Lecture II

The Start of the Cold War and the Soviet Bomb

The responses of the Soviet Union and that of the United States after the war were completely different. As we discussed yesterday, the Soviet Union started a crash programme to develop their own bomb. The American programme ground gradually almost to a complete halt. The secrecy of the bomb years was replaced by great publicity and public awareness. The scientists who had worked on the bomb were first greeted as conquering heroes but the realisation of the magnitude of these weapons startled the public and made them wary of scientists. What was called the “first team” of scientists, Neils Bohr, Enrico Fermi, Richard Feynman, Robert Oppenheimer, Hans Bethe, all left Los Alamos to return to academic pursuits. They wanted their old lives back. Willing to serve as consultants, they just wanted to return to fundamental research. Feynman joined Bethe at Cornell but, at age twenty-six, was deeply depressed by the death of his wife Arlene in Albuquerque from tuberculosis. He also was deeply upset about the number of deaths caused in Japan. He was somewhat consoled by the advice that, unable to even save his wife from her disease, he certainly could not save the world from the devastation of nuclear weapons.

Oppenheimer oscillated for a long time between a great personal burden of guilt and responsibility and serious advocacy of a decent future direction. On August 17, 1945, just eight days after the bombing of Nagasaki, Oppenheimer drafted a letter, along with Ernest Lawrence, Arthur Compton, who had headed the work at the University of Chicago, and Enrico Fermi, that went to Secretary of War Henry Stimson. In it they warned that this new weapon would be quickly superseded by weapons far more effective both qualitatively and quantitatively. Such weapons would pose a severe threat not only to a potential enemy but also to the United States. Security could only be guaranteed by making future wars impossible. In the sense that there have been only local wars and not any world wide conflicts, at least so far, is indicative of the strength of this conclusion. Oppenheimer had an unhappy meeting with Harry Truman in which he bemoaned having blood on his hands. Truman was indignant but also was very uneasy about the results of the use of such weapons. It was he, after all, who ordered the use of the bomb. The US had a third bomb ready on Tinian before the end of the war but Truman forbade its use. Enough was enough, was his comment.

Oppenheimer decided to return to teaching and his own research and had, not surprisingly, numerous offers. He chose Cal Tech in Pasadena, but was travelling to Washington several times a month for consultation work. Los Alamos had a new director, Norris Bradbury, who had been nominated for the position by Oppenheimer. In the confusion of this time, many of the best physicists left. Oppenheimer recommended that Teller leave as well, but Teller did not want to see the lab stop its work. He insisted that it was necessary to continue work on nuclear weapons and that Russia was as dangerous an enemy as Germany had been. He was, of course, deeply invested in pursuing his idea of the Super, the hydrogen or fusion bomb, hundreds or even thousands of times more powerful than its fission counterpart. The letter drafted by the committee Oppenheimer chaired called for no research on this weapon but that the question should be revisited in ten years, or 1955. The message clearly was “do research into the basic physics of thermonuclear fusion but no development.”

Teller continued to push for the Super, claiming that moral objections to such a weapon were meaningless before technological progress.

“There is among my scientific colleagues some hesitancy as to the advisability of this development on the grounds that it might make the international problems even more difficult than they are now.

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My opinion is that this is a fallacy. If the development is possible, it is out of our powers to prevent it.”

SLIDE 22 Teller’s wordsThe eventual construction of this most horrible weapon gave Teller a powerful position in what has come to be called the military-industrial complex. He used this argument for decades, even up to the Strategic Defence Initiative, or SDI, under Ronald Reagan, an initiative forty years later which came to be called Star Wars.

Disheartened by the lack of enthusiasm, Teller left for a position with Fermi at the University of Chicago in February 1946. The possibility of another nation, meaning of course, the Soviet Union, building a bomb differed widely amongst different groups. The scientists, and the Secretary of War Henry Stimson, both wrote that there were n secrets involved in nature and progress would be swift, if the desire was present. The intelligence community was more conservative claiming five to ten years. General Groves estimated twenty years. This was 1946. It took three years, the first Soviet bomb tested was in 1949. Groves also asserted that the Soviets were highly mistrustful of any information they received. He said that even if a complete set of blueprints of the entire Manhattan Project were to be shipped to the Soviet Union, they would waste a couple of years searching for a gimmick in the design. In reality, he was very prescient about that as they had received almost a complete set of blueprint from Klaus Fuchs well before Hiroshima and had already wasted a couple of years due to the mistrustfulness of both Stalin and particularly Beria. But the capabilities of the Soviets were grossly underestimated, as evidenced by the joke in Washington that the Soviets could not deliver an atomic bomb in a suitcase because they didn’t know how to make a suitcase.

