Category Archives: POWER

Tеплый пол Aura

В настоящее время каждый современный человек сможет быстро дать определение теплому полу. Кроме того люди интересуются производителями систем отопления, чтобы выбрать самого лучшего. В списке лидеров на сегодняшний день находится теплый пол Aura купить который вы можете в любую минуту. Данный немецкий бренд за годы своего существования смог зарекомендовать себя с наилучшей стороны. Отличное качество, долговечность, отсутствие негативного влияния на организм человека. Именно такими словами можно описать Теплый пол Aura. Кстати, вы можете самостоятельно его установить. Если у вас нет времени и желания, то лучше обратиться к профессионалам. Если вы не разбираетесь в системе теплых полов, то попросите помощи работника магазина, который вам расскажет о плюсах и характеристике системы «Аура».

Tеплый пол

Оформление заказа

Напоминаем всем пользователям о том, что пол марки «Аура» можно без проблем купить в специализированном онлайн магазине по цене от производителя. Согласитесь, что это не только выгодное приобретение, но и экономное. Переходите на ресурс немецкой компании и сделайте онлайн заказ. Оплата может быть произведена с помощью карты банка. Закажите доставку продукции «Аура» на дом, воспользовавшись услугой курьера. Уверяем, что каждый покупатель, отдавший предпочтение немецкой компании Aura останется довольным. После установки теплого пола, в вашей квартире станет не только тепло, но и комфортно находиться.

Где уместен теплый пол «Аура»?

Вся продукция марки «Аура» — сертифицированная, надежная и прослужит вам много лет. У системы этой нет никакого электромагнитного излучения, поэтому можно не бояться негативного влияния на организм. Теплый поток воздуха равномерно распределяется по поверхности вашего пола. Будь то плитка, ламинат или что-то другое. Обращаем ваше внимание на то, что отопительная немецкая система является качественной, безопасной и достаточно долговечной. Полы Aura соответствуют всем нормам, которые были приняты в нашей стране и не только. Обратите свое внимание на комплектацию немецкой продукции. Вместе с теплым полом вы купите и качественный терморегулятор для регулировки температурного режима. Кроме современного дизайна система немецкая имеет функцию «умной» программы. Кроме теплого пола, вы можете приобрести любой строительный материал, без которого вам не обойтись в процессе монтажной работы.

THE REMOTE COLLABORATION OF OTTO HAHN (1879-1968) AND LISE MEITNER (1878-1968)

Otto Hahn was born in Frankfurt, Germany, the son of a prosperous gla­zier and property owner. He led a sheltered childhood, and at 15 he became interested in chemistry, performing experiments in the laundry room of the family home. Although his father wanted him to study architecture, Otto convinced him that industrial chemistry would be a better occupa­tion. He began his studies in chemistry and mineralogy at the University of Marburg in 1879 and received his doctorate in chemistry in 1901. After completing a year of required military service, he returned to Marburg to work as a research assistant. In 1904, he took a job at University College London in England, working in the new field of radiochemistry. He moved

back to Germany in 1906 and by 1910 was head of the radioactivity depart­ment of the new Kaiser Wilhelm Institute of Chemistry in Berlin.

In 1907, Hahn met Dr. Lise Meitner at a University of Berlin physics colloquium. She was from Vienna, Austria, and had already published papers on alpha and beta radiation. They both needed collaborators, and as a physicist and a radiochemist they would make a strong team. They quickly became friends and worked closely together for 30 years.

When Chadwick announced the discovery of the neutron in 1932, radiochemistry assumed a heightened importance. It was suspected that neutron capture by a nucleus would cause transmutation to another ele­ment, one atom at a time, but neutron sources were weak and the effect could be small. A good polonium-210 source was desirable but unavailable to most labs. Researchers used radium salt, an alpha particle emitter and a workable substitute for polonium, mixed with beryllium powder to make neutrons, using the effect discovered by Chadwick. There was no way to detect a transmutation except by exceedingly careful chemistry that would detect tiny amounts of a new element mixed in with the original sample. The amount of transmutation to be detected could be as small as hundreds of atoms. Otto Hahn was the world’s leading radiochemist, and he used fractional crystallization as a method of finding minute contami­nants in a sample. It is a method that was pioneered by Marie Curie, and it uses the fact that different substances dissolved in water crystallize out of supersaturated solution at different temperatures.

In 1938, Hahn and Meitner were getting some interesting chemical results of bombarding uranium with neutrons, but in July the political conditions in Germany for Meitner, who was Jewish, were becoming dan­gerous, and she had to drop everything and escape to Holland. The unsafe atmosphere for Jewish people was quickly becoming critical, and Ger­many seemed to be preparing for war. Hahn’s work in radiochemistry was superb, but he needed Meitner’s knowledge of nuclear physics to help inter­pret experimental results. With Meitner in exile, the two scientists kept in touch by mail and with one secret meeting in Copenhagen, Denmark.

Hahn repeatedly performed chemical analysis of the neutron-exposed uranium with very puzzling results. It was obvious that the neutron expo­sure resulted in new, radioactive elements in the uranium sample, as the radiation-counting instrument showed increased radioactivity, but the product of this transmutation was not clear. Hahn guessed it was a new, previously undiscovered isotope of radium. To detect small contaminants

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of radium, Hahn used barium as a carrier for the fractional crystallization. Meitner did not believe it was radium, as it would require a double alpha disintegration to go from uranium down to radium. To Hahns amaze­ment, all his tests for radium were negative, with nothing showing up in the barium carrier. In a burst of insight, Meitner figured out the problem, and she and Hahn exchanged excited letters on December 21,1938. Hahn had not detected any radium in his barium because there was no radium. The product of the neutrons hitting the uranium was radioactive barium.

