physics graduates in American universities, and technical campuses needed small research reactors in place to encourage these studies and excite some interest in nuclear topics. The Aerojet General Corporation had already introduced an inexpensive “swimming pool” reactor for use in schools. It was simply a concrete-lined pool of water, sunk in the floor, with uranium fuel assemblies and control rods clustered in the middle. “Is it safe?” asked the AEC. “What would happen if a control rod came loose and dropped out the center of the core?”

It would explode, of course, with the water shooting out the open top of the reactor and hitting the roof really hard, but that was not a sufficient answer. Details of everything that could possibly happen to an open-topped, water-moderated, low-power reactor were demanded. The SPERT contract was given to the Phillips Petroleum Company, and a site was chosen about 15 miles west of the eastern boundary of the NRTS. The first of four SPERT reactors was started up in June 1955, and it was run through a series of torturous accident scenarios.

The setup was very much similar to BORAX-I, but it was enhanced with a metal shed covering the reactor. Controls were inserted through the bottom of the reactor core leaving the top completely open, with one master control in the center. Two periscopes looked down into the core from above, and a tilted mirror showed the open reactor top from the side. These optical features were used to make motion pictures of every experiment simulating wrongful operation

by undergraduates horsing around with the controls.110 Nuclear instruments and recording procedures had improved since BORAX, and better data collection was anticipated. Experiments with fast power transients blew the water out the top of the reactor, just as seen in the BORAX excursions. The fuel was the same as was used in most of the test reactors at NRTS, thin plates of aluminum-uranium alloy clad with pure aluminum. It was not meant as a high-temperature fuel, and some plate warpage and slight melting were observed in the core.

November was the end of the open experiment season in Idaho, as the temperature began to drop to Greenland levels, and the team was out of tortures for the SPERT-I. SPERT-II was designed and ready to build. As one last experiment for 1962, the team wanted to simulate AEC’s worst fear, that the main control rod would fall out. The control-rod drive was modified to break free and fall with gravity, and the metal roof was removed so that the driven water would have nothing to blow away. A 3.2-millisecond period was predicted, with some fuel melting this time. The test was not cut out to be such an event as the BORAX-I excursion. SL-1 had taken the thrill out of seeing water reactors explode.

It was a sunny day in the desert, and the wind was calm. Three… two… one… RELEASE. The main control rod went into freefall. The little reactor suddenly lit up with a blue flash in the mirror as 30.7 megajoules of energy came alive and started heating the fuel. All 270 fuel plates melted, and the fission process shut down completely, as predicted. Everything was going according to plan for about 15 milliseconds, and then all hell broke loose as the unexpected transpired.

The melting fuel sagged and changed shape. Heat transfer between the fuel and the water was suddenly improved, and the resulting steam explosion was more energetic than expected. It completely destroyed the reactor. Contents of the reactor vessel were pounded out of shape and thrown skyward. There was no roof to carry away, but a flying periscope hit a steel roof — beam and bent it outward. Bits and pieces of reactor were scattered all over the place. There were no injuries except to a few egos, and the large bank of instruments could find no harmful release of radioactive gasses into the atmosphere. I will not say that the fine engineers at the NRTS were slow to learn, but this sort of behavior in a suddenly uncontrolled water reactor was hardly a new finding.

This was not the last reactor blown up at NRTS, but all the others were predictable, controlled, and not considered accidents. NASA planned to send up a nuclear reactor into space in the System for Nuclear Auxiliary Power program, and the SNAP-10A nuclear power

generating station was scheduled to be launched into orbit in 1965.111 There were, of course, concerns that the booster could fail before achieving orbit and a power reactor could come down in the ocean. What would be the hazards if this worst launch failure happened?

At NRTS the recently vacated ANP test facilities at Test Area North were converted to test the SNAP-10A in a simulated high-speed crash into the Pacific Ocean. It was correctly predicted that a severe nuclear power transient would result from slamming into the salt water. The reactor was naked of any shielding, and it was moderated by zirconium hydride mixed with the uranium fuel. Hitting the surface would suddenly introduce extra moderating material favorable to fission (water) and the reactor would go prompt supercritical.

A huge water tank was mounted on one of the ANP double-wide rail cars that carried a nuclear jet engine with a SNAP reactor mounted in the middle. The reactor was protected from the water with a Plexiglas shield until an explosive charge threw it out of the way and let the

water crash in. The resulting fireball on April 1, 1964, threw reactor fragments far and wide.112 To keep thermocouples and radiation instruments from being melted and lost in the explosion, the measurements were done remotely, using infrared pyrometers looking into a mirror behind a lead wall. Just to be sure, the test was run three times in experiments SNAPTRAN-1, 2, and

3, and three perfectly good SNAP reactors were destroyed.113 They took movies.

There was also the LOFT (Loss Of Fluid Test) reactor and Semiscale, which was not really a reactor. Both experiment series were used to find what would happen if a water-cooled reactor breaks a major steam pipe. The LOFT reactor was a half-scale, fully operational pressurized water reactor, while Semiscale was a slightly safer experiment using an electrical heat source instead of fission to make the steam in a simulated power plant. These programs and the accidental experiments dating back to EBR-I were all valuable in finding how to build a safe power reactor and how not to build one. This knowledge was put to use in designing the Generation II nuclear reactors that now produce 20 percent of the electrical power in the United States. There would be commercial reactor accidents in America, but never a steam explosion, and the three men who stood on top of the SL-1 were the last people ever to die in a power reactor accident in this country.

Today, there are no ongoing reactor safety experiments, anywhere in the world.

Torturing nuclear reactors to make them give up the secrets to safe power production was not the only activity at the NRTS. Among the first building sites at the new reservation in 1948 was the Idaho Chemical Processing Plant, known to all as the “Chem Plant.” If the techniques for building civilian power plants were to be sorted out in the Idaho desert, then it made perfect sense to also work on fuel reprocessing and waste handling. A model plant was built to recycle the fuel used in reactor experiments and to develop practical methods for extracting the various components made in the fission process.

Commercial reactor fuel is uranium oxide, with two out of every three atoms in the solid material being oxygen. The uranium content in fuel is usually enriched to 3.5% fissile uranium — 235. The rest is uranium-238. After about 4.4% of the uranium-235 has fissioned, the fuel can no longer support the self-sustained chain reaction, and it must be replaced. Approximately 20.5% of the waste product embedded in the spent fuel is plutonium resulting from neutron activation of the U-238. The rest of the waste, 79.5%, is fission products, 82.9% of which are stable. That leaves 1.1% of the spent U-235 as radioactive waste which must be either disposed of or put to use as industrial and medical isotopes. The idea of fuel reprocessing is to remove the remaining U-235 and Pu-239 from the spent fuel and return it to the energy production process. As you can see from the breakdown of the used fuel components, the waste to be buried is a tiny part of the original fuel. In 1948 when uranium was thought to be scarce, it made no sense to bury an entire used fuel-load without breaking it down and sorting the portions.

The Foster Wheeler Company of New York, experts at making oil refineries, designed the plant, the Bechtel Corporation out of San Francisco built it, and American Cyanamid ran it. The Army had wanted to operate it under military control, but the AEC wisely argued that if it was to model a commercial process, then civilians should learn how to do it. Construction took 31 months on 83 acres of flat-as-pool-table desert north of Big Southern Butte. The first shipment of fuel arrived to be processed in November 1951.

Spent fuel arrived in heavily shielded casks, strapped down to flatbed trucks. A truck would make it past the security checkpoint and roll into a special bay in the storage building. Remotely controlled mechanical hands would take off the top of the cask and gently place the spent fuel in stainless steel buckets suspended from the ceiling. Using motorized overhead tracks, the fuel rolled into the long crane building and was diverted into its appropriate place to be processed. The fuel was dissolved and then broken down into components by specific chemical reactions. The fuel solution ran through stainless steel pipes and tanks, with the routings automatically controlled by pneumatic valve sequencers behind a shield wall in the building. Pressures, temperatures, flow rates, and tank levels were monitored and recorded. Every aspect of the facility was designed to shield human workers from any contact with radiation. There were radiation detectors and alarms everywhere, and to prevent possible power outages the plant had its own motor generator.

In general, the Chem Plant was well managed and well designed, and there was never a radiation injury or an accident that damaged the equipment. There were, however, three criticality accidents in which uranium dissolved in solution managed to find itself in a critical mass and go supercritical. Enriched uranium dissolved in water or an organic solvent will become an active nuclear reactor, increasing in power, if a specific “critical mass” is accumulated. The hydrogen in the water or the solvent acts as a moderator, slowing the fission neutrons to an advantageous speed, and even a fairly low U-235 enrichment level, like 3%, will overcome neutron losses by non-productive absorption in the moderator. This has been realized since the earliest days of reactor engineering, and those who work with uranium solutions are quite aware of the possibility.

The volume or mass of the potentially critical solution is not the only factor. Any shape that reduces the surface-area-to-volume ratio is a bad choice for a vessel that is to contain a uranium solution. In a worst-case configuration, such as a spherical tank, a minimum critical mass is needed to start a chain reaction, because the neutron leakage from the surface is minimized. Another example of a shape that is good for making an impromptu reactor is a cylindrical tank, especially one built with the “tomato can” height-to-diameter ratio. Tin cans holding food are purposely made to optimize the amount of material they can contain using the least amount of sheet metal, to lessen the manufacturing cost. A uranium solution shaped like a can is a disaster waiting to happen. If any concentration of uranium in solution is held in a tank in a reprocessing plant, then the tank has to have a seriously bad magnitude of surface area compared to its volume. It absolutely must promote neutron loss by surface leakage. The tanks are therefore vertically mounted, thin tubes. They look like thickened pipes.

The Chem Plant at the NRTS was not the only one being built in the world. Eventually Canada, England, France, the Soviet Union, and Japan would have fuel processing and reprocessing plants serving their nuclear power plants and, in a few cases, bomb manufacturing. I would like to think that not one of these plants was built having a container inside the building that could hold a critical mass and configuration of uranium in solution, but I would be wrong. Incredibly, there has never been a Chem Plant made that could not support a critical mass in at least one tank. Given time, uranium will eventually find this tank, usually by inappropriate means, and a problematic supercriticality will result. A death in a power-reactor accident is exceedingly rare, but many people have died worldwide in criticality accidents involving nuclear fuel.

On October 16, 1959, the graveyard shift was working on 34 kilograms of uranium fuel enriched to 91% U-235 in the form of liquid uranyl nitrate diluted with water. The next step of the processing was to extract impurities by mixing the nitrate solution with sulfuric acid in three steps. The first step had been completed, and the mixture was held in two vertical “pencil tanks.” These vessels were specifically designed to defeat criticality, being too small to hold the entire fuel load in one tank and being thin, measuring 3.050 meters tall and 0.125 meters in diameter. There was a tube leading from the drain end of the pencil tanks to a 5,000-gallon waste-receiving tank, looking like a tomato can. This tank was never, of course, supposed to have any uranium in it. It was there to hold the non-fissile waste products that were being extracted from the fuel. Just to make sure that it was impossible to siphon uranium solution out of the pencils or start a gravity drain, there was a loop in the connecting tube, located way above the top of the tanks. Only deliberate sabotage, it was thought, could cause any uranium to get into the receiving vessel.

An operator, reading his instructions, turned on two valves to spray some air into the two pencil tanks to stir it up and make sure that the acid and the uranyl nitrate were thoroughly mixed. Pencil tank number one had a pressure gauge on it so that the operator could make certain that he was applying the air at the correct sparge rate. Pencil tank number two did not have a pressure gauge, so the operator just opened the valve until he was sure the thing was good and sparged. Unfortunately, the excessive blast of air forced the liquid up through the anti­siphon loop, defeating it, and causing uranyl nitrate to siphon into the tomato can at 13 liters per minute.

The tank waited until it had 800 liters of 91% U-235 in solution before it went supercritical. Radiation alarms started going off all over the place. They were ignored. If you evacuated the building every time one of those hyper-active alarms sounded, nothing would ever get done in this place. The third time somebody hit the evacuation alarm, people started moving. Nobody took the clearly marked evacuation routes, only the well-worn paths that they took out of the building every working day. As a result, there was a log jam at the door. Fortunately it was a small staff for this shift, and everybody showed up at the guard shack alive and well.

In the initial blue flash, hidden by the stainless steel tank walls if anyone had been looking, a hundred million billion fissions occurred. There were several excursions, with the contents of the tank boiling furiously, which would dilute the moderator with steam and kill the reaction. The steam bubbles would then collapse, and the supercritical condition would start over and do it again. After about 20 minutes, half the water content of the solution had boiled away, and the unplanned reactor aborted itself.

The lessons learned from this accident were sobering. Those particular pencil tanks were seldom used, and nobody on shift that night had any experience with them, so they had to read the written instructions, which were out of date. Routinely used waste tanks had better anti­siphoning systems. This one did not. The evacuation procedure, which had never been used before, obviously needed work. It did not take a sabotage to put uranium where it was not supposed to go. It only took the turn of an unfamiliar valve.

On January 25, 1961, the Chem Plant had been down for a year of renovation and had been operating 24 hours a day for the past four days. At 9:50 in the morning, another batch of uranyl nitrate found an “unfavorable geometry” in the upper disengagement head of the H-110 product evaporator. This was thought impossible because of an overflow line in the head that was supposed to prevent it from holding enough uranium solution to be critical. Someone had cleared out a clogged line downstream using compressed air, and it managed to blow enough uranyl nitrate into the cylindrical vessel to cause another big boil-off. Nobody was hurt, and nothing was damaged, but again it called into question several philosophies and engineering practices. The general boredom of working a shift in a chemical processing facility may have had something to do with it.

Finally, on October 17, 1978, a slow leak in a water valve eventually let the uranyl nitrate concentration in the lower disengagement section of scrubbing column H-100 grow to a supercritical level. It was another non-damaging, zero-death, embarrassing reactor where there should not have been one.

The Chem plant is still there, but it is now called INTEC, the Idaho Nuclear Technology and Engineering Center. It is working on a liquid-waste-processing method as part of the Department of Energy’s Idaho Cleanup Project. The exciting days of reactor experiments are long gone, and the purpose of this federally funded effort is to erase radiological traces of the old NRTS off the desert. Now, irrigated circles of land, planted with Idaho potatoes, encroach on the property once alight with the technology of the future.

Despite all the fine development work and all the logical reasons for reprocessing, such as greatly reducing the throw-away waste product, there is no commercial fuel reprocessing plant in the United States. Our fuel would be buried whole, if it were buried. There is currently no place to bury spent fuel in this country, so it just piles up at the power-plant sites. All other countries relying on nuclear power as a base-load source of electricity have routine reprocessing and waste burial, from Great Britain to Japan.

In spite of three criticality accidents, the Idaho Chemical Processing Plant was probably the safest fuel reprocessing facility in the entire world. We will visit this topic again in glorious detail, but now let’s remain calm, go across The Pond, and see what the reserved and quiet Brits were up to.

was testing blast shields, boxcars, and explosive bunkers to see how they would perform when subjected to 250,000 pounds of TNT going off all at once. Although the Navy no longer owned the facility they were allowed to test 16-inch guns from the USS New Jersey battleship as late as 1970. Unexploded ordnance was still showing up on the ground in 1990.

93 Probability factors into all sub-atomic processes. In the case of neutron release, every 100 fissions in U-235 at thermal speed produce eventually an average of 243 free neutrons. Some of those neutrons are delayed, and may wait hours to release. In Pu-239, you get 290 neutrons per 100 fissions, but when high-speed neutrons cause fission in U-235, you also get nearly 290 neutrons.

94 Recently the phrase “fast breeder reactor” has been changed to “integral fast reactor.” I’m not sure why A sign on Highway 20 leading into the NRTS cautioned travelers, “warning: do not disturb breeding reactors.” It was a real knee-slapper at the time.

95 The use of plutonium in a fast-neutron reactor had already been proven. In 1945, an experimental reactor was built at Los Alamos in a deep canyon, far removed from other activities in case it misbehaved. At the time, the code-name for plutonium was “49,” and the scientists involved in the project were called “49ers.” You can probably guess the name of the reactor: Clementine. It ran experimentally at a maximum power of 25 kilowatts for six years, until a fuel-cladding failure shut it down for good. The dangerous coolant was pure mercury which would enthusiastically activate into radioactive Hg — 203. The purpose of Clementine was not to advance power-reactor technology, but to test bomb materials under the neutron-soak expected in a nuclear explos ion.

96 So it is written in the official history of the world, but nothing is that simple. On September 3, 1948, Logan Emlet opened the valve on a toy steam engine connected to a water pipe running through the air-cooled X-10 graphite reactor at Oak Ridge, Tennessee. The reactor, running at one megawatt, was making steam in the pipe, and the little engine started puffing. The flywheel was belt-driving a classroom demonstration generator, which was connected to a 1/3-watt flashlight bulb. It wasn’t much light, but it was definitely the first. Everything done on the X-10 was still secret, so this historical generation of electrical power by nuclear means was buried. Buried deeper was the first use of a reactor to heat a building, which occurred in England in the fall of 1948. The reactor was named “Bepo,” meant to sound like an unknown Marx brother. I’m not making this up.

97 In the popular literature, I have seen the initial rate of power-climb for EBR-I listed as “doubling every 60 seconds.” Not quite true. The “period” of reactor power increase or decrease is expressed in “e-folding time,” or the time required for the power to change by a factor of e, where e is the root of the natural logarithm, 2.718281828459045… . In breeder parlance, “doubling time” is actually the time required for the amount of bred plutonium to increase by a factor of two.

98 Not to be outdone by the Air Force, the U. S. Navy in 1954 commissioned a study by E. W. Locke Jr. to find the feasibility of an atomic-powered dirigible. That’s right, a rigid airship filled with two million cubic feet of helium with a feather-light nuclear reactor driving two T56 gas turbine engines. The design combined two dubious technologies: an enormous, lumbering military air vehicle blown around by the wind, and an unshielded nuclear power plant weighing less than 40,000 pounds. The Navy decided instead to build a nuclear-powered float plane (the Princess Project), but in 1959 Goodyear Tire and Rubber invested time in preliminary designs of a nuclear blimp. Francis Morse at the University of Boston proposed a 980-foot-long nuclear dirigible for the New York World’s Fair in 1964. It would be a “flying hotel” carrying 400 passengers. He argued that the spread of radioactive debris in the event of a crash would be manageable, because dirigibles crash softly Fortunately for the public impression of nuclear technology, none of these plans were implemented.

99 There were two nuclear jet engine designs in the ANP program: the direct cycle at GE of Ohio, and an indirect cycle at Pratt & Whitney of Massachusetts. For the indirect cycle, an intermediate heat exchanger would transfer heat from a centrally located reactor to multiple jet engines, while it was assumed that in the direct cycle a small reactor would take the place of the fuel burners in the middle of the jet engine. The P&W design was complicated, and its development was at least a year behind the GE engine. The ideal circulating coolant for the indirect cycle engine turned out to be lead, which seemed a cruel material to be used on a high-performance jet.

100I first saw the HTRE-3 and HTRE-2 in 1980. They were near the security checkpoint for TAN. They were still considered to be radiologically unapproachable, and to examine them closely you had to use binoculars. A fellow who had worked on the project damned HTRE-3 with faint praise, saying “It was so powerful, it could practically lift its own weight off the ground.” Today the two engines are tourist traps. You can go up and take a picture of your kids pointing into the exhaust nozzles. They are in the parking lot of the EBR-I, which is a National Historic Landmark, opened for touring between Memorial Day and Labor Day.

101There is a bit of confusion here. The NRTS records show that the HTRE-3 operated between September 1959 and December 1960, but this account is taken from Summary Report of HTRE no. 3 Nuclear Excursion. APEX-509, and it places the accident in 1958. This type of event was usually classified SECRET, and the operating schedule may have been distorted to hide it.

102I’m not sure there was anywhere to eat near the test stand, so they probably brought lunch with them or had it trucked in. I once had lunch at what was possibly the only restaurant within 40 miles of the HTRE test stand on Highway 33, called the “Broken Wheel.” As I stared out the window at the featureless, dun-colored desert, suddenly the ground-cover moved and a ripple went through it. An earthquake? No, as it turned out I had been looking at a vast herd of sheep, covered with dust and huddled close together against the extreme cold.

103Hold on to your seat. Three quarters of the free world’s supply of mercury was used to shield the HTRE-3. At the end of the project it had to be released slowly back into the market to prevent an economic crash in the liquid metals trade.

104Although I and everyone else call it BORAX-I, it may not have been known as a numbered unit until BORAX-II was built. Contemporary reports from the field simply call it “The Borax Experiment.” Local newsmen called it “The Runaway,” and this name stuck to it like cobalt-60 contamination.

105I could not at this writing be certain how the central control was blown out of the core. Some accounts say compressed air, but others say it was an explosive charge or a cocked steel spring. The pneumatic cylinder seemed most likely, but other mechanisms are possible.

106There had been serious talk of burying a case of dynamite under the reactor vessel to ensure a visually satisfying event in case the steam explosion fizzled. I find no record of this ploy being carried out.

107Although the plans for Camp Century were profiled in the Saturday Evening Post in 1960, its military purpose was not revealed to the public until January 1997, when the Danish Foreign Policy Institute spilled the beans in a report to the Danish Parliament. Greenland, the site of the missile base, is owned by Denmark.

108Some accounts say that the rod was pulled 20 inches, but the revised figure of 23 inches is based on careful reevaluation of the data. The rod was pushed out an additional 7 inches by the upward force of the steam blast. The weight of the master control was originally recorded as 85 pounds, but this did not take into account the weight of the rack plus the handling rod.

109See it on YouTube. http://www. youtube. com/watch? v=0FIhafVX_6I&feature=related

110On May 3, 1958, Frederic de Hoffman announced the introduction of the Test, Research, and Isotope reactor of General Atomic, or the TRIGA. It was a brilliant design, started as an exercise for young nuclear engineers by Dr. Edward Teller, co-inventor of the H-bomb and the inspiration for the movie “Dr. Strangelove, Or How I Learned to Stop Worrying and Love the Bomb.” Dr. Freeman Dyson, also a nuclear genius, contributed to the concept, and the design was influenced by findings at the NRTS in the BORAX and SPERT programs. The TRIGA pool reactor was “safe even in the hands of a young graduate student,” which is saying a lot. The unique fuel formula was a mixture of uranium and zirconium hydride. Being co-located with the uranium, the hydrogen moderator would heat instantly in the event of a fission runaway and the hot hydrogen would lose its ability to moderate the neutrons down to the advantageous low speed. The result was a reactor that absolutely could not be made to explode or melt down. The TRIGA is still available from General Atomics of San Diego, California. Three new ones were sold recently overseas.

111 There were actually seven SNAP-10As built. Three were blown up at the NRTS, one was a spare, two were used for flight system ground tests, and only one was orbited.

112What burned, causing a “fireball?” Ask yourself, why is fire visible? Why does fire glow bright yellow? The answer is sodium contamination. Sodium atoms glow yellow when heated by an otherwise invisible flame, and the slightest trace of sodium in a fire is what makes it look like fire. In the case of SNAP-10A, it used nack, or a sodium-potassium alloy as the coolant. There was plenty of sodium on hand to light up the event when the reactor violently overheated. The sodium and potassium reacting explosively with the water topped it off.

113I have been unable to find a report that describes the destruction of SNAPTRAN-1. I’m not sure whether it was too insignificant to warrant a report, or too significant to be declassified.

Chapter 5

"Will you please issue the following operating instructions to the operator engaged in controlling the Wigner Energy Release. If the highest Uranium or Graphite temperature reaches 300°C, then Mr Fair, Mr Gausden and Mr Robertson are

114

to be informed at once, and the PCE alerted, to be ready to insert plugs and close the chimney base.”

—D R R Fair, Manager, Pile

The atomic enthusiasm of the 1950s was supposed to acclimatize the general public to all things nuclear and prepare us for a future that was in the advanced planning stage, but just the opposite seemed to be happening. Instead of getting used to it, people seemed to develop general fears and anxieties that in the previous generation had existed in railway stations. This was true even among the servicemen who would be tasked with deploying nuclear weapons systems and remote power plants and fighting in conflicts using this new paradigm of warfare. In the case of the civilian public, a problem was the overbearing secrecy of the entire nuclear business. There is nothing more frightening than the unknown. In the case of the armed forces, it was an excess of knowledge.

Servicemen had been subjected to the flash, the thunderclap, and the ground shock of an atomic-bomb detonation in multiple test exercises using real weapons and real soldiers. In the next war, the infantry would have to move forward into territory that had just been sterilized by the radiation pulse of a nuclear detonation, moving toward ground zero as the mushroom cloud formed in front of them, wearing only light protective gear. This test series was both a confirmation that this maneuver was possible and an effort to allay the soldiers’ fears. They had to be convinced that they could advance into the freshly destroyed target area without dropping dead from some invisible, undetectable agent. The men had been prepared for the experience by sitting through several mass lectures, hearing about rems, rads, roentgens per hour, the importance of beating the dust off your clothing, symptoms of radiation poisoning, and how to aim a rifle while wearing a respirator. It was more than they wanted to know. The fact that the AEC observers were wearing full-body radiation suits and waving Geiger counters did not help.

As early as 1951, the Air Force had pushed for an atomic weapon that could be used against massed air attacks, and by January 1, 1957, Project Bell Boy had produced an air-to-air nuclear-tipped missile that could be launched from an F-89J pursuit plane. It looked short and fat, with a bulging nose cone and stubby fins. It had a solid-fuel rocket engine in the tail and no guidance system. The beauty of firing a nuclear warhead at another airplane was that you didn’t need a guidance system or even a particularly good aim. Any airplane within a mile of it would be destroyed as the 2-kiloton warhead exploded and made a hole in the atmosphere.

The warhead designation was changed from EC 25 (Emergency Capability) to fully operational MK 25 Mod 0 in July 1957, just before its proof of function and weapons effectiveness trial at the Nevada Test Site. The test was scheduled for July 19 in Shot John of Operation Plumbbob. The rocket-propelled weapon was designated MB-1, or, affectionately, “Genie.”

Genie was a well-designed system, and eventually 3,150 units would be manufactured and stored safely away, waiting for an appropriate war. There were two problems with Genie, mostly of a philosophical nature: there was nothing to use it against, and the troops were scared to death of it.

The concept of a massed air attack, in which a squadron of heavy bombers would blot out the sky and rain gravity bombs down on cities, was from World War II. It was a strategy used by the United States Army Air Force against enemy assets in Germany and Japan, and not the other way around. America had actually never seen a bomber group dropping explosives on it. We had therefore invented the perfect weapon for blowing up an entire sky full of multi-engine aircraft in one swat, so we could have defeated ourselves two wars back. If the UK had had a few Genies in 1940, the Battle of Britain could have been over in about 20 minutes, but the idea of attacking North America using a close formation of airplanes had never been seriously considered. In the Cold War era there was basically nothing to shoot down that an inexpensive Sidewinder air-to-air missile would not take care of.

Be that as it may, the problem of human squeamishness at having an A-bomb explode overhead could be addressed. Simply explaining to soldiers that a nuclear detonation at 10,000 feet was not the same as having it go off at 1,000 feet was true but insufficient. To the soldiers it was a matter of degree. At the high altitude there would be no ground disturbance. No radioactive dust kicked up into a mushroom cloud, no neutron activation of the ground, and negligible fallout. It was all a function of range. The fission neutrons could not travel that far in air before they decayed into hydrogen gas, and the gamma ray pulse would be short-lived and dissipated in a spherical wave-front with a diameter of four miles when it hit the ground.

Air Force Major Don Luttrell had a master’s degree in nuclear engineering, and he did not require convincing, but he came up with an idea to calm the fears of those unwashed by the firehose of knowledge. He persuaded four other officers and a camera operator to stand with him directly under the detonation point of Shot John and prove on film that the weapon was perfectly safe unless you were flying in a bomber group.

The camera man was George Yoshitake. For protective gear he wore a baseball cap as he filmed five officers squinting up into the sky, standing by a crude sign saying “GROUND ZERO,

POPULATION: 5,” disregarding George as a participant.115 The F-89J interceptor fired the Genie at a coordinate in the air directly over the men. It traveled the 20,000 feet from the plane in 4.5 seconds and exploded, causing a brilliant burst of light. In the bright desert sun the photon flash fell over the men and briefly washed out the picture. They felt the wave of heat, like opening the door on an oven. The shock wave followed in a few seconds, causing them to cringe from the thunderclap as they watched the bright spot turn into a red ball of fire, eventually disassembling into a weird atmospheric display. It was a cloud of white mist surrounded by an orange donut. There was no debris to fall, as the rocket and its payload had been reduced to individual atoms.116

The film was shown to military personnel likely to deal with nuclear weapons, but not to the public. The average citizen had no idea that such a weapon existed, regardless of President Dwight Eisenhower’s Peaceful Atom proclamation that declassified much of the atomic bomb development activities. The engine of the atomic submarine Nautilus, which was destined to become the model for standard civilian nuclear power plants, was also classified secret.

Typical of the public’s concept of a nuclear reactor was shown in 1953 on the very popular television program, The Adventures of Superman, starring George Reeves as the Man of Steel. It was episode 33, “Superman in Exile,” in which Clark Kent detects an atomic pile running out of control 100 miles away. He rips off his glasses and ducks into a janitor’s closet where he can change his clothing. Jumping out an open window, he flies to the reactor site and finds a scientist in a lab coat, obviously suffering badly from the radiation load, trying to push a control rod back into the face of the pile. Superman, who can withstand just about anything, pushes the rod home without breaking a sweat, and the world is saved from an impending

reactor explosion.117

From a nuclear engineering perspective, there are several things wrong with this picture, the first being the manually operated control. A reactor control rod had not been moved by hand since 1942, when the original CP-1 was in operation in Chicago, and even that rudimentary pile would have automatically shut down if any part of its operation were out of normal bounds. The fact that the reactor was shown as a vertical wall painted white with a matrix of round holes in it was modeled after the X-10 reactor (the “Clinton Pile”) at Oak Ridge, which everyone had seen in the newsreels and a few still pictures. It was the graphite-moderated, air-cooled, low-power job that had been banged together during the war to test fuel slugs for the plutonium production reactors being installed at Hanford, Washington, and it was probably the only reactor configuration that civilians had ever seen. The loading face of the pile, which was painted white, was a seven-foot-thick concrete wall, acting as a bio-shield for workers standing in front of it.

An impressive science fiction film in 1956, Forbidden Planet, starring Leslie Nielsen and Anne Francis, did greater harm with its depiction of a nuclear reactor. In the movie, which was loosely based on William Shakespeare’s shot at sci-fi, The Tempest, Nielsen and his crew land the flying saucer C57-D on the planet Altair-IV and find two survivors of an exploration party that had landed 20 years ago, ‘ in an abandoned extra-terrestrial civilization. Nielsen decides to contact Earth for instructions on dealing with this odd situation, and in a refreshing twist of drama such a message is not easy to send. Earth is 16 light-years away.

To accomplish this feat it is necessary to dig a shielding trench and remove the ship’s power reactor to drive the transmitter, which must be assembled in situ. At this point any remaining credibility is blown away, as the men are shown hauling the graphite reactor out of the engine room. Nuclear engineers watching this movie cringe as they see an unshielded core, which had just been used to hurl a ship across interstellar space, pulled casually through the crowd of crewmen with a motorized crane. The naked core would have painted them all with a withering blast of fission-product radiation. This is what the public saw of reactor design and practice: a technology full of danger that was safe as long as it was turned off, and neatly blocked piles of graphite with cross-holes drilled in them and stuffed with uranium.

It is an exaggeration to say that the British Atomic Energy Authority after the end of World War II had about the same picture of how a nuclear reactor looks as the set designers of The Adventures of Superman, but not by much. The only reactor that the British scientists and engineers had ever seen was the X-10 pile at Oak Ridge, the first and almost the last

megawatt-capable air-cooled reactor ever built in the United States.118

The British had contributed greatly to the war-time atomic bomb project with a special delegation working at the Los Alamos lab in New Mexico, providing us with personnel ranging from William Penney, a brilliant mathematician, to Klaus Fuchs, the man who spilled every secret he could get his hands on to the Soviet Union. The Brits were useful and trusted, and they knew everything about atomic bomb theory and construction techniques. Everything, that is, except for the reactors. They were not allowed anywhere near the plutonium production reactors or fuel-processing facilities at the Hanford Site. The bombs were top secret, but the water-cooled graphite reactors, being extremely valuable industrial assets, were even more so. Just about any country having some physicists and engineers could figure out how to build an A-bomb, but producing the materials for this bomb was where the secrets lay. After the war was over, the British were very disappointed to learn that all the camaraderie and warm feelings of brotherhood were blown away by the United States Congress Atomic Energy Act of August 1946, forbidding any sharing of atomic secrets with anyone, even close allies. The Brits were left to fend for themselves in the twisted new world of Cold War and Mutually Assured Destruction. All they had in the world was Canada, an ambitious prime minister, a tour of the X-

10 pile, and a willing spirit.119

William Penney, fresh from working for the Americans on blast effects studies at the Bikini Atoll tests in 1946, was put in charge of the British atomic bomb development. Bill Penney was born in British-owned Gibraltar in 1909 and reared in Sheerness, Kent. Early interest in science and primary education in technical schools led eventually to a Ph. D. in mathematics from London University in 1932. After that he did time at the University of Wisconsin-Madison as a foreign research associate. This work persuaded him to change his career from math to physics, and he made it back to England, applied to the University of Cambridge, and earned a D. Sc. in Mathematical Physics in 1935.

In front of newsreel cameras, Penney always had the silliest grin, speaking with a back — country drawl and answering questions with the intellectual presence of a slow-witted kindergartner, but underneath it he was a razor-sharp scientist with experience and an ability to make people work together in harmony. As the guiding light for the steadfast British nuclear weapons program, he was awarded every honor, culminating in Queen Elizabeth II granting him the title The Lord William George Penney, Baron Penney.