The new Director of Los Alamos, Norris Bradbury, worked hard to keep the lab alive. He encouraged people to stay and encouraged the government to give the lab legal status and an administrative home, not in the military. Eventually, it became part of the Atomic Energy Commission and went on to change from making what Bradbury called “lousy bombs” to weapons with increased reliability, ease of assembly, safety and performance. Several thousand staff remained, about half the wartime population. Bradbury set everyone the task of writing down everything he or she had learned during the war, which became a large series of technical reports and a significant historical record of the first atomic bombs. Already by October 1945, they had the hardware for some sixty bombs, but lacked the plutonium or uranium for all of them. The lab was on the road to survival.

In the Soviet Union, there were the beginnings of recovery from the devastation of the War. There was a shortage of everything, including people, particularly men. But the effort to build an atomic bomb knew no such limits. New institutes were created. The American ambassador in Moscow noted activity and purchases that suggested suspicious nuclear activity. Soviet troops had crossed the border with North Korea and had seized ores with uranium and thorium. These, of course, are still being exploited for the construction of nuclear weapons by the present North Korean regime. The presence of Soviet troops in eastern Europe made sources in Czechoslovakia available as well. Ore deposits were discovered in southern Siberia and in Kyrgyzstan. A small reactor was under construction in Kurchatov’s Institute in Moscow but a serious reactor site was to be located in the southern Ural mountains. This was to be used for the generation of plutonium, and was the Soviet equivalent to the Hanford Washington laboratory. It was located in the town of Kyshtym, the site known as Mayak, then Chelyabinsk 40, then Chelyabinsk 65.

SLIDE 23 and 24 Maps of Urals

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Seventy thousand prisoners from twelve labor camps began construction of the underground city in 1945. The first nuclear reactor, Anotchka, was constructed in 18 months.

Additional nearby facilities would be constructed which would house nearly 100,000 people and encompass some 90 square kilometres. Aside from the nuclear scientists, most of the workers in the underground nuclear facility were prisoners who agreed to work in such conditions in exchange for a lesser sentence. Russian convicts were given the option to work 25 years hard labor in Siberia or 5 years underground in Chelyabinsk-40.

It really was a death sentence, however; no workers would live beyond five years with that level of radioactive exposure. Of course at the time, the convicts did not know what they’d be doing at this facility nor were they aware of the ramifications of increased exposure to radioactive material. Ultimately, the entire Mayak complex would be closed for nearly 45 years.

During the first six years of operation, the entire Mayak complex dumped its radioactive waste into the Techa River, which happened to be the only source of water for the 24 villages along its banks. By 1951, it became obvious the waste run-off was damaging the river and surrounding population. Soon after, nuclear waste from Chelyabinsk-40 was found in the Arctic Ocean. This prompted the decision to dump radioactive waste elsewhere. Lake Karachay was chosen, in part because the lake had no outlet.

To limit future incidents of residents interacting with the radioactive Techa River, authorities strung barbed-wire fences up and down the river banks restricting any human habitation. One thing they did not do was disclose the reasons why to the local population.

In 1957 a radioactive waste containment sector failed and exploded. Radiation was immediately spread throughout the region, affecting over 250,000 people. This was long before the Chernobyl incident and it occurred in a secret underground facility; less than half of one percent of the population was evacuated, and public awareness of the incident was non-existent.

Experts have said the explosion itself was a force of 70 to 100 tons of TNT, although the radioactivity released into the atmosphere was estimated to only be one-fourth that of the later Chernobyl disaster.

The first evacuations didn’t take place until ten days later, and other areas were not evacuated until a year later. During this time, the entire population had been unknowingly consuming contaminated food and water.