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Подпись: A reconstruction of the setup used by Otto Hahn and Lise Meitner to discover nuclear fission in 1938 (Foto Deutsches Museum)

A uranium atom is slightly less than twice the mass of a barium atom. The uranium nuclei had split roughly in half, resulting in one barium atom and one krypton atom per disintegration. Krypton is an inert gas, undetectable by chemical means. The barium atoms in Hahns experi­ment were neutron-heavy and therefore unstable and subject to radio­active decay, as was detected by his radiation counter. The next day, on

THE NEED FOR SECRECY

With the U. S. formal engagement in World War II and the elevation of nuclear research to highest priority, secrecy of all aspects of the project became absolute. First, no physicist could publish papers having to do with nuclear fission, so as not to reveal to external governments that bomb research was proceeding. The sudden stoppage of any nuclear publications only indicated to the Soviet Union, always sensitive to West­ern secrets, that something was going on in the United States, and they immediately started an infiltration effort.

immense laboratory complexes were built in remote, uninhabited locations and given names “Site X" and “Site Y.” Workers never knew what they were building, industrial workers at production facilities were never told what they were producing and were forbidden from talking to the workers standing next to them, much less anyone outside the building or from another building. There were words that could not be said. No one could say uranium-235. The material was referred to as “oral — loy.” One could never refer to the uranium isotope separation plant as anything but Y-12, K-25, or S-50. Plants and laboratories were ringed with high fences, barbed wire, and armed watchtowers. Photography was highly restricted, and every piece of paper had to go in a combination lock safe or vault if it was not being written on or read from. There was a counter-story written to explain every odd sound, flash of light, or truck leaving a hidden facility. Foreign scientists working on the project, of which there were many, could find themselves being tailed by security operatives if they left the laboratory grounds.

Scientists were given working names, which were printed on their security badges. Enrico Fermi was Mr. Farmer and Niels Bohr was Mr. Baker. Once Bohr wound up at a checkpoint without his badge, but Fermi was able to vouch for him, saying, “I assure you that this is Mr. Baker, sure as my name is Mr. Farmer.” Scientists disappeared from their university positions and were not heard from again until after the war. The general public in the United States had no idea that atomic weapons were being developed in their country. Knowledge was dispensed only on a strict need-to-know basis. The vice president of the United States, Harry S. Truman (1884-1972), was not advised that his country was developing an atomic bomb until he was sworn in as the commander in chief on Franklin Roosevelt’s death on April 12, 1945. Neither the Germans nor the Japanese knew anything about the U. S. bomb project and did not know to be concerned.

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The British were also very aware of the need for atomic security, and they care­fully monitored all correspondence and radio traffic into and out of the home islands. When Copenhagen was occupied by German forces, Niels Bohr sent a message to a German physicist working in England, mentioning a “Miss Maud Rey at Kent.” Think­ing that it was surely a coded message, the British code masters found that the let­ters could be rearranged to form “radium taken.” Miss Maud Rey turned out to be the former governess of Bohr’s children, and she was indeed living in Kent. There was no coded message. The MAUD Committee was named in her honor.

already be engaging in nuclear work. On August 15, Szilard transmitted the document to Sachs with the authoritative Einstein signature.

Sachs knew that the concept had to be sprung on the president at just the right time, when he was in the correct mood, and unfortunately events in Europe were monopolizing his attention. Weeks passed. Finally, as Szi­lard’s patience was at the boil, Sachs saw the opportunity to approach the president and present the letter on October 11 at the White House in the Oval Office. Neither man actually read the letter, but Sachs gave Roosevelt an 800-word synopsis of what he had learned from Szilard.

Roosevelt absorbed it all and summed it up, saying, “Alex, what you are after is to see that the Nazis don’t blow us up.”

“Precisely,” said Sachs.

Roosevelt called in his aide, saying, “This requires action.”

So began the largest scientific research and development program in history. It would take another letter from Einstein five months later on April 25, 1940, to speed things along, but the ball was now rolling, and there was no stopping it.

THE ENERGY RELEASED BY RADiOACTiVE DECAY

In 1903, Rutherford collaborated with Frederick Soddy to write an impor­tant paper, “Radioactive Change.” In this work they offered the first exper­imentally verified calculations of the energy released from an atom due to radioactive decay. The power involved in the transmutation of radioactive elements was astounding. They had found that the energy released by the decay of one gram of radium could not be less than 100,000,000 gram calories. It was probably closer to 10,000,000,000 or 10 billion gram calories.

In 1903, at the University of Kiel in Germany, Philipp Lenard (1862­1947) reached an interesting conclusion regarding atomic structure. Ruth­erford was in accordance with J. J. Thomson’s opinion that the atom was one solid mass, like a plum pudding, with electrons adhering to the out­side, remarking that, “I was brought up to look at the atom as a nice hard fellow, red or gray in color, according to taste.” Thomson was, after all, his thesis adviser for his doctorate, awarded in 1900. A solid object, such as a block of metal, was obviously hard, massive, opaque, continuous, and homogeneous.

Lenard had been working on cathode ray tubes, hoping to accomplish what Roentgen had tried, bringing cathode rays out the end of the glass vacuum tube and into the laboratory. He had devised a metal window thick enough to withstand the air pressure outside the tube but thin enough for

cathode rays to penetrate and flow into the atmosphere. It worked. He was able to detect cathode rays outside the tube using a fluorescent screen, but he noticed that the rays were scattered somewhat when they blew through the metal window. This seemed to contradict the theory that they were

ADMIRAL HYMAN RICKOVER:. FATHER OF THE NUCLEAR NAVY

Hyman George Rickover was born in 1900 in the all-Jewish village of Makover in Russian-occupied Poland. His father, Abraham, was a tailor, and the Rickovers were the poorest of the poor. The future did not look bright. The expressed objective of the Russian government was to convert one-third of the Polish Jews to the Russian Orthodox religion, force one-third to leave, and kill the rest. The Rickovers chose the second option, working west across Germany in 1905 and finding passage to New York City at Antwerp, Belgium. Young Rickover, the future admiral, reportedly burst into tears at the sight of an oceangoing ship. His older sister, Fanny, reports that, "The boats were so big, they frightened him.”