Putting things in the order of priority, the first thing would be to figure out how to build an atomic pile. A heap of graphite called GLEEP (Graphite Low Energy Experimental Pile) was assembled at the new research center at Harwell, an abandoned World War II airfield in Oxfordshire, in an airplane hangar. It was first started up on August 15, 1947, and was used to

get the hang of how a nuclear reactor works.120 Time was of the essence. A month later, before there was any significant experimental work using GLEEP, construction of the first plutonium production pile began at a spot called Windscale.

Seascale was a vacation spot on the northwestern coast of England, or it had been during the Victorian age. Now it was a depressed area. A couple of hundred yards inland was an abandoned royal ordnance factory named Windscale, and here the British nuclear industry would begin. It was in the middle of dairy-farming country, and putting open-loop, air-cooled reactors there made as much sense as installing a fireworks stand in the middle of a high school auditorium. So be it.

The two production reactors would be like the X-10, only larger, with more capacity for making plutonium. X-10 was basically a short cylinder of solid neutron-moderation material, not perfectly circular but octagonal, laid on its side with holes bored clean through it to hold uranium fuel. A long platform in front moved up and down and would allow men, working like window washers, to poke little fuel cartridges into the holes on the vertical face. Each fuel element was metallic, natural uranium, having the small U-235 content allowed in nature, sealed up in an aluminum can, about the size of a roll of quarters. Using metal poles, workers could push in new fuel on the face of the reactor, and used-up fuel, still hot from having fissioned to exhaustion, would fall out the back, landing in a deep pool of cooling water sunk into the floor. It would be a terribly clumsy way to make a power reactor, but as a plutonium production pile the fast turnaround of the inefficient fuel and the enormous size necessary to keep a chain reaction going were perfect. Instead of wasting a lot of effort trying to make electricity, all exertion would be to convert the otherwise worthless uranium-238 in the fuel into plutonium-239, and the power was thrown overboard. A short time in the neutron-rich environment for the fuel meant that the probability of plutonium-239, the ideal bomb material, being up-converted into the undesirable plutonium-240 was minimized.

The two Windscale reactors were huge. The core, built like X-10, was 50 feet high and 25 feet deep. The fuel-loading face was covered with a four-foot-thick concrete bio-shield, backed with six inches of steel and drilled with the holes for inserting fuel cartridges into corresponding channels cut in the core and running clean through, horizontally. There were 3,440 fuel channels. Each square array of four fuel channels was serviced from one hole in the loading face, normally sealed with a round plug. Every fifth horizontal row of access holes had the positions numbered from left to right. When running, the core would be loaded with 21 fuel cartridges in each channel, or about 70,000 slugs of metallic uranium. The fissions would be controlled using 24 moving rods made of boron steel, engineered to absorb neutrons and discourage fission, trundling in and out using electric motors wired to the control room, located in front of the building. A scram of an emergency shutdown was handled separately, using 16 additional control rods inserted into vertical channels. Under normal operation, these rods were withheld using electromagnets. If anything went wrong, electricity to the magnets was cut and the heavy rods would fall by gravity into the core, shutting it completely down.

The first set of plutonium production reactors at Hanford were water-cooled, but even the Americans admitted that this scheme, while elegant and impressively complicated, invited a disastrous steam explosion. Let a water pump fail, and the coolant stalled in the reactor would flash into steam, sending the works skyward. Besides all that, unlike the Yanks, the Brits had no mighty river like the Columbia to waste as an open-loop cooling system. Using seawater was a possibility, but there would be destructive corrosion. Penney’s design team decided to do it the easy way, just like X-10, blowing air through the loose-fitting fuel channels and up a smokestack, sending the generated heat and whatever else managed to break loose up into the sky and out over the Irish Sea. Each reactor would be equipped with eight very large

blowers, two auxiliary fans, and four fans dedicated to shutdown cooling.121 Each main blower was a monster, driven by a 2,300-horsepower electric motor running on 11,000 volts. The exhaust stacks were designed to be an imposing 410 feet high, made of steel-reinforced concrete.

The Windscale Unit 1 plutonium production reactor, shown from the top looking down. Not shown are the two auxiliary buildings, left and right, containing air-blowers the sizes of double-decker buses. The water duct was used to cool off the used fuel as it was poked out the back of the graphite reactor core and move it out of the reactor building for plutonium extraction.

Such a reactor could be made using heavy water as the neutron moderator, as the Canadians were demonstrating, but it was cheaper and easier to use graphite, just like the X-10. It would take 2,000 tons of precision-machined graphite blocks to make one reactor.

The Windscale Unit 1 reactor, shown from the left side. Only a small portion of the chimney is shown so that the diagram would fit on the page. The charge hoist was a movable platform used to position workers on the front of the reactor, located behind a thick concrete shield and the space for cooling air to enter the fuel channels from the front.

Graphite is a strange and wonderful material. It is a crystalline form of carbon. So is diamond, and a diamond is the hardest material on Earth, hard enough to saw through a sapphire. Graphite is completely different, being soft enough to cut with a butter knife and be used to lubricate automobile window channels. In recorded history, an enormous deposit of natural graphite was first discovered on the approach to Grey Knotts from the town of Seathwaite in Borrowdale parish, Cumbria, England, about 13 miles northeast of Windscale. Locals found it exceedingly useful for marking sheep, and news of this proprietary livestock branding method leaked out in 1565 after decades of use. Expanding on this theme, entrepreneurs in Cumbria proceeded to invent the lead pencil, and from this wonderful application the mineral acquired its official name from the Greek word grapho, meaning to write or draw.

As happens to many such discoveries, a military use was soon found and the English government clamped down on the source. It had been determined that lining the molds for making cast-iron cannonballs with graphite resulted in smooth, well-thrown projectiles, and the military-industrial complex of 16th century England was well pleased. Afterward, the manufacturing enterprise found myriad uses for the fine, pure English graphite from Cumbria, from arc-light electrodes to the throw-out bearings for MGB sports cars. British industry thus had a long and complete history of working with graphite. They may not have known much about working with uranium in a controlled-fission environment, but they knew their black, greasy mineral like the bottom of a Guinness glass.

The United Kingdom, still aching from the post-war abandonment, was trying to impress the United States nuclear establishment with their rapid ascent to atomic power status and thus reestablish a badly needed intimate connection to the material and industrial strength of its former colony. By showing that they were on equal footing and had expertise to contribute, they wished to demonstrate that an Anglo-American nuclear alliance could be a strong bulwark against the Red Menace that was having its way with Eastern Europe. The Windscale construction job was one of the largest, most time-pressed in English history, employing nearly 5,000 workers, including more than 300 surveyors, architects, and building engineers. Everything was in short supply except determination.

The Americans, irritatingly miles ahead of the Brits in these matters, were hard to impress, but they were concerned with what they had heard about the British plutonium production initiative. In 1948, a team from Los Alamos slipped into the headquarters at Harwell to give some advice. There were a couple of days of classified seminars with Bill Penney’s top scientists. All the talk came down to this: Whatever you think you know about graphite is wrong. The conversation between the American scientific delegation and their British counterparts might have gone like this:

“For example,” offered the Yank, “there’s the Wigner Growth.”

The Brit lowered his teacup slowly, seeming to twitch slightly. “Say what?”

“The Wigner Growth. If graphite is exposed to fast neutron flux, as it will be in your production pile design, the recoil action of neutrons colliding with carbon atoms will displace these atoms in the graphite crystal. Over time, changing the distance between atoms changes the physical size of your graphite block. It seems to grow.”

“But how do you… ,” Nigel sputtered.

“Control it? You don’t. You have to allow for it in the design. The only thing you can control is the direction in which it grows. If you make your blocks by extruding them, then the blocks will lengthen only at right angles to the extrusion axis.”

“Well, dash it all.”

It was best to learn of this wrinkle early on in the construction. Heroic redesign of the core allowed each block to expand horizontally, at right angles to the axis of extrusion, while being held in place with graphite slats. By March 1949, word had arrived from hastily convened experiments at Harwell, trying to replicate the effect claimed by the Americans. British graphite, so wonderful for making pencils, was completely different from the synthetic graphite they used in the U. S.A. It expanded in all directions. That was bad. The prediction was that after running just 2.5 years, the pile would be warped and unusable. The fuel channels would close up and trap the aluminum canisters in the core. The Canadians came through with a modified prediction. Yes, British graphite would expand on all axes, but only at one fifth the length of the American product. That was good. Under that condition, the pile might operate for as long as 35 years, if the internal stresses did not crumble it like a tea biscuit. Other potential problems were revealed too late to be designed out so easily.

Later in 1948, Cockcroft, head of the entire British nuclear enterprise, came back from a fact­finding tour of the X-10 at Oak Ridge with some more disturbing news. They would have to filter the pile-cooling air before releasing it to the general atmosphere. Of all the 70,000 fuel canisters in one pile, if the delicate aluminum case around just one of them were to break open, then its highly radioactive contents would go straight up the chimney and rain down on the dairy farms of Cumbria. That could be a problem. When building their improved version of the X-10 up on Long Island, New York, the Americans had put filters between the atomic pile and the air exhaust stack, just to prevent a fission product spread if the fuel broke apart or caught fire. “We shall do the same,” pronounced Cockcroft.

Impossible. The base of the Unit 1 chimney had already been poured, and 70 laboriously laid feet of vertical brickwork was already in place. If filtering were necessary, then it should have been designed in to begin with, in the gallery between the core and the chimney base. There was no way to tear the thing down and start over, and, at this late stage, the only place to put filters would be atop the chimneys. Cockcroft was adamant, and he was in command. The filter assemblies, aptly named “Cockcroft’s Follies,” were built as specified, using 200 tons of structural steel, concrete, and bricks hauled up 400 feet to the tops of the air stacks.

Several filter packs were tried. In early 1953, a temporary lash-up was settled on. The filters would be fiberglass tissue, sprayed with mineral oil to trap dust made radioactive by going through the reactor core and any fuel that might disintegrate and escape. There was much grumbling, not only among the men who had to retrofit this ghastly mess, but from Penney’s bomb makers. To make plutonium at the necessary rate, a ton of cooling air had to go up each of the two stacks every second. That meant that the hot air had to be moving at 2,000 feet per minute as it exited at the top, but at that point it would hit the drag-inducing filter pack like a brick wall. Delicate fiberglass tissue would quickly come apart, and the oil would be blown off the fibers. The air speed would have to be reduced, and this would mean less plutonium per month. The Canadians would have to pick up the slack using their heavy-water reactor at Chalk

River.122

With further improvements and changes in the filter packs, including substituting silicon oil for the mineral oil, Cockcroft’s follies were preventing the occasional radioactive dust particle from ejecting into the atmosphere. An exception was the volatile fission product iodine-131. As a gas, it was largely unhindered by the filters. There was nothing to worry about. When one was striving to build an arsenal of weapons, one of which can obliterate a large city, it seemed almost inappropriate to fret over probabilistic health effects on individuals. At this point, production speed outweighed all but the most basic safety concerns.

On they labored. Engineering problems were knocked down one at a time. Of particular concern were the fuel canisters. The metallic uranium, which would catch fire spontaneously if exposed to air, had to be cast into small cylinders a few inches long and sealed up in aluminum cans with heliarc-welded seams. The hot uranium would react chemically with the aluminum, so the inside of each can was coated with insulating graphite. The uranium slug would expand as it heated and burst the can, so it had to be made to fit loosely. Each can was filled with pressurized helium to ensure heat conduction to the aluminum, and the assembly was covered with cooling fins. In early summer 1950, Cockcroft threw another serious monkey wrench into the business. New calculations seemed to indicate that the critical mass of Pile. No. 1 would have to be increased by as much as 250 percent, or it would not work.

Reeling briefly with this news, the design team proceeded to inventory every material in the reactor that would parasitically absorb neutrons, affecting the core reactivity. There was one item that could be reduced enough to compensate for the lack of critical mass: the fins on the fuel cartridges. In three weeks the team managed to trim one sixteenth of an inch off each of the one million cooling fins, thus solving the problem.

In October 1950, craftsmanship triumphed over knowledge, and the Windscale Pile No. 1 achieved self-sustaining fission. By January 1951, used fuel cartridges had been chemically processed, and Tom Tuohy, the Works General Manager, held the first lump of British plutonium in his hands. In June 1951, Pile No. 2 became operational, and plutonium production was proceeding at full capacity. The people of the United Kingdom under hard postwar circumstances had put their backs into it and prevailed.

There were problems. On May 7, 1952, there was an unexplained temperature rise in Pile No. 2, only in the upper portion of the core. The operators were able to bring the temperature down with the fans, but there was not a clue as to why this had happened. In September the same thing happened to Pile No. 1, but this time there was smoke coming out of the stack. Was the graphite burning? They had been warned by the Americans: Whatever you do, do not let the graphite catch fire. Once it gets going, water will not extinguish the fire. It will only make it burn hotter, and the graphite sucks the oxygen out of the water and leaves you with explosive hydrogen. Analysis showed that the smoke was caused by lubricating oil leaking from a fan bearing, but the high temperature remained inexplicable.

In May 1952, Pile No. 2 was taken down for maintenance. The workers found that 2,140 cartridges had migrated out of the fuel channels. Some were hanging precariously out the back of the core, and some had flown over the pool of water below and into the wall behind it. The air flowing from front to back had literally blown them out of the reactor. Each fuel cartridge had a little graphite boat under it, so that the cooling fins would not make it stick in the channel, but this would have to be changed. A worse finding was that the Burst Cartridge Detection Gear (BCDG) had punched a hole in the end of a cartridge, putting fission products in the air stream.

There were eight BCDGs, called “Christmas trees,” in each reactor. A Christmas tree was a rectangular matrix of 32 vacuum nozzles, arranged to fit over any 4-by-8 array of exit holes in the back of the reactor core. It could be positioned remotely from the control room to sniff the holes, looking for escaping radioactivity that would indicate a broken fuel can, but the operation was completely blind. From the control room or even from the face of the pile where fuel was pushed in, you could not see the BCDGs in action. During normal operation the eight of them would crawl over the back end of the pile, like very large insects, looking for trouble. It was a good idea to have equipment that could tell exactly which hole was leaking, but it could be too strident and cause what it was trying to detect, punching the vacuum nozzle through the aluminum. Some fuel cartridges were even jammed into the frames of the Christmas trees, never making it to the recovery pool below for plutonium extraction.

The American delegation made another informative visit, this time bringing the big guns, Dr. Edward Teller, the brilliant Hungarian theoretician and Mother of the H-bomb, and Dr. Gioacchino Failla from the Columbia University Radiological Research Laboratory. They could

explain the mysterious temperature transients in Piles No. 1 and 2.123 Technically, it was illegal to give such information to a foreign power, but the Brits had to be informed before their entire atomic bomb program went up in smoke.

There is another Wigner effect, called Wigner Energy. The same phenomenon that would bend the crystalline structure of graphite would store a great deal of potential energy in the material. If you allowed this energy to accumulate over a long period of time, it could reach a break-down point, at which it would all release at once, igniting the graphite with extremely high temperature and sending your plutonium production machinery up the chimney. The way to keep this from happening is to stage a periodic annealing, in which the core is heated to an abnormally high temperature, about 250°C, using nuclear fission with reduced cooling. At this point a “Wigner release” should occur, with the graphite providing its own heating without the need for fission. Shut down the reactor, and adjust the fans to slowly bring down the temperature.

It was not quite that simple, but the Atomic Energy Authority appreciated the heads-up, and thanks for not waiting until the Windscale facility was wiped out to let us know what had happened. The Windscale piles were very large, and Wigner Energy could collect in various regions or pockets in the graphite stack, meaning that the pile would have to be selectively heated and annealed by skillful use of the controls. There was never a written procedure for annealing. It was more of an art than a science. The first anneal on Pile No. 1 was in August

1953, and they were scheduled for once every 30,000 megawatt days of operation.124 There were eight anneals from the first until July 1957, and during the first operation three scientists hovered over the operators, giving advice and asking questions. After that, it seemed like a routine task, and no science was needed.

The two Windscale piles, with some help from the Canadian NRX, produced enough plutonium for an official British atomic bomb test on October 3, 1952. The blast, occurring under water a few hundred yards from Trimouille Island, Australia, released a respectable 25 kilotons of raw energy, digging a crater 20 feet deep and 980 feet across. William Penney’s bomb design crew and the efforts of thousands working at Windscale had paid off in the most visible way. This would prove to the United States that Britain had achieved parity in the arms race, and an immediate summit meeting was expected.

Unfortunately for this motive, a month later the United States set off “Ivy Mike,” the world’s first thermonuclear bomb on Elugelab Island at Enewetak Atoll, releasing the energy equivalent of 11 million tons of TNT high explosive. Elugelab Island vanished, replaced with a crater 64 feet deep and 6,240 feet across. The British arms industry would have to go a bit farther to come up even with that.

Penney’s team had the imposing task of coming up with a thermonuclear weapon design quickly, starting from scratch. They had not so much as an encouraging word from the Americans, and making hydrogen isotopes fuse explosively was not an easy problem. It was only obvious that a source of tritium, the heaviest isotope of hydrogen and one most likely to fuse, would be necessary.

There is no natural source of tritium, and, like plutonium, it must be manufactured using fission reactors. To accomplish this, a rod of lithium-magnesium alloy, about half an inch in diameter, is encased in a sealed aluminum can and pushed into one of many special “isotope channels” in the reactor. Neutrons from the fission process are captured by the lithium-6 nuclide component of natural lithium, and the atom subsequently breaks down into one helium atom and one tritium atom. The helium pressurizes the can, and the tritium combines chemically with the magnesium component of the alloy, becoming magnesium-tritide. After being in the reactor for about a week, the rods in several cans are harvested and chemically processed to remove the pure tritium. So far, so good.

The tritium production cartridges were given the code name “AM,” and the Mark I cartridges were built using standard fuel cans with a lead weight added so that they would not fly away.

The Mark II cartridges were an improvement, having the lithium-magnesium rod diameter increased to 0.63 inches. Under the extreme needs of the hydrogen bomb program, the even more improved Mark III cartridges were built using thinner cans, no lead weight, and alloy rods an inch in diameter. The Mark III’s were admittedly dangerous. The lithium-magnesium rods were pyrophoric, meaning they would burst into hot flame and burn like gasoline if they were exposed to air. The cans were as thin as possible, and the helium pressure could blow them open if the temperature was as high as 440°C. In addition, there were now so many AM cartridges in the Windscale cores, they dragged the fission process down. Absorbing neutrons without adding any to the fission process made the reactor subcritical. To work at all, the reactor fuel had to be beefed up with a slight uranium-235 enrichment, coming from the new

gaseous diffusion plant at Capenhurst.125

On January 9, 1957, the British Prime Minister, Anthony Eden, having just presided over the political disaster of the Suez Crisis, resigned from office after being accused of misleading the parliament. The British Army had done a splendid job of tearing up Port Said, Egypt, with French assistance, but internationally it was seen as the wrong force applied at the wrong time as a reaction to Egypt having nationalized the Suez Canal. Eden was succeeded by Harold Macmillan, who desperately wanted to recapture the benevolence and camaraderie of the United States, and the hydrogen bomb initiative was the point of the spear. It would proceed at an ever-accelerated pace.

By May 1957, Penney’s group had put together the first British thermonuclear test device, code named Short Granite, to be exploded in Operation Grapple I off the shore of Malden Island in the middle of the Pacific Ocean. Time was becoming crucial, as a nuclear test-ban treaty was in the works, and the end of unrestricted nuclear weapon experimentation was in sight. The expected yield was north of a megaton. On May 15 Short Granite was dropped from a Vickers Valiant bomber, and it was an embarrassing wipeout, giving an energy release of

only 300 kilotons. The first attempt at a British hydrogen bomb had failed.126 They would get it right the next time, but a lot more tritium was required.

After Grapple I, the Windscale piles were operating in emergency mode at the highest possible power level using flammable metallic uranium fuel and flammable lithium-magnesium in piles of flammable graphite with gale-force air blowing through them. Fire was prevented by coverings of thin aluminum on the fuel and AM cartridges sitting in graphite bricks that could become superheated on their own at an unpredictable time for reasons that were not entirely understood. The annealing interval was increased to once every 40,000 megawatt days for the sake of more plutonium and tritium production. It is not unreasonable to predict an eventual problem under these conditions.

Sunday night, October 6, 1957, was in the middle of a local influenza epidemic, and Windscale Pile No. 1 was well overdue for an anneal. The front lower part of the graphite had not really released any energy at the last anneal in July 1957, and it probably had 80,000 megawatt days of Wigner energy buildup ready to let go at any time. Production was halted, the pile was cooled down, and the ninth anneal would begin Monday morning.

The temperature of the pile was monitored using 66 thermocouples placed at three depths in the reactor face in selected fuel channels. Considering that the core occupied 62,000 cubic feet, and a detailed map of the temperature throughout the graphite was necessary to monitor an anneal, having only 66 thermocouples was pitifully inadequate. There were also 13 uranium — temperature monitors in the control room and another seven on top of the pile in the crane room. The operations staff had performed these measurements before, and there was no concern about this weakness in the instrumentation. On October 7, the main blowers were turned off at 11:45 a. m., and an extremely slow and cautious approach to criticality in the lower part of the core was begun. Stopping twice to look at the temperature readings, it took the operators seven and a half hours to withdraw the controls and reach criticality. There was a holdup to work on some faulty thermocouple connectors. Once the pile was maintaining a low power level, the crew wrangled with some control rod positions to concentrate the fissions in the lower front of the core, where annealing was obviously needed. The goal was to bring this section in the core up to 250°C.

The facts that Windscale Pile No. 1 was able to achieve criticality and maintain it could give one with a religious bent the belief that God was on the side of the United Kingdom. Or, perhaps the Devil was. Driving it was like trying to steer the RMS Titanic around an iceberg. The core was so big, the peak of the neutron flux curve could be put just about anywhere in the massive block of graphite by artistic positioning of the controls, but it was ponderously slow to respond to control movements, and the instrumentation was a bit numb. The pile would not do anything quickly, and the dangers of a sudden runaway or an explosion were nonexistent.

An hour after the beginning of Tuesday, October 8, the pile seemed to be running cool, reading between 50° and 80°C in the graphite. One thermocouple indicated 210°C, and this was obviously where the annealing process had begun. An anneal would always start somewhere and then spread out slowly, hopefully infecting the entire pile. The operators ran in the controls to shut it down, letting it cook, and sat back to watch it happen. For some odd reason, two uranium thermocouples read 250°C. Uranium does not anneal; only graphite. Ian Robertson, the pile physicist on duty, had the flu, and he went home to collapse in bed at 2:00 am. The anneal seemed well in hand by the operating crew.

Robertson came back on duty at 9:00 the next morning, sick as a dog, to find that the temperature was not spreading the way it was supposed to, and the operators had decided to reheat the reactor by bringing it back to criticality. In a couple of hours they had it back running at low power, but something was not right. One uranium thermocouple showed a sudden temperature rise to 380°C. What’s that all about? This type of reactor was run by the graphite temperature and not necessarily by the neutron counts, and it was meandering all over the place, from 328° to 336°C. Pile No. 1 had its own quirks, but meandering was not one of them. Something was amiss, but the annealing had to proceed. The fission process was shut down again at 7:25 PM. Robertson was starting to get woozy, and the operating crew insisted that he go home.

By Wednesday morning, things seemed to have calmed down. The crew shut the inspection ports atop the core and turned on the shutdown fans to give it some air and bring the wayward temperatures down. At about midnight, the temperature readings off the graphite thermocouples started to go wild.

It was now early Thursday morning. One thermocouple in the middle of hole 20-53, 20 rows up from the bottom and 53 across, was reading extremely high at 400°C. Air dampers were opened. In 15 minutes the temperature rose to 412°C. It did not make sense. At 5:10 am. the dampers were opened again, and this time the smokestack radiation monitor indicated a bit of radioactivity in the filter. At about the same time, the stack on Windscale Pile No. 2, which was running plutonium production at balls-to-the-wall power, indicated increased radioactivity. Obviously a fuel cartridge had burst in No. 2. They really should do something about that.

Attempts to bring the annealing under control continued. Air dampers were opened and closed again, with no expected results. By 1:30 P. M., the stack radiation was unusually high, and it was clear that there was a problem. The uranium temperature was at 420°C and rising quickly. The Pile Manager, Ron Gausden, was called in. He gave instructions to open the dampers, turn on the shutdown fans, and try to bring down this temperature. Obviously, a fuel cartridge had broken open and fission products were collecting in the stack filter. The Christmas trees, which were parked off to the side at the back of the core, would not work with the pile at this elevated temperature, so they could not identify the broken cartridge. The temperatures were not going down, and at 2:30 P. M. Gausden told the operators to turn on the main blowers. He picked up the phone to call Tom Hughes and share the excitement.

The Windscale operation was critically understaffed, particularly for this running emergency to produce bomb material. Of the 784 professional posts, 52 were vacant. Hughes had worked at Windscale since 1951 as the Assistant Works Manager in charge of the chemical group. He was also Acting Works Manager for the entire site and had just been assigned a third post as Works Manager for the pile group. His response to the call from Gausden would mark his first visit to an actual pile.

Huw Howells, the Health Physics Manager, was already there to inquire about radiation coming out of the stack. With a short rundown of the situation in the control room, Hughes and Howells decided to call H. Gethin Davey, the Works General Manager with bad news about Pile No. 1. A crew from the control room rode the lift to the refueling platform and pressed the

UP button to take them to row 20 on the loading face and have a peek behind plug 53.127

The loading face was a bio-shield, built to protect workers who could stand there and push fuel into the graphite pile behind the shield with long poles. When not in use, each hole was plugged with a metal cylinder. A worker pulled out the plug in 20-53 and looked in the hole. Normally, it would take a flashlight to illumine the black-as-carbon fuel channels to see what was inside, but in this case a bright red glare greeted them. All five holes behind the plug were glowing.

The pile was on fire, and it had been burning since Tuesday. Windscale Pile No. 1, running too fast in the dark, had crashed into its iceberg.

Gausden ordered the crew to make a firebreak by removing all the fuel around the burning channels. Easier said than done. Even some fuel cartridges that were not on fire were so swollen from the high temperature, they would not budge. The men dressed out in rubber suits, full-mask respirators, gloves, and dosimeters to monitor their radiation exposures. It was going to be a long night. They started dumping fuel into the cooling pool in back of the core, pushing it out with the heavy rods. It was hot, difficult work, but the main blowers put positive air pressure behind the loading face, and clean, cool air blew out the loading holes and onto the men. The airflow was all that made the work possible.

The graphite on the front of the pile below where the men were ejecting fuel was now a mass of flames, and the highest temperature reading had passed 1,200°C. At 5:00 P. M. on Thursday,

Davey picked up his phone and rang his deputy, Tom Tuohy. “Come at once,” he said. “Pile No.

1 is on fire.”

Tuohy was at home caring for his wife and children, who were all down with the flu, and when he got off the phone he instructed them to please keep all the windows closed and not to leave the house.

Tom Tuohy, excitable, bubbly, and auburn-haired, was born at the eastern end of Hadrian’s Wall in northern England in a town named Wallsend in 1917. He studied chemistry at Reading University, worked for the Royal Ordnance Corps during the war, and had joined the nuclear effort in 1946. He arrived at the stricken pile in minutes and went straight to the loading face. He saw men struggling to punch the fuel out the back of the pile and got a grim impression of the situation. They were pulling back rods that were glowing yellow on the ends and dripping molten uranium. Back in Davey’s office he found a knot of scientists arguing over using carbon dioxide or argon to quench the fire. By 7:00 P. M. he decided to get a better look. He took the stairs to the crane room and lifted an inspection plate so he could see the front of the reactor. It was glowing. He went back at 8:00 P. M. and found flames shooting from the fuel channels, colored yellow by the sodium in the construction workers’ sweaty handprints on the graphite blocks. At 11:30 he pried up the viewing port, which was becoming quite warm, and saw blue flames hitting the concrete wall many feet behind the back of the pile, and a new fear gripped him. The flames were hot enough to ionize the nitrogen in the air. Not only could the hot flames burn through the concrete wall, but he was not certain about the floor under him staying put much longer.

Early on Friday, October 11, Davey was sent home sick and in pain with the flu. Between 4:00 and 5:00 am., the largest tank of carbon dioxide that could be found was expended into the fire, with zero effect. There was nothing to do but start pumping water into the fuel channels, a desperate move. The concept of flooding a graphite reactor with water was so remote, there were no fire-hose taps in the building. The works fire brigade was called in with pumper trucks, and nozzles were jury-rigged to force water through the holes in the loading face and deep into the fuel channels, two feet above the highest point of the fire. The water was turned on just before 9:00 am. K. B. Ross, the Director of Operations, dispatched the following message to the Authority Chairman, Sir Edwin Plowden, in London:

Windscale Pile No. 1 found to be on fire in the middle of lattice at 4:30 pm yesterday during Wigner release. Position been

held all night but fire still fierce. Emission has not been very serious and hope continue to hold this. Are now injecting water

above fire and are watching results. Do not require help at present.

Plowden dashed off a note to the Minister of Agriculture, wisely anticipating trouble with radiation contamination of the dairy farms in the area.

Tuohy was relieved when there was no explosion from the water interacting with the graphite. Watching through the viewing port at the back end of the pile, he could see the water gushing out of the fuel channels and cascading down the pile into the cooling pool at the bottom. The water looked good tumbling down, but still the fire raged out of control. The back of the core remained a wall of flames. He watched for an hour, starting to feel that the situation was hopeless, when he was struck by a brilliant idea. All the men had evacuated the loading face. There was no longer any need for the blowers. He decided to turn them off.

Almost instantly, the flames died away.

This time when Tuohy went up to the crane room to look, the viewing port seemed firmly cemented to the floor. The fire in its dying gasp was sucking oxygen out of the remaining air and causing a vacuum in the reactor core. With no more air forced through the fuel channels, there was no more fire. By noon Tuohy was able to report to Davey that the fire was out and the situation was now under control. Just to make certain of his pronouncement, the water was kept flowing for another 30 hours.

The core of Windscale Pile No. 1 was a total loss. Over 10 tons of uranium were melted and five tons were burned. Very little of the uranium or even the fission products went up the chimney. A brittle oxide crust had formed in the extreme heat of the fire, and the heavy oxides were bogged down in it before they made it to the air outlet. The immediate concern was the volatile fission product, iodine-131. The filter packs, which were no longer called “Cockcroft’s follies,” were not expected to capture any of the 70,000 curies of iodine-131 that were present in the fuel when the fire began, but there was a fortuitous happening. The LM cartridges, containing bismuth oxide meant to activate into polonium-210, burned up, and the light bismuth oxide dust went up the stack and caught in the filters. This and some vaporized lead from the weights in the AM cartridges reacted chemically with the free iodine and captured some of it in the filters. Although 20,000 curies of iodine-131 blew out the top of the stack and over the dairy farms, about 30,000 curies of it were caught in the filters. It was better than no capture at all.128

The immediate bad thing about loose iodine-131 is that it falls on the grass, cows eat it, it winds up concentrated in the milk, people drink it, it goes straight to the thyroid gland, and the tightly contained radiation load has a good chance of causing thyroid cancer. The good thing is that it has a short half-life of only eight days. On Sunday night, October 6, the reactor was shut down, iodine-131 production by fission stopped, and the countdown for the decay of the iodine — 131 began. By eight days later, half of it was gone. On Saturday it was estimated that 20,000 curies of it were contaminating 200 square miles of territory north of the reactor, but in about 80 days that contamination would drop to 1/1,000 of that level.

However, 20,000 curies divided by 1,000 is 20 curies, and that is still a great deal of radiation. It is 7.4 3 1011 becquerels, or 7.4 3 1011 iodine-131 disintegrations per second, emitting first a 606 kev beta ray and then a 364 kev gamma ray, becoming a stable xenon isotope. The dairy industry in Cumbria was thus in serious trouble. On Saturday morning there was enough active iodine-131 on the grass, 132,000 disintegrations per second per square foot, to rattle a Geiger counter in a most alarming way.

This was new, untrod territory in the nuclear business, in which a private industry would have to be shut down because of an unfortunate situation in the government-owned, secret, dangerously handled fissile-isotope-production endeavor. There were no safety standards; no maximum limit for the amount of radiation to which a toddler should be subjected in its otherwise wholesome cow’s milk. The government did the right thing and bought every pint of contaminated milk. It was poured away into ditches, and the countryside smelled of sour milk

for quite a while.129 After a year, not a trace of iodine-131 could be found in the farmland. One good thing about radiation contamination is that it improves with age.

Neither Windscale reactor would ever be started up again, and there would be no more open — looped, air-cooled reactors built anywhere in the world. Pile No. 2, which was in perfect operating condition, was shut down permanently five days after the fire was stopped, and as much remaining fuel as could be moved was carefully taken out of the wrecked Pile No. 1 and processed to remove the plutonium. Unusable radioactive debris was dumped offshore into the Irish Sea. The cores of both reactors were sealed off with concrete, and the buildings were used for several decades as offices, labs, workshops, and for bulk storage. The 6,700 damaged fuel cartridges and 1,700 AM and LM cartridges in Pile No. 1 will be removed by remote-controlled robots by 2037. The core is still a bit warm. The name Windscale, carrying bad karma, was buried and the site was renamed Sellafield. It is now owned by the Nuclear Decommissioning Authority (NDA).

The people who worked at Windscale in 1957 and who participated in the cleanup operations have been studied, looking for radiation-caused diseases. Statistical analysis indicates that the widespread radiation release should have caused 240 thyroid cancers, but no correlation has been found. The last accounting in 2010 could find no evidence of health effects from the radiation release back in 1957. Tom Tuohy, who stood alone in the most hazardous conditions of radiation exposure at the height of the Windscale fire, died in his sleep on March 12, 2008,

at the advanced age of 90 years.130

Bill Penney, the man whose relentless demands for more tritium, plutonium, and polonium-210 had caused Pile No. 1 to be overworked to the point that it burned down, was assigned as the chairman of the inquiry committee. On October 26, 1957, 16 days after the fire was put out, he submitted his report to the Chairman of the United Kingdom Atomic Energy Authority. His committee found the operating staff at fault for causing the fire. During the annealing process, they had reapplied nuclear heating to the reactor too soon after the first try. He did not point out that the fire had started in hole 20-53 when the overheated lithium in a Mark III AM cartridge diffused through the aluminum and set fire to the adjoining fuel, and he assigned no responsibility to himself or to the questionable engineering of the isotope production

cartridges.131 In retrospect, the Windscale piles were a disaster waiting to happen. Panic — containment photos were released showing contented cows grazing in the grass with the Windscale chimneys looming in the background.