By 1959 every tree within a 20-km radius of Chelyabinsk-40 was dead. Later, the government would finally plough nearly 200 hectares of radioactive land in an attempt to re-start agricultural use, but this would not be completed until 1978.

In 1967 a drought reduced water levels in Lake Karachay where the waste was being dumped, exposing radioactive dust. The dust was spread by gale-force winds in the area, spread over 25,000 square kilometres and exposing another 500,000 residents to nuclear fallout.

The lake would eventually accumulate over 120 million curies of radionuclides. To put that in perspective, the Chernobyl incident released 1 million.

I mentioned the Smyth report yesterday. Six copies of this report, detailing most of the US effort to build the bomb, went to the Soviets in mid August 1945. But there was one item that was changed. These first copies were printed by lithography, from the original typewritten manuscript. Later, a

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hardbound edition was distributed. Between these two editions a sentence had been deleted. Leslie Groves was horrified to see this, as the sentence was considered very sensitive. A single sentence

In spite of a great deal of preliminary study of fission products, an unforeseen poisoning effect of this kind very nearly prevents operation of the Hanford piles, as we shall see later.

SLIDE 21 These wordsThe fission process was discovered by Hahn and Strassmann in 1938 because of the appearance of Barium in a sample of uranium. This was due to the splitting of the uranium nucleus, element 92, into Barium, element 56, and krypton, element 36. Notice 56 + 36 = 92, charge (protons) must be conserved, it cannot change. But this is not the only possible fissions result. Another was iodine (53) and yttrium (39). That strange sounding name is due to the fact that this element was discovered near the town of Ytterby in Sweden, not far from Stockholm. Various isotopes of iodine would be created by the enormous neutron flux in the gigantic Hanford piles. Among the Iodine isotopes would be I135, where the 53 protons would be accompanied by 82 neutrons. (I131, where the 53 protons are accompanied by 78 neutrons, is the isotope used for medical purposes intreating thyroids.) This heavier iodine is a radioactive isotope, with a half life of about six hours. It beta decayed into an isotope of the noble gas Xenon, which had not previously been discovered, Xe135. This isotope is an excellent absorber of neutrons. So it would swallow up the neutrons necessary for converting the uranium into plutonium and the pile would stop working. But this Xenon isotope had a 9 hour half life, so it would eventually disappear and the pile would start up again. This would be followed by more Xenon production, poisoning the pile. This start and stop action was exactly what was seen in Hanford. It was overcome by adding so much uranium that there were an enormous number of neutrons and the poisoning didn’t really matter. The Xenon was acting as an extra, and basically unknown, control rod. When the pile was constructed it had more slots for uranium than was thought necessary for basic operation so that fixing it was possible. Groves did not want this knowledge shown to anyone, especially not the Soviets. And there it was, in the lithographed copies which the Soviets had. It was removed from the printed hardbound copies but that was too late. The fact that it was deleted, of course, alerted the Soviets to its importance.

In addition to the Smyth report, the Soviets had noted that Neils Bohr had proposed an open world, in which there were no secrets in atomic energy, and communication was total. The led some in the Soviet hierarchy to believe he could be a source of special information. They picked a young physicist, Yakov Terletsky, gave him a letter to Bohr from Peter Kapitza, an old friend, and sent him off to Copenhagen with a list of questions to ask Bohr. One of the most important questions was about poisoning but Bohr was not an expert on reactors. He just knew that it happened. He was also neither foolish nor stupid and had conversations with Terletsky only with a witness, his physicist son Aage, present. He also immediately reported the contact to Danish, British and American intelligence services.

Despite the enormous difficulties the Soviets had in recovering from the devastation of the war, Stalin took care to provide the very best possible life for the scientists working on the bomb. They were treated as well as the members of the Politburo, and Kurchatov had a very fine house specially built for him.

The destruction of Hiroshima and Nagasaki by single weapons delivered from a solitary airplane frightened the world. Americans felt themselves vulnerable for the first time, a feeling they had escaped during WWII. Debates raged in 1945 and 1946 with calls to outlaw the bomb or to promote world government or some other form of internationalism. The Truman administration took the step of creating civilian control of atomic energy, rather than leaving it in the hands of the military.