The family landed in New York and moved west to Chicago. Rickover added income to his father’s tailoring work beginning at the age of 9. He would later sum up his childhood as a time of "hard work, discipline, and a decided lack of good times." While attending John Marshall High School in Chicago, Rickover had a full-time job delivering Western Union telegrams by bicycle. By fate, he was appointed a Western Union messenger at the Republican National Convention in Chicago in 1916, where he met Congressman Adolph Sabath, a fellow Jewish immigrant from Czechoslovakia.

naval reactor design, the Windscale units had to use natural uranium in metallic form. No other country had the luxury of large industrial — scale uranium enrichment, and early reactor designs in other countries seemed to all rely on natural fuel. Rickovers naval reactor design also used uranium fuel in oxidized form, considered advantageous because of its high melting point. The Windscale had to use pure uranium metal, to maximize the poor reactivity of its unenriched uranium. Unfortunately, uranium metal has a low melting point, and it will catch fire in air and burn like gasoline.

A Windscale reactor simply pulled air in one side of the building with a fan, blew it through holes in the pile of graphite and fuel, and sent it up a smokestack, to cool the reactor as it converted U-238 into Pu-239. A large fiberglass filter at the top of the stack was supposed to trap fission products that could escape the reactor core. As might be predicted, on

In 1918, Sabath nominated Rickover for appointment to the U. S. Naval Academy, and he won a coveted place in the class of 1922.

Never known as one to enjoy a party, Rickover quickly gained a reputation as a silent scholar, learning to stay up long after lights-out for studying. Promptly after reporting to the academy, Rickover came down with diphtheria and missed several weeks of introductory instruction. He struggled to overcome his late start by avoiding weekends and sociable get-togethers as he withdrew to the privacy of his room. He was academically above the mean, but his abysmally poor military drilling skills pulled down the class average.

After additional education in submarine school, Rickover was assigned service in the submersible boat S-48. It was a cramped, damp working environment, and he and the crew seemed in constant danger from the failure of unreliable equipment. A sister submarine, the S-49, had recently suffered an explosion of the storage battery, and the S-5 and S-51 boats had sunk with all hands for reasons unknown. U. S. Navy submarines were risky transportation at the time, and within 40 miles of leaving port, the battery in Rickover’s boat, the S-48, caught fire while running on the surface.

Rickover was able to evacuate the crew to the narrow, wooden deck. He went back down into the smoke-filled boat to the battery hold, found the fire, and extinguished it. From that moment on, he decided to make submarines the safest and most pres­tigious service in the armed forces, in time, he would succeed in glorious fashion.

October 1,1957, the Windscale Pile-1 was running hot and the fuel caught fire. Released into the surrounding countryside were 20,000 curies (750 tbq) of radiation up the smokestack, making it the second worst reactor accident in history. It took a while, but eventually the graphite moderator also caught fire as the fuel glowed bright red. Inadequate instrumentation and cost-saving construction measures were blamed. The British nuclear establishment, shaken by the Windscale experience, improved its engi­neering and built a carbon dioxide-cooled graphite reactor named Calder Hall. This reactor produced 50 megawatts of electricity, as well as pluto­nium for bombs, and it went online on August 27,1956. It was the world s first commercial power reactor.

Canada started its own nuclear program immediately after World War II, using knowledge gained by Canadian scientists on temporary loan to the Manhattan Project. An impressive research complex was built at

Chalk River, Ontario, and a 10-megawatt research reactor came online in 1947. It was named the NRX, or the nuclear reactor experiment, and it would have the dubious distinction of experiencing the world’s first core meltdown on December 12, 1952. The Canadian reactor at least did not use graphite as the moderator, but it did use natural uranium fuel, and to achieve criticality with the low U-235 content a highly efficient moderator was needed. Heavy water, produced in Canada, was chosen, with ordinary or light water run through tubes in the reactor core to act as coolant.

The combination of heavy water moderation and light water cooling was a weakness in the design, as a loss of light water by boiling or leakage would actually improve the use of neutrons, causing the power level to increase out of control. Through a series of unfortunate errors, the power level ran away, melting a portion of the reactor’s metallic uranium fuel. Several months of cleanup were required to remove radioactive contami­nation from the failed fuel, and the U. S. Navy sent 150 nuclear-trained personnel to help. Among the workers sent was Ensign James Earl Carter (1924- ), future president of the United States during the most critical

period of nuclear power development. Ensign Carter developed a cautious attitude toward nuclear power during his duty in Canada.

The hidden advantages of Admiral Rickover’s unrealistically expensive excursion into nuclear power production, using exotic materials, relent­less testing, and a cost-is-no-object attitude began to make grudging sense in the nuclear world. To approach a nuclear power economy from a sen­sible, businesslike, cost-saving direction was possibly not the best strategy.

Rickover’s submarine was a nuclear-powered weapons platform, armed with the latest undersea torpedoes, but this warship was not built by the armed forces. Technically, it was built and owned by a civilian agency, the AEC, and to administer the project Rickover had to be a member of this new organization. The Congress, after months of intense debate among politicians, military planners, and nuclear scientists, presented the McMahon Act to President Truman. He signed it into law on August 1, 1946. This law transferred ownership of all nuclear weapons, uranium stockpiles, and research facilities from the army to the AEC. David Lil — ienthal (1899-1981), former head of the Tennessee Valley Authority and a capable public servant, was named chairman.

Being head of the AEC was rough duty in the early days, and chairmen changed every few years. Bare-knuckle politics, communist infiltration, Soviet bomb-making, and controversial regulatory stances took their toll. The existing nuclear labs, hastily built during the war, were reorganized

into a network of national laboratories. The first formed was Argonne National Laboratory, created near Chicago by Enrico Fermi’s CP-1 proj­ect. The Oak Ridge Laboratory, Los Alamos, and Hanford soon followed, and additional laboratories would be built all over the country.