The secrecy covering the Windscale site and its mission did not help the publicity crisis that arose when it hit the newspapers in London and Manchester. Simply cautioning people about drinking milk or leaving windows open was enough to cause some concern. At one leak point a scientist at Windscale, Dr. Frank Leslie, wrote a letter to the Manchester Guardian on October 15, expressing disappointment that the government had given no warning to the public until the matter was resolved. Harold Macmillan, the excitable Prime Minister, had to be restrained from seeking out Dr. Leslie and strangling him manually. The Penney report was finally declassified and released to the public in January 1988.

On November 8, 1957, about a month after the Windscale fire, the British bomb program achieved what it had so dearly sought. Above the southern end of Christmas Island in the Pacific Ocean, the two-stage thermonuclear device Grapple X went off with a bang, yielding 1.8 megatons. Penney’s development crew had done it almost correctly, and a bomb that was built to give one megaton unexpectedly wiped out the military installations on the other end of the island with 80% over yield. A triumphant British delegation of scientists was invited to Washington to talk about thermonuclear topics with some fellows from the Lawrence Livermore

Lab, and the shutout was broken. From that point on, the United Kingdom was granted technical parity with the United States in matters of nuclear weapons and use of the Nevada Test Site.

The replacement plutonium production reactors for the Windscale units were already up and running, as of August 27, 1956, at the Windscale site. Four large graphite reactors using closed-loop cooling by carbon dioxide, named Calder Hall Piles 1 through 4, produced 60 megawatts of electricity each, and were considered to be the world’s first nuclear reactors making significant commercial power. In reality, the purpose of these reactors was to convert uranium-238 into plutonium-239 and to manufacture tritium. Calder Hall Pile No. 1 ran for nearly 47 years before it was finally shut down in 2003.

A sister plant named Chapelcross was built on an abandoned airfield in southwest Scotland near the town of Annan. The plant, comprising four 180-megawatt Calder Hall reactors, was completed in 1959. Its purpose was to produce plutonium and tritium, with 184 megawatts of electricity on the grid being a secondary byproduct. The Calder Hall and Chapelcross reactors were safer and more complex than the antique Windscale units. The carbon dioxide cooling gas worked just like air being blown through, but it was contained in a closed loop, pumped back into the bottom of the core after the heated gas had been used to make steam in heat exchangers. The steam, which was used to turn the turbo-generators, was also in a closed loop, and the ultimate heat sink for disposing of the waste energy was one large cooling tower per reactor, dumping heat into the atmosphere. There was not much worry of fire in a graphite pile cooled with fire-suppressing carbon dioxide. Even an unlikely steam explosion would not release fission products into Scotland.

For efficient plutonium production, the fuel was still metallic uranium, this time enclosed in cans made of magnesium oxide. It was code-named MAGNOX, and this became the type designation for a series of 26 power reactors built in the UK. Magnesium oxide is perfectly fine as a canning material, as long as it does not get too hot or too wet. If left too long in a cooling pond, the magnesium oxide corrodes and leaks, and the fuel inside can melt easily if deprived of coolant while fissioning.

Given the Cold War pressures of producing Poseidon and Trident missile warheads and the risky fuel design, these improved graphite reactors were remarkably safe. There were no meltdowns or fires of the Windscale severity, but there were some interesting incidents.

The British MAGNOX reactors used graphite neutron moderators and a fast-flowing gas for cooling. This design was different from the Windscale reactors in that the primary cooling system was closed, using the same gas over and over as it was recycled back into the reactor alter it had given up its heat to a steam generator. In this design, the gas was carbon dioxide or helium, and with the closed system the graphite would never be exposed to oxygen and would be unlikely to burst into flame.

The Chapelcross piles were just like the Calder Hall piles, only different. They were built in series, starting with Pile No. 1, and improvements were added as the construction progressed. Pile No. 1 required annealing, similar to the Windscale piles, but, starting with Pile No. 2, the graphite fuel channels were lined with graphite sleeves. The sleeves were fragile and were something else that could break, but they were designed to let the graphite run so hot it would never require annealing. In Chapelcross Pile No. 2 on May 19, 1967, after seven years of running at full power, the graphite sleeve inside one of 1,696 fuel channels crumbled and blocked the flow of carbon dioxide coolant over the fuel canisters. At least one fuel canister overheated, the uranium melted and caught fire, breaking open the can and sending radiation

alarms into a tizzy.132 Considering that a MAGNOX reactor is loaded with more than 9,000 fuel canisters at one time, this would seem a small statistical problem, but full-blown disasters can start small and memories of the Windscale fire were still fresh. The reactor was scrammed immediately, and the accident investigation began.

Unlike the Windscale piles, the more advanced gas-cooled reactors were built with the fuel channels cut vertically, and fuel handling was semi-automated to prevent workers from having to get anywhere near the reactor cores. The entire core was encased both in a steel pseudo­sphere as protection from fission product leakage and a pressure vessel, containing the cooling gas and keeping broken fuel cartridges off the landscape. This was an excellent plan, but peeking into a fuel channel was not as easy as it was in the old days. A special television camera was built, mounted on the end of a pole that could be positioned over the burned fuel channel to look in and see what had happened. This device confirmed that the fuel channel was blocked with graphite debris and that it would have to be cleaned of this and the remains of the burned fuel, but unfortunately the camera broke off and fell into the reactor. It did everything but scream as it tumbled off into the abyss, with the monitor screen image spinning and then going black. This would complicate the repair.

It took two years, but the men at Pile No. 2 were able to design a workable plan for restoring the plant to full operation. Three men were outfitted in fully sealed radiation suits with closed respirators. Each man was given only three minutes to work, during which he would receive his entire year’s allowed radiation dose working at the top end of the core in a concentrated radiation field. One at a time, they moved quickly through the forest of control rods to the clogged fuel passage and ran a scrubber on a long pole down the hole, cleaning the passage and restoring its roundness.

The cleanout was successful, and Chapelcross Pile No. 2 resumed operation. All was good until 2001, when the Chapelcross power plants seemed to trip over a streak of bad luck.

Fuel has to be changed-out at the MAGNOX reactors at least twice a year. First, the burned fuel, blisteringly radioactive with fission products, must be pulled out of the fuel channels and lowered down a chute and into a lead coffin. This is accomplished using the discharge machine, which runs on rails on the floor of the crane room, addressing holes that are opened one at a time, giving access to the reactor below. An operator rides in a seat on the back of the machine, which weighs a hefty 60 tons. Half of that weight is lead shielding to protect the operator from what he is pulling out of the reactor, and if the machine is operating properly, the workers never see or touch the fuel cartridge.

The operator positions the discharge machine over a hole in the floor, grabs a fuel cartridge down in the reactor, and pulls it up into the shield. The machine then rolls on rails to the end of the room, where the well hoist grabs the cartridge away from the discharge machine and lowers it on a cable down five floors, through the concrete-shielded discharge well. It drops into a lead barrel, which then rolls out on rails to the transit hoist for a trip to Windscale for fuel reprocessing. After you have discharged a few hundred thousand fuel cartridges, it seems routine and foolproof; but one day early in 2001, one fuel cartridge out of 10,176 had a problem.

The operator sent the cartridge down the discharge well and into the lead barrel. For some reason it did not release, and the cable came back up, ready to snag another cartridge after it had been snaked out of the core. Instead of an empty grabber, up came a live cartridge, broadcasting gamma radiation all over the refueling floor. Alarms jangled everyone’s nerves as they leaped from the chairs on their discharge machines and hot-footed for the door. Nobody was injured by the radiation, but it was considered a serious accident, and inadequate design, improper operation of the discharge machine, and statistical probability were blamed. All refueling of the early MAGNOX reactors at Chapelcross and Calder Hall was halted while the incident was investigated.

In July 2001, the workers at Chapelcross discovered that steel drums filled with depleted uranium trioxide tend to rust and develop holes when they are left out in the rain for several years. It was decided to substitute stainless steel barrels.

Later in July, corrections to the problem experienced earlier that year, when a fuel cartridge grabber would not let go, seemed to cause the opposite problem. After hearing something heavy crash into the door at the bottom of the discharge well, investigators sent a remote — controlled TV camera into the area and had a look. Twelve fuel cartridges had let go of the grabber and fallen over 80 feet into the transport barrel, splattering the irradiated uranium over the discharge bay. A careful cleanup was accomplished.

In August it was time for the annual maintenance and cleanup at Chapelcross, starting with Pile No. 1. There was a disturbing finding. It was known that graphite could “grow” in just about any direction under neutron bombardment at temperatures lower than 300°C, but in Pile No. 1 the graphite had shrunken. The pile was now not quite as tall as it had been, and the steel charging pans, designed to guide new cartridges into the core when refueling, were now hanging in space, supported perilously by the nozzles on the burst-can-detection gear. The other piles were found to have similar defects, but not as bad as Pile No. 1, which was built differently.

Only Piles 2 and 3 were in decent enough shape to be restarted. In June 2004, the entire power station was shut down for good. The sister plant, Calder Hall at Sellafield, had been shut down permanently in 2003. The British graphite reactors had made a good run of it, but they were now obsolete and it was time to call it quits. By 2004, there was no longer a need to manufacture plutonium, and better ways to build a power reactor had been developed. On May 20, 2007, at 9:00 am., the four 300-foot hyperboloid cooling towers, visible on a clear day from a distance of 50 miles, were brought down in 10 seconds by demolition explosives, and that was that.

The fuel-reprocessing industry in the UK has reported only one criticality accident in which fissile material managed to come together accidentally in a supercritical configuration. Just about every other country that has tried to separate plutonium from uranium in spent reactor fuel has experienced at least one such excursion, and this was Britain’s. This incident at the Windscale Works on August 24, 1970, is described by the criticality review committee at Los Alamos as “one of the most interesting and complex because of the intricate configurations involved.” An entire book could be written to describe this accident, but I will be brief.

It is the goal of every chemical engineer working on a reprocessing plant design to allow no vessel large enough or of an optimizing shape, such as a sphere or tomato can, to exist in the complicated pipe-works of a reprocessing plant. Occasionally, however, when there is no conceivable way that fissile material, such as plutonium, can collect there, a round tank finds its way into the layout. At Windscale, plutonium was recovered from spent MAGNOX fuel, and near the end of the process it was refined in 300-gram batches. The plutonium was dissolved in a mixture of tributyl phosphate and kerosene and fed to a conditioner vessel, where the amount of plutonium in solution was adjusted to between 6 and 7 grams per liter. This was safely less than the concentration required for criticality.

From there, the small batch was lifted through a pipe to a transfer vessel by vacuum, where it would be fed through a U-shaped trap to a refining operation called the pulsed column. The transfer vessel was a short, cylindrical tank having hemispherical top and bottom. It was a near-perfect size and shape to house an impromptu reactor, but surely no such concentration of fissile material could be fed to it from the conditioner in one gulp, and the trap prevented any backflow into it. It was a mistake to think this.

It turned out that after every transfer of a subcritical amount of plutonium to the transfer vessel, a small amount of plutonium was stripped out of the solution by water sitting in the bottom of the tank. Ordinarily, that would be no problem, because the concentration of plutonium in the tank would never be greater than 7 grams per liter of solvent, but the amount of plutonium dissolved in the water grew gradually. This went on for two years, until the bottom of the tank held a whopping 2.15 kilograms of fissile plutonium-239.

On the last batch through the system, 30 grams of plutonium were dumped in on top of the water, mixing the solvent and water together and causing a supercritical nuclear reactor to suddenly exist in the plumbing for 10 seconds.

It was not a fatal accident. Nobody was injured, and the intricate piping in the plant looked exactly the same before and after the supercriticality, but the fact that it happened in such a carefully designed process was unnerving. It goes down in history as proof of how difficult it is to predict what will happen in a maze of pipes, valves, tanks, and traps carrying a fluid for which its volume and shape are important. The concept of impossibility becomes murky.

Windscale became Sellafield, and the THORP, or the Thermal Oxide Reprocessing Plant, became operational in 1997. It took 19 years to build the facility at the place formerly known as Windscale. Its mission is to take used reactor fuel from Britain, Germany, and Japan and separate it into 96% uranium, 1% plutonium, and 3% radioactive waste, using a modified PUREX process.

In July 2004, a pipe broke and started filling the basement with highly radioactive, pre­processed fuel dissolved in nitric acid. The loss of inventory after nine months had climbed to 18,250 gallons. This went unnoticed until staff reported the discrepancy between solution going out of one tank and not arriving in another tank.

As it turned out, the liquid flow was monitored by weighing it periodically in an “accountancy tank.” This tank had to be free to move up and down as it accumulated the heavy uranium — plutonium waste in dissolved form, and the extent of sag as it filled was translated into weight. As the tank was being installed, it was decided to leave off the restraints that would keep it from wagging side to side as it accumulated liquid. This move, thought to protect it in case of earthquake, proved to be too much for the pipe connecting it to another process downstream, and it broke under the floor where it could not be seen.

On April 19, 2005, a remote TV camera was sent down to see what was going on, and it confirmed that the radioactive soup had formed a lake in the secondary containment under the Feed Clarification Cell. The spill was nicely contained in the stainless steel liner of the containment structure, but it contained 44,092 pounds of uranium, 353 pounds of plutonium, and 1,378 pounds of fission products. It was the fission products that made it a problem, as no human being would ever be able to enter the room and repair the broken pipe, even when the solution was removed using existing steam ejectors. The only possibility is to repair the break using a robot, but building a mechanical plumber is proving to be difficult. THORP will possibly complete its existing reprocessing contracts, bypassing the accountancy tank, and close down in 2018.

The history of atomic accidents in Britain is thus a story of ambition, impatience, originality, and accomplishment under hard circumstances, marked by a spectacular incident the year that David Lean filmed The Bridge on the River Kwai. If you find yourself cornered by a force of Brits who rib you mercilessly about the SL-1 explosion, it is correct to remind them of the British Blue Peacock nuclear weapon, in which the batteries were kept warm by two chickens living in

the electronics module aft of the warhead. It is an effective diversion, and it is almost true.133

114I am not sure what “PCE” means. It was possibly a typographical error in the original memo, meant to be “PEC,” or Production Executive Committee.

115See the film at http://dvice. com/archives/2012/07/this-is-what-st. php.

116Two of the men, Luttrell and Yoshitake, are still alive, although all six participants eventually suffered from cancer. It is doubtful that any disease was caused by standing under Shot John. It was only a short pulse of radiation that hit them, and not the chronic exposure that can cause cancer. They as well as the majority of soldiers in the armed forces, smoked tobacco, and this dangerous habit typically overwhelms any signal of radiation-induced cancer in the thousands of nuclear test participants. The study of cancer in Cold War veterans continues.

117Superman finds that his few seconds in front of the reactor face have infused him with radiation, and he must exile himself to prevent harm to anyone around him. It has been over 55 years since I saw that episode, but I also remember the radiation making noise and electrical sparks, all of which is wrong. However, episode 69, “Peril,” has Perry White, the editor of the Daily Planet, exercising his inner scientist by engaging in astonishingly prescient nuclear research. Perry is working on a process that extracts uranium from seawater, named “formula U183.” A large percentage of the Earth’s available uranium is dissolved in the ocean, and Japanese scientists are currently working on a system to extract it for use in power reactors. I have been advised of their secret uranium-extraction filter material, but there is not room in this footnote to discuss it.

118An updated replica of the X-10 was built at the Brookhaven National Laboratory in 1948, and it was in constant use for research until final shutdown in 1968. The Brookhaven Graphite Research Reactor was not a military secret, and newsreels showing workers pushing fuel rods or experiment samples into the holes on its front can be difficult to distinguish from similar films made at X-10. I think that the power-scram point on the X-10 was set for 1.8 megawatts.

119All was not lost. Some leeway was granted quietly in 1948 by an agreement called the “Modus Vivendi.” It allowed American scientists to tell their British colleagues that they were perhaps going in the wrong direction in their bomb-production development, but not exactly how.

120GLEEP was initially thought to be the first working reactor in the Eastern Hemisphere, but the Soviets had beaten them to it. The F-1, which was an excellent copy of the Hanford 305 plutonium production reactor, first started up at 6:00 P. M. local time on Christmas Day 1946. The Soviet espionage network, which was second to none, obtained the plans for this top secret system at the Hanford Works, and this was a short-cut to production without a lot of rediscovery and experimental development as was necessary in the UK.

121No published plan diagram of the Windscale reactors shows the blowers. That is because the blowers were located in two separate buildings per reactor, one left and one right, connected by large concrete tunnels. The Windscale reactors are still there and can be seen on Google Earth. Windscale Unit 1 is at latitude 54.423796°, longitude -3.496658°. The stack on Unit 1 has been torn down and the base is filled with concrete. Unit 2, to the left of Unit 1, looks complete, but the west-side blower building has been torn down and made into a parking lot.

122The Canadians did indeed supply plutonium for the time-critical atomic bomb project, but unlike the Windscale reactors, the NRX reactor at Chalk River was not designed specifically to make Pu-239. The Windscale pile operations would purposefully run the fuel through very quickly whereas NRX would use the fuel to useful depletion. As a result, the fissile material for the bomb contained a lot of Pu-240, which fissions spontaneously and threatens to melt the bomb core before it can explode. The Brits solved this problem by using a “levitated pit,” in which the bomb core was suspended in the middle of a hollow sphere of high explosive, removing it from close contact with any neutron-reflecting material. It seemed a brilliant innovation, but the Americans had been using this design feature since 1948 in the MK-4 A-bomb, tested in Operation Sandstone.

123Inside nuclear engineering, Dr. Teller is considered to be the mother of the H-bomb and not the father because he “took it to full term.”

124The operating power of a Windscale reactor has never been published, but near as I can tell it was 90 days between anneal no. 8 and anneal no. 9 on Pile No. 1. The plutonium/tritium production was so pressed at this time, it was decided to go 40,000 megawatt days between anneals for no. 9. Assuming that Pile No. 1 ran 24/7, a power rating of over 400 megawatts can be calculated. That is a lot of power for an air-cooled reactor.

125The piles were also loaded with LM cartridges. These special canisters were used to produce polonium-210 from neutron capture in bismuth oxide for use in A-bomb triggers. The LM cans were not considered flammable.

126I am told that Short Granite was a full-scale two-stage hydrogen bomb weighing 4,550 kilograms, and the active fusion component had to be the light solid, lithium deuteride. So what was all the furious tritium production for if not a liquid tritium-deuterium bomb? A tritium-based two-stage thermonuclear weapon, such as the American EC-16, would weigh about 32,000 kilograms, which would have nailed the Vickers Valiant bomber to the ground. As it turns out, the tritium production in the Windscale piles was not for the Short Granite bomb. It was used in the electrically driven neutron generator, or “initiator,” used in the A-bomb “Orange Herald,” tested over Malden Island on May 31, 1957. Short Granite used a beryllium — polonium solid-state initiator, made using the polonium-210 produced in the Windscale piles in the LM cartridges. The accelerated production at Windscale was to make bomb-trigger components.

127An interesting bit of trivia from B. J. Marsden of the Nuclear Graphite Research Group at the University of Manchester: the refueling platforms at the Windscale reactors, called “charging hoists,” were airplane elevators salvaged from WWII aircraft carriers.

128There was also a great deal of radioactive xenon-133 gas released at Windscale, 16 times more than the iodine-131. This sounds terrible to the general public, but xenon-133 has zero body burden and it cannot react chemically with anything, unlike iodine-131. Animal body chemistry has no use for xenon. The xenon-133 floats away and decays to stable cadmium with a half-life of 5.24 days. There is no xenon filter, and radioactive xenon escapes regularly from every nuclear power plant in the world.

129There are also reports that the milk was diluted with water and then dumped into the Irish Sea. It seems a bit odd to dilute it with water before pouring it into the ocean, and the aroma of decomposing milk was mentioned in local newspapers. It’s possible that farmers who were not found to have contaminated milk disposed of it anyway on their own initiatives, but more likely they took advantage of the inflated milk prices and sold it.

130See an interesting British documentary on the Windscale fire from 2007 at http://www. youtube. com/watch? v=ElotW9oKv1s&feature=relmfu. Some important technical details are garbled, and the recreated scenes of men working at the loading face are seriously wrong.

131The actual cause of the Windscale fire remains a controversial and unresolved topic. It is probable that it was started in an isotope channel by one of the many AM cartridges, which were the most temperature-sensitive components in the entire pile. There was one isotope channel for every four fuel channels, and when you opened an access plug, the isotope channel was in the center, with four fuel channels surrounding it. The first man to open plug 20-53 reported that “it was glowing bright red, and so were the four channels around it.” It is often assumed that the center hole was a fuel channel, but clearly he was referring to the isotope channel behind 20-53.

132Quoting the OSHA Occupational Safety and Health Guidelines for Uranium and Insoluble Compounds, under Reactivity: “Contact of uranium with carbon dioxide causes fires and explosions.” The carbon dioxide coolant probably protected against graphite fires, but it was dangerous in contact with metallic uranium. Ironically, the suggested method for putting out a uranium fire is to smother it with graphite chips.

133Although the use of live chickens, installed with a one-week supply of food and water, as a heat source was a serious proposal for the Blue Peacock

(originally Blue Bunny) in October 1954, accounts of its implementation are difficult to find. Unfortunately this specification was declassified on April 1, 2004, and it was immediately assumed to be an April fool’s joke. Tom O’Leary head of Education and Interpretation at the National Archives, responded with: “The civil service does not do jokes.”

Chapter 6

"If the oceans were filled with liquid sodium, then some crazy scientist would want to build a water-cooled reactor.”

—Hyman Rickover, grousing about the sodium-cooled USS Seawolf

Admiral Hyman Rickover pushed his passion for a nuclear-powered submarine as hard as he could without being formally charged with criminal intent, and he was rewarded with one of the most successful projects in the history of engineering. His finished prototype submarine, the USS Nautilus, was all that he had hoped. First put to sea at 11:00 a. m. on January 17, 1955, she broke every existing record of submersible boat performance, made all anti-submarine tactics obsolete, and never endangered a crew member.

At the end of World War II the Navy, whether it knew it or not, was ready for the improved submarine power plant of a nuclear reactor. All the groundwork was in place after the Army’s startling success in the development of atomic bombs and the infrastructure for their manufacture. As an engineering exercise, the task of reducing the size of a power reactor from that of a two-story townhouse to something that would fit in a large sewer pipe was seen as possible, but there were a couple of serious considerations.

First, there was the nagging dread of a steam explosion. It was one thing to lose a boiler or two on a battleship, but in the tightly confined spaces of a submarine everyone would be killed and the boat lost if a steam line broke. If a reactor were to lapse into runaway mode, the water coolant could flash into high-pressure steam and tear the sub in half under water. Experience was in short supply and it was hard to convince mechanical engineers that this was a very unlikely occurrence in those early years of nuclear power. The use of water in the primary coolant loop was considered too dangerous to pursue.

Second, in the early 1950s there was concern over the availability of uranium as reactor fuel. To build exactly one uranium bomb in World War II the United States depended on all the uranium ore that could be mined in the Belgian Congo and Canada. There was no guarantee that enough uranium would ever be available to power a fleet of submarines, even from multiple foreign sources working at maximum efficiency. Plutonium, on the other hand, was a perfectly good power reactor fuel and we had plenty of it. It was manufactured at the Hanford Works in Washington State. It was therefore obvious that a nuclear submarine should be fueled with plutonium, and to fission plutonium fast neutrons were optimal. It was best to have no neutron moderation in a plutonium reactor, and this meant that there could be no water coolant in the primary loop. The coolant would have to be something heavy and liquid, such as melted metallic sodium. It would run hot and thermally efficient at atmospheric pressure, putting no expansive stress on pipes and associated hardware.

Rickover strongly disagreed with this “fast reactor” philosophy. Unlike many engineers assigned to the nuclear submarine project, Rickover had paid his dues riding around in the

ocean in submarines S-9 and S-48, which were feeble death-traps built in the 1920s.134 He knew from miserable experience and alert observation that there is no such thing in a submarine as a pipe, tank, flange, or valve that will never leak. In fact, with the combined stresses of being crushed, twisted, hammered, vibrated, abused, and built by the lowest bidder, a submarine’s bilge ditch would slosh with a sickening mixture of sea water, diesel fuel, sweat, lubricating oil, salad dressing, vomit, battery acid, head overflow, and coffee. Anything in the boat that conducted or contained compressed air or any fluid was capable of leaking, regardless of how well it was welded together or tightened with threaded fasteners. The captain in an S-boat had to wear a raincoat when operating the periscope, and dampness covered every surface inside the craft. Running in cold water meant that standing in the control room you could peer down the centerline and lose sight of the end of the compartment in the fog.

The concept of cooling an engine with liquid sodium thus seemed wrongheaded to this experienced submariner. The slightest sodium leakage would react with water or with water vapor in the air, burning vigorously and leaving a highly corrosive, flesh-eating sodium hydroxide ash. Sailors could perish just from breathing the hot vapor. Furthermore, Rickover had confidence that when there is an attractive price put on a mineral, such as uranium ore, people will dig up the earth to find it. In time he would be proven correct on both issues, the difficulties of using sodium and the abundance of uranium. With the safety of the crew being his primary design factor, his uranium-fueled pressurized-water reactor became the standard for submarine propulsion and for most of the civilian nuclear power industry. With a well-trained and disciplined reactor operations crew, there was no safer way to generate power in a confined space.

There were several experimental liquid-metal cooled and breeder reactors built in the United States, beginning in 1945 with Clementine, and unforeseen problems with these exotic designs

were experienced. Never was a serious sodium leakage encountered.135

The United States Atomic Energy Commission (AEC), starting work on January 1, 1947, had among its tasks the job of persuading private enterprise to build nuclear power plants. It was a noble goal, born of some very long-term projections. It was seen, even back in the late 1940s, that civilization would require more and more electrical power, and we could not generate it by burning coal forever. Coal and oil were seen as limited resources that were not being regenerated, and there were a finite number of rivers left to be dammed. Wind, used to make power since the days of the Roman Empire, was seen as too feeble and unreliable to meet the growing power demand, and solar power was limited to hot-water heaters in Florida. A plausible power supply for the future was nuclear fission, and it was not too early to begin an experimental phase of development.

A stellar committee met to come up with five nuclear reactor concepts to be prototyped and tested as candidates for the standard civilian power reactor. Uranium, the fuel of choice for all military reactors, was not seen as plentiful. Even if a hundred mines were dug, it was just another commodity that we would run out of eventually. Therefore, the ideal civilian nuclear power reactor would be a breeder, which paradoxically produces more fuel than it burns. Furthermore, the danger of a steam explosion should be minimized by vigorous application of the engineering art.

There are two types of breeder reactor, the fast breeder and the thermal breeder. The fast breeder runs on plutonium-239. The thermal breeder runs on uranium-233. The first of the five prototype reactor programs to be funded by the AEC in June 1954 was a sodium-cooled thermal breeder named the Sodium Reactor Experiment, or the SRE. Winner of the contract for the project was the North American Aviation’s Santa Susana Field Laboratory, located in a rocky wilderness about 35 miles northwest of Los Angeles, California, called Simi Hills.

The 2,850-acre site was divided into four sections. Three of the sections were devoted to testing high-performance rocket engines and explosives, and the fourth was populated with exotic nuclear-reactor experiments. The lab was thus blessed with all the fun stuff of the era except above-ground nuclear weapon and aircraft ejection-seat tests, and it should have been located in Idaho instead of in a place that would experience a population explosion in the next few decades. As the years passed, the valley below would jam tight with Californians, some of whom would find fault with the Santa Susana lab for no good reason other than what it was doing.

Admittedly, over the decades Santa Susana saw its share of accidents. The hot lab facility at the lab was the largest in the United States at the time. Workers could take apart highly radioactive reactor fuel assemblies using robotics behind windows three feet thick, offering complete radiation protection. Every now and then a fire would break out behind the hot-cell glass, causing massive internal contamination. The cores in four experimental reactors on site strayed outside the operating envelope and melted. Highly toxic waste disposal was handled by shooting at the barrels at a safe distance with a rifle until they exploded, sending the contents high into the air and wafting away into the valley below. In July 1994 three workers were trying to test some rocket fuel catalyst and it exploded unexpectedly, killing two, seriously injuring the

third, destroying a steel rocket fuel test stand, and setting a 15-acre brush fire.136 In 2005 a wildfire swept through Simi Hills and burned everything flammable in its path.

By April 25, 1957, the SRE was up and running and soon providing 6.5 megawatts of electricity to the Moorpark community, using a generator courtesy of Southern California Edison. It was the first civilian nuclear power consumed in the United States. In November, Edward R. Murrow featured the SRE power plant on his See It Now program on CBS television.

By current standards, the SRE was an odd power-reactor design. It was to run on fissions caused by neutrons slowed down to thermal speed, and yet the coolant was to operate at atmospheric pressure. The moderator material was graphite, a stable, solid-state material. Preventing any chance of a graphite fire, the moderator was formed into columns with a

hexagonal cross-section and covered with gas-tight, pure zirconium.137 The coolant was liquid sodium. Liquid sodium, being a dense, heat-conductive metal, is a very efficient coolant, and under foreseeable operating conditions, it never boils or produces dangerous gas pressure, as could water. It does, however, absorb an occasional neutron in a non-productive way, to much the same extent as ordinary water. Although the ultimate purpose of the SRE was to begin development of a civilian thermal breeder, its first fuel loading would be metallic uranium, slightly enriched to make up for the neutron losses in the coolant. As the basic configuration was proven by experiments, thorium-232 breeding material and uranium-233 fuel would be

introduced later.138

The Sodium Reactor Experiment ran with a graphite moderator at very high temperature, giving an efficient means to make high — pressure steam. The coolant was liquid sodium, which would never boil away, could operate at atmospheric pressure, and would never react chemically with the graphite. It was a sound concept, but the problems of dealing with a flowing liquid metal that reacts explosively with water have plagued reactors with sodium-based coolants.

There was another good reason to use sodium instead of water as the coolant. In water — cooled graphite reactors, such as the plutonium production reactors at Hanford, the unintended loss of coolant in the reactor always improves the neutron population, and the reactivity of the pile increases. The power starts going up without human intention. Graphite is a near-perfect moderator material, and any action that reduces the amount of non-graphite in a reactor, including the formation of steam bubbles, is fission-favorable. There was no such worry if sodium, with a boiling point of 1,621°F, were used instead of water. With an intended coolant outlet temperature of 650°F at full power, bubble formation in the reactor was hardly a concern, and the reactor could operate at an ideal temperature for external steam production while running under no pressure at all.

It was early in the history of power reactor development, and there were few successful plans to draw on, so there were novelties in the SRE embodiment. At least one aspect of the plan, the sodium pumps, seemed sub-optimal. The EBR-I sodium-cooled breeder reactor in Idaho had been built back in 1951 using exceedingly clever magnetic induction pumps for the coolant. A sodium pump in this system was simply a modified section of pipe, having a copper electrode on either side of the inner channel. A direct current was applied to the electrodes with a static magnetic field running vertically through the pipe, and the electrically conductive liquid metal was dragged along through the pipe by the same induced force that turns the starter motor on a car. The pump had no moving parts. EBR-I reported no problems using induction pumps, but the EBR-I was producing a scant 200 kilowatts of electricity.

For the SRE, hot oil pumps used in gasoline refineries were used to push the sodium.139 A large electric motor, capable of moving molten sodium at 1,480 gallons per minute up a vertical pipe 60 feet high, turned a long steel shaft, ending in a turbo impeller in a tightly sealed metal case. A single, liquid-cooled ball bearing supported the working end of the shaft. The problem of keeping liquid sodium from leaking past the impeller and into the bearing was solved by modifying the end of the pump. The shaft was sealed with a ring of sodium, frozen solid in place by a separate cooling system. The coolant to be pumped into the seal could not, of course, be water, which would react enthusiastically with the sodium. It had to be a liquid that had zero trouble being next to sodium. Tetralin was chosen.

1,2,3,4-tetradhydronapthalene, or “tetralin,” is a solvent, similar to paint thinner you would buy at the hardware store, first synthesized by Auguste George Darzens in 1926. Its molecule is ten carbon atoms and a dozen hydrogens, looking like two benzene rings stuck together. It has no particular problem with sodium, and it evaporates at about 403°F. The tetralin was circulated through the sodium seal, keeping it solidified, in a continuous loop using two parallel evaporation coolers to shed the heat from the seal. Electrically driven pumps kept it moving, with a gasoline engine for a backup in case of an electrical failure. It was a complicated sub­system in a complicated power plant, requiring pipes, valves, pumps, wiring, instrumentation, tanks, and coolers, just to keep the sodium off the pump bearings. The fact that it had to be backed up was ominous. It is always a better system when if everything fails, the wreckage reduces to an inert, safe condition.

The cooling system used three closed loops. The primary loop was liquid sodium running through the reactor. The natural sodium was constantly being activated into radioactive sodium — 24 by contact with the neutrons in the reactor. To eliminate the potential accident of radioactive sodium leaking into the steam system, a second sodium loop took the heat from the first loop and took it outside the reactor building, where it was used to generate steam for the turbo­generator in a water loop. For low-power experiments in which electrical power was not generated, the water loop was diverted into an air-blast heat exchanger, dumping all the power into the atmosphere. There was no danger of broken or melted fuel leaking radioactive fission products into the surroundings, as the second sodium loop was a well-designed buffer. No expensive containment structure was needed for the reactor, because there was no chance of a radiation-scattering steam explosion in the building. The steam was generated out in the yard, and it was not connected directly to the reactor.