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Meanwhile both the military and the intelligence agencies turned their full attention to the Soviet Union.

The US very seriously considered a pre-emptive strike against the Soviet Union while they had a clear monopoly on the A bomb. In fact, the US has carefully avoided ever endorsing a No First Use policy, which other countries have done. On September 20, 1945, a military planning document stressed that during a crisis, while diplomacy continued, the military should be making all preparations to strike a first blow if necessary. The power and destructiveness of these new weapons, far greater than anything previously known, meant that the side which struck the first blow would come out on top. In their words, “Offence, recognised in the past as the best means of defence, in atomic warfare will be the only general means of defence.”

SLIDE 26 These Joint Chiefs of Staff wordsLeslie Groves also considered the possibility of using nuclear bombs to destroy the nuclear potential of any country not firmly allied with the United States. While this was being mooted by the military, preventive war never became United States policy. Truman certainly found the idea morally repugnant and said so publicly. But what the US Air Force now did, no longer part of the Army but a completely independent branch, was to create the Strategic Air Command (SAC) and to appoint Curtis LeMay to run it.

At the same time, the facilities at Oak Ridge and Hanford were busily at work producing U235 and plutonium respectively. They were vastly different in effect, as the Hiroshima bomb, a uranium bomb, required 64 kilos of metal, which at their production rate meant 6 bombs per year, but the Fat Man Nagasaki bomb used just 6 kg of plutonium, and the production of plutonium at Hanford meant 10 to 12 bombs per year. A new design, called a composite core, reduced the mass from 6 kg to 3.2 kg. The Fat Man bomb was the size of the cue ball on a billiards table while the composite core was the size of a golf ball.

The Nagasaki bomb used a solid core of plutonium. There was fear that this composite core, which was hollow, would not be symmetric enough to compress evenly. In the bomb, there was always a uranium, U238, tamper surrounding the plutonium core. This was designed to reflect neutrons back into the plutonium and increase the number of fissions before everything blew itself apart. The levitated core idea meant that the tamper, following the chemical explosion of the lens, would have a higher speed, more momentum when it struck the core, thus giving it an ability to compress it more easily. This also meant that the inner core had to be supported by thin wires or a thin piece of aluminium, strong enough to allow the bomb to be moved and dropped but light enough not to interfere with the compression. It is similar to the idea of using momentum and the analogy is hammering a nail. Do you put the hammer on the head of the nail and push or do you swing the hammer from well above. Which is the more effective? The answer is obvious.

They also surrounded the inner plutonium with a U235 lining. The purpose of this was to make better use of the neutrons emitted by the plutonium..

SLIDE 27 Levitated CoreIn this slide, there is a little tritium-deuterium gas mixture in the very centre. This gas will fuse, greatly increasing the bomb’s yield. It is thought that this is what the North Koreans have tested, rather than a genuine thermonuclear, or hydrogen, bomb.

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LeMay was doing what he called considerable strategic thinking. America had escaped ruin in WWII for two reasons, one was the distance from the war scene and the other was that it was given the time to prepare. But in a nuclear war fought with jet planes, rockets etc, distance would not be a factor, nor would there be any time to prepare. The situation was greatly different. His fundamental belief was that no air attack could be completely stopped. Some planes would always get through. In that case, retaliation would destroy the country of the enemy but could not prevent the destruction of the United States. Therefore, the threat of retaliation must be sufficient to prevent an attack in the first place. As he said, no nation will dare attack us if we are adequately prepared. Already in November 1945, LeMay was thinking of what would become known as deterrence. He also worried about what would happen if they were not deterred?

Lewis Strauss, who had financed some of the earliest fission work done by Leo Szilard and who will become an important figure in our story, was then an Assistant Secretary of the Navy. He was concerned with the opposite of LeMay. That General wanted the Air Force to be absolutely dominant. But Strauss wanted to show that the Navy was still important. So the Navy agreed with the Air Force to do a joint experiment to see how naval ships would withstand a nuclear attack. They would anchor ships at Bikini atoll in the Pacific (the island group that gave its name to the swim suit), using old US Navy ships as well as captured Japanese and German vessels, and atom bomb this fleet.