The AEC made itself the only legal buyer of uranium, and by artifi­cially setting the price high hoped to increase the incentive for prospect­ing, particularly in the old vanadium mining territory in the Southwest where uranium could be extracted as a by-product. By December 1949, there was a uranium rush, begun by an article in the Engineering and Mining Journal detailing new AEC bonuses. Miners, geologists, and prospectors bought radiation counters and began sweeping the Four Corners area of the Colorado Plateau. One particularly impoverished prospector, Charles A. Steen (1919-2006), unable to afford a Geiger coun­ter, made a massive find using unconventional geological theories. He made claim to a huge, concentrated uranium deposit in the Big Indian Wash of Lisbon Valley, southwest of Moab, Utah. His single “Mi Vida” mine would produce all the uranium the AEC could use for the next decade. To replace his tar-paper shack, Steen built a $250,000 mansion overlooking the works.

On December 8, 1953, President Dwight D. Eisenhower (1890-1969) delivered a speech at the United Nations General Assembly in New York City. It is known as the “Atoms for Peace” speech, and it was the tipping point for international focus on the potential uses for nuclear power in a world without war. It was a profound and noble speech, and a quotation from it follows:

To the making of these fateful decisions, the United States pledges before you—and therefore before the world—its determination to help solve the fearful atomic dilemma—to devote its entire heart and mind to find the way by which the miraculous inventiveness of man shall not be dedicated to his death, but consecrated to his life.

Hoping to avoid a protracted nuclear weapons race with the Soviet Union, Eisenhower tried to emphasize the possible beneficial uses of nuclear energy, with particular interest in electrical power. To back up his words, Eisenhower then launched a declassification effort, taking any documents sealed during the Manhattan Project that were not directly related to bomb production out of secret status and making the information avail­able worldwide.

THE BORAX REACTORS IN IDAHO

In 1949, the lack of uranium fuel resources in the United States was con­sidered serious, so the earliest government-funded nuclear power project was to build a plutonium-fueled breeder reactor. Walter Zinn (1906-2000), the Canadian-born head of the Argonne National Laboratory, led the design of the first power reactor, designated Experimental Breeder Reac­tor One, or EBR-1. Dr. Zinn had been in nuclear engineering from the very beginning, having worked with Leo Szilard in 1939. He had manned a control rod at Fermi’s CP-1 experiment in Chicago in 1942.

EBR-1 was built in the barren desert of Idaho, 18 miles (29 km) south­east of Arco, and it first achieved nuclear criticality on August 24, 1951. On December 20, the secondary steam-coolant loop was switched into a turbogenerator, and electrical power was generated for the first time using nuclear power. Enough electricity was generated to light exactly four bulbs. This modest triumph was added to in 1953, when analysis of the fuel proved that it was making more plutonium than it burned, thus proving the breeder hypothesis. On November 29, 1955, a slight operator error led to a partial core meltdown, which seemed the fate of a few early reactors. EBR-1 seemed unstable at high coolant flow rates, as the rushing liquid metal coolant would buckle the fuel rods and cause the power to rise. It was not the behavior desired in a power source.

In 1952, Samuel Untermyer II (1912-2001), a mechanical engineer from MIT who had worked with Walter Zinn at Argonne, theorized a bold simplification of Rickover’s compact pressurized water reactor. The PWR required two coolant loops. An inner loop ran water through the reac­tor core, transferring out the power and keeping the core at well below melting temperature. The water was under pressure, so that it would not boil. The secondary loop of water ran through a heat exchanger, or steam generator, transferring power out of the inner loop and into turbogenera­tors. Untermyer suggested eliminating the inner loop, boiling the cooling water to steam in the reactor core, instead of in an external steam genera­tor. This would eliminate much plumbing and pumping, and it appealed very much to the mechanical engineers.

Nuclear physicists were skeptical, arguing that a chaotic boiling of water in the core would result in unpredictable controls, spoiling one of the great advantages to light water moderation and cooling. Untermyer promised that just the opposite was true. The fact that the moderator was allowed to boil in the reactor core would lead to greater stability, and not less. If a steam bubble develops in a reactor core, then moderator is dis-

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image064placed out of the core. With less moderation, the average neutron energy goes up, and the fission rate goes down. Power drops. If the water becomes too cool, then bubbles stop forming. The density of the water increases, and the moderating quality of the water improves. The fission rate climbs. Power goes up. Not only would a boiling water reactor, or BWR, be stable, it would be self-controlling, with no need to constantly adjust neutron­absorbing control rods to keep the power level steady. Lose coolant cata­strophically in an accident, such as a pipe rupture, and the reactor shuts down instantly, just as in a PWR being designed for the navy.

Подпись: A cutaway diagram of the BORAX-V boiling water reactor test facility. The five BORAX reactor setups in Idaho proved the utility and safety of the boiling water concept. (Argonne National Laboratory)

The BORAX-1 experimental boiling water reactor was built in 1953, and the experiments had to be performed in the summer, because there was no building housing the reactor and snow would cover it in the winter. The core tank was semi-buried, four feet (1.2 m) in diameter and 13 feet (4 m) high. The small reactor performed perfectly, proving Untermyers hypothesis. In 70 experiments, the core was put through severe runaway situations that would have surely melted a lesser design and proved that the BWR provided inherent protection from water-loss hazards. As a final ultimate test, the scientists decided to subject the reactor to the worst possible accident situation before dismantling it. They rigged the control rods to blow out the top of the core, subjecting

the reactor to prompt supercriticality. There was nothing worse that could happen to a nuclear device.

The results of this experiment were somewhat larger than predicted. The instant power increase and the resulting steam explosion carried away the entire control rod mechanism, weighing 2,200 pounds (998 kg), and released 135 megajoules of energy, the equivalent of 70 pounds (32 kg) of high explosive. Pieces of the uranium fuel were found up to 200 feet (61 m) away. Still, the reactor was no longer generating power immediately after it had exploded. This was the worst that could happen, and the BWR concept had proven to be a highly advantageous reactor design.