Radioactive gases produced by fission, such as vaporized iodine-131 and xenon-135, were controlled in the stainless steel reactor tank by a bellows structure at the top, giving the tightly sealed system room to expand. Helium was kept over the reactor core to prevent air from leaking in and reacting with the sodium. The fission gases were piped off and compressed into holding tanks for controlled release into the environment after having been held long enough for the radioactivity to have decayed away. There were outer space reactors, rocket engines, and military systems being developed at Santa Susana, and all had their considerations of performance, weight, and reliability, but this SRE was to be a prototype civilian power plant. As such, the prevention of harm to the public was a primary and noble design consideration.

All newly designed sub-systems were actively tested at Santa Susana before they were integrated into this new type of power reactor. It was an experimental setup stacked with many unknowns, and there was a lot to learn about graphite-moderated, sodium-cooled reactors. The operation log shows that almost immediately there was trouble with the sodium pumps. Hours after the first power startup on April 25, 1957, the shaft seal on the main primary pump failed. A few weeks later, tetralin was leaking from an auxiliary secondary pump. A week later, the main secondary pump was replaced. In August, the sodium was found to be contaminated with tetralin. In November, the cold trap was clogged with sodium oxide. Air was getting in somewhere. In January 1958, sodium smoke filled the high bay, and men had to go in with oxygen masks to find the leaking bellows valves. In May the shaft seal on an auxiliary primary pump failed, and out of a main primary pump they could smell the strong odor of tetralin. Two months later all the pumps were taken apart and the ball bearings were replaced. The entire main primary pump was replaced with a spare. A month later, the electromagnetic pump clogged with sodium oxide again, and in September the main secondary pump was leaking tetralin. By April 1959 the main primary pump was leaking tetralin from the sodium seal, and the entire unit had to be replaced. A month later, a tetralin fire was extinguished without causing

reportable damage.140

So, pumping sodium around in a nuclear reactor was not as easy as it seemed on paper, and the SRE was being taken apart and worked on all the time. That is the life of an experimental reactor, and Rickover’s insistence on no sodium in his precious Nautilus seemed to make sense if you were outside looking in. Every time a component from the reactor tank or the primary coolant loop was removed for repair or examination, the sodium frozen to it had to be cleaned off. For this purpose, the pump or the fuel assembly was moved to the wash cell, a special setup behind an atmospherically sealed hot-cell window. Using remote arms, a technician would hose down the sodium coating with warm water. It would instantly turn into hot sodium hydroxide and wash down the drain at the bottom of the stainless steel hot-cell chamber, leaving the once-contaminated piece bright and sparkling clean.

Real trouble did not start until RUN 13, from May 27, 1959 to June 3, 1959. The crew was supposed to run the coolant outlet temperature up to 1,000°F to see if the system could stand to work at higher power. They hoped to log 150 megawatt days. All was well until two days after startup at 11:24 a. m., when the reactor scrammed due to an abnormal sodium flow rate. Not hesitating to contemplate why the flow rate was wrong, the operating crew restarted the reactor immediately and ran it back up to power. There it stayed until 9:00 the next morning, May 30. At that point, the reactor system went squirrelly.

First, the reactor inlet temperature began to rise slowly over three days. On June 1, the temperature difference across the heat exchanger rose sharply, indicating that something wasn’t working. The thermocouple in one fuel assembly, number 67, showed a temperature increase from a normal 860°F to 945°F. The temperature in the graphite abruptly jumped by 30°F, also on May 30, and the thermocouple in fuel assembly number 16 showed a similar increase in temperature. They did not notice it at the time, but the automatic control-rod positioner was compensating for a slow increase in reactivity in the reactor. Obviously, something had occurred that was impairing the coolant flow, and by June 2 the main primary pump casing was reeking of leaking tetralin. The reactor was shut down on June 3 to examine the fuel and repair the coolant pump.

As the pump was being torn down, fuel assembly number 56 was removed using the impressive automatic fuel-removal machine and transferred to the wash cell for examination. To quote the accident report exactly, “During the washing operation a pressure excursion occurred of sufficient magnitude to sever the fuel hanger rod and lift the shield plug out of the wash cell.” Translation: The damned thing exploded and put the wash cell out of commission for a year.

Nobody was killed, thanks to the three-foot-thick window and aggressive ventilation.141

Retrospective analysis would find that the vent at the bottom of the fuel assembly, where coolant was supposed to flow in and past the hot fuel rods, had been blocked by a substance technically referred to as “black stuff,” and this left a large remainder of sodium in the bottom of the assembly. When the technician aimed the hose into the top of the assembly, the big sodium wad went off like a hand grenade. This was not noted at the time, and number 56 was put back in the reactor. Damage to the wash cell diverted attention from further identification of the black stuff, but a working explanation was that it was residue from tetralin decomposed in the hot coolant. There was not supposed to be any tetralin in the coolant, but three pints of it were found in the cold trap plus a couple of quarts of naphthalene crystals, or tetralin with the extra hydrogens stripped off. No connection in particular was seen between these contaminations and the strange behavior at the end of RUN 13. The troublesome tetralin-cooled seal on one pump, the main primary, was replaced with a nack-cooled sodium seal, and the reactor was

ready for RUN 14.142

RUN 14 was started on July 12, 1959. The experimenters expected some trouble with the fuel-channel outlet temperature, but they were not sure why. Perhaps if they could intensify the effect, the cause would snap into focus. The reactor was brought smoothly to criticality at 6:50 am. At 8:35 they increased the power level to a modest 500 kilowatts, and the graphite temperature started to flop around wildly, running up and down by about 10°F, and various fuel — channel temperatures started to diverge by 200°F. Not seeing this as a problem, they kept going until 11:42 when the reactor, hinting that something was amiss, scrammed due to a loss of sodium flow in the primary loop.

At this point I must find fault with the way they were operating the SRE. Something about the reactor was not working, and yet they kept restarting it without knowing why. Today, this disregard of trouble signs would be unheard of, I hope. You would never restart a reactor without knowing exactly why it scrammed. There would be inquiries, hearings, lost licenses, and firings, but apparently not in 1959, when the screws of bureaucracy weren’t tightened as they seem now. Start her up again and let’s see if that was just a fluke. By 12:15 they had SRE back up to power and were increasing the power and the outlet temperature. At 1.5 megawatts the temperature was fluctuating inexplicably by 30°F.

At 3:30 P. M., both air-radiation monitors in the reactor building indicated a sharp rise in activity. By 5:00 P. M., radioactive air was going up the exhaust stack and into the atmosphere, and the radiation level over coolant channel seven was extremely high, at 25 roentgens per hour. Something had obviously broken, but for some reason it did not occur to the experimenters that radioactive products that would cause such an indication are produced in the fuel, and the fuel is welded up tight in stainless steel tubes. If all the fuel is intact, then nothing radioactive should be leaking into a coolant channel, and certainly not through the gas-tight reactor vessel and into the air in the room. By 8:57 P. M. they had shut down the reactor. They fixed the problem of leaking radioisotopes by replacing the sodium-level indicator over channel seven with a shield plug, and they restarted the reactor at 4:40 am. the next day, July 13.

By 1:30 that afternoon, they noticed that the graphite temperature was not going down when they increased the coolant flow. They knew not why. At 5:28 P. M., they were running at 1.6 megawatts and commenced a controlled power increase. The power seemed to increase faster than one would expect up to 4.2 megawatts, but then the reactor went suddenly subcritical and the power was dropping away. They started pulling controls to bring it back, and by 6:21 P. M. they had managed to coax it to run at 3.0 megawatts.

Up to this point, the reactor had been recalcitrant and unusual, but now it went rogue. Power started to run away. Control-rod motion was quickly turned around, sending them back into the reactor to soak up neutrons and stop the power increase. Instead, the power rise speeded up. By 6:25 P. M., the power was on a 7.5-second period, or increasing by a factor of 2.7 every 7.5 seconds. The fission process was out of control, and a glance at the power meter showed 24 megawatts and climbing.

Deducing that if this trend continued, then in a few minutes the reactor would be a gurgling puddle in the floor, the operator palmed the scram button, throwing in all the controls in the reactor at once and bringing the errant fissions to a stop.

As the reactor cooled down, only one question came up: Why was there not an automatic scram when the reactor period, spiraling down out of control, passed 10 seconds? The period recorder, which leaves a blue-line-on-paper graph of period versus time for posterity, had a switch that was supposed to be tripped when the pen hit 10 seconds on the horizontal recorder

scale. This switch was supposed to trigger an automatic scram.143 Testing found that the switch would have worked, but only if the period had been falling slowly. The trip-cam was modified so that the switch would operate even when a scram was most needed, with the period falling rapidly.

Seeing nothing else to fix, the operating staff brought the reactor back to criticality at 7:55 P. M. and proceeded to increase the power. By 7:00 am. the next morning, July 14, they were running hot, straight, and normal at 4.0 megawatts. Two hours later, the radioactivity in the reactor building was reading at 14,000 counts per minute on the air monitors. Technicians put duct tape over places where fission products were found escaping. There was only one other automatic scram for the whole rest of the day, when workers setting up a test of the main primary sodium pump accidentally short-circuited something.

On July 15, it was seen as pointless to be trying to run the electrical generator while trying to test at high temperature, so the staff drained out the secondary coolant loop and switched to the air-blast heat exchanger. The next day, at 7:04 am., the SRE was made critical once more. On July 18, the motor-generator set, which was supposed to prevent power surges into the control room instruments, failed. The operators switched power to unstabilized house current and continued operation. At 2:10 a. m. on July 21, the reactor scrammed suddenly, having picked up another fast power rise. The scram was attributed to the unstabilized power, and the reactor was restarted 15 minutes later. One more scram at 9:45 am.

The next day, July 22, channel 55 was giving trouble. This assembly contained various experimental fuels, and the temperature was fluctuating in the 1,100 to 1,200°F range. There was only one automatic scram on July 23, probably just a fluke, but by 1:00 PM. the temperature in channel 55 was up to an eyebrow-raising 1,465°F. Operation continued. In the early morning on July 24, eight hours were spent trying to dislodge some apparent debris stuck in the fuel channels by jiggling the assemblies. It was noted in passing that four of the fuel modules seemed jammed and stuck firmly in place. There were two annoying automatic scrams later that day.

At 11:20 am., the Sodium Reactor Experiment RUN 14 was terminated, and the long-suffering machinery was allowed to rest quietly while the experimenters poked around in the core with a television camera. To their surprise, they found that the core of a nuclear reactor that had been acting oddly for six weeks, subjected to overheating and temperature fluctuations, many automatic scrams, pump seal coolant failures, oxidizing sodium, radiation leakage, and a power runaway, was wrecked. Of the 43 sealed, stainless-steel fuel rods in the core, 13 had fallen apart, scattering loose fuel into the bottom of the reactor vessel. How the thing had managed to run at all under this condition was an amazement in itself. Attempts to remove the fuel rods came to an end when the contents of channel 12 became firmly jammed in the fuel handling cask. An investigation of the damage and its cause was started immediately.

The interim report, “SRE Fuel Element Damage,” was issued on November 15, 1959. It was found that tetralin had been leaking into the sodium coolant through the frozen sodium seals in the pumps. In the high-temperature environment of the active reactor core, the solvent had decomposed into a hard, black substance, which would tend to stick in the lower inlet nozzles of the graphite/fuel modules and prevent coolant from flowing. In the blocked coolant channels, the sodium vaporized, which had been thought unlikely, and denied coolant to the fuel. The stainless steel covering the cylindrical fuel slugs melted, and structural integrity of the fuel assemblies was lost. Naked uranium fuel, having fissioned for hundreds of megawatt-hours, was able to mix with the coolant. Gaseous fission products presumably escaped the sealed reactor vessel, probably through the same leakpoint that allowed the sodium to oxidize, and other fission waste dissolved in the coolant, making the primary loop radioactive.

The most puzzling part of these findings was: Why did the stainless steel melt instead of the metallic uranium? The 304 stainless used for fuel cladding melts at 2,642°F, and the temperature in the reactor was nowhere close to that. Uranium melts at 2,060°F, and yet the stainless steel melted away, leaving the uranium unclad and unsupported. The fuel assemblies were, however, operating at temperatures for which the reactor was not designed. Where fuel slugs within the tubes were leaning against the inner walls, uranium diffused into the stainless steel, making a new alloy, a stainless steel/uranium eutectic. This uranium/steel mixture melts at 1,340°F, so with the reactor core overheating, the fuel assemblies fell apart. This problem would have been hard to foresee.

Another puzzle was harder to figure out. Why did the reactor run away, increasing power on a short period? The power excursion was simulated using the AIREK generalized reactor-kinetics code running on an IBM 704 mainframe. If the parameters were tweaked hard enough, the simulation could even be forced to agree with the recorded data, but even a well-tuned digital simulation could not indicate why the transient had occurred. It was easier to explain the subcritical plunge than the short-period lift-off. Further calculations and physical experiments proved that it was the sodium void in the blocked coolant channels that caused the fission process to run wild. It was the same phenomenon that caused the fuel assemblies to melt. Graphite is a better neutron moderator than just about anything, and the fission process improves when there is no other substance, such as coolant, in the way.

Those inert, radioactive gases produced in the accident that had not leaked out and made it up the exhaust stack, xenon-135 and krypton-85, were kept in holding tanks for a few weeks for the radiation to decay away and then slowly released up the stack and into the environment. The iodine isotopes had apparently reacted with something in the building and were not found in the released gas. On August 29, 1959, a news release was issued to the Associated Press, United Press International, The Wall Street Journal, and seven local newspapers, informing the public of the incident. The wording tended to downplay it to the point that one would wonder what made it news, beginning with “During inspection of the fuel elements on July 26 … a parted fuel element was observed.” So? What’s a “parted fuel element”? No big deal was made.

The SRE fuel melt was a unique accident, and yet it was typical. It was unique in that so many obvious trouble clues were ignored for so long. I am not aware of another incident quite like this. It was typical of reactor accidents in that nobody was hurt, and the only way you could tell from looking at it that something had happened was to take it apart. As in many cases of reactor accidents, the fuel was damaged by a lack of coolant. There was no steam explosion. Lessons were learned, extensive modifications were made to the system to improve its reliability. For the newly funded SRE Power Expansion Program, the hot-oil pumps were junked and Hallum-type primary and secondary sodium pumps were installed, and SRE was restarted

on September 7, I960.144 It ran well, generating 37 gigawatt-hours of electricity for the Moore Park community. It last ran on February 15, 1964, and decommissioning of the nuclear components was started in 1976. In 1999, the last remainder of the Sodium Reactor Experiment was cleaned off Simi Hills. The idea of a graphite-sodium reactor died.

Real trouble did not begin until February 2004, when locals filed a class action lawsuit against the Santa Susana Field Laboratory’s current owner, The Boeing Company, for causing harm to people with the Sodium Reactor Experiment. They had been stirred to action by a new analysis of the 1959 incident by Dr. Arjun Makhijani, an electrical engineer. In a way, the suit was like building a house in the glide path of an airport and then suing because airplanes were found to be flying low overhead. When Santa Susana was built, Simi Valley was a dry, desert-like landscape. Makhijani estimated that the accident released 260 times more iodine-131 than the Three Mile Island core melt in Pennsylvania in 1979, which speaks well of Three Mile Island. His estimate was speculative, because no iodine-131 contamination could be detected at the time. Over 99% of the volatile isotope was captured as it bubbled up out of the naked fuel into the coolant, becoming solid sodium iodide, which collected in the cold trap in the primary cooling loop. Any pollutant that might have made its way up the stack was diluted in the air, and 80 days later there could be no detectable trace, as if there were any to begin with. There were no milk cows living in Simi Valley and no edible grass to contaminate. There was no detectable thyroid cancer epidemic. Nobody was hurt. Boeing settled with a large payout to nearby residents.

In those early decades of nuclear power, it was an unwritten rule in the AEC that the public was not to be burdened with radiation release figures or the mention of minor contamination. It was true that the general population had no training in nuclear physics and radiation effects, and if given numbers with error bars and a map of an airborne radiation plume, imaginations could take control in nonproductive ways. Nobody wanted to cause a panic or unwarranted anguish or to undermine the public’s fragile confidence in government-sponsored research. The results of such a policy are worse than what it is trying to forestall, as the government is commonly accused of purposefully withholding information, and misinformation rushes in to fill the vacuum. Conspiracy theories thrive. This fundamental problem of nuclear work has yet to be turned around.

Our next adventure in sodium takes us to Lagoona Beach, which sounds like a secluded spot somewhere in Hawaii, but it’s not. It is in Frenchtown Charter Township, Michigan, 27.8 miles from downtown Detroit, looking out onto Lake Erie.

Walker Lee Cisler was born on October 8, 1897, in Marietta, Ohio. An exceptionally bright student, Cisler sealed his fate by receiving an engineering degree at Cornell University in 1922. With that credential, he was hired at the Public Service Electric and Gas Company in New Jersey, was named chief of the Equipment Production branch of the U. S. War Production Board in 1941, and in 1943 was tapped as the chief engineer for Detroit Edison.

In 1944 he joined the Supreme Headquarters, Allied Expeditionary Force (SHAEF) in Europe, assigned the task of rebuilding the electrical power systems on the continent as the German army retreated. By 1945, he had the power system in France generating more electricity than it had before the war. Impressed, the early embodiment of the AEC named him secretary of the AEC Industrial Advisory group in 1947. Resuming work at Detroit Edison, he became president in 1951 and CEO in 1954.

As a visionary, pushing for a greater and everlasting energy supply in his native land, Cisler became an early advocate of the breeder reactor concept, and by October 1952 he established the Nuclear Power Development Department at Detroit Edison. His dream of a civilian-owned, commercial breeder played right into the AEC plans, and it was the second breeder concept in their set of demonstration power reactors to be built. The first, the thermal U-233 breeder, would be built at Santa Susanna. The second, the fast plutonium breeder, would be Cisler’s baby. A kick-off meeting was held with the AEC at Detroit Edison on November 10, 1954. Present at the meeting was Walter Zinn, the scientist who headed the slightly melted EBR-I project at National Reactor Testing Station in Idaho. The plant would be named Fermi 1, in honor of the man whose name, along with Leo Szilard’s, was on the patent for the original nuclear reactor. Ground was broken at Lagoona Beach in 1956, after Cisler had secured $5 million in equipment and design work from the AEC and a $50 million commitment from Detroit Edison.

It would be a long crawl to implementation of Cisler’s plan, fraught with ballooning costs, many engineering novelties, and strong opposition to the project by Walter Reuther. Reuther was an interesting fellow. A card-carrying Socialist Party member, anti-Stalinist, and a fine tool & die machinist, he became a United Auto Workers organizer/hell-raiser and was attacked by a phalanx of Ford Motor Company security personnel in the “Battle of the Overpass” in 1937.

This, at the very least, made him a well-known figure in Detroit.145 Reuther, the UAW, and eventually the AFL-CIO filed suit after suit opposed to the building permit for the plant and later the operating license, based on multiple safety concerns and the fact that it was not an automobile. The suits ate up a vast amount of time and money, and court decisions finding against Fermi 1 were taken all the way to the Supreme Court. In the summer of 1961, the court decided seven to two in favor of Cisler, the AEC, and Detroit Edison. Construction could proceed, and the projected cost had risen to $70 million.

Because Fermi 1 was designed as a plutonium breeder, liquid sodium was chosen as the coolant. A fast breeder core was much smaller than a thermal reactor of similar power, so the coolant had to be more efficient than water, and to hit the activation cross section resonance in uranium-238, the breeding material, the fast neutrons from fission had to endure a minimum loss of speed. Sodium was the logical choice, and two sodium loops in series were used, similar to the SRE design. It doubled the complexity of the cooling system, but it ensured that no radioactive coolant could contaminate the turbo-generator.

The use of sodium made things difficult and complicated. Refueling, for example, was comparatively simple in a water-cooled reactor. To refuel a water-cooled reactor you shut it down, and after it cools a while, unbolt the vessel head, crane it off, and lay it aside. Flood the floor with water, which acts as a coolant and a radiation shield. You pick up the worn-out uranium in the core, one bundle at a time using the overhead crane, and trolley it over to the spent-fuel pool. Carefully lower new fuel bundles into the core, drain the water off the floor, and replace the steel dome atop the reactor vessel. You’re done.

There is no way to do this with a sodium-cooled system. For one thing, the sodium gets radioactive running in the neutron-rich environment of fission, and it would take a week of down­time just to let it decay to a level of marginal safety. You cannot let it cool down, because in this state the sodium is solid metal, and you could not pull the fuel out of it. It cannot be exposed to air, and everything done must be in an inert-gas atmosphere. The entire building would have to be pumped down and back-filled with argon. Also, sodium, liquid or solid, is absolutely opaque. You cannot see through it, so, unlike looking down from the refueling crane through the water to see what you are doing, you would have to be able to refuel the reactor blindfolded. If anything weird happened in a water-cooled reactor core, you could conceivably stick a periscope down in it and have a look. Not so with sodium coolant. Fermi 1 was to be an electrical power-production reactor, running at 200 megawatts. Although in later terms this would be a very small reactor, in 1961 it was a clear challenge to design a machine of this size running in sodium.

The problems of dealing with refueling a sodium-cooled fast reactor were solved by enclosing the works in a big, gas-tight stainless steel cylinder, about two stories tall. In the bottom of the cylinder, off to the side, was an open-topped stainless tank containing the U-235 reactor core,

surrounded by the U-238 breeding blanket.146 Liquid sodium in the primary cooling loop was pumped into the bottom of the reactor tank through a 14-inch pipe. The sodium flowed up, through small passages between fuel-rods, taking the heat away from the fissioning fuel. The thick, hot fluid was removed by a 30-inch pipe at the top and sent to a steam generator for running the electrical turbo-generator. A “hold-down plate” pressed down on the top of the fuel to keep it from being blown out of the can by the blast of liquid sodium coming up from the bottom. Under normal operation, the liquid sodium in the structure was 34 feet deep. Any open space left was filled with inert argon gas.

An ingenious, complex mechanism was used to refuel the reactor and extract and replenish the irradiated U-238 rods in the breeding blanket. To one side of the reactor tank and inside the stainless vessel was another round can, this one containing a revolving turntable loaded with fuel and blanket rod-assemblies. It worked like the cylinder in a revolving pistol or the carousel in a CD changer, indexing around and stopping automatically with a rod assembly in position to be extracted or inserted. An exit tube led vertically to an airlock on the top floor of the reactor building, where a refueling car ran on rails and was able to reach down into the reactor vessel, through the air lock, and remove or replace rod assemblies in the rotor. The car, gamma-ray shielded by 17,500 pounds of depleted uranium, was driven back and forth on the rails by a human operator, under absolutely no danger from radiation in the reactor, the coolant, or in fuel being inserted or removed.

To refuel the core, the hold-down device was first lifted off the top of the core. The fuel — transfer rotor was turned by a motor until it clicked into place with an empty slot under the handling mechanism, which was a long, motor-driven arm hanging down next to the reactor. The arm then turned to the core, gently snatching a designated rod assembly, picking it up and out of the reactor, swinging over to the transfer rotor, and lowering it down into the open slot. The rotor then rotated clockwise and clicked to the next open slot. After the rotor became completely full, the refueling car would bring up the rod assemblies one at a time and put them into shielded storage. To put new fuel or breeding material in the reactor, the process was reversed, with the empty rotor first loaded with fresh fuel from the refueling car. The rotor would index around, presenting the new rod assemblies one at a time to the arm, which would pick them up, swing them through the core, and insert them. All this happened under liquid sodium. It was a totally blind operation, depending only on mechanical precision to find rod assemblies where they were supposed to be and transporting them with great accuracy. When a refueling operation was completed, the hold-down device would descend and cover the top of the core. To be able to automatically refuel this reactor from the comfort of a swivel chair by

pushing a few buttons was a marvel to behold.147

Given the recent tribulations at the SRE, great attention was given to the design of the coolant pumps. Made of pure 304 stainless steel, one primary pump was the size of a Buick. It was a simple centrifugal impeller, driven by a 1,000-horsepower wound-rotor electric motor, with a vertically mounted drive shaft 18 feet long. It turned at 900 RPM to move 11,800 gallons of thick, heavy, 1,000°F liquid sodium per minute and lift it 360 feet. The motor speed was controlled using a simple 19th century invention, a liquid rheostat, as once used to dim the lights in theaters.

The Fermi-1 fast breeder reactor was a bold move in the development of commercial power reactors, ensuring a future with no problems of obtaining fuel to generate power in a growing economy. Unfortunately, the fuel-supply problem failed to materialize, and the complexity of its sodium-based cooling system proved to be its downfall.

There were no liquid-cooled ball bearings to worry about, and no seal to keep sodium out of the pump motor. There was no tetralin seal coolant, of course. The main bearing at the impeller end was a simple metal sleeve, with the stainless shaft running loose inside it. It was a “hydrostatic bearing,” like the bearing on a grocery-cart wheel, but instead of having oily grease to keep it from squeaking, the lubricant was liquid sodium, supplied out of the fluid that the impeller was supposed to pump. The sodium was allowed to puddle up in the long shaft gallery, rising several feet above the impeller housing. Its depth was controlled by compressed argon gas introduced into the top of the pump, and this kept the sodium off the motor and out of contact with air.

As one last step before the reactor tank was assembled, the engineers decided to enhance a safety feature. A problem with fast reactors was that in the unlikely event of a core meltdown, the destroyed fuel matrix, becoming a blob of melted uranium in the bottom of the tank, could become supercritical. In this condition, it would continue making heat at an increasing rate and exacerbating a terrible situation. An ordinary thermal, water-cooled reactor, losing its symmetry and carefully planned geometric shape in a meltdown, would definitely go subcritical, shutting completely down. The thermal reactor depends greatly on its moderator, the water running

between fuel rods, to make fission possible. The fast reactor does not.148 To ensure a subcritical melt in a fast reactor, at the bottom of the tank is a cone-shaped “core spreader,” intended to make the liquefied fuel flow out into a shape that does not encourage fission, flat and neutron-leaky, like pancake dough in a skillet. Before the core tank was finished, the builders installed triangular sheets of zirconium on the stainless steel core spreader, just to make it more high-temperature resistant. They beat it into shape with hammers, making the sheet metal conform to the cone. This last-minute improvement was not noted on the prints approved of by the AEC.

During operational tests, the check valves on the pumps, meant to prevent backflow if something stopped working, would slam shut instead of closing gently but firmly, as they were supposed to. This flaw was re-engineered, and further extensive testing would ensure no problems from the pumps.

Still, working with a large volume of pure sodium would prove challenging. Tests were being performed in an abandoned gravel pit about 20 miles north of the building site on August 24, 1959, when a load of sodium exploded in air. Houses in the nearest neighborhoods, Trenton and Riverview, were damaged by the blast and six people were hospitalized. By December 12, 1962, there was enough of the reactor assembled to test the main cooling loop. An operator was at the control console watching the instruments as the sodium circulated at full speed through the system. The temperature started reading high on a thermocouple gauge. There was no fuel in the reactor, so where was the heat coming from all of a sudden? Were sodium and water mixing due to a flaw in the steam generator? Thinking this through, the operator reached over and hit the red water-dump button. Water gushed out of the secondary cooling loop into a holding tank, taking it quickly out of the steam generator and away from possible contact with the sodium loop. Unfortunately, this caused a sudden vacuum in the system, which was designed to hold high-pressure steam and not an airless void. A safety disk blew open, and sodium started oozing out a relief vent, hit the air in the reactor building, and made a ghastly mess.

No one was hurt. When such a complicated system is built using so many new ideas and mechanisms, there will be unexpected turns, and this was one of them. The reactor was in a double-hulled stainless steel container, and it and the entire sodium loop were encased in a domed metal building, designed to remain sealed if a 500-pound box of TNT were exploded on the main floor. It was honestly felt that Detroit was not in danger, no matter what happened.

Cost of the Fermi 1 project reached $100 million, and it was too far along to turn back. The

fuel was loaded on July 13, 1963, and the fuel car was not acting well.149 The first startup was a few weeks later, on August 23 at 12:35 P. M. A system shakedown at low power would continue until June of 1964. A few problems surfaced. The number 4 control rod delatched from the drive mechanism, leaving it stuck in the core. The large, rotating plug in the top of the reactor vessel, used to move the refueling arm between the fuel rotor and the core, jammed and wouldn’t move. A sodium pump had to be repaired, and the cap on the reactor vessel had to be rebuilt so that it would fit correctly. Some electrical connections and cable runs were defective, causing instrument problems. These glitches were all knocked down.

By January 1966, the Fermi 1 plant was wrung out and ready to go to full 200 megawatts of heat in several cautious steps. August 6, 1966, was a day of triumph. The thermal power was brought up to 100 megawatts, enough to make 33 megawatts of electricity, or about half what the backup diesel generators could produce. The project cost had also reached a high point, at a cool $120 million, and critics pointed out that the reactor had so far been able to generate measurable electricity for a total of only 52 hours.

At this half-power level, unusually high temperatures were indicated in fuel assemblies M-091 and M-140, the steam generator started leaking steam, and control rod no. 3 seemed to stick in the guides. The next day, August 7, the positions of the hot fuel assemblies were swapped with trouble-free fuel assemblies, to see if the problem moved. There seemed no correlation between the specific fuel assemblies and overheating. The problem seemed to be the position

in the core, and not the fuel.150 Could it be that the thermocouples in those locations were just reading wrong?

The operating crew was ready to try another cautious power-up on October 4, 1966. The Fermi 1 reached criticality at 11:08 P. M., and it idled at low power while every little thing was checked. At 8:00 am. the next day, the operators were ready to bring the reactor to half-power, but a steam-generator valve seemed stuck. It took until 2:00 P. M. to resolve that problem, and then the feed-water pump in the secondary loop was not working. They powered down and worked on it. By 3:05 P. M. they had resolved the problem and the power was increased to 34 megawatts and rising.

Something was not right. The neutron activity in the reactor core was erratic and bouncy. There was no reason for the neutron level to be anything but smooth and steady. The power ascension was halted while Mike Wilbur, the assistant nuclear engineer in the control room, contemplated the meaning of these instrument readings. Based on previous problems, Wilbur had a hunch. He stepped behind the main control panel to take a look at the thermocouple readouts on the fuel assembly outlet nozzles. These instruments were not considered essential for running the power plant, so they were not mounted on the main panels. They were included in the hundreds of instrument readouts, lights, and switches in the control room for diagnostics, and here was a problem that required a deeper look.

Fuel assemblies M-140 and M-098 were both running hot. At this power level, the temperature of coolant flowing out the top of fuel assembly M-140, which had given trouble in the past, should have been 580°F. It was reading 700°F. As Wilbur was taking this in, at 3:08 P. M. the building radiation alarms started sounding. It was a rude, air-horn sound: two mind — numbing blasts every three seconds. There were several possible explanations for the radiation alarms, but the assistant nuclear engineer knew deep in his heart that one was likely. Fuel had melted, spreading fission products into the coolant. The only thing that was not clear at all was: Why?

The crew executed emergency procedures as specified in the operations manual. All doors were closed, and all fresh-air intakes were closed in the building. Detecting radiation in the building was an emergency condition. It was supremely important to not let it leak out into the world outside Lagoona Beach, which would make it a big, public emergency. They executed a manual scram at 3:20 P. M., shutting Fermi 1 down with the floor-trembling shudder of all controls dropped in at once. One rod would not go in all the way. Not good. Was a fuel assembly warped? They tried another scram. This time, it went in. With the neutron-poisoning control rods all in, there was no fear of the core being jostled or melted into a critical condition. There could be no supercritical runaway accident, and if the core were completely collapsed and flowing onto the spreader cone, the uranium would be mixed with melted control material, which would definitely discourage fission. News of the accident, specifying that the engineers did not know what had happened, spread across the land.

The reactor had never run at full power, and only for a short time trying to get to half power, so there was no worry that it could melt down any further in the shutdown condition. There were not enough delayed fissions and fission product decays to cause havoc with high temperatures in the fuel. Over the next few weeks, the operators and engineers tried to find the extent of the damage without being able to see inside the reactor core. One at a time, they pulled control rods and noted the increase in neutron activity in the core. A few control rod locations did not return the activity they expected. Near these, the fuel may have sagged out of shape.

Next, they attached a contact microphone to a control-rod extension and listened as the liquid sodium was pumped around the primary loop. They heard a clapping sound. They slowed the pumps. The clapping sound slowed. Was there something loose in the core? It was impossible to see.

They had to feel around using the fuel-loading devices to determine the state of the core. Proceeding slowly and cautiously, it would take four months, into January 1967, to confirm that fuel had melted. First they raised the hold-down column on top of the core, and they found that it was not welded to the reactor. This was good. Next, they swung the refueling arm over the core and tried to lift the fuel assemblies, one at a time. The strain gauge on the arm would weigh each assembly. Two seemed light. Fuel had dropped out the bottom, apparently. Two were stuck together and could not be moved without breaking something. It took five months, until May 1967, to remove the fuel using the automatic equipment. Finally, seeing the fuel assemblies in the light of day, it was clear that two had melted and one had warped. There was still no explanation as to why.

The sodium was drained out of the reactor tank, although there was no provision in the design for doing so. A periscope, 40 feet long with a quartz light attached, was specially built to be lowered into the darkness from the top of the reactor vessel. Finally, the engineers could see the bottom of the reactor tank. It looked clean and neat. There was no melted uranium dripped onto the spreader cone. No loose fuel slugs were scattered around. All of the damaged fuel had collected on the support plate for the bottom of the reactor core. There was, however, something out of place. It looked like… a stepped-on beer can, lying on the floor of the reactor tank? That could explain the core melt and the clapping noise. Caught in the maelstrom of coolant forcing its way through the bottom of the reactor core, this piece of metal had slapped up against an inlet nozzle and blocked sodium from flowing past a couple of red-hot fuel assemblies. But what was it, and how did it get in the reactor?

To answer that question, the metal thing would have to be removed from the reactor, and that was not easy. Cisler stood firm under a hail of abuse from anti-nuclear factions as the Fermi 1 engineers accomplished the impossible. They built a special remote-manipulating tool and lowered it down into the floor of the reactor tank through the sodium inlet pipe. It had to make two 90-degree turns to get there. With the new tool in place, they were able to move the metal thing closer to the periscope, flip it over, and take pictures.