Truman had already moved the atomic weapons programme from military to civilian control. Now he appointed a committee to study ways of banning the military use of atomic energy and promote the civilian benefits. This committee created a scientific advisory panel on which Oppenheimer was the leading technical expert. They came up with a really radical plan, called the Acheson-Lilienthal report. It said that outlawing atomic bombs by inspection was unreliable. Every stage, from mining to weapon design, would need control. And that would require removing the rivalry between nations. The way to do serious control was to assign the dangerous phases to an international organisation responsible to all nations. If only this international body could own and refine the ore, for example, then anyone owning such ore would immediately be in violation. That would be an immediate red light without waiting for them to move further along with development. Their truly radical proposal called for forbidding a country such as the United States from having mines, Oak Ridge and Hanford for refinement and production of the metals, and Los Alamos for the production of the bombs, They wanted the various facilities needed for bombs to be in different countries. No single country could have them all, but the mines somewhere, the processing plants somewhere completely different and the development labs somewhere else again.This was a version of what Niels Bohr had always hoped for, a world where all the knowledge for bomb production would be free and open, but the facilities for doing so would never be available in any one place. This plan was, of course, far too idealistic ever to have a chance of realisation.

Two events in early 1946, one in the Soviet Union and the other in the US, darkened relations considerably. A speech by Stalin on 9 February 1946 meant that there would be no relief from poverty for the masses of people. The Soviet Union had lost 20 million dead, lost 30% of its national wealth, had 25 million homeless, but the Communist system would be preserved. He said that “the Soviet system had won, the Red Army had proved itself first class, war production had met with the utmost success, and that there would be extensive construction of scientific institutes.” This was seen in the US as a Declaration of World War III.

The second great defining event was what is know as the Long Telegram from George Kennan, US chargé d’affaires in Moscow on February 26. Thirty years later Kennan expressed surprise and a little dismay at the tone of his message but he was clearly in dead earnest at the time. He wrote, “The USSR still lives in antagonistic ‘capitalist encirclement,’ with which there can be no permanent peaceful coexistence.” There is “a neurotic view of world affairs which, at bottom, was

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the traditional and instinctive Russian sense of insecurity…so that the possibilities for distorting or poisoning sources and currents of information are infinite….we have a political force committed fanatically to the belief that with the US there can be no permanent modus vivendi, that they believe it is desirable and necessary that the internal harmony of our society be disrupted, our traditional way of life be destroyed, the international authority of our state be broken.”

SLIDE 28 The first words of the Long TelegramTo contain the Communists, Kennan urged“Soviet power, unlike that of Hitlerite German, is neither schematic nor adventuristic. It does not work by fixed plans. It does not take unnecessary risks. Impervious to the logic of reason, it is highly sensitive to the logic of force. For this reason it can easily withdraw - and usually does - when strong resistance is encountered at any point. Thus, if the adversary has sufficient force and makes clear his readiness to use it. he rarely has to do so.”

SLIDE 29 The rest of the telegram This telegram was received with great approbation in Washington and had a huge effect. It became required reading for thousands of people both in the military and in the foreign service. This defined a new American policy toward the Soviet Union that was basically as ideologically rigid as Stalin’s policy towards the West.

A third event at the time was provided by Winston Churchill. A military aide to President Truman was a graduate of a small religious men’s university in Missouri, Truman’s home state. This general had managed an invitation to Churchill to address this small school in Fulton Missouri. Truman promised to travel with him and introduce him to the audience. Deeply concerned about the growing Soviet takeover of Eastern Europe, Churchill was set to deliver a major speech following the award of an Honorary degree. It was in this speech that he said

From Stettin in the Baltic to Trieste in the Adriatic, an iron curtain has descended across the Continent. Behind that line lie all the capitals of the ancient states of central and eastern Europe. Warsaw, Berlin, Prague, Vienna, Budapest, Bucharest and Sofia, all these famous cities and the populations around them lie in the Soviet sphere and all are subject in one form or another, not only to Soviet influence but to a very high and increasing measure of control from Moscow.