In 1954, BORAX-II was built, this time having a tin building over it and producing 6.4 megawatts of steam. It proved an important point, that fuel contamination in the single coolant loop would not be a problem, as had been suggested, and in 1955 a turbogenerator was added. For an hour on July 17, 1955, it was connected to the local power grid, and it provided electricity for the city of Arco, the entire BORAX test facility, and part of the National Reactor Test Station. Arco, Idaho, thus became the first city in the world to be powered solely by nuclear energy, and the experiment became BORAX-III.

Samuel Untermyer was the sole inventor of the boiling water reactor, and he was granted U. S. patent number 2,936,273 in 1960. Today there are 90 boiling water reactor plants operating in 10 different countries. It is possibly the safest power reactor design in the world.

LISE MEITNER: A REFUGEE SCIENTIST

Bom in Vienna, Austria, on November 17, 1878, Elise Meitner was the third of eight children in a prosperous Jewish family living in the Leopoldstadt suburb of Vienna. Slight of figure, shy, and a formidable scientist, she was the second woman to earn a Ph. D. in physics at the University of Vienna. For reasons unknown, Elise shortened her first name to Lise and her birthday to November 7. Her teaming with Otto Hahn in 1907 would result in one of the most fortunate collaborations in the history of nuclear science, but its culmination in the discovery of fission would occur with her in exile and unable to share the credit.

in 1932, with Chadwick’s discovery of the neutron, an unofficial scientific race began. Dr. Meitner rejoined the person who had invented applied radiochemistry, Dr. Hahn, for an investigation of the effects of neutrons on uranium. Also in the competi­tion were Ernest Rutherford in Britain, Irene Joliot-Curie in France, and Enrico Fermi (1901-54) in Italy.

The next year, Adolf Hitler was named chancellor of Germany, and life immediately became very difficult for German Jews. It became illegal for them to work in German technical institutes or universities, and most, including Leo Szilard, were forced to leave the country. Lise Meitner got by on a technicality. She was Austrian, not Ger­man, and she kept working at the institute for Chemistry in Berlin as if she were immune to the Nazi mind-set. She and Otto Hahn were approaching an important

December 22, Hahn submitted his paper cautiously titled, “Concerning the existence of alkaline earth metals resulting from the neutron irra­diation of uranium,” and the discovery of nuclear fission was announced. Two months later Hahn wrote a second paper predicting the liberation of at least two neutrons during the fission process. With the discovery of fis­sion in uranium, Szilard’s nuclear power reactor was not only possible, it was almost inevitable.

Acknowledgments

I wish to thank Dr. Don S. Harmer, retired Professor Emeritus from the Georgia Institute of Technology School of Physics, an old friend from the Old School who not only taught me much of what I know in the field of nuclear physics but also did a thorough and constructive technical edit of the manuscript. Thanks also to Dr. Douglas E. Wrege, a physicist, a teacher, and a friend from Georgia Tech, who also read the manuscript, finding exotic errors that apparently only he could detect. Special credit is due Frank K. Darmstadt, my editor at Facts On File, who helped me at every step in making a coherent book out of a massive jumble of myths, rumors, and anecdotes. Franks semi-infinite patience and his love of cor­rect writing result in a very satisfying product. Credit is also due to Alex­andra Simon, copy editor at Facts On File, for her superlative job of finessing and polishing the manuscript. The support and the editing skills of my wife, Carolyn, were also essential. She held up the financial life of the household while I wrote, and she tried to make sure that everything was spelled correctly, all sentences were punctuated, and the narrative made sense to a nonscientist.

 

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Nuclear Power is a multivolume set that explores the inner workings, his­tory, science, global politics, future hopes, triumphs, and disasters of an industry that was, in a sense, born backward. Nuclear technology may be unique among the great technical achievements, in that its greatest moments of discovery and advancement were kept hidden from all except those most closely involved in the complex and sophisticated experimen­tal work related to it. The public first became aware of nuclear energy at the end of World War II, when the United States brought the hostilities in the Pacific to an abrupt end by destroying two Japanese cities with atomic weapons. This was a practical demonstration of a newly developed source of intensely concentrated power. To have wiped out two cities with only two bombs was unique in human experience. The entire world was stunned by the implications, and the specter of nuclear annihilation has not entirely subsided in the 60 years since Hiroshima and Nagasaki.

The introduction of nuclear power was unusual in that it began with specialized explosives rather than small demonstrations of electrical­generating plants, for example. In any similar industry, this new, intrigu­ing source of potential power would have been developed in academic and then industrial laboratories, first as a series of theories, then incremental experiments, graduating to small-scale demonstrations, and, finally, with financial support from some forward-looking industrial firms, an advan­tageous, alternate form of energy production having an established place in the industrial world. This was not the case for the nuclear industry. The relevant theories required too much effort in an area that was too risky for the usual industrial investment, and the full engagement and commitment of governments was necessary, with military implications for all develop­ments. The future, which could be accurately predicted to involve nuclear power, arrived too soon, before humankind was convinced that renewable energy was needed. After many thousands of years of burning things as fuel, it was a hard habit to shake. Nuclear technology was never developed with public participation, and the atmosphere of secrecy and danger sur­rounding it eventually led to distrust and distortion. The nuclear power industry exists today, benefiting civilization with a respectable percentage

of the total energy supply, despite the unusual lack of understanding and general knowledge among people who tap into it.

This set is designed to address the problems of public perception of nuclear power and to instill interest and arouse curiosity for this branch of technology. The History of Nuclear Power, the first volume in the set, explains how a full understanding of matter and energy developed as sci­ence emerged and developed. It was only logical that eventually an atomic theory of matter would emerge, and from that a nuclear theory of atoms would be elucidated. Once matter was understood, it was discovered that it could be destroyed and converted directly into energy. From there it was a downhill struggle to capture the energy and direct it to useful purposes.

