Separating out the plutonium and uranium from the fission products is not the end of the story. The plutonium oxide that was sealed in canisters is shipped once or twice a week by gendarme-escorted truck from La Hague to a plant in the Provence region of France just north of Avignon. The drive from Avignon to the

Melox plant is a trip through Van Gogh land filled with vineyards and cypress trees swaying in the wind and the French Alps in the distant east.

I met my host, Joe Faldowski, at the security office. We went to a meeting room and met Jean-Pierre Barriteau, the director of International Projects for AREVA. He told me that France gets over 10% of its electricity from mixed-oxide (MOX) fuel, which is derived from the plutonium recycled at La Hague and made into new fuel pellets at Melox. In France, 21 of 58 light water reactors use MOX for fuel, while Germany has 10 reactors that burn MOX. The United States has used four MOX fuel assemblies in a reactor as part of a demonstration program, but that has now ended, and no US reactors currently burn MOX fuel. In a refueling operation, about 30% of the fuel assemblies can be from MOX while the rest are conventional uranium fuel assemblies.

Joe took me on a tour of the plant to see how the pellets are made and processed into the final assemblies. The plutonium coming from La Hague is first combined with depleted uranium10 in a grinder machine, making a primary blend of about 30% plutonium. About 60% of the plutonium is fissile 239Pu and 241Pu, and the rest is 238Pu, 240Pu, and 242Pu. This is later processed into the final concentration of plutonium for the specific contract by a customer, usually about 8%. Because the concentration of plutonium in spent nuclear fuel pellets is about 1%, it takes 8 recycled fuel pellets to make one MOX fuel pellet containing 8% plutonium. The powder is poured into a machine that compresses the powder into pellets. The pellets are heated to about 1,700°C, which eliminates cavities and water for more efficient fission and reduces their size to about the size of a pencil eraser, then ground to tolerances of 10 micrometers. Very stringent quality control measures assure that all pellets meet specifications.

The pellets are cleaned, inserted into 12-foot-long zirconium alloy (ZIRCALOY) tubes (about 300 per tube) with a spring added at the end to compress them, and helium is added before the tubes are welded shut to make the final fuel rods. The helium is added to improve heat transfer and reduce the operating temperature of the fuel; a void space is left to accommodate gaseous fission products that are produced when the fuel is burned. The rods are tested for integrity and linearity and a leak test is done to detect any helium coming from them when put in a vacuum. If all is well, they are then put into a fuel assembly that depends on the specific reactor requirements, but is typically a matrix of 17 by 17 rods. They are then ready to be sent to the country that ordered them to be put into a nuclear reactor to generate electricity.

The Melox plant is very impressive and the quality control measures are extreme. Radiation is not nearly as much of a problem here as at La Hague because it is only plutonium and uranium being used instead of all of the highly radioactive fission products. Plutonium and uranium are a particle emitters, except for 241Pu, which is a p emitter. Little shielding is necessary for a particles, since they can travel only a few centimeters in air and can be stopped by a piece of paper. However, there is also some emission of у rays and neutrons, so the MOX fuel pellets are more dan­gerous than the usual uranium oxide fuel pellets. Security is tight and it would be very difficult to divert material from here. Both the International Atomic Energy

Agency (IAEA) and Euratom constantly monitor the Melox plant as well as the La Hague reprocessing plant to make sure the plutonium inventory is accounted for.

At another great French lunch with Joe and Jean-Pierre, I asked whether the plutonium could be diverted by a terrorist group and made into a bomb. They said that the plant is very secure and terrorists would have a very difficult time getting in and getting any material. There is a potential problem in the fact that all of the plutonium is transported from La Hague to Melox by road, but the military escorts the trucks, and it would be very difficult to steal the material. Even more impor­tant, the mixture of isotopes in the plutonium would make it almost impossible to make a bomb. Certainly it could not be done by a terrorist organization. The reason is because the mixture of plutonium isotopes, especially the 240Pu, which undergoes spontaneous fission and emits neutrons, makes it extremely difficult to build a plutonium bomb that does not fizzle in a premature explosion (35).