Still, the experts could not tell what it was. They all agreed on one thing: it was not a component for the reactor as shown on the design prints. It would have to be removed. With enormous effort and a great deal of money, another special remote operator was built and inserted through the sodium inlet. One worker swung the quartz light on the end of the periscope to bat the object into the grabber at the end of the new tool. Another man, working 30 feet away, manipulated the grabber tool blindly from instructions over an intercom. Finally, a year and a half after the accident, on a Friday night at 6:10 P. M., the mystery object fell into the grip of the tool. Slowly, taking 90 minutes, they snaked it up through the pipe and into the hands of the awaiting engineers.

They looked at it, turned it over, looked again, and finally truth dawned. It was a piece of the zirconium cover that they had attached to the stainless steel spreader cone, nine years ago. They had not bothered to have it approved and put on the final prints. It had cost an additional $12 million to figure this out.

By May 1970, all repairs had been made and Fermi 1 was ready for a restart. AEC inspectors were on hand, making the operators nervous at the close monitoring of their every action. Things were tense as 200 pounds of sodium suddenly broke loose in the primary transfer tank room, tearing out a water-pipe run and causing a loud thud as the mixture of water, air, and sodium exploded. This embarrassing incident cost another two months of down­time to repair the damage, but in October the plant finally reached its designed power level, making 200 megawatts of heat. For the next year of operation, the plant was able to remain

online for only 3.4% of the time.151 Denied an extension to its operating license in August 1972, its operation ended on September 22, 1972. The plant was officially decommissioned on December 31, 1975, the fuel and the sodium were removed, and it still sits quietly at Lagoona Beach, next to Fermi 2, a General Electric boiling-water reactor that is currently making power for DTE Energy. All things considered, Fermi 1 failed at its mission, to spearhead the age of commercial plutonium breeding in the United States. Admiral Rickover had summed it up clearly back in ’57 in one sentence, saying that sodium-cooled reactors were “expensive to build, complex to operate, susceptible to prolonged shutdown as a result of even minor malfunctions, and difficult and time-consuming to repair.”

Did we almost lose Detroit? No. There was no water in the reactor vessel to destructively explode into steam with a suddenly overheated reactor core. No steam meant that there was no source of force to break open the containment dome and spread fission products from the

core.152 The water and steam were out in another building, and the worst that could happen was to mix them with the secondary sodium loop and not with the primary loop containing radioactive sodium. The results of a massive breakdown in the secondary loop could dissolve every aluminum drink can within five miles with vaporized sodium hydroxide, but it would spread no radioactivity. The reactor was too feeble to build up enough fission product to justify the thousands of casualties predicted if the core were to somehow explode. In a maximum accident, the entire core would overheat and melt into the bottom of the reactor vessel, but it would melt the controls and the non-fissile core structure along with it, making it unable to maintain a critical mass. The dire predictions and warnings had been dramatic, but hardly realistic.

The school of business at Northern Michigan University was renamed the Walker L. Cisler College of Business. He died in 1994 at the age of 97.

Not even slightly discouraged, the AEC proceeded to secure funding for yet another stab at a commercial sodium-cooled contraption in 1970, the Clinch River Breeder Reactor Project, to be built inside the city limits of Oak Ridge, Tennessee. This would be a full-sized power reactor, making a billion watts of heat, turning out 350 megawatts of electricity, and producing more plutonium than it burned. Lessons learned from Fermi 1 were applied to the design, including multiple coolant intake passages per fuel assembly to make inlet blockages “impossible.”

Estimated cost of the plant was $400 million, with $256 million to be paid by private industry. Being built right in the middle of the Great Atomic Downturn in the mid-seventies, the project spun out of budgetary control and was plagued with contracting abuse charges, including bribery and fraud. By the time the Senate drove a stake through its heart in 1983, $8 billion had washed away, and plans for a commercial breeder economy in the United States went with lt.152

The U. S. was not alone in an early quest for a sodium-cooled plutonium breeder. In 1964, the Soviet Union under Minister of Atomic Energy Yefim P Slavsky began construction of what would become the world’s first and only nuclear-heated desalination unit making more fuel than it used, the BN-350 power station. The site was two miles in from the shore of the Caspian Sea on the Mangyshlak Peninsula. The reactor was designed to run at 750 megawatts, driving five sodium loops at the same time with one spare. It was first started up in 1972, and although it was not able to make its designed power level, it ran for 26 years. For 22 of those years, it actually had an operating license, and the fact that it kept going for so long speaks well of the operating staff. They were an exceptionally tough bunch, eventually developing an immunity to frequent sodium fires and explosions.

Startup tests immediately found weld problems in the steam generators. Both the endcaps and the tubesheets would tend to break and mix water with sodium. In the first three years of operation, there were eight sodium explosions. For some odd reason, loop No. 4 never came apart. In 1974, after two major leaks and three small ones, it was decided to rebuild all the steam generators except No. 4. By February 1975, three loops had been fixed, and they decided to start up. Seven days later, loop No. 5 disintegrated. The steam generator in loop No. 5 was replaced with one made in Czechoslovakia.

As of December 16, 1991, the BN-350 was no longer in the Soviet Union. It was in the newly formed Republic of Kazakhstan, and it was re-named the Aktau Nuclear Power Plant. It continued to supply 120,000 cubic meters of fresh water for the city of Aktau way past its projected lifetime of 1993. BN-350 fissioned its last nucleus in 1999, due to a lack of funds to

buy more fuel.154

Before the BN-350 was started up, the Soviet government was building an even larger sodium-cooled fast breeder reactor, the BN-600 in Zarechny, Sverdlovsk Oblast, Russia. It successfully started up in 1980, but a larger Russian sodium-cooled reactor means larger sodium explosions. As of 1997, there had been 27 sodium leaks, 14 of which caused serious fires, and the largest accident released over a ton of sodium. Fortunately, each steam generator is in its own blast-wall-protected cubicle, and any one can be reconstructed by the on-site workers while the reactor is running. That is one way to solve the problem of bad welds. A BN-800 and a BN-1600, still larger breeder reactors of the same type, are currently under construction in Russia.

We move on to France, a country firmly committed to a nuclear economy.

France saw the same writing on the wall that warned others about the limited supply of uranium, and in 1962 started construction of a modest-sized, experimental sodium-cooled fast breeder reactor named Rapsodie, in Cardache. It began operations on January 28, 1967, making 20 megawatts of heat. It ran okay, and in 1970 the core was redesigned and the power was increased to 40 megawatts. Under the stress of the higher output, the reactor vessel developed cracks, and it was reduced to 24 megawatts. By April 1983, the sodium leakage in Rapsodie was too costly to fix, and it was put to sleep. On March 31, 1994, a highly experienced, specialized, 59-year-old CEA engineer was killed in an explosion while cleaning the sodium out of a tank at Rapsodie. Four people were injured.

In February 1968, after Rapsodie had run for a year, ground was broken in Marcoule for a bigger, 563-megawatt sodium-cooled breeder named Phenix. Ownership and construction costs were shared by the French Atomic Energy Commission (CEA) and Electricite de France (EDF), the government-owned electrical utility. It was big and ambitious. The starting core was 22,351 rods of pure plutonium, with 17,360 depleted uranium rods in the breeding blanket and an awesome 285,789 around the periphery for neutron reflection back into the blanket and radiation shielding. Its 250 megawatts of electrical power were connected to the grid on December 13, 1973, two months after the Organization of Petroleum Exporting Countries (OPEC) halted oil deliveries to countries that supported Israel and increased the market price of crude oil by a factor of four. The first sodium leak occurred in September 1974. In March and July there were two more, causing slow spontaneous combustion in pipe insulation.

The engineering innovation of Phenix was a free-standing or “free-flowering” core restraint, allowing it to expand or contract as it wished due to thermal, mechanical, or irradiation effects without bending or breaking anything. It ran perfectly for 16 years, as the spot price for uranium went from $6 per pound in 1973 to $40 per pound in 1976. Running on plutonium seemed a splendid idea. On July 11, 1976, a sodium fire broke out at the intermediate heat exchanger. Another one on October 5, and three more by the end of 1988. In May 1979, the fuel cladding failed, releasing radioactive xenon-135.

On August 6, 1989, something very odd happened to Phenix. A sudden very negative reactivity excursion triggered a scram. The reactor simply quit making neutrons, and the power level fell like a lead brick. The engineers had no idea why. The reactor restarted without a problem, but 18 days later it happened again. This time, the instruments were blamed for both negative excursions, but nothing wrong could be found. The ability to make electrical power

dropped to near zero as the incidents continued.155

On September 14, 1989, the power again went to zero. The cause was believed to be a gas bubble in the core periphery. The problem was solved with mechanical maintenance, and Phenix was restarted in December. It happened again on September 9, 1990, and the gas — bubble hypothesis went out the window.

For the next 12 years, panels of experts pondered the problem, and the plant was tested, taken apart, put back together, repaired, modified, and refurbished, not generating any power to speak of. No one specific scenario or cause of the strange incidents was identified, but the only thing that made sense, given the speed and extent of the events, was that the core was in motion, moving in different directions as it generated power and disturbing the critical configuration of the reactor as designed. Lesson learned: avoid free-flowering core restraints in future reactor designs. In June 2003, Phenix was restarted and ran at reduced power, 130 megawatts, until final shutdown in 2009.

In 1974, a European fast-neutron reactor consortium, NERSA, was established by France, Germany, and Italy to build the biggest plutonium-fueled breeder reactor in the world. This extraordinary allegiance of countries lasted about a year. Germany spun off and decided to make their own breeder, the SNR-300 in Kalkar, and in the middle of 1976 President Valery Giscard d’Estaing of France proclaimed that his country would build the Superphenix, a 3- gigawatt sodium-cooled breeder, at Creys-Malville, 45 kilometers east of Lyon. Italy stood still and did not make a sound.

Minister of Industry Andre Giraud announced to a spellbound crowd at the American Nuclear Society meeting in Washington, D. C., that there would be 540 Superphenix-sized breeder reactors in the world by the year 2000, and 20 of them would be in France. Meanwhile, 20,000 people occupied the building site to protest the thought of another reactor project. On July 31, 1977, the protest got serious, with 50,000 participants, and riot police went in armed with grenades. A local teacher, Vital Michalon, was killed, another protester lost a foot, and a third lost a hand in the battle. Ongoing protest and sabotage made construction work difficult, and on the night of January 18, 1982, militant Swiss eco-pacifists fired five rocket-propelled grenades

at the containment building, causing cosmetic damage.156

Construction continued under bombardment, and the completed Superphenix went critical on September 7, 1985. It was connected to the grid on January 14, 1986. A series of administrative hurdles and incidents prevented any significant power production until March 8, 1987, when a massive liquid-sodium leak was discovered issuing forth from the refueling rotor tank (storage carousel). The reactor was down until April 1989 as an alternate refueling scheme was designed. The rotor tank was too far down in the guts of the reactor, and there was no way to repair the leak, a crack 24 inches long, without dismantling the entire plant.

Operation at very low power proceeded until July 1990, when a defective compressor was found to be blowing air into the liquid sodium line and making solid sodium oxide. In December the roof of the turbine hall collapsed in a heavy snowstorm. Superphenix seemed cursed.

The reactor was shut down for good by government decree on December 30, 1998. It had remained offline for two years because of technical difficulties and four and a half years for administrative debating. It never ran at its designed power level. Superphenix is scheduled to be completely dismantled by 2025. No new breeder reactor is planned in Europe.

The Germans’ 327-megawatt SNR-300 sodium-cooled fast breeder reactor, costing a scant $4 billion to build, was completed, filled with sodium, and ready to be started up in 1985. Political hand-wringing kept it in standby condition for six years, costing about $6 million per month to keep the sodium liquefied using electric heaters. On March 21, 1991, the project was officially cancelled. The SNR-300 and the ground it was sitting on were sold at auction for half the monthly upkeep cost to a Dutch developer, who turned it into an amusement park named

Kernwasser Wunderland.

Of all the countries building sodium-cooled fast breeder reactors, India would be voted least likely to pull it off without blowing something to kingdom come. A list of sodium fires, explosions, and inexplicable power excursions in their Fast Breeder Test Reactor (FBTR) would be monotonous, but one accident stands out as unique. The reactor was first started up in October 1985. FBTR is a copy of the French Rapsodie, built at Kalpakkam using elephants for heavy lifting. Like every other fast breeder made since 1957, the blind fuel-handling machinery was based on the ingenious and complex Fermi 1 design.

In May 1987, a fuel assembly was being transferred from the reactor core to the radiation shield at the periphery. Each assembly held 217 fuel rods in a square metal matrix. For reasons unknown, one fuel assembly was sticking up one foot above the core as the handling arm swept across to find the one it was supposed to pick up. The electrical interlock that normally prevents the arm from moving if anything is in the way had been bypassed. Crunch. The arm rammed the protruding assembly, bending it out of shape, and then knocked the heads off 28 assemblies in the reflector as it tried to back away. Trying to make everything back like it was, the arm mechanism accidentally ejected an assembly in the reflector and put a 12.6-inch bend in a substantial guide tube. It took two years to sort out the damage and repair the core. Reasons for the accident were never really understood.

India is presently building two larger sodium-cooled fast breeder reactors. Be afraid.

The Japan Atomic Energy Commission published its first Long Term Plan in 1956, and at the top of the list of technologies to be developed were a sodium-cooled fast breeder and an associated fuel cycle using plutonium extraction. Of all countries in the game, Japan had the strongest incentive to build breeder reactors and become energy-independent. Domestic power options were few, and they had recently fought a war over energy resources and lost.

Two breeder reactor projects were started in parallel. The smaller unit, Joyo (Eternal Sun), achieved criticality on April 24, 1977, developing 50 megawatts of heat energy. Located in Onari, Ibaraki, this reactor is now on its third core-loading, and the power has been increased to 140 megawatts. It has been used as a test-bed for fuel mixtures and materials for use in future breeder reactors.

The second breeder, Monju, was built in Tsuruga, Fukui Prefecture, and was first brought to

criticality in April 1994.157 It is less of a test reactor than Joyo, producing 280 megawatts of electricity from 714 megawatts of heat. It has three double-loop core coolers, A, B, and C. The inside loop is full of radioactive sodium, and the outside loop, of course, has non-radioactive sodium, connected to the steam generator.

All was well with Monju until December 8, 1995. It was operating at 43% power when a smoke alarm went off near the hot-leg pipe for outside loop C, about where it exited the reactor vessel. It was 7:47 P. M. High-temperature alarms went off. The operating crew started a slow controlled shutdown 13 minutes later. It was beginning to look like a sodium leak, so at 9:20 P. M. they went ahead and hit the scram button. By 12:15 a. m. they had successfully drained the outside C-loop of sodium.

Turbulent flow in the sodium pipe had caused intense vibration, which broke off a sealed thermocouple well inside the pipe and bent the thermocouple 45°. Hot, liquefied sodium oozed through the now-opened thermocouple penetration in the pipe to the electrical connection and started dripping on the floor. Eventually, three tons of sodium collected in a clump on the concrete, and it caught fire, hot enough to warp and melt steel structures in the room. No one was hurt, and no radioactivity was released, but there was a lot of eternal shame.

The government-established Power Reactor and Nuclear Fuel Development Corporation (PNC) tried to cover up the accident, but when accounts broke free there was a public and political uproar and questions as to what else they had not divulged. A restart after repairs was delayed until May 8, 2010. Fuel was replaced, but on August 26, 2010, a 3.6-ton in-vessel transfer machine being hoisted into place slipped its bindings and did a free dive into the reactor vessel. It was somewhat mangled and could not be retrieved from the opening through which it had fallen. A lot of engineering work by the Japan Atomic Energy Agency achieved removal on June 23, 2011. To this date, Monja has managed to generate power and put it on the grid for one hour. Another, larger fast breeder in Japan is planned, but plans have gone awry in recent years.

Given this interesting set of mini-disasters in which there were no injuries, one would have to consider the truth in Admiral Rickover’s terse assessment of liquid-metal-cooled reactors. Take a step back for the longer gaze, and it starts to look like the most awful way to build a machine that has ever been designed. The people who championed and worked hard for this new and dangerous technology were visionaries. There was actually no particular need for an advanced power system that would last forever and free entire nations from a dependence on others. In the 1950s, there was enough burnable material, oil, coal, and gas, to go around, and enormous reserves of uranium were discovered throughout the decade. These individuals were forcing us into the future with all the speed we could handle, developing novel and outrageous concepts, materials, and machinery, to a place where mankind would eventually have no choice but to go. They were just too early. Was this wrong?

Next, we will explore an area in which the man-machine interface is pushed to the limit, and people die.158

134The USS S-48, built in 1921, was possibly the only submarine to find peril in a heavy snowstorm. She was returning home to Portsmouth, Connecticut, on the night of January 29, 1925. At about 6:30 P. M. off the coast of New Hampshire, the wind picked up and heavy snow started falling. With visibility zeroed, she ran onto the rocks off Jeffery Point, rolled off, then grounded again in Little Harbor. Early next morning, still stuck and listing badly the battery compartment started taking water, and the ensuing electrolysis action broke down the salt water and released chlorine gas inside the sub. The Coast Guard picked up the crew an hour and a half later, and they were transferred to the hospital at Fort Stark for treatment.

135At least no leakage problem while running. The USS Seawolfsubmarine with a liquid-sodium-cooled fast reactor did experience an unscheduled sodium expulsion, but the boat was in dock at the time. The Superphoenix fast breeder reactor in Creys-Malville, France, has suffered from sodium leaking and corrosion in the cooling system, and it has been out of service since September 1998.

136Otto K. Helney a 53-year-old engineer, Larry A. Pugh, a 51-year-old physicist, and Lee Wells, a 62-year-old assistant, seemed old enough to know better when they mixed 10 pounds of gycidal azide polymer and nitrocellulose (gun cotton) together in an aluminum pan, hoping to measure the shock wave when the two chemicals ignited. Helney and Pugh died instantly and Wells was blown against vertical terrain and burned over 20% of his body Six other men died at Santa Susana in various incidents in the early 1960s. It was an exciting place to work.

137Zirconium was an excellent choice. It is transparent to neutrons and able to withstand very high temperatures, but it was expensive. For graphite moderator units out on the periphery of the reactor core where the temperature would never be very high, stainless steel was substituted for the zirconium.

138From whose stockpile would this U-233 come? U-233 does not occur in nature, and it must be made by production reactor from Th-232. Experimental U-233 reactor fuel probably came from a stockpile at Los Alamos. In 1955 a composite Pu-239/U-233 atomic bomb named MET was built and tested in Operation Teapot. The U-233 was made using the B Reactor at the Hanford site, and this material was used in several thermal breeder experiments in the late 1950s and early 1960s. The stockpile wound up at Oak Ridge, and a $511M contract from the DOE to dispose of this material is currently under way.

139Electromagnetic sodium pumps were not unknown to the SRE design group. In fact, one was used to load the cold trap, designed to remove oxidized sodium and any other contaminants from the primary cooling loop. This pump failed about 60 days into operation at power in late June 1957. Similar electromagnetic devices, called “eddy current brakes,” were used on the primary and secondary coolant loops to stop the coolant from moving after a reactor scram.

140I can’t tell exactly where the fire occurred. It was in the “XX vault,” where X indicates an unreadable character in the SRE operations log summary There was an NAS vault, a main pipe vault, an aux pipe vault, and a primary sodium fill tank vault. There was no tetralin in any of these locations.

141 The window was three feet thick, but not the glass. Hot cell windows were made of two very thick panes of glass, mounted in parallel and spaced about three feet apart in a sealed tank, very much like an aquarium. The space between the glass windows is filled with zinc bromide dissolved in water. Objects in the hot cell are given a yellow cast by looking through the zinc solution, which is an excellent high-energy gamma-ray shield.

142The “nack” cooled seal used a mixture of sodium and potassium, or NaK, as the cooling fluid into the sodium seal to keep it frozen solid. Nack is liquid at room temperature, and it flows as freely as water. It was used in the fuel pins to fill the space between the solid uranium fuel pellets and the stainless steel tubes in which they were encased, giving a thermal coupling that would ensure heat flow to the coolant, which flowed around the tubes. The tetralin was a low-viscosity solvent, and it was hard to keep it from finding a way past the sodium seal and into the coolant. The nack would leak less, and if it did, so what? In all the other motorized sodium pumps in the system, tetralin was retained as a coolant.

143At least I assume it was a scram actuation. In the SRE plans, this switch is listed as a “setback ” actuator. Does this indicate that it was meant only to limit the power rise rate and not stop it completely? If so, it would not have worked as planned. With power increasing exponentially, a scram is quite appropriate.

144The Hallum Nuclear Generating Station is a little-known, second graphite-sodium reactor built near Lincoln, Nebraska, starting in 1958. This experiment was also funded by the AEC. Unlike the SRE, the vertical-shaft centrifugal sodium pumps for this reactor were designed from scratch and were considered far superior to the ill-fated SRE pumps. Unfortunately, the modified Hallum-type pumps used in the rebuilt SRE had undersized overflow loops which produced a serious gas-entrapment problem. The Hallum reactor operated only briefly from 1962 to 1964. The graphite moderator cans were clad in stainless steel, and stress cracking and corrosion caused irreducible problems. By 1969, evidence of the Hallum reactor was erased from the prairie, but the Hallum-type pump remains as a credible means of moving liquid sodium.

145Walter worked as a “wage slave” at the Ford Motor Company starting in 1927. Henry Ford sent him to Nizhny Novgorod, Soviet Union to help build a tractor factory but he became overly interested in the proletarian industrial democracy and Ford fired him in 1932. After working for a few years at an auto plant in Gorky Reuther returned to the U. S. and became a very active member of the UAW. On May 26, 1937, at 2:00 P. M., he and Richard Frankensteen were in the middle of a leaflet campaign (“Unionism, Not Fordism”) and they were asked by a news photographer to pose on the pedestrian overpass in front of the Ford sign. Ford’s modest army of about 40 security specialists walked into the frame from the left and proceeded to discipline the uninvited visitors. The Dearborn police stood out of range and shouted advice while the union men were beaten, kicked, dragged by the feet, slammed down on the concrete, and thrown down two flights of steps. Reuther, always a champion of the underpaid and the underappreciated worker with too little money died on May 9, 1970, when his privately chartered LearJet smacked the runway at the Pellston, Michigan, airstrip in rain and heavy fog. He was on his way to the UAW recreational facility at Black Lake.

146A breeder reactor is supposed to run off fuel that it produces, which in this case was plutonium-239. Until it has actually made fuel and it has been extracted from the breeding blanket, the breeder usually starts off with a load of uranium-235. Unlike a water-cooled reactor, a fast breeder runs off pure fissile isotope, so the starter fuel must be highly enriched to simulate its eventual load of Pu-239.

147When I was in school, fast breeder reactors were all the rage, and a wild story about the refueling machinery in the Fermi 1 was going around. It was said that a spin-off of the breeder reactor project was the AMF pin-spotting machine, now used in many bowling alleys. The method used for collecting and placing fuel assemblies in an automatic, utterly blind situation under liquid sodium was found useful for doing a similar job with bowling pins. I am sad to say that I can find no connection between bowling alley machinery and fast reactor refueling devices, much as I would like to. The patent for the AMF “candlepin” pin spotting machine was filed on April 14, 1964, which is close to when the Fermi 1 was designed, but it was based on the original AMF 82-10 pin spotter, first demonstrated in 1946.

148An enduring question of fast reactor design is: “What is the sodium void coefficient?” If the sodium coolant leaks out of a fast reactor, does it go subcritical or supercritical? The correct answer if this question should come up on your Ph. D. qualifying exam is: “That depends.” There are many factors that come to bear, including the geometrical shape of the core.

149It is difficult to find a cross-section view of the Fermi 1 reactor that does not have a big X drawn through the refueling car. It was not a popular accessory.

150Geek-joke from 1975: How does a Digital Equipment Corporation computer-repair technician fix a flat tire? He swaps the wheels to see if the problem moves. You had to be there… .

151This number, 3.4%, is the capacity factor for Fermi 1. In 2011 the average capacity factor for a nuclear power plant in the United States was 89%. A wind-turbine plant, such as the Burton Wold Wind Farm, consisting of ten Enercon E70-E4 wind turbines, had a capacity factor of 25% in 2008. The Hoover hydroelectric dam has an average capacity factor of 23%. The capacity factor of a power plant is the amount of energy produced over a set period of time divided by the energy it could have produced if working at full capacity during the same period.

152No steam not only meant that there could be no steam explosion, it also meant that there could be no explosive hydrogen buildup. Hydrogen gas can be made from steam in a reactor accident by heat-induced corrosion of metals or radiolysis. More on this topic in the Fukushima chapter.

153Meanwhile, in 1975 the Shippingport Atomic Power Station in Pennsylvania, a pressurized water reactor based on a Westinghouse aircraft carrier engine, was converted into a thermal breeder using a thorium-uranium-233 fuel cycle. The Shippingport reactor had been running since May 26, 1958, and was the first commercial reactor making significant electrical power in the U. S. The reactor ran smooth and quiet for 25 years, and it never gave any trouble.

154Even a breeder reactor has to buy fuel. If the supply services had been operating as planned, the plant would exchange its spent fuel and breeding material for a fresh load of plutonium and depleted uranium. Plutonium would be extracted chemically from the spent load, and there would be enough extra in the breeding stock to more than pay for the chemical separation and fuel-rod fabrication. The BN-350 started out with an expensive load of 20% enriched uranium with some mixed uranium-plutonium surplus from the Soviet nuclear weapons being demilitarized. By 1999, the now-obsolete fuel-rods would have to be custom-built.

155Subsequent investigations found that similar incidents had occurred in April 1976 and June 1978. They were explained away as “control rod slippage,” which turned out to be wrong.

156The unnamed group of terrorists obtained a Soviet RPG-7 shoulder-fired rocket launcher and eight rockets (“bonbons”) from the German “Red Army Faction” via the Belgian counterpart Cellules Communistes Combattantes. They lost three of the missiles in the dark. Chaim Nissim, elected to the Swiss Geneva cantonal government for the Green Party in 1985, admitted 22 years later to leading the attack. He should stay out of France.

157Monju is the Japanese word for Manjusri, a bodhisattva or enlightenment-being inMahayana Buddhism. The Japanese tradition holds that Monju invented male homosexual love. What this has to do with a sodium-cooled fast breeder reactor, I’m not sure.

158I had to leave out the other participant in the sodium-cooled circus, Great Britain, not because they never had a coolant leak, but because the British incidents were too routine to stir the reader. There were two notable British fast reactors built at Dounreay near the chilly northernmost frontier of Scotland. There was the Dounreay Fast Reactor (DFR), which was nack-cooled, and the Prototype Fast Reactor (PFR), cooled with sodium. DFR was started up on November 14, 1959, and PFR was the last to shut down permanently in 1994. The U. K. push for a plutonium economy has since been declared dead.

Chapter 7

"Expect to have a fire.”

—the concluding sentence in AEC Accident and Fire Prevention issue no. 21,

28 October 1955, "Plutonium Fires”

At 64 years of age, Harold McCluskey was hovering near retirement vintage, but he wanted to pass along his skills as a chemical operator to the dwindling supply of youngsters eager to enter the exciting life of a plutonium production engineer. He worked for the Atlantic Richfield Hanford Company of Richland, located in the middle of absolute nowhere in southeastern Washington State, and he was not in particularly good shape to be punching a clock at Hanford. McCluskey had recovered from a near-fatal heart attack two years before, and three years before that he had an aortic aneurism, treated with a prosthetic graft.

It was August 30, 1976, 2:45 a. m. on the graveyard shift when McCluskey entered the Americium Recovery Room, Building 242-Z of the Plutonium Finishing Plant. The operator on duty turned the recovery task over to him and left, and a few minutes later the junior chemical operator showed up to assist, observe, and learn.

Americium-241 is a transuranic byproduct of plutonium production. Rather than throw it away into the atomic landfill, Atlantic Richfield found that it was a valuable substance that could be sold and offset the cost of making fissile bomb material. This particular nuclide decays with a powerful alpha-particle emission, much like polonium-210, but unlike polonium with its short half­life, this species would outlast a Galapagos tortoise. Only half of it is gone after 433 years, and this makes it an attractive material for use in air-ionizing smoke detectors. Eventually every house in the country will have at least one smoke detector stuck to the ceiling, and that will require a lot of americium. It decays into neptunium-237 with a spray of gamma rays accompanying the alphas. The neptunium stays around for about two million years.

It is removed from fission waste products in very small batches, about 10 grams each, by dissolving it in 7-molar nitric acid and dribbling it down through a long cylindrical column filled with Dowex 50W-X8 ion-exchange resin beads. This process is observed, controlled, and adjusted using a large glove box, which allows the worker to insert his hands into two long­sleeved rubber gloves, bolted to the front of a metal workstation. The worker can manipulate objects in the glove box as if they were on a tabletop, yet he or she is completely isolated from the materials in the tightly sealed box, never directly touching anything. No radioactive

contamination can get through the gloves or the box, and the worker is perfectly safe. He or she can see the work through the lead-glass window.

A general-purpose glove box is a simple affair, having a wide, tilted window on the front and two gloves at elbow level, but the americium recovery glove box was tall and rather strange. Each station in the line of americium boxes had not two but six glove positions, so that you could get hold of something at the top, the middle, or the bottom of the 6-foot ion-exchange column. There were seven windows. One long, thin window, right in front of the column, came down from the top, halfway to the floor. Five diamond-shaped windows were spaced all around, and a triangular window was at the top on the right side, all giving special viewing to certain parts of the chemical extraction process. Each window was made of laminated safety glass, to prevent shattering, covered with quarter-inch lead glass for gamma-ray protection. The inside of the box was dominated by the metal column, festooned with a confusion of tubes, valves, and conduits. There was a two-step metal ladder to help you see the top of the column and put your hands into the upper set of gloves. To work in the Americium Recovery Room, you had to love complexity and the fact that not just anybody could do this.

It was unfortunate that the americium recovery had been shut down for five months due to a labor dispute, and starting it up again was not going to be trivial, which is why an old-timer like McCluskey was on board. As it turned out, when the workers struck, the column was left in mid ion-exchange with acid on top of the resin and the drain valve at the bottom closed. In five months of sitting there, the resin beads had compacted into an unnatural configuration, saturated with americium.

McCluskey stood on the top ladder step and opened the valves on the column to get the process started, with the americium dissolved in acid dripping into the resin. Satisfied that it was started, he retraced his steps through a narrow corridor and back to the control panel desk, where the junior engineer was sitting.

He had just sat down, verbally downloading wisdom to his young associate, when the junior engineer interrupted the conversation. He heard something. Hissing. Like, a steam leak? McCluskey got up and went back to the recovery station, listening and following the sound. The entire glove box was filled with dense brown smoke. Uh oh. He shouted to the junior operator, telling him to call the control room up on the fourth floor and ask for help. Junior had just arrived at the glove box. He took one quick look and ran to the intercom back at the desk.

McCluskey climbed the stepladder and put his hands into the top gloves. They felt strangely warm. Had he forgotten to open the drain valve? He tried it. It was already open. He could not see the pressure gauge because the fumes were so dense, but now he could hear a new hiss, out the bottom of the column. He turned his face to the left and called out to junior, “It’s gonna blow!”

WHAM tinkle tinkle. The operator in the control room heard it over the intercom as the resin column disintegrated in a heavy blast, and the junior operator turned around to see the cloud of debris make it through the corridor maze and to the desk. As soon as his ears cleared, he heard McCluskey’s voice. “I can’t see! I can’t see!”

Junior ran to him and found him knocked to the floor, covered with blood, and the room socked in with americium fog. The windows in the glove box were blown all over the room, two gloves had turned inside out, and three gloves were simply gone. He tried to hold his breath as he rolled McCluskey over and helped him crawl back past the desk and to the outer door. Just then, the control-room operator, having heard and felt the explosion, was scrambling down the stairs to see what was going on, and he saw Junior and McCluskey near the door. He called back to the man following behind him, “A tank has blown up. Call the ambulance and shut down the plant as quick as you can.” It was 2:55 a. m., only 10 minutes after McCluskey had clocked in.

At that instant, a health physicist, trained to monitor radiation and assist in any emergency and called “HP,” ambled through the door and immediately perceived that an explosive radiation release had occurred. The potential for further contamination was obvious to him. He held up both hands and said, “Stay right there. I’ll come and get you.” He turned to the control room operator and told him to back off. No sense getting more people contaminated. He opened the emergency cabinet, pulled a respirator mask over his head and tossed one to Junior and one to the control room operator, telling them to put them on.

As Junior tried to adjust his mask so he could breathe, he heard HP’s muffled voice saying, “We’ve got to get him under some water.” McCluskey looked like he was about to faint. It had to sting like hell, particularly with the nitric acid in his eyes. HP and Junior took him to the emergency shower in the next room, but they hesitated to put him in it. The water would be ice — cold. They were afraid that with his well-known heart condition, the temperature shock could kill him. They stripped off his clothes, took him to the sink on the opposite wall, and sat him down on a stool. HP wiped McCluskey’s face with wet rags while Junior scrounged more rags and some soap.

They tried to keep McCluskey conscious and talking. The glove box had blown up, he said. The last thing he saw was a blue-white flame. HP knew that no criticality alarm had gone off, so it was not a rogue chain reaction with plutonium, as was constantly the concern. It had to have been a chemical reaction, but unfortunately it was a big one. McCluskey’s face and neck, particularly the right side, were perforated with bits of glass, heavily contaminated with radioactive americium-241. His eyes were swollen shut. The right one looked particularly bad, with “black stuff” around it and his right ear, and there was a cut above on his forehead.