Nuclear Accidents and Disasters, the second book in the set, concerns the long period of lessons learned in the emergent nuclear industry. It was a new way of doing things, and a great deal of learning by accident analy­sis was inevitable. These lessons were expensive but well learned, and the body of knowledge gained now results in one of the safest industries on Earth. Radiation, the third volume in the set, covers radiation, its long­term and short-term effects, and the ways that humankind is affected by and protected from it. One of the great public concerns about nuclear power is the collateral effect of radiation, and full knowledge of this will be essential for living in a world powered by nuclear means.

Nuclear Fission Reactors, the fourth book in this set, gives a detailed examination of a typical nuclear power plant of the type that now pro­vides 20 percent of the electrical energy in the United States. Fusion, the fifth book, covers nuclear fusion, the power source of the universe. Fusion is often overlooked in discussions of nuclear power, but it has great poten­tial as a long-term source of electrical energy. The Future of Nuclear Power, the final book in the set, surveys all that is possible in the world of nuclear technology, from spaceflights beyond the solar system to power systems that have the potential to light the Earth after the Sun has burned out.

At the Georgia Institute of Technology, I earned a bachelor of science degree in physics, a master of science, and a doctorate in nuclear engi­neering. I remained there for more than 30 years, gaining experience in scientific and engineering research in many fields of technology, includ­ing nuclear power. Sitting at the control console of a nuclear reactor, I have cold-started the fission process many times, run the reactor at power, and shut it down. Once, I stood atop a reactor core. I also stood on the bottom core plate of a reactor in construction, and on occasion I watched the eerie blue glow at the heart of a reactor running at full power. I did some time in a radiation suit, waved the Geiger counter probe, and spent many days and nights counting neutrons. As a student of nuclear technology, I bring a near-complete view of this, from theories to daily operation of a power plant. Notes and apparatus from my nuclear fusion research have been requested by and given to the National Museum of American History of the Smithsonian Institution. My friends, superiors, and competitors for research funds were people who served on the USS Nautilus nuclear sub­marine, those who assembled the early atomic bombs, and those who were there when nuclear power was born. I knew to listen to their tales.

The Nuclear Power set is written for those who are facing a growing world population with fewer resources and an increasingly fragile envi­ronment. A deep understanding of physics, mathematics, or the special­ized vocabulary of nuclear technology is not necessary to read the books in this series and grasp what is going on in this important branch of science. It is hoped that you can understand the problems, meet the challenges, and be ready for the future with the information in these books. Each volume in the set includes an index, a chronology of important events, and a glossary of scientific terms. A list of books and Internet resources for further information provides the young reader with additional means to investigate every topic, as the study of nuclear technology expands to touch every aspect of the technical world.

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THE FIRST NUCLEAR REACTOR

An unused football stadium, Stagg Field, with abandoned squash courts underneath the west stands at the University of Chicago was the perfect setting for a large, secret experiment. It was not a place anyone would look for world-changing science. Although preliminary studies of a graphite­moderated fission reaction had been studied at Columbia and Princeton,

the groups were combined and sent to Chicago for the definitive experi­ment by the sponsoring agency, the Office of Scientific Research and Development, directed by Arthur H. Compton.

With his methodical, thorough experimental ethic, Dr. Enrico Fermi directed the project, building 30 test assemblies out of larger and larger piles of pure graphite bricks, with interspersed cylinders of pressed ura­nium oxide. Everything was carefully considered and designed, from the allowable impurities in the graphite to the radius and length of each ura­nium cylinder, to the optimum spacing between uranium pieces, with calculations improving as larger and larger subcritical piles were assem­bled, observed, and dismantled. On November 16, 1942, when the team thought they had enough data to predict the size of a fully critical, con­tinuously running nuclear reactor, they started stacking layers of graphite and uranium on the wooden floor of the squash court, building “CP-1,” or Chicago Pile number 1.

Chemically pure graphite seemed the ideal moderator material to slow the neutrons down to fission speed. Under severe badgering from the eccentric Hungarian genius, Leo Szilard, three companies were encour­aged to produce some remarkably pure synthetic graphite. On the Ger­man side of the race to produce nuclear power, graphite had been quickly dismissed as a possibility. In Europe, graphite was mined, for use in pro­ducing pencils, and graphite was readily available, but its mineral impu­rities made it unusable. The Germans chose to use the exceedingly rare material deuterium oxide, or heavy water, as a moderator.

The Chicago pile was big. It was roughly a sphere, 25 feet (7.6 m) in diameter, looking like a huge basketball made of black Legos. Wooden timbers held up the bottom half of the thing, and the cadmium control — rods, intended to absorb neutrons to selectively kill the fission reaction, ran in from the front, through channels routed in the graphite. Electronic radiation counters and controllers for the control rod motors were piled up in the squash court balcony. On December 2, 1942, the reactor was fully built, checked out, and ready to be tested. Forty-two men and one woman, Leona Woods (1919-86), crowded onto the squash court balcony and a couple of stations on the pile to see the first sustained nuclear reaction. George Weil stood on the floor in front of the pile to move one critical control rod by hand. Harold Lichtenberger, W. E. Nyler, and A. C. Graves got to stand on a wooden platform in back of the reactor, holding car­boys full of cadmium salt solution, poised to drop them on the graphite and kill the reaction in case things got seriously out of control. Fermi,

Process of Chain-reacting Nuclear Fission

 

Control

rod

 

Control

rod

 

Escaped Absorbed Fast Moderated neutrons neutrons neutrons neutrons

 

Ге? New, unique fission products

 

© Infobase Learning

 

In a nuclear reactor, neutrons born from fission are slowed down to a crawl by traveling through a moderator, such as graphite. They can then cause other fissions or be lost to a control rod that is meant to absorb neutrons, or they can simply leak out of the reactor.

 

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Compton, Herb Anderson, and Walter Zinn, from Canada, sat at the con­trol desk. Norm Hilberry stood ready with an axe to cut the rope holding the zip rod, which would fall by gravity into the pile if they needed a quick shutdown. Everybody else was there to watch.