Plutonium used in nuclear weapons is made in a specially designed reactor and the fuel is taken out very quickly, after about 100 days rather than 3 or 4 years in a power reactor, so that it is nearly all 239Pu, with less than 7% of the contami­nating isotope 2 40Pu. This is called weapons-grade plutonium, as contrasted to reactor-grade plutonium (1). That is how the five officially acknowledged nuclear weapons countries (United States, Russian Federation, France, United Kingdom, and China) and rogue countries such as North Korea actually build nuclear bombs. They do not take plutonium from reprocessed fuel to make the bombs because it is only about 60% 239Pu, making it impossible to make a bomb that does not fizzle with a greatly reduced yield, perhaps equivalent to one or two kilotons of dynamite. Furthermore, the high radioactivity of 240Pu and 238Pu makes the reactor-grade plutonium thermally hot and dangerous, making it very difficult to work with (36). Because of the contamination of 240Pu that causes pre-ignition, a plutonium bomb cannot be built in a gun design where one sub-critical piece is shot into another to reach criticality, but has to be made as an implosion device. This is not easily done and takes the resources of a nation to accomplish. Richard Rhodes tells the story of how the greatest scientists in the world developed the technology to do this, and it wasn’t easy (35)! So the biggest concern about repro­cessing—and the reason that President Carter canceled the US reprocessing pro­gram—is based on a faulty notion that terrorists could readily divert plutonium from a reprocessing plant and make plutonium bombs.

It is apparently true that the US weapons labs were able to build and explode a plutonium bomb in 1962 using reprocessed reactor fuel from a British reactor, but the 239Pu concentration is not public information (1). However, it is interest­ing that the plutonium came from a British reactor. Only three reactors existed then, and they produced a lower level of the contaminating 240Pu than US power reactors. These reactors were of a type called Magnox and were designed for dual use, either for power or for producing weapons-grade plutonium. Thus, it is likely that the plutonium for the bomb was closer to weapons grade than normal reac­tor grade. Furthermore, reactors of this type are all retired now (37). Thus, it is an oft-repeated red herring to say that plutonium taken from reprocessed fuel of a power reactor could be used in a nuclear weapon by a terrorist group. It is just not feasible because of physics!

AREVA is helping to build a plant at the Savannah River Site in South Carolina to convert plutonium from nuclear weapons into MOX fuel. Work on the Savannah River plant was begun in 2007 and is expected to be finished in 2016. In contrast, Melox was built in five years (1990-1995). Joe said that US utilities are very conservative and reticent to change their fuel to MOX, so the new plant will give utilities experience with burning MOX fuel. It makes a lot of sense to extract usable fuel from spent nuclear fuel and from nuclear weapons. This is truly turn­ing swords into plowshares.

I asked about Princeton professor Frank von Hippel, who is opposed to repro­cessing and who claims that burning MOX requires fast neutron reactors (7). Jean-Pierre said that it clearly is not true since they and other countries are using MOX in conventional reactors. Used MOX fuel can be reprocessed again, but it is not economical at present to do so and it does become degraded with a higher proportion of non-fissile (but fissionable) isotopes of plutonium, such as 240Pu, 242Pu, and 238Pu. However, it is true that the used fuel after MOX does need to be burned in a fast neutron reactor (see Chapter 11) such as the Phenix reactor that operated in France for 30 years and is now being decommissioned. A new fast neutron reactor, the SuperPhenix, was canceled by the government in a deal with the socialists for political reasons, not problems with the reactor.

Michael McMahon told me, “In France the used MOX is never considered to be a ‘waste’ and there are no plans to dispose of used MOX in a geological reposi­tory. The used MOX is considered to be a strategic energy resource. Current plans in France are to have a next generation Fast Reactor prototype (called ASTRID) operational in 2020" In other words, France is planning for the long-term use of the uranium as well as the plutonium in nuclear fuel to get the maximum output of energy while minimizing nuclear waste. Shouldn’t we do the same?

SUMMARY

Now that we have journeyed through the land of nuclear waste disposal, what can we conclude? Is nuclear waste disposal truly the Achilles’ heel of nuclear power, or can it be managed so that nuclear power can grow and supplant much of the coal used to produce electricity? Are we really consigning future generations to a high risk of cancer?