SLIDE 30 Churchill's famous words (March 1946)An interesting side is that the phrase, Behind the Iron Curtain, had been used by Josef Göbbels, in May 1943. In German, it is Hinter dem eisenen Vorhang. Churchill called for a strong Anglo-American alliance to counteract the new Soviet expansion. The speech was received icily in Moscow and Stalin’s reaction was to claim that it would be wrong and imprudent to entrust the secret knowledge or experience of the atomic bomb, which the United States, Great Britain and Canada now share, to the United Nations while it is still in its infancy.

Slide 31 Stalin ’s response wordsThis was a call to an all out atomic arms race, something which proceeded horribly for decades!

In this growing icy atmosphere, the Acheson-Lilienthal conciliatory report had no chance. The US proposal to the United Nations was to be presented by Bernard Baruch, a millionaire and deeply

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conservative man who had little international experience but whose monetary contributions to politicians had given him access to them. The Acheson-Lilienthal report outraged him. He ignored the report and drafted his own. And his single most serious concern was enforcement, a problem he considered the most crucial. He claimed that “peace is impossible without the force to sustain it. And so he insisted on sanctions against those who violated any rules. But, he said, the veto power in the UN Security Council meant that any such enforcement could be blocked. Therefore, he insisted that the veto power be suspended in matters of atomic control. He called for “swift and sure punishment” which could only be interpreted by the Soviets as a means of turning the UN into an alliance to support the United States. Acheson thought that “swift and sure punishment’ was either a call to war or serious sanctions. But Baruch prevailed and the deliberations at the UN went nowhere. Only bad will resulted from all of this. Oppenheimer said that the appointment of Baruch was “the day I gave up hope.” However, Baruch asked Oppenheimer to be an advisor and he reluctantly agreed. I I Rabi, a good friend, wrote that Oppenheimer wanted every experience. But, said Rabi, my own feeling is that if he had studied Hebrew and the Talmud rather than Sanskrit and the Bhagavad Gita he would have been a much greater physicist. I never met anyone who was brighter than he was. But to be more original and profound I think you have to be more focused.

SLIDE 32 Rabi’s wordsOppenheimer recalled a conversation with Truman. When will the Russian be able to build the bomb? Asked Truman.I don’t know, said Oppenheimer.I know, said TrumanWhen?Never!

SLIDE 33 Truman to OppenheimerWhat a gross misunderstanding both of physics and politics. At the very time of Churchill’s speech, the Soviet physicist Yuri Khariton, was looking for a suitable place to create the Soviet Los Alamos. They found it near the town of Sarov, some four hundred kilometres east of Moscow and just south of what was then the city of Gorky, now called Nizhny Novgorod. It was called, among other things, Arzamas-16 but is generally known just as Sarov. It disappeared from the maps! The Soviets had their own Los Alamos.

The work at Los Alamos was almost entirely devoted to improving the design and construction of atomic bombs. Some thought was going into the idea of a thermonuclear bomb, the so-called Super, but , in 1946, that was a side issue. The same was true in the Soviet Union where it was understood that a Super bomb was a possibility but the emphasis was the overwhelming need to get a fission bomb produced. Klaus Fuchs had, of course, supplied them with some details on American thoughts of the new bomb. And, despite the frantic work on a fission bomb, a few people were assigned the problem of thermonuclear ideas.

Living conditions in the Soviet Union worsened in 1946. A drought covered much of the European portion of the country, the greatest drought since 1891. Famine followed and widespread starvation. The UN distributed food aid through the Ukraine. Stalin saw some of this devastation in his travels but it caused him only to retreat further into the Kremlin. The bomb project had the highest priority and plants were constructed not by the day but by the hour. Uranium mining was emphasised and production of uranium metal to be used in reactors organised. In 1946 the CIA estimated a Soviet bomb in five years. It took three.

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In 1947, Klaus Fuchs, then back in Britain, turned over material on the technology of plutonium production. Beria, suspicious as ever, sent two men to the south Pacific to spy on US nuclear tests so that he could have someone who had actually seen such an explosion. He wanted their testimony when the Soviets ran a test. Comparison of mushroom clouds would ensure what really happened.