For most historical scientific experiments and discoveries, we have only a sketchy, incomplete account of the detailed activity, and we must rely on recollections and cleaned-up summaries of what happened. The worlds first reactor startup is a very rare exception. Neither recordings nor photographs were made, due to the military secrecy of the operation, but Leona Woods, the youngest person to witness the event, took detailed, minute-by-minute notes. Fermi was not a very talkative person, and the
gallery remained mostly in awed silence. Woodss written record of each action and spoken word is considered correct.

Подпись: Chicago Pile-1 (CP-1)
Подпись: © Infobase Learning
Подпись: The first nuclear reactor ever built was literally a pile of graphite bricks, with rounded cylinders of uranium evenly dispersed throughout. The three cylinders wired in front are neutron detectors used to monitor the fission activity.

At 9:45 a. m., the experiment began. Fermi called for withdrawal of the electrically driven control rods, somebody threw the switch, and the crowd hushed as the DC motor whined. Out slithered the cadmium rods from the middle of the slippery graphite pile. All eyes turned to the neu­tron counter dial and the pen chart recorder, which was keeping a record of the neutron activity in the pile on a continuous roll of paper, with a motor-controlled blue pen. The count rate stepped up a little, but nothing to write a paper about. An audio amplifier and a speaker were connected

to the counting equipment, giving an occasional click sound as a neutron strayed into the detector tube.

Fermi, a man of few extraneous words, said, “Zip out.” It was just after 10:00 a. m. Zinn pulled out the gravity rod and tied its rope to the balcony. The neutron count rate rose noticeably.

It was 10:37 a. m. With his eyes locked on the neutron rate dial, Fermi called to Weil, “Pull it to 13 feet, George.” Weil, standing at the reactor face, carefully withdrew his small vernier control to 13 feet (4 m), marked on the side of the rod. The neutron count jumped. The crowd murmured, as slide rules slid and pencils scratched.

“This is not it,” predicted Fermi. “The trace will go to this point and level off.” He pointed to a blank spot on the pen chart. Slowly the pen moved up and leveled off, right where he said it would. The crowd was enraptured and studied the new flatline for seven minutes, then Fermi called to Weil for another foot of rod. Weil complied. The count rate increased but leveled out. For nuclear fission to be happening at a useful level, the rate would have to increase exponentially, tending to become a vertical line on the graph.

At 11:00 a. m., Fermi, seeming not in the slightest way impatient, called to Weil for another six inches of vernier control. At 11:15 a. m., a little more. At 11:25 a. m., another smidgen. After each movement, the count rate would increase slightly, and the clicks of neutrons hitting the detec­tor tube, amplified and put over a loudspeaker, became irritating. Fermi seemed to be enjoying the drama, as he correctly predicted each level out of the pen on the chart. He knew they were getting close. Just to be absolutely sure of things, Fermi ordered that the automatically actuated control rod be dropped in, to test the circuit. The safety rod banged home, and the count rate dropped abruptly, just as it should.

Satisfied, Fermi called for a restart, and at 11:35 a. m. the safety rod was reset in out position, and the vernier was carefully pulled out a little more. The count rate rose and rose. The crowd watched and waited, silent, enthralled by the rising neutron count. Suddenly, there was a loud bang.

Everybody froze. Then, as nothing seemed to be melting through the floor, they realized that the safety rod had automatically tripped, sending it rapidly into the reactor core to stop the reactions. The tripping point was set too low on the neutron rate meter. It was quickly adjusted.

Fermi announced that “I’m hungry. Let’s go to lunch.” Weil parked the vernier rod, the motor rods were driven in, the zip was lowered in, and the party broke for the dining hall.

Over lunch, not a word was said about neutrons, graphite, or the unspeakable substance uranium. Fermi just ate lunch, giving not a hint of a pep talk, as the others went on about anything except the “game.”

At 2:00 P. M., they assumed their positions in the squash court, and it took 20 minutes to warm up the equipment and withdraw the safeties to their previous condition. “All right, George,” called Fermi. Weil took this to mean restore the vernier to its last position, and he did so. The count rate was high.

At 2:50 p. m., Fermi called for another foot of rod. Out it came. The pen chart ran off the top of the graph, but they still weren’t exponential. Some­body clicked the pen chart range up by a factor of 10, to get the pen back on the chart. Everybody watched.

At 3:20 P. M., Fermi said “Move it six inches.” Weil pulled six inches. The random ticking sound on the speaker, indicating individual neutrons counted, was becoming frantic. What was once a series of clicks now sounded like air escaping or waves crashing on rocks. Over the hiss from the speaker Fermi called “Pull it out another foot.” Weil pulled.

Fermi, supremely confident, turned to Compton and said, “This is going to do it. Now it will become self-sustaining. The trace will climb and

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The Birth of the Atomic Age by artist Gary Sheahan (1893-1978). Although the room in which the first nuclear reactor was built was too crowded to take a picture in, this painting captures the moment of the first self-sustaining chain reaction at the University of Chicago in 1942 (Chicago History Museum)

continue to climb. It will not level off.” He pulled his slide rule and began calculating. He flipped his rule over and penciled temporary numbers on the back. He looked grim, as the count rate rose.

Three minutes later, Fermi made another calculation, and the crowd was jostling for position to see the count rate on the chart. Wilcox Over­beck began calling out the numbers from the chart as the pen traversed. Fermi, stone-faced and a picture of calm throughout the exercise, sud­denly closed the C-scale on his slide-rule and grinned broadly. “The reac­tion is self-sustaining,” he announced. “The curve is exponential.” The time was 3:52 p. m. on December 2, 1942. Power production by the direct conversion of matter to energy had been proven feasible.

It was a closely held secret. The construction of CP-1 was finally declas­sified on May 18, 1955, when Enrico Fermi and Leo Szilard were awarded the patent, number 2,708,656, for the nuclear reactor. The people of the United States were given their first glimpse of what their tax money had paid for in 1942. The experiment cost about $1 million, or, adjusted for inflation, $12.5 million.