First, let’s recognize that there is no immediately pressing problem with spent nuclear fuel. It is being managed quite well at nuclear power plants by stor­age for a few years in cooling pools to let much of the heat and radiation decay away. Moving the waste into dry cask storage on-site or in regional sites is the next step and it is widely agreed by industry experts, by the Nuclear Regulatory Commission, by scientists, and by the National Academy of Sciences that this can be done for the next century if needed. There are significant advantages of storing the spent nuclear fuel this way because it is safe from terrorists and it becomes easier to store long-term as the heat and radiation decay. This interim storage solution is strongly supported by a recent MIT report on the fuel cycle (10) and by the report of the Blue Ribbon Commission (31).

The next question is whether to recycle or to simply permanently store the waste after dry-cask storage. France and other countries have shown that recy­cling is indeed feasible and as a result, their waste problem is greatly diminished. The vitrified fission products can be safely stored in a geological repository such as Yucca Mountain or WIPP (if the law were changed) for a few thousand years until the radiation has decayed away to safe levels. There would be no danger whatsoever to any current or future population from doing this. Also, this extends the supply of nuclear fuel enormously because the unused 235U and the 239Pu that is created from 238U can be used in reactors again. In the long run, fast-neutron reactors can be built to burn up nearly all of the plutonium iso­topes and other actinides produced in the reactor. In a world that will run out of fossil fuels eventually and will heat up to truly dangerous levels if we actually burn them all up, it will be increasingly necessary to look at spent nuclear fuel as a resource that can be reprocessed and provide greenhouse-gas-free energy.

The United States currently has no capability for reprocessing spent nuclear fuel, and there are many experts who think it is not a good strategy (7, 38). The two major concerns expressed by opponents of reprocessing are that it is too costly and that it could lead to proliferation of nuclear weapons. A 1996 National Academy of Sciences study estimated that the cost of reprocessing and building new reactors to use up the plutonium and other transuranics could cost between $50 and $100 billion dollars and raise the cost of generating electricity by 2-7% (39). AREVA estimates the difference in cost between an open cycle and recy­cling at just 2% (4). At the present time, it is not necessary to do this because spent nuclear fuel can be safely stored in dry cask storage. For the future, though, as other fuels become more expensive, this may well be a relatively inexpensive option. Furthermore, countries such as France, England, and Japan have already built these systems, and it has not apparently been a huge burden to them. In fact, France has some of the lowest electricity prices in Europe. The United States is contracting with AREVA and US partners to build a plant in South Carolina to reprocess plutonium from US nuclear weapons to make MOX fuel that can be burned in current reactors. This is not the same as recycling spent nuclear fuel, but that technology could be developed in the future after the United States has more experience with using MOX fuel in reactors.

The other issue frequently cited by those opposed to recycling is that it would lead to the proliferation of nuclear weapons. But the nuclear genie is already out of the bottle! Recycling of spent nuclear fuel is already occurring in several coun­tries, so it would not be a big change if the United States also started recycling also. Five countries are officially acknowledged as nuclear weapons states by the Nuclear Non-Proliferation Treaty (NPT), while Israel, India, and Pakistan have not signed the NPT but have nuclear weapons. North Korea originally was a sig­natory of the NPT but withdrew in 2003 and has tested nuclear weapons (40). The possibility that terrorists could steal reprocessed plutonium from nuclear power reactors and make weapons is very small because of the complex mixture of plu­tonium isotopes present. We already live in a nuclear world and have since 1945. That is not going to change.

My own view is that a sensible strategy for the United States is to plan on dry cask storage for the next 50 to 100 years while developing the capability to recycle spent nuclear fuel, build additional reactors to burn the MOX fuel, and provide electricity while reducing CO2 emissions. Yucca Mountain could then be rede­signed as a permanent storage for vitrified waste of the fission products. As I said at the beginning of the chapter, it is primarily a political problem, not a scientific or engineering problem, to make the decisions to have a sensible policy in place. It is time to move forward with a sensible and long-term strategy for the future.