The tests that Strauss desired to show the importance of the Navy now were ready and the old Japanese and American ships were anchored off Bikini atoll to see what the effect was in Operation Crossroads. There was an air drop of a bomb on the ships, but the navigators made errors, the bomb missed the target area by a large amount and no ships were destroyed. However, the tests did show that sampling air currents at high altitude could find traces of rare isotopes that would indicate a nuclear test had occurred. This has proved to be a vital piece of information from the first Soviet test in 1949 to the recent North Korean explosions.

The US had its bomb laboratory at Los Alamos, but its uranium production facility was at Oak Ridge Tennessee and the plutonium facility at Hanford Washington. The first test reactor was built in Chicago. Similarly the Soviets had their laboratory at Sarov and built a test reactor in Moscow. It was called Fysik-1 or F-1. It was remarkably similar to a reactor built in the US and such a coincidence is considered by reactor experts highly unlikely to be an accident. It is likely that espionage was involved. Still, the materials that Kurchatov had, the graphite and uranium, were not of the same high quality and purity as those in the US. Moreover, he (and Beria) were always very cautious about mis-information and had to repeat all of the measurements and tests done by US physicists. They could not just copy and repeat what the Americans had done.

Because of the Soviet emphasis on heavy industry, the country did not have the precision instruments necessary to do such things as measure the purity of the graphite. a great deal was done by trial and error. There were, of course, no computers anywhere in the world and so people built small models to check their ideas, stage by stage. Fermi had done this and now Kurchatov did the same. By Christmas afternoon in 1946, everything was ready. But unlike Fermi, who believed his calculations and had a crowd on hand for the achievement of criticality, Kurchatov was unsure and cleared the building of everyone but himself and three crucial assistants. By evening, the experiment ended and the Soviets had their first successful nuclear reactor. Criticality had been achieved. A few days later Beria was called in to see the reactor working. But all he saw were flashing lights and heard loud clicks. He was deeply unimpressed and believed his scientists were fooling him. He was deeply paranoid and thought of the espionage of scientists in the US. If they could not be trusted by their country, how could he trust his own scientists?

At the same time the US was shutting down reactors. There was another serious problem with the reactors at Hanford producing plutonium. They suffered from what came to be called Wigner’s disease. after Eugene Wigner (later Nobel Laureate) who had designed the original reactors and who figured out the problem that was stopping them from working. This was in addition to the problem of I135 discussed earlier. The graphite moderator in the reactors, that which slow the neutrons so that they can be captured and cause fission, gain energy from being bombarded by radiation all the time. The carbon atoms in this pure graphite are in a regular symmetric crystal pattern called a lattice. The large number of neutron collisions destroys some of the lattice structure and the graphite heats up and swells. The pile stops working. After a while, the atoms return to their lattice structure and the reactor starts up again. More modern reactors work at temperatures to force the atoms to return to their best structure and the reactors continue to work. But this problem at Hanford caused grave problems in plutonium production and seriously hampered the continued research and production of new bombs.

Los Alamos faced a problem of lack of plutonium. It also had virtually no decent housing as everything on the mesa had been poorly and quickly built as temporary shelter. It also faced a more

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serious problem in the production of bombs. Little Boy and Fat Man had been carefully constructed and difficult bombs. They were designed to be handled and armed by experts. What were needed now were bombs that were much more rugged, ones that could be easily transported and handled by ordinary soldiers rather than careful scientists. All of these serious problems meant that there was basically no time left for research into thermonuclear weapons, the Super.

In August 1946, President Truman signed the Atomic Energy Act which ceded control over the atomic programme to civilians, the Atomic Energy Commission, or AEC. This created a national structure similar to the international structure that had been envisaged in the Acheson-Lilienthal report. It provided for civilian control over atomic energy with five commissioners. David Lilienthal was made the new chairman and Lewis Strauss became a member as well. The Congressional act authorised a General Advisory Committee, or GAC, of scientists as advisors. It included Fermi, Rabi, Seaborg and Oppenheimer, who became chairman by acclimation. US policy toward the Soviet Union hardened significantly and it went from an ally in 1945 to a serious enemy in 1946. The Soviets were now seen as a direct threat to the US and they were preparing for war. The US must have the strength and arms to resist. Above all, it needed nuclear weapons. Unfortunately for these warriors, it didn’t have weapons. It had parts, it had problems but it had only one usable weapon.