At 3:00 am., the ambulance arrived and a nurse, fully decked out in radiation protection clothing, took over. Workers were already putting down plastic sheets on the floor leading to the outer door. The physician-on-call arrived, intending to treat McCluskey for radiation poisoning on the spot, but as he examined the patient it became obvious that a great deal more attention would be required. He and two nurses cleaned him of any obvious contamination, loaded him into the ambulance, and pulled out with full siren and flashing lights at 4:37 am. It was 25 miles to the hospital in Richland. The Geiger counters on board were tapping out gamma-ray hits as fast as possible, sounding like radio static. There was no way to estimate the extent of his americium contamination, because the radiation instruments ran off scale when held to his face or his neck. McCluskey was hot as a pistol. It had to be somewhere between 1 and 5 curies. There had been 17 previous incidents of human americium contamination at Hanford, starting in 1956, but those were all microcuries or nanocuries, a billion times less activity. This was new, unexplored territory.

It was similar to the contamination that the three workers had received at SL-1 back in 1961 in Idaho. They had been standing on the reactor vessel when it steam-exploded, and fuel and fission products, reduced to a fine aerosol, had been driven deeply and irretrievably into their bodies by proximity to the blast. McCluskey’s condition was similar, inoculated by the americium-241. The main difference was that he had survived the explosion. The men at SL-1 had died instantly of the mechanical trauma, before the radiation could have any effect. McCluskey would have to be decontaminated, as if he were a truck sandblasted by an above­ground weapon test, only much more gently.

He was lucky. In 1967 the AEC had paid for an extensive Emergency Decontamination Facility (EDF) to be built at the Richland Hospital, all in response to the SL-1 incident. Everything was made to minimize radiation exposure to the health professionals from a heavily radioactive patient, while preventing a spread of the contamination by radioactive fluids, dust, or gases. An electrically operated hoist and monorail system was in place to move the patient from the ambulance to the operating room, which was equipped with an operating table shielded on all sides with lead. Heavy concrete walls and labyrinthine entrance halls stopped gamma rays from dosing anyone not attending the patient, with movable sheets of lead hanging from the monorail to shield those who were. Lead holding tanks were used for all waste collection, and a two-

stage HEPA-filtered exhaust blower took care of the air.159 Closed-circuit television cameras were used for remote viewing, and there was even a room dedicated to medical-equipment decontamination. There were long-term sleeping quarters for contaminated patients. It was not exactly homey, but to have it in place was good planning. HP had called ahead at 3:08 a. m. to activate the facility.

The ambulance arrived at the EDF at 5:14 am., and treatment for McCluskey’s americium contamination began promptly. Bits of glass, metal, resin, acid, and plastic, mostly too small to see and all covered with americium, were embedded in his right face and shoulder. The danger was from it leaking into his bloodstream, which would take it to his bones and liver. That would kill him if left untreated. Fortunately there was a medicine available that would chemically capture any americium in the blood stream and excrete it through the kidneys. This treatment is called chelation therapy, and it had been extensively tested using beagle dogs. The drug, calcium diethylene-triaminepentaacetate or Ca-DTPA, was quite efficient at cleansing the bloodstream of americium, but in large doses it was toxic. The calcium would displace zinc in the delicate human metabolism. There was Zn-DTPA made to eliminate this problem, but there were very limited supplies of it and it had yet to achieve FDA approval. McCluskey would require megadoses of unprecedented size. For the first five days he would receive large doses of Ca-DTPA with zinc sulfide tablets to counteract the zinc depletion. He was immediately given a gram of Ca-DTPA through a 21-gauge needle, and the gate to the road of recovery swung open.

It would be a long journey, but McCluskey was in the most capable hands. By the end of the first day of treatment, the thorough cleanup and chelation start had reduced his level of contamination to 6 millicuries, or reduction by a factor of 1,000. By day five, chemists at the Pacific Northwest Lab in Richland had produced some Zn-DTPA, and permission to use it was granted by the FDA over the phone. X-rays revealed a galaxy of tiny pieces of debris embedded in his face and neck, but there was no way to go after them with surgery. You cannot remove what is too small to see and pick out with tweezers. On day nine McCluskey was up and walking, and on day 12 he was able to walk around outside. He was taking a big dose of Zn-DTPA twice a day, and his only complaint was eye irritation from the acid burns. On

day 22 a splinter was removed from his right cornea, and that helped.

By day 45 he was becoming depressed with the living conditions in the long-term sleeping quarters, and plans were devised to put him in a house-trailer adjacent to the building. The physicians did not feel that they could send him home yet, because highly radioactive debris particles were gradually working their way to the surface in his face and were being left on his pillow at night. Dealing with that level of contamination spread would be a problem if he were at home. McCluskey, his wife, and his dog moved into their new mobile home on day 79. On day 103 he was allowed a trip by automobile to his home in Prosser, Washington, 30 miles away, where he was pleased with a six-hour stay. His contamination level was falling steadily with chelation, and there were no measurable health effects from his continuous and extremely close bombardment with alpha and gamma radiation. On day 125 he attended church, and here the story of Harold McCluskey took an interesting turn.

All aspects of McCluskey’s injuries had been treated with appropriate care, including for the first time the psychological effects of being in an industrial accident and being a mobile, talking piece of radioactive contamination. Everywhere he went, he carried millicuries of unshielded radioisotope with him. To carry that much radiation in a lead bucket, you have to have a federal license. He harbored a deep concern of contaminating his home, his loved ones, and everything he touched. The psychologists worked on this, assuring him that he would do no harm, but his friends and fellow church members were not so certain. They were overjoyed that he had survived and that he was back in the world with them, but they did not want to get too close to him. They would rather wave to him at a distance and move on. He heard it over and over: “Harold, I like you, but I can never come to your house.” Even though they lived in proximity to a sprawling plant that manufactured plutonium-239 by the ton and had been steeped in the atomic culture all their lives, they were terrified of the fact that he was radioactive. McCluskey had

become the Atomic Man. He felt shunned.160

His growing despair was somewhat lifted when his church pastor gave an impassioned sermon on his behalf, convincing people that it was both Christian and physically safe to be around Harold McCluskey. The senior physician in charge of his case at Hanford, Dr. Bryce D. Breitenstein, gave several lectures concerning his now-famous and unprecedented case of human contamination, with McCluskey along as the actual specimen.

On day 150 of treatment, he was able to return home permanently, visiting the EDF at least twice a week for continued chelation treatment. On day 885 he was taken off Zn-DTPA, and on day 1,115 a slowly decreasing platelet count was noticed, probably due to the continuous radiation exposure. He was put back onto Zn-DTPA on day 1,254, and on day 1,596 his blood platelets were still trending low, but by that time he had bigger health problems. McCluskey died of coronary artery disease, not attributable to radiation, on August 17, 1987. He was 75 years old, and to the last he was in favor of all things nuclear, including nuclear power. He had insisted to all who would get near him that his injuries were a result of an industrial accident and nothing more.

The Atomic Man incident is a representation of the nuclear industry in the late 20th century. It was, even into the 1990s, obsessed with building nuclear weapons. This mission, protected from deep public scrutiny by the often-cited need for national security, seemed to be given priority above any peaceful application of nuclear energy release, and the impression given to the general public continued to erode and distort individual beliefs about the dangerous and the not-dangerous aspects of the industry. It shows that the plutonium production plant in Hanford was better equipped than one might have thought to deal with extreme accidents involving radiation. It also shows that many improvements had been made to the national labs involved in defense nuclear work after the SL-1 explosion, which was a definite wakeup call. McCluskey’s medical treatment was the most advanced state-of-the-art and was expertly applied.

Although it seems illogical, McCluskey’s level of lingering contamination was higher than that of any one person on Earth, yet he was not as affected by it as he was by nitric acid burns on his corneas and clogged arteries in his heart. The nuclear production plants were run with reasonable industrial safety measures in place, but nothing was foolproof, and there were plenty of figurative land mines to step on. Was it any more safe to work there than in a peanut butter factory?

The Hanford Plant made raw plutonium-239, a fissile nuclear fuel, delivered in roughly cast “buttons,” about the size of hockey pucks. It was up to other plants in other states to make it into something useful, and it was always shipped to them in very small batches. Care was taken at every step not to let too much of it bunch up and become an impromptu nuclear reactor, enthusiastically making a great deal of heat and flesh-withering radiation. The next stop in making it into weapons was the Rocky Flats Plutonium Component Fabrication Plant, where it

would be formed into shiny, barely subcritical spheres.161

Rocky Flats was a flat mesa covered with rocks, devoid of trees, about 15 miles northwest of Denver, Colorado, bought by Henry Church for $1.25 an acre back in 1869. It was good for grazing cows if you spread them out. Then came World War II, which the United States brought to an end with its new and unique weapons, catapulting technology abruptly forward. Shortly after came the Korean Civil Conflict in 1950, and the United States, weary of war, found itself trying to prevent North Korea from invading South Korea.

President Harry S Truman sought to gather his options. “If we wanted to drop atomic bombs on somebody, how many do we have in stockpile?” he asked.

“Well,” he was told, “at Los Alamos if we use all the parts that are lying around, we can probably put together two of them.”

President Truman found this answer disturbing. The other nations are looking to us as the benevolent, all-powerful force, able to crush any aggression with a single, white-hot fireball, and we don’t have atomic bombs piled up in a warehouse somewhere? And so began the extended bomb crisis, soon becoming the H-bomb development scramble. The AEC commenced Project Apple to build a special factory to produce the core or “pit” for plutonium-fueled implosion weapons and hydrogen bomb triggers, operating under enforced secrecy. This would take the strain off the Los Alamos Lab so that it could devote most of its effort to improving bomb designs. Dow Chemical of Michigan was awarded the contract, and Senator Edwin “Big Ed”

Johnson of Colorado pushed really hard for his state to be the site of this new venture.162

The U. S. Army Corps of Engineers, real-estate division, acquired the 2,560 acres of Rocky Flats from Marcus Church by the 5th Amendment of the Constitution and took possession on July 10, 1951. They offered $15 an acre, but the purchase price bounced around in the courts for a couple of decades. In the meantime, bulldozers gouged out the foundation of Building D, and construction proceeded at a rapid pace. Building D was for final bomb-core assembly using parts made of plutonium, uranium, and stainless steel built in other buildings. It was eventually renamed Building 991. Building C, or 771, was where the plutonium parts were made.

Everybody who worked at or on the plant, more than 1,000 people, had to have a Q clearance from the AEC, requiring extensive background checks of each person, his or her relatives, and everyone he or she knew. A guard shack was built at the entrance to the property. Three layers of barbed-wire-topped fencing and concertina wire were installed, and security holes were closed. By 1953 the plant was tuned up for full bomb production with 15 shielded, windowless buildings. By 1957, there would be 67 buildings on the site, with only its general mission known to those who did not work there. The Rocky Flats facility was thus a prime example of a Cold War battlefield, where front-line fighting was done in locked rooms, paranoia was actively encouraged, and not a shot was ever fired.

Plutonium is an inherently dangerous material to work with, but there are worse, more radioactive substances. The main problem with plutonium or any of the transuranic elements such as uranium or neptunium is its pyrophoric tendency, or the enthusiasm with which it oxidizes. It is similar to wood, in that a fresh-cut log will burn, but ignition is not necessarily easy. You can waste a lot of matches trying to set fire to a log, even though you know it will burn. It is too massive to heat to combustion temperature easily, and the surface area, where burning takes place, is tiny compared to the volume of the heavy piece of wood. If you really want to set fire to it, then carve it into slivers with a knife. Each thin slice of wood is all surface area, without much mass that has to be heated up. Strike a match to a big pile of shavings, fluffed up and full of oxygen-bearing air, and it will burn like gasoline. The same principle applies to metallic plutonium. A billet of it weighing over a pound (under critical mass!) will sit there in air and smolder. Work it down in a lathe, peeling off a pile of curly shavings, and you have made a fire. No match is necessary. Machining and close work with plutonium components must be done in an inert atmosphere, such as argon.

The problem with a plutonium fire is putting it out. Exposure to the usual extinguisher substances, such as water, carbon dioxide, foam, soda-acid, carbon tetrachloride, or dry chemical, can cause an explosion as the extreme chemical reduction scavenges oxygen or chlorine wherever the plutonium can find it. The predominant nuclide, Pu-239, is an alpha — gamma emitter, but it radiates at a slow, 24,000-year half-life, and it is not difficult to shield workers from the radiation. The smoke from burning plutonium is, however, another matter. If you breathe it, the tiny, alpha-active vapor particles lodge in your lungs, and subsequent cancer by genetic scrambling is practically unavoidable. However, the smoke is extremely heavy, and it drops to the ground quickly. It is not something that will rise into the air, drift with a breeze, and contaminate a large city 15 miles away, or even an adjacent building. It travels beyond the burn site on the bottoms of your shoes.

One cannot work in an argon atmosphere for very long without passing out for lack of oxygen, so the plutonium workpieces and the workers must be insulated from each other. At Rocky Flats in Building 771, long lines of stainless steel glove boxes, raised three feet off the ground, were welded together. A worker standing in front of a glove box would insert his hands in the gloves and perform whatever fabrication task was assigned to that position in the line. The small, always subcritical plutonium units were carried on a continuous conveyor belt, made of small platforms linked together. A plutonium thing would move down the line, from glove box to glove box filled with inert argon gas, and the workers could perform close, precision work using the touch-sensitive gloves, looking through Plexiglas windows, with practically zero exposure to radiation. The conveyor could then turn 180 degrees and continue down the next line in the room, with the plutonium object finally being removed from the line once the nickel plating had been applied.

The room was so crowded with continuous lines of glove boxes, the only way to get from one side of the room to the other was to go under the boxes. For this purpose, each line had a sloping valley dug out under it in the middle, where a person could stoop over slightly and get

under the boxes without having to crawl.163 The air in each assembly room was kept at below atmospheric pressure using blowers and racks of expensive HEPA filters. Air could therefore not leak out of the building and carry any plutonium oxide dust with it. Air could only leak into the building from outside, through imperfections in the airtight structure or when a door was opened. The world outside the building and certainly beyond the fence line was thus protected from plutonium contamination. Of even greater importance, no enemy could tell what was going on inside the buildings or tell how much was going on by reading the radiation signature at a distance. There was no radiation signature.

Plutonium was shipped to Rocky Flats from Hanford as liquid plutonium nitrate in small stainless steel flasks. Each flask, which held seven ounces of plutonium, was purposely isolated from all other flasks by putting each in the center of a cylinder the size of a truck tire. In Building 771, the flasks were emptied using a tube connected to a vacuum pump, and the liquid was transferred to a tall glass cylinder in a special glove box that looked very similar to the one that blew up at Hanford. Hydrogen peroxide was added to the plutonium nitrate, and a solid, plutonium peroxide or “green cake,” precipitated to the bottom. Moving through the glove-box line, the solid material was washed with alcohol, desiccated using a hair dryer, and pressed into 1.1-pound biscuits.

Continuing down the line, the biscuits were sent down the “chem line” to the G furnace, were they were baked into plutonium dioxide and mixed with hydrogen fluoride to make “pink cake,” or plutonium tetrafluoride. On they went on the conveyor to another furnace, where the pink biscuits were reduced to 10.5-ounce buttons of pure plutonium metal. In a day, Building 771

could produce 26.4 pounds of plutonium.164 This raw material was then transferred to the fabrication line, where it was cast and machined into bomb parts, touched only with rubber gloves.

In 1955, a radical design change for atomic bomb cores came up from Los Alamos. Instead of a solid sphere of plutonium with a small cutout at the center for a modulated neutron source, the new cores would be thin, hollow spheres of alternating uranium-235 and plutonium-239. This design change would result in a lighter bomb that could be lobbed by a compact missile aboard a submarine, a ground-launched anti-aircraft missile, or an air-to-air missile on a fighter plane. It could also be boosted by injecting into the empty space in the core a mixture of deuterium and tritium gases, giving the atomic bomb a kick from hydrogen fusion. The management at Rocky Flats was delighted by the news and said that it should not take more than two years of construction and $21 million to make the necessary improvements to the physical plant.

The improvement schedule was fine, but in the meantime Rocky Flats would have to accommodate the new core design with whatever they could put together quickly. The timing was critical, because the Soviets seemed to be improving their arsenal at an alarming rate, and it was critically important to stay ahead of whatever they were doing. The new hollow core would require a lot more complicated machining and casting. There would be many times more machine cuttings and shavings to be recycled back, and larger lathes would be necessary. The fabrication room in Building 771 became extremely crowded as new box-lines were installed. It was hard to walk in the modified building with all the new glove boxes in the way, and the new lathe boxes were made of Plexiglas on all sides, instead of being a metal box with a Plexiglas window. The machinists had to be able to see the work from any angle, and to make a box out of leaded glass was too expensive. The Plexiglas could catch fire easily, and it was against AEC policy to use it in a plutonium line. The policy was waived under these emergency conditions, as it had been when the windows were installed in the original glove boxes.

With the time-critical, crowded work now at the factory, accidents were inevitable. It was June 1957, and the facility was still dealing with several times more plutonium than it was designed for.

The first problem occurred in the glass column used to mix plutonium nitrate with hydrogen peroxide. When you do too much of it too fast, oxygen builds up and pressurizes the column. One day without warning it exploded, blowing the side off the tall, metal glove box and wetting down two workers with plutonium nitrate. It was similar to the Atomic Man incident that happened two decades later at Hanford, but it was minor compared to the next accident. On September 11 the fabrication space, Room 180, in Building 771 caught fire. It was the result of production stress, exactly a month before the plutonium-conversion reactor at Windscale, England, caught fire for basically the same reason. Resolution of the Rocky Flats fire would be eerily similar to that of the Windscale disaster.

A box in the middle of the room was filled with leftover pieces of plutonium and machine shavings, contained in six steel cans and amounting to 22 pounds of fissile, flammable material. In one can was the result of a casting operation. The plutonium metal had been melted as usual in a hemispherical cast-iron crucible, shaped like a punch ladle. To make a plutonium casting, you melt it over a flame in the ladle, holding it by the long handle with the glove. When the metal goes liquid, you carefully pour it into the mold and let it cool and become solid. There is a thin film of plutonium left in the ladle. You peel it off and put it in a can for recycling. It is very thin and perfect for starting a fire. It is called a “skull.”

Just on its own, the skull caught fire at about 10:00 P. M. Plutonium burns with a brilliant white heat. Soon the all-Plexiglas glove box was on fire, and Room 180 was filled with smoke. Two security guards discovered it, seeing flames out of the glove boxes reaching for the ceiling. One went for a CO2 fire extinguisher, and the other called the Rocky Flats fire department.

By 10:15 P. M., the firemen under Verle “Lefty” Eminger were unreeling hose and going in, but Bob Vandegriff, the production supervisor, and Bruce Owen, the night radiation monitor, advised that no water be used. There were 137.5 pounds of plutonium in the room. Water covering it would amount to a neutron moderator, and the fissile plutonium could go critical and become a problem even larger than a raging conflagration. The two men quickly dressed down in Chemox breathing apparatus and went in with CO2 extinguishers, which they quickly emptied into the mass of flames. Nothing happened. They retreated, ran down the hall, and found the large fire extinguisher cart, dragged it into the room, which was now fully engaged, and opened the release valve. The firemen watched as the massive blast of carbon dioxide filled the room and engulfed the fire. It had absolutely no effect on the flames. Where was all the fresh air coming from to feed the blaze?

The 771 supervisor, Bud Venable, had been called at home at 10:23 P. M. and told that his building was on fire. Venable worried that the men going into Room 180 would suffocate or pass out in the heat. He ordered that the fans be turned up to the highest speed.

There were four huge exhaust fans up on the second floor, designed to keep the first floor at negative pressure. They blew the air into a concrete tunnel and up a smokestack, 142 feet high. To keep any plutonium dust particles from making their way into the atmosphere, the air from the first floor passed through a massive bank of HEPA filters on the second floor before exiting the building. The filter bank ran the entire length of the floor, over 200 feet long, made of 620 paper filters. Each filter was a foot thick and presented four square feet to the airflow. The fans, pulling 200,000 cubic feet of air per minute at high speed, sucked fresh air into the blazing fire and sent the flames up to the second floor, where by 10:28 they set fire to the paper filter elements. As was exactly the case with Windscale, thoughtful consideration for the men who were fighting the fire was keeping it going and spreading it.

The blowers should have automatically shut down by now because of the heat buildup in the filter bank, but the fire-detection equipment had been disabled earlier because it was always going off and disrupting production. Fire was obviously being sucked into the air vents in the corner of Room 180. Owen was still apprehensive about causing a criticality in the room, but by now Vandegriff was willing to allow the fire department to hose it down with water. He suggested fog nozzles on the inch-and-a-half hose that the firemen had already laid, and told them not to aim at the glove boxes. The flames went down almost immediately.

Eminger and Vandegriff rushed to the second floor to see if the filters were on fire. The filters had not been changed in four years, and there was a large buildup of finely divided plutonium detritus from all the machining. Just as they opened the door, the dust exploded, knocking Vandegriff to the floor and Eminger back through the double doors. The filtering function was destroyed, and plutonium dust was forced to where it would not go if left on its own, up the stack and into the air over Colorado, by the four powerful blowers. The blast was intense enough to dislodge the lead cap on top of the smokestack. By 10:40 P. M., the remains of the filter bank were engulfed in flame, and at 11:10 P. M. the electrical power failed, finally turning the blowers off. By 11:28 the fire was officially extinguished.

Building 771 was back in business by December 1, 1957, but Room 180 would not be decontaminated until April 1960. The cleanup and replacement of the filter bank cost $818,000.

Of the plutonium known to be in the building, 18.3 pounds of it could not be found.165

That was the small fire. The big one started in connected Buildings 776-777 on Sunday, May 11, 1969. Mother’s Day.

Small, controllable plutonium fires had become a way of life at Rocky Flats. The fire trucks had been called to hundreds of fires since Building 771 was smoked back in ’57. The worst small fire broke out in 1966, when workers were trying to unclog a drain. In that barely mentionable incident 400 people were contaminated, with most of them inhaling plutonium smoke. Countless fires were smothered in the day-to-day work without calling the fire department or mentioning it to superiors.

Plutonium is a very strange element, and some of its characteristics are not understood. It has seven allotopes, each with a different crystal structure, density, and internal energy, and it can switch from one state to another very quickly, depending on temperature, pressure, or surrounding chemistry. This makes a billet of plutonium difficult to machine, as the simple act of peeling off shavings in a lathe can cause an allotropic change as it sits clamped in the chuck. Its machining characteristic can shift from that of cast iron to that of polyethylene, and at the same time its size can change. You can safely hold a billet in the palm of your hand, but only if its mass and even more importantly its shape does not encourage it to start fissioning at an exponentially increasing rate. The inert blob of metal can become deadly just because you picked it up, using the hydrogen in the structure of your hand as a moderator and reflecting thermalized neutrons back into it and making it go supercritical. The ignition temperature of plutonium has never been established. In some form, it can burst into white-hot flame sitting in a freezer.

Unfortunately, the frequent plutonium fires did not make everyone wary of this bad-behaving material. The effect was just the opposite. Everyone in the plant, starting with the top management, became convinced, at least subconsciously, that a plutonium fire was easy to control and was no big problem. Starting in 1965, there were more than 7,000 pounds of plutonium in Building 776-777 at a given time, and it was not given a second thought. There was a list of dangerous procedures, equipment configurations, and building materials at Rocky Flats that converged on Mother’s Day 1969.

First, there was the Benelex. It was a type of synthetic wallboard, no longer made, that resembled Masonite. It had a high density, it could be put together with glue, and unfortunately it was flammable. It was used to make boxes to hold plutonium, shielding for entire glove-box lines, and even the walls of fabrication rooms. Compared to other versatile materials, it was inexpensive. In 1968, 1.17 million pounds of flammable Benelex and Plexiglas were added to

Building 776-777.166

The walls and the glove boxes were flammable, and to top that the hangers on the overhead conveyor belt, used to hook heavy parts and take them to another building, were made of magnesium. Magnesium cut down on the weight, but if it caught fire, it would burn white-hot, like a flare.

Another problem was the cleanup of the machine tools, which made a lot of plutonium chips, scraps, and even dust. These remnants were always oily from the coolant that was sprayed on the plutonium parts as they were shaved down into shape on the lathes and milling machine. When this stuff started building up under the machine, it was gathered, put in a can with a lid, and sent by conveyer to Room 134. Here it was supposed to be degreased using carbon tetrachloride and then pressed into a rough briquette, three inches in diameter and an inch thick, weighing about 3.3 pounds. The degreasing was unofficially dropped from the procedure, as the carbon tetrachloride treatment would too often result in a fire or an annoying explosion. When the press squeezed down on the non-degreased plutonium debris, oil flowed onto the floor, taking with it little pieces of plutonium. Workers sopped it up off the floor using rags.

On that Mother’s Day in ’69, late in the morning, a heap of oily, plutonium-enriched rags beneath the briquette press spontaneously caught fire. There was nobody at work on the plutonium line that day. The Benelex glove box above the burning rags had a ventilation fan, feeding air into the big filters on the second floor. It pulled the hot air from the fire into the box, where there was a can holding a briquette. Someone had neglected to put the lid on the can. The plutonium briquette caught fire, and it burned white hot. The Benelex glove box started smoldering. It lighted some more briquettes. At this point, the fire alarms should have been blaring and automatically calling the fire department, but the detection equipment had been removed to make room for all the new Benelex shielding. More plutonium ignited. The Plexiglass windows and the rubber gloves caught fire, flaming up, and this left the arm-holes open. Air rushed into the glove boxes and fanned the burning plutonium. The fire moved down the north-south conveyer line, away from the connected building 777, taking everything that would burn.

At 2:27 P. M., the heat sensors in the building triggered, alarms sounded, and the fire department rushed to the scene. The firemen found the north plutonium foundry in Building 776 fully engaged. Captain Wayne Jesser ordered a man to discharge a hand-held carbon dioxide extinguisher at the fire to try to scare it while he rolled a fifty-pound extinguisher to the east end and emptied it into the flames. The fire was not impressed. Aware of all the dangers of using water on a plutonium fire, the risk of a hydrogen explosion from oxygen being pulled out of the water and a possible criticality from the moderation effect, he could see no choice. At 2:34 P. M., he ordered his men to deploy the fire hoses and wet it down.

It was not your average industrial fire. In the black smoke the plutonium and the magnesium were burning furiously, and the room was lighted up like a new shopping center opening, even as the fluorescent lights melted and came crashing down on the firemen. Molten lead from the gamma-ray shielding was hitting the floor in globs, and even the glue used to hold the Benelex together was on fire. The Styrofoam in the roof started melting, and the tar on top was getting soft. The powerful blowers were pulling air through the wall on the second floor, just as they were supposed to do, and the filters were already burning. All seemed lost when, in a miraculous stroke of good fortune, a fireman accidentally backed a truck into a power pole and killed the electricity to the building. The fans squeaked to a stop.

Firefighters in full radiation gear were now able to enter the room without being incinerated by

the air-fed flames.167 They came into the crowded space spraying water, and when they moved from line to line, they had to go under, using the sheep dips. The ravines were now filled with water, so it was like wading through a creek in a space suit, up to your chest. The firemen noticed that the oxidized plutonium powder stuck together when wet, like gray Play-Doh. They tried to corral it into a corner using the high-pressure hoses. Fortunately it was too sticky, and it clung to the floor. If they had been able to push it with the hoses as they desired, it would have assumed a critical shape and killed them all with an unshielded supercriticality.

By 8:00 P. M., the fire was declared not burning, but the wet plutonium was still flaring up as late as Monday morning. The AEC investigated the cause of the accident, and its report, criticizing both itself and Dow Chemical for allowing obvious safety lapses, was classified SECRET. With $70.7 million in damages, it broke the record for industrial loss in a fire in the United States. The report from the fire in 1957 had apparently not been read, possibly because it too was SECRET, and no lessons had been learned and applied to preventing further plutonium fires. There were no injuries, and no wind-borne contamination of the surrounding area was detected. Connected Buildings 776-777 were turned into a large parking lot.

By 1992, the mission of Rocky Flats, to fabricate nuclear weapon components, had completely dried up. The Cold War was over, and the last remaining fabrication job, making cores for the W88 “Trident II” submarine missiles, reached the end-of-contract. Of the 8,500 workers, 4,500 were laid off permanently and 4,000 were kept on for cleanup. In 2001, the Rocky Flats National Wildlife Refuge Act of Congress turned the bomb factory site into a nature park. It was amazing, but in three decades of difficult work at Rocky Flats using a great deal of a very dangerous material, plutonium, nobody died in an accident. The work was so secret, negative publicity from it could not do much damage to the public perceptions of radiation and nuclear energy release.

The parts built at Rocky Flats, Colorado, were shipped to the Pantex bomb assembly plant, about 17 miles northeast of Amarillo, Texas, to be made into nuclear weapons. Before 1942, Pantex was a large, 16,000-acre, utterly flat wheat field; but with the pressing need for bombs to drop in World War II, an ordnance factory was built on the site. For the next three years, thousands of workers loaded gravity bombs and artillery shells with TNT. It was dangerous work, and an unusual amount of care was needed to keep from accidentally blowing everything up. The pay was good, but there was no smoking. All nicotine-delivery systems had to be held in the mouth, closed, and chewed. At the end of the war, on VJ Day, the plant was deactivated, and the workers had to find something else to do.

In 1951, the AEC had a sudden need for a centralized plant in the middle of nowhere to manufacture atomic bombs, and the old Pantex site was ideal. The original buildings were expanded and refurbished for $25 million. Proctor & Gamble, expert at making shampoo and

laundry detergent, was put in charge.168 The metal parts for the bombs, including the fissile material, were built elsewhere, but at Pantex the chemical explosives used to set off the nuclear detonations were cast and machined to fit, as if they were made of plastic.

The nuclear weapons used by the United States were almost all “implosion” types, in which the fissile material is forced into a hypercritical configuration using a hollow sphere of high explosives. The shell of explosive material is assembled from curved segments, like a soccer ball. In a normal explosion of a sphere, such as a hand grenade, a detonator at the center of the explosive sets it off. The explosion starts at the point of detonation and moves rapidly outward in a spherical wave-front until the entire mass of explosive is burned up. The wave­front then proceeds outward, as a sphere of compressed gas moving outward very fast. The spherical wave grows larger and larger, and the energy imparted to it by the brief explosion becomes stretched thinner and thinner. Far enough from the explosion, it is no longer strong enough to knock you down, and the destructive explosion is reduced to a loud noise as the energy pulse is spread out over the entire surface area of the sphere.

The implosion works in reverse. Instead of being detonated from a point in the middle, the sphere of explosive must be detonated from its entire outer surface. There is still a spherical wave-front that starts at the surface heading away from the bomb, but this is a waste of energy. There are two wave-fronts. One heads out, and one heads in. Inside the sphere, the wave-front grows smaller and smaller as it heads for the center. The energy from the brief explosion, instead of being dispersed and losing impact, is concentrated down, losing nothing. At the center of the sphere is a small ball of plutonium. The converging wave-front hits it so hard, it bends the molecular forces that are maintaining its density, and it shrinks to a concentrated, smaller size. This new configuration makes it hypercritical. Flying neutrons do not have as far to travel to hit a nucleus, and with the nuclei crowded closer together, it becomes hard to miss. The ball explodes with a sudden release of nuclear power.

The problem is detonating the entire outer surface of the sphere all at once. It is not really possible to do so. The best you can do is to set off about 40 point-detonators placed around the outside of the explosive shell. These can be made to all go off at once, but the explosion does not make a perfectly spherical wave-front. To form this unacceptable, knobby wave-front into a perfect sphere does not require expertise in making hand grenades. It requires optics.

Optics is the art of taking a wave-front of light and warping it into a desired shape using the fact that light travels at different speeds in air and glass. When a light wave traveling in air hits clear glass, it must slow down, and if it hits at an angle, then it is bent, or refracted. Controlling the angle at which the light encounters the glass controls the refraction. This is accomplished by grinding the glass into a curved surface, specifically designed to bend the incoming wave-front into the desired shape. This is how telescopes, microscopes, and vision-correcting glasses are made.

The chemical explosives in an atomic bomb work exactly the same way. There are actually two, nested explosive shells. The outer shell, having the point-detonators, is a fast explosive, producing a high-speed shock wave. The inner shell is a slower explosive, making a lower — speed shock wave. The interface between the two shells is shaped in very specific ways to refract the segmented knobs of the outer shell explosion into a perfectly spherical shock wave in the inner shell, based on the difference in wave-speed in the two media. Explosion in the outer shell is caused by little firecracker-like detonators, and the inner shell is set off by the shock-wave from the outer shell hitting it. Shaping of the solid explosive segments to make this happen must be precise, and one must be careful not to impart a shock to the explosive while machining it.

Post-war improvements on the World War II atomic bombs were numerous and rapidly applied. The old Fat Man nuclear device that wiped out Nagasaki was five feet in diameter and contained 5,300 pounds of high explosive. That seemed clumsy, but by the late 1950s the bomb engineers had it down to 44 pounds of explosive in a bomb that was many times more powerful. At one point, they got it down to 15 pounds. This improvement meant lighter, smaller atomic bombs that could be put in cruise missiles, air-to-air missiles, or a rocket fired from a recoilless rifle bolted to a jeep. The antique formulas having baratol or RDX explosives were supplanted with such exotics as cyclotetramethylenetetranitromine (HMX) and

triaminotrinitrobenzine (TATB).169

Making bombs less bulky was all well and good, but as the energy from the explosives became concentrated into smaller spaces, they got touchy, or very sensitive to being slapped. There were three accidental explosion events in the 1960s, when improper handling procedures led to detonations, but there were no deaths. All operations at the plant were carefully sequestered, with strong blast walls separating an operation from all other operations and not letting an accident become a catastrophe, setting off adjacent explosives or even setting off a nuclear event. All steps of explosive manufacture were done in the smallest possible batches.

On March 30, 1977, the luck ran out at Pantex in Building 11-14A, Bay 8. A machinist had chucked a billet of high explosive in the lathe chuck and turned it by hand to see how it would spin. It was slightly out of alignment, running a bit wobbly on the lathe spindle, and at cutting speed it would vibrate. This is a common occurrence when using a gear-chuck on a lathe. As careful as you are, the work-piece will not necessarily sit right in the chuck when you tighten it up. To remedy this, an experienced machinist will pick up his much-used wooden mallet and tap the piece into alignment, hitting it on the edge that causes the most “run-out.” The last thing the machinist saw was the mallet coming down on the edge of the explosive work-piece. He and two others died instantly in the blast.

