believed to be “probably true and of great interest for our work in this country.” Igor Golovin says Fuchs gave the Soviet Union Teller's Super concept. Khariton confirms that “Zeldovich looked at the plans, which were Teller's work.”
In their brief presentation, Gurevich and his colleagues explained why light elements might serve for nuclear explosives and reviewed some of the problems that would have to be solved to make such explosives work. They did not propose using tritium, probably because the design they had in mind did not require that exotic material. Tritium, which is radioactive and has a half-life of only 12.5 years, does not exist in nature; like plutonium, it must be bred in a nuclear reactor, a machine the Soviet scientists had yet to build.
Gurevich and his colleagues outlined a design for a thermonuclear explosive different from the Super, a design which was a logical extension of the implosion system which Fuchs had passed in 1945: “In order to improve the conditions of ignition it appears possible to use uranium charges of increased sizes and of a special shape (cumulation [i.e., concentric shells]) and to introduce into the deuterium heavy elements near the initiator which might be capable of receiving the radiation pulse.” They also noted that “the greatest possible density of deuterium is desirable, and this should be realized by using it under high pressure” and proposed employing “massive enveloping shells [to] delay… the dispersal [of the material].” Teller invented a similar spherical, layered design in mid-1946 which he called the “Alarm Clock” (because it might “wake up the world” to the possibility of a new generation of nuclear explosives). A committee of Los Alamos senior scientists, including Bradbury, Teller and John Manley, judged in 1950 that Fuchs “was probably familiar with [the] ‘booster’ idea and may have obtained vague information on the very early proposals of the ‘alarm clock’ from another member of the British Mission.”
Soviet physicist Yuri A. Romanov remembers that “research on the [thermonuclear] problem was begun” as a consequence of the 1946 Gurevich report, suggesting that Gurevich's claim that Stalin and Beria “waved us away” is at least ingenuous. “A small group of associates… under Zeldo-vich's direction was soon formed at the Chemical Physics Institute of the
USSR Academy of Sciences… ” The United States had begun work on a thermonuclear weapon in 1942. Sometime in 1946, the Soviet Union joined in the quest for that unholy grail. Romanov notes that “the status of their research [at that point] was about identical.” It should have been, since Klaus Fuchs had shared American progress with Soviet intelligence.
Lavrenti Beria had his hands full with the Soviet bomb program. He was flying blind and it made him snappish. His deputy Avrami Zavenyagin remembered being lashed one day by Stalin's whip:
We had received a telegram from Czechoslovakia, reporting that the program for uranium extraction… would need many funds. Some obviously incorrect, astronomical figures were quoted. Reading the telegram, Beria became indignant and began to swear. I couldn't stand it and I replied, Enough [theatrics], we are executing a decision of the government by which we are charged to make an agreement with the Czechs on a program for extraction. These stupid jacked-up figures named here are incorrect, we will correct them. Again swearing: “Oh, we have a hero.” I reply, No hero, and no fool, you've no business duping people. “Get lost.” I had to get lost. Then Beria softened up and tried to smooth things over.
Beria soon had another reason for apprehension. Stalin moved to diffuse his power. “One day Stalin suddenly asked Beria why all his generals and security staff seemed to be Georgians,” writes historian Robert Conquest. “Beria answered that they were devoted and loyal. Stalin said angrily that not only Georgians but also Russians could be loyal.” In March 1946, the aging Soviet dictator made Beria a full member of the Politburo and deputy chairman of the Council of Ministers. He raised the NKVD and NKGB from commissariats to ministries — they became the Ministry of Internal Affairs (MVD) and the Ministry of State Security (MGB) — but he removed Beria from direct authority over them and replaced Beria's men with Russians. Stalin's mistrust made Beria's successful delivery of an atomic bomb at the earliest possible date that much more imperative.