ERNEST RUTHERFORD: THE MAN WHO SORTED OUT THE ATOMIC STRUCTURE

Ernest Rutherford, first baron Rutherford of Nelson, OM PC PRS, or, simply, Lord Rutherford, invented the discipline of nuclear physics by discovering the atomic nucleus and is considered a primary pioneer in the field of nuclear research.

Rutherford was born near the town of Nelson, New Zealand. His parents had moved there from Perth, Scotland, to raise flax and children when New Zealand was still a rough frontier outpost of the British Empire. Young Ernest won academic scholarships, first to Nelson College and then to the University of New Zealand. After earning his BA, MA, and BSc in 1893, he performed two years of research at the university, looking into Hertz’s 1887 discovery of electromagnetic radiation from a spark gap.

impressed with his work on Hertzian oscillators, Cambridge University in England offered him a scholarship. His mother gave him the triumphant news from a received telegram, shouting it to him as he dug up potatoes in the family garden. Rutherford reportedly tossed away his spade, exclaiming, “That’s the last potato I’ll dig!” He was correct. His genuine genius, his ability to be continuously astonished, and his country-boy ability to improvise would converge in one of the finest talents ever in experimental physics, right in the middle of an exciting time in science when the basis of matter and energy required analysis. He moved to Cambridge in 1895 to work with the director J. J. Thomson, and they soon turned to investigations of the radioactiv­ity discovered by Becquerel, the Curies, and Roentgen. Over the next decades of his work, Rutherford would systematically dissect the atomic structure, discover the nucleus, and win the Nobel Prize in chemistry in 1905.

Rutherford’s most famous saying was made in 1933, when he was quoted in a newspaper article commenting offhand that any attempt to derive usable power from nuclear processes was pure "moonshine," and that such research would lead to noth­ing useful. This article so irritated the Hungarian physicist Leo Szilard (1898-1964) that he immediately visualized the nuclear chain reaction and invented the nuclear reactor before nuclear fission was discovered.

electromagnetic radiation and indicated that they were tiny particles, an idea that was definitely backed up by J. J. Thomson’s work. Some of the particles would make it straight through, but some seemed to hit some­thing hard and be absorbed. He noticed that the amount of absorption of the cathode rays was roughly proportional to the density of the material they were shot through. Moreover, the rays could make it through inches of air but were scattered by it, indicating that the air was composed of particles that were heavier than the cathode ray particles.

From those observations, Lenard made an unacceptable conclusion: The atoms, of which matter is composed, are made of almost entirely empty space. He intensified his assertion with a metaphor, saying that the volume occupied by a cubic meter of platinum was as empty as outer space. Within four years, Rutherford would come to agree with him.

America Goes Nuclear

Подпись:In 1953, Lewis L. Strauss (1896-1974), a retired rear admiral in the U. S. Navy, was named head of the Atomic Energy Commission (AEC). It was an optimistic time, with the world experiencing peace, stability, and ris­ing prosperity, and there was hope and expectation that the secretive technology that had been developed during the atomic bomb project would be put to good and practical use. In 1954, the U. S. Congress passed amendments to the Atomic Energy Act of 1946, freeing information and technology held by the military and making it possible to develop com­mercial nuclear power operations. By this amendment, the AEC was assigned the dual role of encouraging the use of nuclear power in the civilian sector and monitoring and regulating its use to ensure public safety.

The nuclear power industry did not exist in 1954, and the results of the past 15 years of intense research were mostly locked under military secrecy. Safety regulations and measures were made up as the situation demanded. Two men had already been killed in criticality accidents at the Los Alamos Laboratory, in which masses of fissile plutonium had been carelessly assembled by hand, resulting in lethal flashes of extreme radia­tion. A reactor core had melted at Chalk River, Canada, because of poor controls and procedures, and then the Experimental Breeder Reactor experienced a meltdown in Idaho. The double assignment of the AEC of pushing forward a new, unknown technology as quickly as possible while

imposing strict but nonexistent safety standards would pose an interest­ing set of problems. The technology to be developed was both ultimately powerful and inherently dangerous. Simply stated, operators of industrial equipment will make errors. If nuclear power was to be part of the com­mercial power industry, then an elementary operator error could lead to equipment damage and injuries, but it could not lead to a melting of the capital equipment and the evacuation of an entire city. The next 25 years would involve much learning.

Strauss stepped vigorously into the role of AEC chairman, and on Sep­tember 16, 1954, he gave an important speech at a meeting of the National Association of Science Writers. Speaking of the coming age of nuclear power, he said the following:

It is not too much to expect that our children will enjoy in their homes electrical power too cheap to meter; will know of great periodic regional famines in the world only as matters of history; will travel effortlessly over the seas and under them and through the air with a minimum of danger and at great speeds, and will experience a lifespan far longer than ours, as disease yields and man comes to understand what causes him to age. This is the forecast of an age of peace.

His prediction of “electrical power too cheap to meter” would haunt the nuclear power industry for decades to come. It was true that using uranium fission electrical power could be made at a rate so inexpensive that a power meter on each house would be a superfluous waste of money. The volume of uranium that would be fissioned for every person in the United States per year for electrical power needs was miniscule, compared with the stockpiles amassed and the potential uranium ore in the ground. However, this prediction assumed that fuel would be used in its cheapest form, and that power plants would be built in the least expensive way pos­sible, just as power plants had been built since the beginning of electrical power usage. The United States and the world would come to learn that nuclear fission was a new way to generate power in more ways than one. The least expensive option would apply no longer.

In this chapter, the maturing process in the nuclear industry and in the world’s perception of nuclear power are examined in chronological order, as new power plants were built and tested on the ascending node, and as major accidents occurred on the descending node. Commercial nuclear power is shown making its debut and its rise in industrial popularity and then its decline as the bottom line of profitability becomes evident. In the final topic of this chapter, the needs of a maturing world economy with respect to nuclear power are examined, as atmospheric chemistry and limited burnable resources become important considerations for power generation. A sidebar details an important federal requirement for nuclear power plant construction, the Final Safety Analysis Report.