The Energy Research and Development Administration report on the accident was issued on March 1, 1979. The sensitive PBX-9404 fast explosive was replaced by less sensitive PBX — 9502, and a movement to change out all the aging, increasingly sensitive explosives in weapons on the shelf gained attention. A Department of Energy Explosive Safety Manual, DOE M 440.1-1A, was in place by the mid-1990s. Pantex is still in business, refurbishing and repairing our aging inventory of weapons, which is probably about 2,200 units.

These misfortunes in the production of nuclear devices are interesting, but none were true atomic accidents. They were industrial accidents of types that could occur anywhere in the technosphere. Authentic nuclear accidents in fuel processing, usually but not always for bomb manufacture, did occur, unlike anything in the history of technology. Some were predictable, and some were not. There have been 22 documented cases of process accidents in which an unexpected criticality occurred in the United States, Russia, Great Britain, and Japan. In these incidents, there were nine fatalities due to close exposure to radiation from self-sustained fission. Accidents occurred with the fissile material in a solution or slurry in 21 cases, and one occurred in a pile of metal ingots. No criticalities were the result of powered fissile material. No accident has occurred in the transportation of fissile material or while it was being stored. Of the many survivors of criticality accidents, three had limbs amputated due to vascular system collapse. Only one incident exposed the public to radiation. There was a clump of 17 accidents between 1957 and 1971, and only two have occurred since.

The first atomic bomb was conceived, designed, and built at the Los Alamos Scientific Laboratory in New Mexico, and after the war it was expanded to one of the largest and most versatile facilities in the galaxy of national labs. In 1958 they were still doing chemical separation of plutonium at Los Alamos, even though most of this was being carried out elsewhere. Somewhere in the above-ground portion of Los Alamos was a dreary, windowless concrete room packed neatly with 264-gallon stainless steel tanks, about three feet in diameter, each held off the floor with four stubby legs and seemingly connected together in all kinds of ways by a maze of pipes, tubes, and cables. They looked like short water heaters. There was a tall sight-glass bolted to the side, so that an observer could see the liquid in the tank and tell how full it was. On top was a push-button switch. Press the switch, and an electric motor would spin a stirring impeller at the very bottom of the tank, mixing the contents into a homogenous fluid.

The tanks were part of the chemical separation system, meant to recover plutonium from machine-shop waste, leftovers in melting crucibles, or slag from casting. The tanks typically held aqueous solutions that were about 0.1 gram of plutonium per liter, which was way below anything that could be made critical, but the tanks, which had been in daily use for the past seven years, were obsolete, and they were scheduled to be replaced soon. They were still in fine condition, but they had been made in a perfect shape for accidental criticality. They had the surface-area-minimizing shape of a soup can, and the ends were rounded. By now it was realized that this was a dangerous shape, even though the procedures were designed to absolutely prohibit there ever being enough plutonium in one tank to go critical. The replacement tanks would be 10 feet high and six inches in diameter, which would discourage anything less than solid plutonium from becoming a runaway reactor.

It was 4:35 P. M. on December 30, 1958, a little before quitting time on the last shift before the New Year’s holiday. A load of 129 gallons of a murky fluid consisting of plutonium, nitric acid, water, and an organic solvent had been drained out of two other

170

vessels and transferred to this particular tank. Allowed to sit for a while, the liquid had separated into 87 gallons of water in the bottom of the tank with 42 gallons of oily solvent sitting on top of the water. This was to be expected, which is why there was an aggressive stirring mechanism built into the tank. Unknown to anyone, plutonium solids, built up from years of processing, had dissolved off the insides of the tanks upstream and landed in this tank. The water in the bottom had only 2 ounces of plutonium dissolved in it, but the thin, disc-like layer of solvent on top contained a barely subcritical 6.8 pounds of plutonium, helped along in its quest to go critical by being homogeneously mixed with a hydrocarbon liquid, an excellent neutron moderator.

It was hard to predict this accident, except for the fact that the steel tank, built to use as little metal as possible, was an ideal shape for nuclear criticality using uranium dissolved in a liquid. When the electric motor was started to stir the two solutions together, it formed a whirlpool in the center. Instead of mixing immediately, the organic solution containing uranium was suddenly reduced in diameter and surrounded by water, making it a supercritical nuclear reactor.

Cecil Kelley had spent the last 11.5 years as a plutonium-process operator at Los Alamos

and he had almost seen it all. He stepped up on a footladder to look at the contents of the tank through a glass porthole on top, cupping his left hand to shut out ambient light. The ceiling fluorescents were illumining the surface of the liquid through another porthole on the other side. It was time to mix the water and the light solvent together. Leaning on the tank, he reached for the stir button with his right hand and pressed it. It took one second for the impeller to reach speed at 60 RPM.

A blast of heat washed over the front of Kelley’s body, going clean through him and coming out the back. It was like being in a microwave oven, as fast neutrons saturated his insides, exchanging momentum with his comparatively still hydrogen nuclei. He felt the strange tingling from gamma rays ionizing the sensitive nerve endings. A rushing noise was coming from the tank, over the whir of the stirring motor. Boiling? There was a slight tremor, moving the tank sideways very slightly, one centimeter, as it walked across the floor on its four legs. He fell backward onto the concrete floor. Dazed and confused, he got to his feet, turned off the stirrer with another push of the button, then turned it back on and ran out of the building.

Two other process workers in the same room saw a flash of blue light on the ceiling, as if a photoflash had gone off, and then they heard a dull thud. No criticality alarms went off, but they both knew that something bad had happened. They rushed to help Kelley and found him outside. He had lost control of his limbs. “I’m burning up!” he cried. “I’m burning up!” They hustled him to the emergency shower, turning off the stirrer as they passed it.

In a few minutes the medical emergency and radiation monitoring staff arrived. Kelley was in deep shock, phasing in and out of consciousness. He looked sunburned all over. By 4:53 they had him in the ambulance and headed for the lab hospital. The radiation monitors ran their Geiger counters over the tank. It was hot—tens of rads per hour. It was the remnant of a criticality in the tank, but how?

When Kelley started the stirring impeller at the bottom of the tank, it was supposed to mix the oily layer on top with the water on the bottom, and it would eventually do this, but first it started the water spinning in a circle, independent of the disc-shaped, plutonium-heavy solvent stratum. The water assumed the shape of a whirlpool, a cone-shaped depression in the middle of the tank. The solvent fell into the cone, losing its large surface area and becoming a shape favorable to fission with the neutron-reflective water surrounding it in a circle. Instantly the cone

of solvent became prompt supercritical, releasing a blast of fast neutrons and gamma rays.171 The criticality only lasted for 0.2 seconds, but in that brief spike there were 1.5 з 1017 fissions. When the two fluids mixed together under the continued influence of the impeller, the plutonium­laden solvent was diluted by the water. The plutonium nuclei became too separated from one another for adequate neutron exchange, and the criticality died off as quickly as it had started.

Kelley’s condition was dire. He was semiconscious, retching, vomiting, and hyperventilating. His lips were blue, his skin was dusky red-violet, and his pulse and blood pressure were unobtainable. He was shaking, and his muscles were convulsing uncontrollably. His body was radioactive from neutron activation.

After an hour and forty minutes, he settled down and was perfectly coherent. He was moved to a private room. The staff drew blood and tried to get an estimate of his radiation dose from counting the activated sodium-24 in the sample. He had absorbed about 900 rad from fast neutrons and somewhere between 3,000 and 4,000 rad from gamma rays. A dose of 1,000 rad was thought fatal.172 His bone marrow had changed to inert, fatty tissue. He started having severe, uncontrollable pain in his abdomen, and he turned an ashen gray. At 35 hours after he had touched the stirrer switch, Cecil Kelley died.

The plutonium process was shut down for six weeks and the tanks were ripped out and replaced with the six-foot columns, as had been planned but put off.

Back in the 1960s, all the fuel reprocessing was not for weapons work, and all was not government-owned. There were also privately owned plants. The early startups were not large operations, but the ultimate goal was to take the spent fuel from power company reactors, extract the unused uranium, sell plutonium waste to the government, compact the fission products for efficient burial, and deprive the Canadians of a monopoly on the manufacture of medical isotopes, such as technetium-99M. Spent reactor fuel was seen as a cash cow, and not as a burden on the power industry. Fuel reprocessing was also considered a necessity for commercial breeder reactor operations, and breeders were expected to start coming online later in the decade.

Spent reactor fuel is mostly unused uranium, which is a natural part of the Earth’s crust and not particularly dangerous. If it could be processed down to the 1.4% that is highly radioactive, nuclear waste disposal would be much easier and reusable fuel would not be wasted.

The United Nuclear Corporation alone owned five plants. There was one in downtown New Haven, Connecticut, one in White Plains, New York, one in Hematite, Missouri, a research lab complete with a nuclear reactor in Pawling, New York, and a brand-new scrap uranium recovery facility in Wood River Junction, Rhode Island.

Before March 16, 1964, Wood River Junction was known for two things. It was the site of a railroad trestle washout leading to a passenger train disaster on April 19, 1873, and it was regarded the coldest spot in Rhode Island. On that day in March, the sparkling new United Nuclear Fuels Recovery Plant began operations. Its first contract was to recover highly enriched uranium from manufacturing scraps left on the floor at a government-owned fuel-

element factory.173

The plant operated on 8-hour shifts, five days a week. Scrap material was received in 55- gallon drums as uranyl nitrate, diluted down to far-below-critical concentrations of uranium. The process to reduce the stuff down into uranium metal used the purex procedure. The incoming liquid was purified by mixing it with a solvent mixture of tributyl phosphate and kerosene, followed by adding nitric acid to strip out the uranium compounds. The uranium concentrate was

then washed of kerosene residue using trichloroethylene, referred to as “TCE.”174

Robert Peabody, 37 years old, lived in nearby Charlestown with his wife, Anna, and their nine children, ranging from nearly 16 years to six months old, and he worked the second shift at the recovery plant. During the day, he worked as an auto mechanic, managing with two jobs to support his family. It was Friday, July 24, 1964, and Peabody had taken time off from his day job to go food shopping. It was getting close to 4:00 P. M. He dropped Ann and the dozen grocery bags at the house and took the five-minute drive to the plant.

The fuel recovery facility was a cluster of nondescript, windowless buildings, no more than three stories tall, painted a cheerful robin’s-egg blue. They were set far back from the road and surrounded by an imposing chain-link fence on a flat, 1,200-acre plot. Peabody clocked in, as usual, and changed into his coveralls.

It had been a nerve-racking week at the plant, mainly due to false criticality alarms. When processing nuclear materials, working with highly enriched uranium in aqueous solutions was about as dangerous as it could get, and an accidental criticality was something to be avoided at all costs. Wednesday he had been working on the second floor, washing down some equipment, when the criticality alarm sounded. Having it blare off nearby was like having a tooth drilled. He and the other four workers left the building in a hard sprint. It took a while to figure out that there was no danger, and that water had splashed into some electrical contacts. The radiation-detection equipment was set to be nervous and sensitive to the slightest provocation.

Later on the same shift, they discovered a substance technically designated “black goo” collecting at the end of the line where uranium was supposed to be coming out. The next day, the line had to be shut down, and everything had to be taken apart and cleaned, and the labeling conventions got a little scrambled as parts and wet rags and bottles were scattered around.

Most of chemical engineering practice had been fully automated by 1964, but this part of nuclear engineering, which was actually similar to other parts of nuclear engineering, seemed based in the nineteenth century. Processing nuclear fuel at this level was an astonishingly manual operation, requiring human beings to carry bottles of liquid material by hand and empty them into vats, tanks, or funnels at the tops of vertical pipes. The system was mostly gravity — driven, with liquid flowing naturally from the top floor to the ground floor in the plant. Somehow it seemed safer to have men carry around batches of uranium in small quantities, knowing exactly where and when it was to be transferred, than letting uncaring machinery do it.

The basic transfer units were specially built bottles, made of polyethylene, four feet tall and five inches in diameter, with plastic screw-on tops. Being tall and skinny, they discouraged a critical mass. No matter how concentrated was the uranium solution, it was impossible to get enough into one bottle to cause a chain reaction. However, it would be possible to stack them together in a corner and make a working nuclear reactor out of filled bottles, as stray neutrons flying back and forth from bottle to bottle would cross-connect them. That possibility was eliminated by having the anti-criticality bottles rolled around from place to place in “safe carts.” Each cart was built to hold the bottle vertically at the center of an open-framed, three-by-three — foot cube, made of angle irons and fitted with four casters at the bottom so it would roll. There was no way that all the bottles in the plant filled with highly enriched uranium solution could go critical as long as they were sitting in safe carts. The bottles were always separated by at least three feet of open space.

The problem with the polyethylene bottles was labeling them to identify the contents. Paper labels stuck on with Scotch tape would come off easily, because the bottles were frequently covered with slippery kerosene residue. The only way to get a label to stick was to hold it on with two rubber bands. On Thursday, the day shift was cleaning out the black goo in the system, and they found a plug of uranium nitrate crystals clogging a pipe. They cleaned it out with steam and drained the highly concentrated, bright yellow solution into polyethylene anti­criticality bottles. Paper labels were attached with rubber bands identifying them as containing a great deal of highly enriched uranium.

Five people at any one time ran the entire plant. On the night shift it was three young technicians, Peabody, George Spencer, and Robert Mastriani, the supervisor, a 30-year-old chemist named Clifford Smith, and the security guard. The plant superintendent, Richard Holthaus, was usually there during the day.

The back-breaking task of the evening was to clean the TCE, which had been used to wash the kerosene out of the uranium concentrate. It was expensive stuff, and it had to be recycled back into the process, but it always picked up a little uranium oxide when washing out the oil. The uranium was separated out of the TCE by adding some sodium carbonate and precipitating it to the bottom of the vessel. This process, like others in the plant, was carried out in small batches, and a shift-load of bottles loaded with dirty TCE was bunched up in safe carts. Peabody was expected to pick up each 35-pound bottle of solution, pour in some carbonate, and shake it for 20 minutes to ensure mixing. There had to be a better way.

Another way of agitating the TCE had been worked out in a previous shift. Weary of manipulating the heavy bottles, a technician had noticed that on the third floor was a perfectly good mixing bowl with a motorized stirrer, and why couldn’t we use that to slosh the TCE? It is not recorded, but I am sure he got the standard nuclear-work answer from the supervisor: “No! Give me a few minutes, and I will think of why you can’t do that.” Technicians could not be allowed to improve operating procedures on a whim. Eventually, the technician was able to wear down the supervisor, and word of an undocumented labor-saving procedure traveled through the plant with the speed of sound. The vessel in question, the carbonate make-up mixer, was about 18 inches in diameter and 26 inches tall, or the size and shape of a very efficient submarine reactor core. It was okay to use it, as long as the uranium content in what it was mixing was less than 800 parts per million, or very, very dilute.

It was nearly 6:00 P. M. Peabody rolled the safe cart with the first bottle in the cluster of what he assumed were bottles of TCE to be cleaned to the base of the stairs. The cart would not make it up the stairs, so he hefted the bottle to his shoulder. The label slipped out of the rubber bands and fluttered to the floor. The contents of this bottle looked about like the stuff in all the bottles. It was yellow, due to the extreme fluorescence of uranium salt, but this was not a bottle of contaminated TCE: it was uranium nitrate dissolved in water, from the black goo cleanout.

It was about as much work to get it up the stairs as it would be to shake the bottle, but Peabody arrived on the third floor, dragged the bottle over to the mixer, and unscrewed the top. The mixer was against the north wall of the room, held a couple of feet off the floor by metal legs, making the rim five feet high. The stirrer motor was hanging over the open top. Workers were protected from falling off the third floor and to the ground floor by a railing on either side of the narrow platform. Leaned against the railing on the right side, very near the mixer, was a folded two-section ladder, lying on its side.

The mixer already had 41 liters of sodium carbonate in it, and the motor was running. Peabody, who was only six inches taller than the lip of the vessel, stepped up on the sideways ladder and tilted the bottle into the mixer. Glug, glug, glug. As the last dregs emptied into the mixer, there was a bright blue flash and the sound of an enormous water balloon being slammed against the wall. As the geometry improved from long and thin to short and round, 6.2 pounds of nearly pure U-235 homogeneously mixed with water went prompt critical. Instantly, the contents of the mixer boiled violently, sending a vertical geyser hitting the ceiling, the walls, and thoroughly soaking Peabody with the products of 1 3 1017 fissions. He fell backwards off the ladder, jumped to his feet, and lunged for the stair well, screaming “Oh, my God!” The criticality alarm went off, and this time it meant it.

Peabody ran full tilt down the stairs, out the door, and was quickly making for the emergency shack, 450 feet away. His fellow workers were right behind him, fleeing the criticality alarm and watching Peabody tear his clothes off. He almost made it, but he fell to the ground naked, vomiting, and bleeding from the mouth and ears. Smith, the supervisor, ran to call Holthaus while Spencer and Mastriani grabbed a blanket from the shack and tried to wrap the injured man on the ground. He got up twice and tried to walk around, but he sank back to the ground with severe stomach cramps.

Soon the company officials and the police were backed up at the gate, and Peabody was loaded into the ambulance. His wife and eldest son, Charles “Chickie” Peabody, were found by a police officer. “There’s been an accident,” he began. “We’ll take you to the hospital.”

At 7:15 P. M., Richard Holthaus arrived at the plant, waving a radiation counter. Peabody had been the only person anywhere near the criticality, and he was the only one affected by the radiation burst. There was no radiation evidence on the ground floor that anything had happened, but nobody had turned off the criticality alarm, and the klaxon was still screaming. At 7:45 Smith joined him, and they cautiously climbed the staircase to the third floor, radiation probe held in front. There was no hint of a continuing criticality. Clearly, enough material had immediately boiled out to stop the chain reaction, but the walls, floor, and mixer showed fission- product contamination and were painted a brightly fluorescent yellow. Peabody’s bottle was still upended in the mixer. Holthaus went over to the mixer, removed the bottle, flipped the switch to turn off the stirrer, and quickly turned to go out the door. Smith took one last look and was right behind him. They had to quickly go downstairs and drain the contents of the mixer into anti­criticality bottles.

The stirring motor coasted to a stop, and the deep, funnel-shaped maelstrom in the mixer vessel relaxed to a momentarily flat surface, before the mixture started another furious boil. The radiation caught Smith in the back as he was hurrying through the doorway. Fortunately for Holthaus, Smith’s body shielded him from the neutrons and he only got a 60-rad dose. Smith at least was not standing directly over the mixer, but he got a serious 100-rad blast of mixed radiation, head to toe.

In its spinning configuration, the uranium-water mixture was a good configuration only when there was a great deal of excess reactivity (uranium) in the mixer. It boiled away the excess until the contents went barely subcritical and the reaction stopped. Holthaus then removed the empty bottle, which was a non-productive void in the would-be reactor, and he stopped the spinning. The surface area of the geometric shape in the mixer went down as the stuff stopped spinning, and the lack of a bottle-shaped void made it complete. The mixture once again went

supercritical.175 The two men were unaware of it, as they were both looking down into the stairwell when it happened, and the alarm was still blaring from the first criticality. Feeling a little strange, they returned to the ground floor, turned off the alarm, and took half an hour draining the mixer.

At the hospital, Anna and Chickie were cautioned to stand at the foot of the bed. Peabody was radioactive, conscious, lucid, and restless. He was given a sedative. “Somebody put a bottle of uranium where it wasn’t supposed to be,” he told them. By Sunday morning he was starting to slip away. His left hand, the one that had held the front of the bottle, was swelling up, and his wedding band had to be sawed off. He drifted off into a coma, and that evening, 49 hours after he saw the blue flash, Robert Peabody died. His exposure had been 10,000 rads, or enough to kill him ten times.

Smith and Holthaus survived with no lasting effects, but they had to give up the silver coins in their pockets, which had been partly activated into radioactive silver isotopes by the neutron bombardment and were quickly decaying into stable cadmium. They were saved only by the distance between them and the supercriticality event and not by any cautious prescience. The walls on the third floor were decontaminated, and production resumed by February 1965. Contracts gradually dwindled away, and the plant closed for good in 1980. Robert Peabody was the first civilian to die from acute radiation exposure in the United States. So far, he was also the only one.

Impressed by the flash-bang end to World War II, the Soviet Union was quick to replicate the nuclear materials production facilities used by the United States. The U. S., in an unprecedented show of openness and generosity, published the final report for the atomic bomb development project, Atomic Energy for Military Purposes, or The Smyth Report, in hardback three days after the Empire of Japan surrendered. It included a map of the Hanford Works, a detailed photo, and an explanation as to how we manufactured the synthetic fissile nuclide plutonium — 239. It was available to anyone in the world with $1.25 to invest, and many copies were bought

for use by Soviet scientists and engineers, eager to get started.176

The robust Soviet building program produced the Tomsk-7 Reprocessing Plant, the Novosibirsk Chemical Concentration Camp, the Siberian Chemical Combine, and, most impressive of all, the Mayak Production Association, covering 35 square miles of flat wilderness.

The production reactors and plutonium extraction plants were built and running by 1948, and the site was treated as the deepest military secret in the Union of Soviet Socialist Republics. Not trusting anyone with anything, the Soviet government was careful not to divulge what was going on at Mayak, particularly to the thousands of people who worked there. This policy resulted in a lack of essential knowledge among the workers, and studies have blamed this for the 19 severe radiation accidents at the site occurring from 1948 through 1958. Among the 59 people who suffered from the effects of radiation exposure, six men and one woman died in criticality accidents. Since the cluster of accidents in those early years of nuclear weapons production, there have been 26 more accidents at Mayak that we know of.

Mayak was an irritating black hole in the intelligence community. It was literally a blank spot on the map of the Soviet Union, and it seemed important to know what was going on there. On

May 1, 1960, an outstanding jet pilot named Francis Gary Powers flew a Lockheed U-2 spy plane 70,000 feet above Mayak. It was a covert CIA mission, the existence of which would be vehemently denied by the President of the United States, Dwight D. Eisenhower. The specially built airplane carried a terrain-recording high-resolution camera in its belly, clicking off frame

after frame as Powers guided it over the plutonium plant.177

Unfortunately for Powers, Eisenhower, and the CIA reconnaissance-photo analysts, the Soviets sent up everything they had against the U-2 flying over their most secret installation. An entire battery of eight S-75 Dvina surface-to-air missiles to blow it up, a MiG-19 fighter jet to shoot it down, and a Sukhoi Su-9 interceptor just to ram into it were deployed in anger. The first S-75 blew up somewhere behind the U-2. It did not hit the plane, but the U-2 was fragile, built only to take pictures and not to withstand roughhousing. The shock wave from the missile destructing in air folded up the U-2 like a wadded piece of junk mail. A second missile shot down the MiG-19, another one caused the Su-9 to auger in, and the remaining five missiles were simply wasted.

Powers bailed out and was immediately captured. His plane was spread out over square miles, but it was gathered up and glued back together as evidence of espionage on the part of the Eisenhower administration. The cover story that it was a weather plane that had strayed off course did not work, and peace talks between Premier Khrushchev and President Eisenhower were cancelled. Powers was eventually repatriated in a prisoner exchange in Berlin, Germany,

with the Soviets getting back their ace spy, Rudolf Abel.178 Mayak remained a mystery until 1992, when the Soviet Union fell apart and true glasnost, or openness, spilled it all.

Of the many ghastly accidents at Mayak, one stands out as unusual and worth a detailed look. Mayak was run under war footing, as were the atomic bomb labs in the United States during World War II, and most workers were undertrained. Carelessness and minimal safety considerations led to many problems, but in this case the participants were nuclear experts near the top of the food chain, and they knew exactly what they were doing.

On December 10, 1968, the night-shift supervisor and a couple of highly placed plant operators conspired to set up an experiment in the basement of the plutonium extraction building. It was an unauthorized research project, breaking the rules and protocols, but they wanted to investigate the purification properties of some organic compounds. They were sure that they would get points for coming up with something better than kerosene and tributyl phosphate as the extraction solvent.

It was 7:00 In the basement was a long, narrow room, having two 1,000-liter tanks bolted to the concrete floor. Four and a half feet above the concrete was built a raised floor with the tops of the two tanks protruding through it. The tanks were used to temporarily hold very dilute mixtures of plutonium salt and water originating upstairs. The pipes had been changed, and there was some resulting confusion as to what the tanks were connected to. Along the walls were two shelves. You entered the room by climbing seven wooden steps to the open doorway, and on the shelf to your left sat an unauthorized stainless steel bucket with two handles. It looked like a cookpot stolen from the cafeteria kitchen, probably used to make soup. It had no business being in the same room with plutonium extract. It could hold 60 liters of fluid.

Scene of the Mayak criticality accident, shown from the side. The first criticality occurred when an inappropriate amount of fissile material was transferred into the tank on the left.

They had tried two extracting solutions the previous day, and somehow the results of both experiments had wound up in tank 2, the one closer to the doorway. The shift supervisor

thought it prudent to find out how much plutonium was sitting in the tank, and he instructed one of the operators to take a sample and have it analyzed. The operator lowered a small glass vial into the tank through a sensor port on top, filled it with fluid, and sent it upstairs to be evaluated.

The sample contained about 0.6 grams of plutonium per liter of fluid. The tank was nearly full, holding 800 liters of liquid. Supervisor made a quick calculation. That meant that there were 480 grams of plutonium in tank 2, which was a nearly ideal shape for criticality. The safety limit for the tank was 400 grams, and he found this puzzling. How could the tank have 480 grams of plutonium in it when 400 was the cutoff for criticality? He ordered operator to take two more samples and confirm it.

While lifting out another sample, operator noticed that the tank was not completely filled with the organic solutions, as they had feared. In fact, it was mostly filled with a weak solution of plutonium in water, with their experimental, oily, concentrated solutions having floated to the top and sitting in a thin disk-shaped layer in the tank. This explained why the tank had not gone supercritical when filled, and supervisor felt slightly better. There may have been enough plutonium in the organic layer to go critical, but only if it were shaped like the entire tank and not spread into a thin layer on top of the water. The process downstream of tank 2 was not set up to work on organic solvents, so they had better decant it off the top of the water before something happened. They found a 20-liter glass bottle, normally used to hold chemical reagents, a two-hole stopper, and two rubber hoses. Operator put the bottle on the shelf, connected the hoses to the stopper, and connected one hose to an active vacuum port on top of tank 1, which was completely empty. He connected the second hose to the stopper and lowered the open end of it into the wide access port on tank 2, being careful to let it suck fluid only from the thin layer of organic solvent on top. The oily stuff was dark brown, indicating that it was thoroughly loaded with plutonium.

Satisfied that all was well, the supervisor left his two operators with the task and went to see how the rest of the shift was performing. When the bottle looked about full, the operators pulled the stopper loose, hefted the 17 liters, and poured it into the big pot, still up on the shelf. One operator had to go to his other duties, and the other found the supervisor to ask him, what next? The supervisor told him to make sure it was all gone out of the tank. By being mindful of the depth of the end of the rubber hose, operator was able to suck out another 20 liters into the bottle, filling it to the top.

Operator pulled the stopper and started emptying the bottle into the big pot up on the shelf. The liquid, a mixture of two plutonium-extraction experiments, was thick, with globs in it. It poured slowly, but the bottle was gradually getting lighter and easier to hold. BANG! A flash of blue light filled the room, and the operator felt the sudden blast of heat hit him right in the face. He instinctively dropped the bottle. It crashed to the floor, sending shards of broken glass and dissolved plutonium scattering across the floor, out the door, dripping down the steps, and to the floor drain. The criticality alarm in the building went off immediately, along with the criticality alarm in the next building, 50 yards away. Everybody in both buildings dropped what they were doing and hastened for the escape tunnels.

The building radiation-control supervisor was the only one not leaving. He switched into emergency mode and made sure that everyone surrendered his or her personal dosimeter before getting away. He then ran into the operator, looking frightened and in shock, and he directed the injured man to decontamination and medical care. Everyone was ordered to not go back into the building until the reason for the criticality alarm could be determined and made safe.

The oily mixture in the stainless steel pot had heated instantly to the boiling point upon going critical, and the resulting thermal expansion turned off the chain reaction. The supercritical condition in these very small, unplanned reactors teeters on a knife-edge, and the slightest modification of the density, the total mass, or the shape of the reactor can shut it down as quickly as it came into being. There it sat, undisturbed, until 11:30 P. M., when, having cooled, it suddenly lapsed again into criticality and faded out when the liquid re-heated. This time, the reaction was too weak to set off the criticality alarm, and nobody was there to be harmed by the mixed radiation pulse.

The shift supervisor was feeling dread about how completely he had botched his experimental program. He had a strong urge to erase what he had done, resetting the situation to normal conditions, but to set everything right he had to get back into the room. The radiation supervisor would hear none of it, but the shift supervisor was adamant. Finally, radiation agreed to follow shift to the area and scope out the extent of the contamination. As they neared the doorway to the tank room, the rate meter on the gamma-sensitive “cutie pie” instrument slid off scale. The room was hot with fission products, and it would be crazy to go in there. Wait for the clean-up team to dress out in radiation suits and come up with a plan to disable the reactor.

Shift supervisor was too impatient for that. Somehow, he talked the radiation supervisor into

leaving him standing in front of the room while he went to check something.179 Shift supervisor, seeing radiation supervisor turn a corner, raced up the steps into the tank room. He saw the pot on the shelf and quickly scoped the problem. The pot was cooling down, and he had to do something very soon, before it had a chance to go critical again. He took the handles in both hands and lifted the pot, planning to dump its contents down the steps and into the floor drain. The plutonium mixture would be so spread out into a thin puddle, it could not possibly regain criticality. The thing was a lot heavier than it looked, and he managed a controlled fall to the floor. It hit with a wet thud, right in the middle of the puddle of plutonium solution.

This time, the supercriticality pulsed like it meant it. As the barely subcritical pot hit the floor, its tendency to fission was extended by the flat field of plutonium-239-bearing solvent now under it. Not only were neutrons reflected back into the pot, they were multiplied by causing fissions outside the critical mass, giving back as many as two neutrons for every one lost by leakage from the surface of the pot. Alarms in both buildings went off again, and supervisor was drenched in fluid as the reactor boiled explosively. Supervisor staggered down the steps and made it to decontamination. He had absorbed 2,450 rem of mixed radiation, and he was a

dead man walking.180

The operator who had made the first criticality suffered from acute, severe radiation sickness. He had absorbed 700 rems of mixed radiation. His vascular system collapsed, and eventually one hand and both legs had to be amputated, but he was still alive 34 years after the accident. A little over a month after the accident, the shift supervisor died.

Mayak is still in business, and safety conditions improved over the decades from “medieval” to levels in keeping with 21st-century handling of radioactive and potentially critical materials.

There has not been a criticality incident since the fatal accident in 1968, and the last death at the plant was in 1990, caused by a chemical explosion in a reagent tank.

The last fatal accident due to an unplanned criticality occurred in Japan in 1999, in a publicly owned nuclear-fuel-processing plant. This accident was unusual in that the criticality was not over in a flash, but would continue to react for an impressive 20 hours, and the two men who died broke the records for length of survival after receiving lethal radiation dosage. It was similar to the previous accident in Rhode Island, in that a break with the standard procedure to make the work easier led to the criticality, and even in 1999 the fuel processing incorporated a surprising amount of manual labor. It was also the first and only criticality accident in which members of the public not involved with uranium processing were exposed to measurable radiation.

The Japan Nuclear Fuel Conversion Co. Ltd. was established in 1979 as a subsidiary of the Sumitomo Metal Mining Co. Ltd. The Fuel Fabrication plant was built in Tokaimura, Ibarakin Prefecture, Japan, on a 37-acre, inner-city plot of ground. Unlike the United States or Russia, where a nuclear plant of any purpose was built in a lonely, isolated place, in Japan it was put in a highly congested, tightly packed city of over 35,000 people. In two large buildings, incoming source material, uranium hexafluoride gas, was converted to either uranium oxide powder or uranyl nitrate dissolved in water. The plant handled uranium used in light-water commercial power reactors. It was a large-scale plant, handling 540 tons of uranium per year at the peak in

1993, but it was only licensed to process low-enriched fuel, about five percent U-235.181 Competition with foreign companies doing the same thing was stiff and production efficiency always needed tightening, but in 1993 the company sold ¥3,276,000,000, or $32,760,000, worth of product.

In 1983, a small facility, the Fuel Conversion Test Building, was erected to be used for special products. The plant’s license was modified to allow the processing of uranium enriched to up to 20 percent U-235 so that startup fuel for the Joy о fast breeder reactor could be produced. Joy о needed fuel enriched to 18.8 percent U-235. Care was supposedly taken in the building’s design to ensure that no enriched uranium would ever be in a critical-sized or — shaped container, so no criticality alarms were called for in the license. An accidental criticality of any

kind in this facility, run by highly disciplined Japanese laborers, was not a credible scenario.182 Gamma-ray detectors were bolted to the walls in all the buildings, in case some mildly radioactive fuel was somehow misplaced.

A step in the licensed procedure for making highly enriched uranyl nitrate was to mix uranium oxide powder and nitric acid together in a dissolver tank. As the nitrate product dripped through the dissolver, it was conveyed by a stainless steel pipe to a long, thin stainless steel holding vessel, specifically designed not to allow a critical mass of liquefied uranium solution to exist in it. The uranyl nitrate solution was then drained out the bottom of the vessel into small polyethylene bottles, each holding a non-critical four liters of solution. A little petcock on the bottom of the vessel controlled the flow into a bottle held under it. Just follow the procedure, being careful not to stack the bottles close together, of course, and nothing can happen.

In 1998 the company’s name was shortened to JCO, requiring less ink to print. By then the fuel-conversion business had fallen to 53 percent of the peak back in 1993, but in September 1999 JCO won a contract to convert 16.8 kilograms of uranium into uranyl nitrate for Joyo. On

September 29, three operators, Masato Shinohara, Yutaka Yokokawa, and Hisashi Ouchi, were assigned the task of dissolving the uranium oxide in nitric acid in seven batches of 2.4 kilograms of uranium each. With each run of uranium being only 2.4 kilograms, there was no chance of criticality.