At the beginning of 1947, Sarov began to be a functioning laboratory. As at Mayak in the Urals, much of the construction work was done by political prisoners, called zeks in Russian. One of Beria’s myriad forced labour camps was located in Sarov with its unfortunate souls sentenced for imaginary crimes. with their work, by summer the lab was up and running.

The Soviet spies were still actively working in 1947 but by now the FBI opened a file on Harry Gold and Abe Brothman. The British spy, Donald Maclean, was now British co-secretary of the Combined Policy Committee in Washington. As such he had complete access to all the relevant files, a pass to both the Pentagon and the Atomic Energy Commission. Roosevelt, Churchill and the Canadians had reached a secret agreement, called the Quebec agreement, providing for the sharing of data about nuclear weapons. Truman had agreed to it following Roosevelt’s death. But Congress had passed the Atomic Energy Act unaware of this secret agreement. This law forbade any sharing of knowledge of nuclear weapons with foreign governments and thus the Secret agreement was now in conflict with US law. Maclean was in perfect position to participate in the delicate negotiations over this matter. The Soviets, not yet possessing nuclear weapons, greatly increased their conventional forces. Truman was made aware that the US had almost no nuclear weapons with which to counter any possible Soviet aggression. At the same time, March 1947, the US President created the Truman Doctrine, “to support free peoples who are resisting attempted subjugation by armed minorities or by outside pressures.” This idea was proposed by the British to support Greece and Turkey against the Soviets which the bankrupt British no longer could do. It was a de facto declaration of Cold War as well.

SLIDE 34 Truman DoctrineThe question of the division of Germany was also rife at the time.

Unwisely, the British chose to make an issue of the wartime agreements. They asked for information on reactor design and, in return, Dean Acheson who was now Assistant Secretary of State (Assistant Foreign Minister) suggested the British relinquish the paragraph giving them a veto on the American use of nuclear weapons. Such agreement was in the original Quebec document. Those who did know of it thought it was only a wartime agreement but there was no such stipulation in it. The Senate, and particularly the most conservative Republican senators were aghast when they learned of this agreement. The idea that the British knew how to make the bomb, were 10

entitled to half the world’s supply of uranium ore, and had a veto over American use of weapons was a rude shock. There was huge outrage.

The Americans had a significant advantage, however, in the fact that the British were essentially bankrupt. In 1947, the Secretary of State, General George Marshall, gave a speech at Harvard in which he stated that it was important for the United States to assist in the return of normal economic health in the world. This came to be called the Marshall Plan and the US forced a quid pro quo on the British.

Ignorant as they were of the American decision to get rid of the Quebec agreement, the British and Canadians sent delegations to Washington for a conference to determine which wartime secrets could now be declassified. Attendees from the British side included the two spies, Donald Maclean and Klaus Fuchs. Atomic weapons were among the topics discussed. The Soviets were quickly made aware of the proceedings.

The Senate was busily debating the Marshall plan and they were set to refuse participation for the British without the abrogation of the Quebec agreement, an article which, as I’ve said, outraged the more conservative Senators. All Congo uranium and the entire British stockpile were to go to the US. At the same time, the Americans ignored information brought to the newly formed CIA by a Jewish rabbinical student that the Soviets were mining uranium in eastern Czechoslovakia.

When the British were finally informed of these new conditions they were both furious and helpless. There followed two weeks of hard negotiations in which Maclean participated. The issues were not all bomb related but were useful to the Soviets in any case. They were also health and safety, radioisotope research. fundamental physics, design of reactors and uranium allocation. The British agreed to removing their veto on American use of nuclear weapons. It was called an agreement among people who disagree and received quite badly. The American senators were gratified, the American diplomats were appalled. Although Maclean passed much information to the Soviets, the Americans had lied about a great number of things in the discussion and much of the information was not very useful.

A British bomb was delayed by several years. But it was built anyway. As I’ve said, every country that has tried to build a nuclear weapon, has succeeded on the first attempt. There are no secrets in science. Once the Americans showed that a bomb was possible, everyone knew that and could figure out the physics involved.

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