There was an immediate problem. The drain petcock on the bottom of the long, thin holding vessel was only four inches off the floor. There was no way to fit a bottle under it. The resourceful workers decided to mix the uranium oxide with acid in a 10-liter stainless steel bucket instead. They could then tip the bucket, pour the solution into a five-liter glass Erlenmeyer flask, and then dump it directly into Precipitation Tank B, which had an electrically driven stirrer. This would save time by not having the solution sit around in little four-liter bottles, and the stirrer in Tank B would do the job a lot faster than just letting it drip through the dissolver. This plan indicated a weak understanding of the factors that lead to criticality. True, 45 liters of 18.8-percent enriched uranium solution is not critical, but only if it is in a geometry that does not encourage criticality, such as the long, thin tank. The 100-liter Precipitation Tank B was round and short, meant to incorporate as little expensive stainless steel as possible in its design, and it was therefore an ideal reactor vessel.

Ouchi stood on the metal platform surrounding the top of the tank, holding a glass funnel with his body draped over it. Shinohara climbed the metal steps to the platform, carefully cradling the flask full of solution, and poured it slowly into the funnel. Yokokawa sat at a desk nearby and completed the paperwork. By quitting time, they had successfully processed four batches, now sitting in Precipitation Tank B.

It is always dangerous to have a liquid containing uranium and a vessel of the right size and shape to make a reactor in the same building. By simplifying a transfer process, workers at JCO in Japan managed to make a supercritical reactor.

Next morning, it was more of the same. By 10:35 am. they had done two more batches, and they were almost through pouring the last of batch number seven into the tank. There were 0.183 liters left in the flask. Drip. Drip. There was a blue flash out the open port, lighting up the ceiling. Shinohara and Ouchi staggered down the steps, starting to feel strange. Then came extreme abdominal pain, waves of nausea, and difficulty taking a breath. Yokogawa looked up from his paperwork and turned in his seat, quizzical. The three workers had no idea what had happened, but the gamma-ray alarms were sounding. Ouchi had lost control of his muscles and was sinking into incoherence. His two fellow workers helped him out of the building. Someone had released gamma radiation somewhere in the plant, and they had to get out of the building. The unshielded reactor they had assembled in Precipitation Tank B was still running at power, boiling the uranium solution and broadcasting a deadly mix of gamma rays and neutrons in all directions.

Workers in all three buildings were streaming out and going to the emergency mustering point as the gamma-ray alarms rang everywhere. A worker from the building next door noticed that three guys from the Fuel Conversion Test Building looked injured and confused. He summoned an ambulance, and they were quickly removed to the nearest hospital.

People high up in the organization began to realize that there had to be a criticality on site, and it looked as if it was in the Fuel Conversion Test Building from the high gamma readings near it. No concentration of the gamma rays from uranium could make radiation with this intensity. Nuclear fuel is radioactive, but not that radioactive. Somewhere, a reactor was running. Studying the pen-chart recordings, they could see that it had started up with a large surge of supercriticality, then settled down into quasi-stable critical condition, and the power level dropped gradually by about half in the next 17 hours. They had to find a way to shut it down.

After 4.5 hours, radiation was detected beyond the plant’s fence, with gamma rays and neutrons streaming into the streets of Tokaimura. The mayor suggested that people living within 0.2 miles of the plant should probably go somewhere else. After 12 hours, government authorities stepped in and suggested that people within 7.5 miles of the plant should stay indoors and not take deep breaths. The solution in the reactor was apparently boiling, with steam coming out the open port on top of the tank. Highly radioactive fission products, the scourge of nuclear power, were falling all around in a light, invisible mist.

A plan was worked out to kill the chain reaction, and workers volunteered to execute it shortly after midnight on October 1. Precipitation Tank B was water-cooled by a jacket encircling it. All they had to do was drain the water out of the cooling jacket and the reaction would stop. Neutrons reflected back into the uranium solution from the jacket were all that was maintaining the fission. It seemed simple, but it turned out that it was a lot easier to put water into the jacket than it was to remove it. The piping would have to be disassembled, and it could be done from outside the walls of the plant, but the radiation was still too high for men to work on the plumbing. They had to approach the pipes in relays, with each man allowed to absorb no more than 10 rem (0.1 sievert) of radiation.

The last drop of water was drained from the cooling jacket after the reactor had been running 17 hours. The power level dropped by a factor of four, but it leveled off. The thing was still critical. There was still water trapped in the system. It took three more hours, but the plant workers were finally able to shut it down by blowing out the water using pressurized argon gas.

Just to make sure, they pumped a borax solution into the tank through a rubber hose.183

Hisashi Ouchi, 35 years old, had received about 1,700 rem of mixed radiation. He was burned over most of his body, and his white-blood-cell count had dropped to near zero. He died 82 days later of multiple organ failure. Masato Shinohara, 40 years old, expired on April 27, 2000, 210 days after the accident. He had absorbed 1,000 rem, teetering on the border of a fatal dose. Yutaka Yokokawa was hit with 300 rem. He left the hospital on December 20, 1999, and he is still alive and well.184

At least 439 plant workers, firemen, and emergency responders were exposed to high levels of radiation, as were 207 residents near the plant. Although their exposures were probably 1,000 times the normal background radiation, there have been no unusual sickness or radiation effects reported from these people. The mindset at all levels of the JCO organization and the government regulators had been that no such accident was possible, and therefore there were no accident plans, no review of work procedures, and little thought was put into the equipment layout. The workers were minimally trained, and the primary goal was for everyone to work more efficiently. The Japanese work ethic, for all its strengths, would have to be modified for this peculiar line of endeavor. The JCO uranium-conversion activities ceased in 2003, due to regulatory pressures and dwindling profits, and Japan’s high hopes for nuclear power suffered along with the rest of the economy in a decades-long recession.

A summary of production disasters would be incomplete without mention of the Kyshtym catastrophe near the Mayak plant in Russia. It may go down in history as the worst release of radioactive fission products to have ever occurred, or it may not. Of all the significant nuclear accidents, this one was a black hole in the firmament of knowledge for many decades, locked up tightly by both the Soviet KGB intelligence service and the Central Intelligence Agency of the

United States.185 With so little information to go on, speculation ran rampant and wild theories rushed into the vacuum. All we had was a trickle of partial, confusing reports taken third-hand from some excitable defectors or exiles. We could not even tell when this contaminating incident had occurred, with dates ranging from 1954 to 1961. It looked as if several lesser incidents may have been woven together into a combined story.

What type of accident was it? It was variously described as an earthquake, a landslide, an accidental A-bomb detonation, a test-drop from a Soviet bomber, a reactor explosion, a graphite fire in a reactor, a meteor hit, and a steam explosion in a holding tank. No explanation made sense, and overflights by U-2 spy planes trying to find visual confirmation of a nuclear catastrophe were curtailed by the loss of Gary Powers’s plane over Mayak. Articles, papers, and even books were written about it, but the mystery of what happened at Kyshtym would not be solved until the beginning of the end of the Soviet Union in 1989.

The first published inkling of a radiological problem in the East Ural Mountains claims to be the

June 1958 edition of Cosmic Voice, the monthly journal of The Aetherius Society.186 On April 18, 1958, George King, founder of the society in 1955, was contacted telepathically by two

beings riding around in a UFO.187 The first message was from an individual identified only by origin, Mars Sector 6:

Owing to an atomic accident just recently in the USSR, a great amount of radioactivity in the shape of radioactive iodine, strontium 90, radioactive nitrogen and radioactive sodium have been released into the atmosphere of Terra.

This message, relayed through King’s larynx and recorded on a reel-to-reel tape, was followed by a second pronouncement from The Master Aetherius from Venus:

All forms of reception from Interplanetary sources will become a little more difficult during the next few weeks because of the foolish actions of Russia. They have not yet declared to the world as a whole, exactly what happened in one of their atomic research establishments. Neither have they declared how many people were killed there. Neither have they declared that they were really frightened by the tremendous release of radioactive materials from this particular establishment during the

The report goes on to claim that the Interplanetary Parliament will have to use an enormous amount of energy to clean up this mess. They were, however, able by Divine Intervention to save 17,000,000 people from having been "forced to vacate their physical bodies,” which may be a euphemism meaning to die of acute radiation poisoning. They were given permission by the Lords of Karma to intervene on behalf of Terra, presumably in cooperation with Divine Intervention.

This brief announcement was followed by mention of the contamination accident in a book, You Are Responsible!, published by The Aetherius Society in 1961, and there it sat for another 15 years, with no further mention outside certain secretive compartments in the CIA.

On November 4, 1976, an article, “Two Decades of Dissidence,” was published in the New Scientist magazine for its 20th anniversary issue. The author, Zhores A. Medvedev, a Soviet biologist, had gone into exile in London with his family in 1972 and gotten a job as senior research scientist at the National Institute for Medical Research. In his article, he mentioned that in 1957 or 1958 an explosive accident had contaminated a thousand square kilometers of territory in the Ural Mountains with radioactive debris. Hundreds of people were killed, thousands had to be evacuated, and the area would be a danger zone from now on. The New Scientist, aware of the stale claim by The Aetherious Society, proclaimed “Scooped by a UFO!” on a back page. Medvedev’s story was roundly denounced as “science fiction,” and was thrown into the same box with the Aetherions.

To be fair to the naysayers, the story was unbelievable. If a ground-level nuclear device had accidentally detonated, its signature of high-thrown radioactive dust would have been picked up by Western governments within hours of the blast, and the same was true if a bomber-dropped weapon had been used to test a simulated city on the ground. It was hard to hide such tests or

accidents.188 It was true that the Soviets had six graphite reactors at Mayak, which was then known as Chelyabinsk-40, but it would be hard for a graphite reactor fire or even a graphite steam explosion to kill hundreds of people unless they were standing on top of it, and how were thousands injured, needing immediate hospitalization? Not even Soviet engineering would place production reactors so close together that an explosion in one could set off the others. A single plutonium production reactor, for all its buildup of radioactivity, is limited in the damage it can do. While it would be possible to contaminate thousands of square kilometers with plutonium and fission products, this would be a low-level contamination. It would be a long-term danger and not producing immediate injuries. A seismic event that would swallow Chelyabinsk-40 would have showed up on seismographs around the world, and a destructive landslide in the heavily wooded Urals seemed unlikely.

Medvedev reasoned that it must have been an underground storage tank filled with waste products from the plutonium processing, heating up in the confined space and causing a sudden, massive steam explosion from the water content of the solutions. It seemed almost plausible, but fresh, concentrated fission waste, straight out of a reactor that had been running at full power, only generates about 60 kilowatts of heat per ton. After a year of sitting quietly, the same waste is putting out 16 kilowatts of heat, and after ten years the rate has fallen to 2 kilowatts per ton. This is certainly enough heat to melt through a steel tank or even to blow the thing wide open, but it lacks the power concentration to cause the reported level of mayhem. Even if left-over plutonium were to make a supercritical mass in a waste tank, it would simply boil the water furiously until it modified its own configuration into subcriticality. As we have seen in all the criticality accidents, to be killed you must have been embracing the reactor. The

reported power of the blast did not correspond to what would be contained in a steel storage tank.

Shortly after Medvedev’s article appeared in the New Scientist, articles appeared in three British newspapers seeming to confirm his incredible story. The newspaper articles, all appearing on December 7, 1976, linked back to a letter to the editor in the Jerusalem Post, sent in by another ex-Soviet, Professor Leo Tumerman, former head of the Biophysics Laboratory at the Moscow Institute of Molecular Biology. Tumerman had written to strongly disagree with Medvedev’s assertion that the supposed accident could have been the result of a reactor explosion. It was common knowledge in Russia, he claimed, that the catastrophe was the result of gross negligence on an industrial scale. He was not sure how, but the careless storage of radioactive wastes at Chelyabinsk-40 had resulted in massive destruction.

Tumerman had not been there at the time, but in an automobile trip in 1960 he had seen evidence of a disaster with his own eyes. He had been visiting his brother, an engineer, at the construction site of the Byeloyarsk power reactor, about 300 kilometers from Sverdlovsk in the Southern Ural Mountains. From there he had to drive about 180 kilometers to Miassovo, near Chelyabinsk-40, for a summer seminar on genetics. He reached the main highway heading south at about 5 a. m., and soon he passed a large declarative road sign. It was a warning to all drivers: DO NOT STOP FOR THE NEXT 30 KILOMETERS! DRIVE THROUGH AT MAXIMUM SPEED!

The next 30 kilometers of highway were quite strange. As far as the eye could see, there was nothing there. No cultivated fields or pastures. No herds of cows. No people. No birds. No insects splatting against the windshield. No towns or villages. No trees. There were only chimneys sticking up all over the place, with no houses connected to them.

Curious about what he had seen on the drive to Miassovo, he got an earful from some seminar participants. The whole countryside was hot from radiation contamination. It was caused by an explosion at either the plutonium production plant or a waste tank. Details were fuzzy, but thousands had been evacuated permanently, and their houses were burned down to prevent looters from hauling away contaminated objects and spreading the radiation farther than it was. Everyone called it the “Kyshtym Disaster.” It actually occurred at Chelyabinsk-40, but Chelyabinsk-40 officially did not exist, and Kyshtym was the nearest town on the map. No further details were forthcoming, and experts were puzzled. Finally, in 1989, formerly secret files concerning the Kyshtym Disaster started finding their way out of the crumbling Union of Soviet Socialist Republics, and the unexpected truth began to crystallize. Nobody had speculated correctly.

Under the Stalin and later the Khrushchev governments in the Soviet Union, the safety of the environment and even workers was not exactly a primary concern. The six graphite plutonium — production reactors at Chelyabinsk-40 used open-loop water cooling, pumping water out of Lake Kyzyltash and dumping it back in. At first, liquid waste from the plutonium extraction plant was simply dumped into the River Ob and allowed to empty into the Arctic Ocean. In 1948, plutonium production was at a fever pitch, and there was no time to work out the details of making the process efficient. It was extremely important that a nuclear weapon be successfully tested before the official celebration of Stalin’s seventieth birthday, which would be on December 18, 1948. They did not quite make it, but the RDS-1 plutonium-fueled bomb was

successfully tested on August 29, 1949. The rest of the world was stunned by this development, thinking that the Soviet Union was farther behind than that.

In the crash program to produce fissile bomb material, a great deal of plutonium was wasted in the crude separation process. Production officials decided that instead of being dumped irretrievably into the river, the plutonium that had failed to precipitate out, remaining in the extraction solution, should be saved for future processing. A big underground tank farm was built in 1953 to hold processed fission waste. Round steel tanks were installed in banks of 20, sitting on one large concrete slab poured at the bottom of an excavation, 27 feet deep. Each bank was equipped with a heat exchanger, removing the heat buildup from fission-product decay using water pipes wrapped around the tanks. The tanks were then buried under a backfill of dirt. The tanks began immediately to fill with various waste solutions from the extraction plant, with no particular distinction among the vessels. The tanks contained all the undesirable fission products, including cobalt-60, strontium-90, and cesium-167, along with unseparated plutonium and uranium, with both acetate and nitrate solutions pumped into the same volume. One tank could hold probably 100 tons of waste product.

In 1956, a cooling-water pipe broke leading to one of the tanks. It would be a lot of work to dig up the tank, find the leak, and replace the pipe, so instead of going to all that trouble, the engineers in charge just turned off the water and forgot about it.

A year passed. Not having any coolant flow and being insulated from the harsh Siberian winter by the fill dirt, the tank retained heat from the fission-product decay. Temperature inside reached 660° Fahrenheit, hot enough to melt lead and cast bullets. Under this condition, the nitrate solutions degraded into ammonium nitrate, or fertilizer, mixed with acetates. The water all boiled away, and what was left was enough solidified ANFO explosive to blow up Sterling

Hall several times, being heated to the detonation point and laced with dangerous nuclides.189

Sometime before 11:00 P. M. on Sunday, September 29, 1957, the bomb went off, throwing a column of black smoke and debris reaching a kilometer into the sky, accented with larger fragments burning orange-red. The 160-ton concrete lid on the tank tumbled upward into the night like a badly thrown discus, and the ground thump was felt many miles away. Residents of Chelyabinsk rushed outside and looked at the lighted display to the northwest, as 20 million curies of radioactive dust spread out over everything sticking above ground. The high-level wind that night was blowing northeast, and a radioactive plume dusted the Earth in a tight line, about 300 kilometers long. This accident had not been a runaway explosion in an overworked Soviet production reactor. It was the world’s first “dirty bomb,” a powerful chemical explosive spreading radioactive nuclides having unusually high body burdens and guaranteed to cause havoc in the biosphere. The accidentally derived explosive in the tank was the equivalent of up to 100 tons of TNT, and there were probably 70 to 80 tons of radioactive waste thrown skyward.

It took a while for the government to rush into damage-control mode. A week later, the Chelyabinsk newspaper published a cheery story concerning the rare display of northern lights in the sky last Sunday, showing “intense red light, sometimes crossing into pale pink and pale blue glow.” It “occupied a large portion of the southwest and northeast part of the sky.” At the same time, massive evacuation measures were enforced, eventually emptying 22 villages along what would become known as the “East Urals Radioactive Trace,” or the EURT. No explanation was given as to why everybody had to leave. Over the next two years, around 10,000 people were permanently relocated. The reason for storing nitrate solution and organic solution together in the same tank has not been revealed. The EURT is now disguised as the “East-Ural Nature Reserve,” as an explanation for its prohibited access.

Although about 475,000 people were probably exposed to dangerous levels of radiation due to this incident, figures detailing radiation sickness and deaths are simply not available, even with the KGB files broken open and published. Refugees from the area reported that all hospitals within a hundred kilometers were inundated with people affected by the blast, coming in with burned skin, vomiting, hair loss, and every symptom of having survived an atomic bomb detonation. Hundreds of immediate deaths are commonly quoted, with thousands of sickened survivors. As has been noticed time after time in mass nuclear disasters outside the plant gates, an information blackout can turn a healthy population into a suffering mob just from the twisted psychology of fear and dread. Rumors can make people sicker than radiation exposure.

Studies of the effects of this disaster are extremely difficult, as records do not exist, and previous residents are hard to track down. A late study by the former Soviet Health Ministry cites 8,015 delayed deaths due to radiation effects in the area from 1962 to 1992, but on the other hand only 6,000 death certificates from all causes of death have been found. Add to that the possibility that just about everybody over 12 years old in the area smoked Turkish cigarettes, and cause of death is a toss-up between lung cancer and the effects of alcoholism. There are no hard records of immediate deaths due to the chemical explosion or acute radiation poisoning on site. Recent epidemiological studies suggest that 49 to 55 people along the EURT have died because of radiation-induced cancer, and at what is now the Mayak plant, 66 workers suffer from chronic radiation sickness dating back to 1957.

All this ranks the Kyshtym Disaster as possibly the worst, most senseless catastrophe in the history of nuclear power. Hopefully the conditions that caused it have subsided and this will never happen again. There would be more mischief in the Union of Soviet Socialist Republics as the world became more information-conscious, and we will have a hard look at it. But first, let us examine how all those nuclear weapons, cited as necessary for world peace, were handled with loving care by the Armed Forces.

159HEPA stands for High Efficiency Particulate Air (or “Arresting”). It was developed for the Manhattan Project during World War II for preventing the spread of airborne radioactive contaminants, and it has become a set of industry standards, a trademark, and a generic term for the best air filters available. It is now used in aerospace, pharmaceutical plants, hospitals, computer chip manufacturing, and all nuclear industries. By specification it must remove 99.97% of all particles larger than 0.3 micrometers from the air that passes through it.

160To be fair, I must point out that wherever he went, McCluskey carried a radiation counter with a speaker to broadcast the amplified sound of gamma rays crashing through the detector tube. If he held it up to his face, it made quite a noise. He thought that doing this would show that although he was still heavily contaminated, he was a normal, healthy human being with whom you could shake hands without dropping dead from radiation poisoning. This message did not get through as he may have hoped. The fear of anything radioactive, even a family friend, still runs deep in the civilized, educated world, and the buzzing Geiger counter could spook a horse.

161Plutonium is a dull-looking metal that quickly corrodes in atmosphere, so the two hemispheres used to make a bomb core were coated with something to keep the air out. The most-used coating was nickel plating, which gave the finely machined parts an attractive metallic shine. You did not want to scratch the plating, as doing so would result in heavy white smoke as the plutonium caught fire.

162Big Ed (six foot two) was one of nine members of the Joint Committee on Atomic Energy (JCAE) as well as senior member of the Senate Military Affairs Committee. He and the other senator from Colorado, Eugene Millikan, were able to divert some big, important projects to their state, including the North American Air Defense Command (NORAD, an A-bomb-proof headquarters in Cheyenne Mountain), the United States Air Force Academy in Colorado Springs, and a lot of uranium mining. The Rocky Flats plant was their crowning achievement. Big Ed eventually made a disastrous slip of the tongue in a live television show, “Court of Current Issues,” in New York on November 1, 1949. Johnson casually mentioned that the United States was developing the hydrogen bomb, which would be 1,000 times more powerful than what we had dropped on Japan. Television being what it was in 1949, it took a while for this incredible announcement to sink in, but the Washington Post took hold of it on November 18. The project was now subjected to the blinding glare of public opinion, and there would be no more quiet examination of the issues. President Truman was not pleased, and he wrote a one-sentence “Dear Ed” letter to Senator Johnson on December 17.

163The workers named the underpass ravine “sheep dip.” There was no drain at the lowest point in the dip, and anything dropped on the floor would eventually end up there. Visiting physicists renamed this feature the “Lamb dip,” having to do with the spectral hole in the HeNe laser cavity at 1.1 microns. The humor went over most heads.

164This was about enough to make two bombs. The old Mark I “Fat Man” used 13.6 pounds of plutonium in the core, but the newer designs used less plutonium, and some had U-235 components as well, reducing the amount of needed Pu-239, increasing the bomb yield, and reducing the weight.

165Dow Chemical’s report of this accident was classified SECRET until 1993. The investigation found that somewhere between 1.8 ounces and 1.1 pounds (50 to 500 grams) of plutonium made it up the smokestack and landed somewhere in Colorado. No trace of it has ever shown up in radiation surveys of the surrounding land. Note that the safety exposure limit for a worker at Rocky Flats was 0.0000005 grams of plutonium.

166Why Benelex? It turns out, Benelex is an excellent neutron shield, and in the 1960s it was used extensively in nuclear research for shielding neutron collimators and interferometers. A component of Benelex is wood fibers, and harvested wood in the U. S. grew up soaked with borax, a wood preservative and insect-damage preventative. Plutonium-239 can spontaneously fission on occasion and send neutrons careering through the room, and the contaminant plutonium-240 is particularly apt to do this. When hit by neutrons of any speed, these particles are slowed to thermal speed by the hydrogen in the cellulose wood fibers and are summarily absorbed by the boron-10 remnants from the borax treatment. The classified purpose of using Benelex was to kill any neutron activity in the building, preventing the plutonium pieces in the building from cross-connecting by neutron flight and causing the building to become one enormous nuclear reactor, running uncontrolled with people inside it. On Mother’s Day 1969 there were 7,641 pounds of plutonium in the building. The first power reactors in the world, the plutonium production reactors at the Hanford Site, used Masonite, a similar material, for neutron shielding beginning in 1944.

167The danger from radiation in most situations aside from criticality is that broken skin, lungs, or the gastro-intestinal system can be contaminated with radioactive dust. You do not want to be inoculated with a long-term radioactive nuclide in small quantities. Wading into a mixed radiation field for a short time is not really what causes health problems, but having dust decay inside you for a long time is. For this reason, a radiation protection suit seals you up against any interaction with the environment. An airtight coverall with tape-sealed gloves and booties is standard, along with self- contained breathing apparatus and a full head-covering. It is not pleasant. You cannot scratch your nose.

168The Maintenance and Operations (M&O) contract for Pantex was reassigned to Mason & Hanger—Silas Mason Co., Inc., Mason Technologies, Inc., in 1956. Mason & Hanger was the oldest engineering and construction company in the United States, dating back to 1827 in Virginia, and they had a lot of experience in managing ammunition plants.

169In the 1960s at the apex of nuclear weapon development, the most favored chemical explosive formulas were PBX-9404 (93% HMX, 6.5% nitrocellulose, 0.5% wax) and LX-17 (92.5% TATB, 7.5% wax). Wax was used as a binder that would melt in heat and re-solidify when cooled. The “exploding wire” detonators used pentaerythritoltetranitrate (PETN).

170The official reports of this incident always refer to an “organic solvent” without specifying what exactly was in the mix. It was surely a 30-percent solution of tributyl phosphate in kerosene, the active ingredient in the ion-exchange process known as PUREX. Invented during the Manhattan Project at the University of Chicago, PUREX (Plutonium URanium EXtraction) was the fuel-processing method of choice through the 1970s. It was classified SECRET at the time of this incident, and report writers were careful not to divulge any information that was not necessary in explaining an accident.

171I remind the reader that “prompt” supercriticality means that the mass of plutonium plus moderator is sufficiently supercritical to begin increasing the rate of fission exponentially without waiting for the delayed fission neutrons to contribute.

172The radiation dose specification of “rad” (Radiation Acquired Dose) used in the official reports is now considered obsolete. It is often expressed in “rem” (Roentgen Equivalent Man,” because radiation counters are calibrated in rem, but that specification has been replaced with the sievert by the Systeme international d’unites, and the rad has been replaced by the “gray” The estimate of Kelley’s total dose has been revised a few times, and it may have been as high as 18,000 rems, or 180 sieverts. The only important point of these numbers is that that much radiation could have killed him 18 times.

173This material was probably MTR fuel scraps from Oak Ridge. The Materials Test Reactor (MTR) was built at the Nuclear Reactor Test Station in Idaho and started up in March 1951. Its fuel was a unique design, made of bomb-grade uranium metal, enriched to 93% U-235. The uranium was mixed with pure aluminum to make an alloy formed into a long rod, and clad in a layer of pure aluminum, or “aluminum 1000.” The rod was then flattened between two steel rollers and bowed slightly along the major axis. This simple fuel-element design became an international standard, and “MTR fuel” was used in dozens of research reactors all over the world. As these aged reactors are decommissioned, particular care is taken to see that the highly enriched uranium fuel does not fall into the wrong hands.

174The trichloroethylene (TCE) used in the wash-out step is incorrectly referred to as trichlorethane (chlorothene) in A Review of Criticality Accidents: 2000 Revision (LA-13638) by the Los Alamos National Laboratory Trichlorethylene was originally formulated in Great Britain as a general anesthetic to replace chloroform, but by 1956 better, less-toxic substitutes were found. Since the 1970s it has been widely banned from use in the food and medical industries, and is considered a carcinogen. Exposure to it seems to lead to Parkinson’s disease.

175At a glance, this incident bears a close resemblance to the fatal accident at Los Alamos detailed in the previous sketch. The two are different in subtle ways, but both are examples of how an unexpected concentration of fissile material can be dangerous if it is shaped just the wrong way At Los Alamos, the tank containing a benign mass of plutonium was made critical by powerful mixing action that first stirred the water beneath the oily solution. For just a second, before the oil and water were able to mix, the funnel in the water caused by the stirring forced the oily plutonium solution to assume a shape with less surface-to-volume ratio, which reduced the non-productive escape of stray neutrons, and the mass went supercritical. In the case of Wood River Junction, a solution of sodium carbonate (washing soda) was already turning slowly at the bottom of the tank before Peabody poured in the uranium dissolved in water. Going from the high-surface-area bottle to the low-surface-area mixing tank is what made the uranium-235 go supercritical. The change in shape made such a huge difference, it did not matter that the uranium solution was diluted when it hit what was already in the tank. In both cases, the plutonium criticality and the uranium criticality, there are always a few stray neutrons bouncing around from spontaneous fissions in the fissile material. Unless there is a critical mass for the given shape, spontaneous fission leads to nothing.

176The first edition did not have the photographs, but there were at least eight editions, and the helpful photos were added. There were over 170,000 copies of the U. S. edition alone, and it was on the New York Times bestseller list until late January 1946. A British edition was published in 1945, and eventually it was published in 40 languages all around the world. At the top of page iv is written: “Reproduction in whole or part is authorized and permitted.”

177This was actually the second flight over Mayak. The first had been made in April, with the camera running as the plane flew over a 300-kilometer line from Kyshtym to Pionerski in the East Ural Mountains. The reason for these expeditions will become clear at the end of this chapter.

178Powers returned home to a cold reception. The CIA was upset because he had not hit the self-destruct button in the U-2, nor had he injected himself with the suicide needle, hidden in a coin. He got a job as a test pilot for Lockheed, and later as a news helicopter pilot. He died in 1977 when covering brush fires in Santa Barbara County when his helicopter ran out of fuel. Although he was awarded the Order of the Red Banner back in the USSR, Rudolf Abel (Willie Fisher) failed to recruit or even identify a single Soviet agent in his eight-year deployment in New York City His cover began to unravel in 1953 when his assistant, a Finnish alcoholic, accidentally spent a nickel containing a microphotograph of a coded message. A newsboy dropped the nickel, and the hollowed-out coin split in half, revealing the strange film negative inside. It was downhill from there, and Abel was captured in 1957.

179The existing record of what happened at Mayak was given to the team at Los Alamos compiling A Review of Criticality Accidents in 1993 by Gennadiy S. Stardubtsev and A. P Suslov This particular report is unusual, in that no written papers or articles were referenced, and the account is apparently taken from memory and notes. This documentation does not specify how the shift supervisor was able to talk the radiation supervisor into leaving him in front of the room. In my imagining of the situation, the shift supervisor probably told the radiation supervisor that he needed to make sure that the heavily dosed operator had not spread radiation all over the floors and walls on his way to decontamination. He would wait quietly here while the radiation supervisor checked it out with his instrument. Radiation supervisor left, reminding shift supervisor not to move.

180We may never know his name, but the night shift supervisor at the Mayak plutonium extraction building was awarded the not-coveted 1994 Darwin Award. The Darwin is given to that individual who has taken his or her (usually his) self out of the gene pool by doing something really stupid, therefore proving that evolution works by not allowing people who should not reproduce to do so. http://darwinawards. com/darwin/darwin1994-25.html

181The company wished to process Mixed OXide fuel (MOX), which is a combination of uranium and plutonium, derived from reprocessing spent power- reactor fuel. The United States opposed this plan under a new nuclear nonproliferation policy fearing that Japan would either secretly build up a nuclear weapons stockpile or sell plutonium under the table to some other Asian tiger, neither of which seemed likely. Heated negotiations went on for three years, beginning in 1977. The U. S. finally gave in, agreeing to a proliferation-resistant process for mixing plutonium and uranium devised by the Japanese Power Reactor and Nuclear Fuel Development Corporation (PNC). Several power reactors, including Fukushima Daiichi 6, have been operated using MOX fuel, saving uranium and burning off otherwise unusable plutonium.

182This “credible accident” criterion would bedevil the Japanese nuclear industry on March 11, 2011, when the Fukushima Daiichi power plant was knocked out of service by an earthquake and tsunami wave. This was not a credible scenario, so no preparations were made to prevent damage during such an event.

183Nothing shuts down a chain reaction faster than boric acid in the coolant. The boron-10 nuclide absorbs thermal neutrons voraciously. There is a legend in nuclear engineering about some janitorial workers who were tasked with cleaning up the inside of an aluminum research reactor vessel. They did a marvelous job, making it sparkle and shine, but they used 20 Mule Team Borax as the detergent. The reactor never again achieved criticality, with the boron scrubbed into the inside surface of the vessel. It doesn’t take much.

184I am expressing radiation doses received in the archaic “rem” notation to try to keep them in context with the earlier accidents. To convert to sieverts, or Sv, divide the rem by 100. Radiation levels, dosage, or exposure is expressed in many ways, on technical grounds, and this can make it difficult to simplify explanations of the effects of radiation on human beings. Please bear with me.

185Why did the CIA keep this locked up? It may have just been a product of the secret mindset of intelligence organizations. Having big secrets was important to the CIA, but if everybody knew about it, it would not be a secret anymore. More likely it was fear that if information concerning an accidental, massive contamination of a large patch of populated territory was released to the public, there would be mass hysteria and a popular call to bring an end to nuclear power. This would ruin the careful campaign of the AEC to promote nuclear power, get it off the ground, and transfer it to the public sector. If so, this was a case of one government agency looking out for the welfare of another.

186I would prefer to think that there was an earlier leak of the story possibly in the Danish newspaper Berlingske Tidende in April 1958. The event was not widely noticed by the Western press.

187UFO is an Air Force term, meaning Unidentified Flying Object, or an apparently controlled machine moving through the atmosphere that cannot be classified by type, country of origin, manufacturer, or serial number. The Aetherius Society is technically a “UFO religion,” in that it depends upon a belief in extraterrestrial entities operating UFOs. There are many such religions, the largest of which is Scientology.

188On the other hand, in 1958 there were more than 100 above-ground nuclear weapon tests in the world, with 71 detonations carried out by the United States alone. The suspended fission-product dust in the atmosphere was getting so dense, it was hard to tell that another bomb had been set off. The U-2 high-altitude photographs would have clearly shown effects of ground-level destruction, but if such evidence existed, would it have been released by the CIA?

189ANFO (Ammonium Nitrate/Fuel Oil) is a tertiary explosive, commonly used as a blasting agent, consisting of a mixture of an oxidizer, ammonium nitrate, plus a flammable organic compound. On August 24, 1970, one ton of ANFO loaded into a Ford Econoline van was parked in front of the physics building, Sterling Hall, at the University of Wisconsin-Madison. As a protest against the university’s military research, the explosive mixture was detonated at 3:42 am., causing massive destruction. Parts of the van were found three blocks away on top of an eight-story building, and overall damage to the university campus was over $2.1 million. A radical anti-war group called the “New Year’s Gang” claimed responsibility, and one member, Leo Burt, remains at large.

Chapter 8