Living conditions worsened in the Soviet Union in 1946. A drought began in Moldavia, east of Romania on the Black Sea, at the end of March and spread north through the Ukraine. By the middle of May, according to a Soviet government report, “the drought… embracfed] a very considerable part of the whole of the European part of the USSR.” The country had not seen such widespread and prolonged drought since 1891. Famine followed. Children's bellies bloated with protein deficiency and there was widespread starvation. The United Nations Relief and Rehabilitation Administration (UNRRA), headed by the former mayor of New York, Fiorello La Guardia, distributed food aid in the Ukraine that year. When Stalin went south on vacation that summer for the first time since 1937, his daughter writes, “the housekeeper… told me… how upset he was when he saw that people were still living in dugouts and that everything was still in ruins.” His answer was to retreat even further into the Kremlin.
The US and Britain refused to support an extension of the UNRRA past 1946, preferring direct charity to countries the former Allies favored. La Guardia was shocked. “Does the government of the United States,” he countered, “intend to adopt a policy which will make innocent men and women suffer because of the political situation which makes their government unacceptable to the United States?” It did, another sign that the Cold War was polarizing the world.
In June 1946, the Soviet Council of Ministers established a new industrial entity, the First Chief Directorate, headed by Boris Vannikov, to manage the atomic-bomb program. Vannikov reported directly to Beria; Mikhail Pervuk-hin and Igor Kurchatov became his deputies, as they had been under the Technical-Scientific Council established the autumn before. Vannikov had been Beria's prisoner in the dread Lubyanka cellar in October 1941, one of a number of senior military officers arrested in the purges. “Merciless beatings were administered,” Beria would admit in 1953; “it was a real meat grinder.” The NKVD executed many of the officers when it evacuated Moscow in the general exodus of October 15–16. Vannikov, one of the two most senior officers in the cellar, was spared. Stalin apparently realized that he needed the officers who were left to run his armies and ordered the interrogations ended. Vannikov was rehabilitated to serve as commissar of the munitions industry during the war.
“Plants were going up not by the day but by the hour,” remembers Per-vukhin of that early postwar period when the bomb program got underway. “Enterprises for the extraction of uranium were created. Production of slugs of metallic uranium was organized — these slugs were needed for the nuclear reactors.” In 1946, the CIA estimated five years later, the Soviet Union invested 270 million rubles in atomic-bomb development.
Spies no less than other veterans had to resettle their lives now that the war was behind them. David Greenglass, despite Julius Rosenberg's encouragement, rejected a Los Alamos solicitation to work on the atomic tests at Bikini because he did not want to be separated from his wife. He was honorably discharged from the army on February 29,1946. He and Ruth moved back to Manhattan; in April he began working with Rosenberg in the business his brother-in-law had promised to set up. When Greenglass applied for telephone service that spring, he listed his occupation as a machinist with the G & R Engineering Company of 300 East 2nd Street — “G&R” presumably standing for Greenglass and Rosenberg. Greenglass knew enough about his brother-in-law's espionage activities to feel comfortable shaking him down from time to time. “I got money from Julius whenever,” he would confess. “.. Julius had money, I went to Julius, [I said] ‘Look, I need money’ and he would give me money.” In the next three years Greenglass collected “about a thousand dollars all told.” According to Greenglass, Rosenberg encouraged him to think about going to college, perhaps to train as a scientist who might work with the scientists he had met at Los Alamos. “He wanted me to go to school full time… and be obligated to him. My wife and I had discussed that a number of times and we agreed to stall.” Ruth Greenglass claimed later that she wanted to do more than stall: “I told my husband in 1946 that I wanted to go to the FBI with the story [of their involvement in espionage]. However, there had been nothing happening, everything was very peaceful, and we thought perhaps it would die down and the thing would never come to light, so we did nothing about it.”
Klaus Fuchs's last act before he left Los Alamos was to review every paper in the Los Alamos document archives on thermonuclear weapons design. Thus fortified, he departed Los Alamos on June 14, 1946, traveling first to Washington, then to Cambridge to visit Kristel, then to Cornell with his sister to talk physics with Hans Bethe. (Fuchs took his sister along to Ithaca, the FBI paraphrased him later, “to give her a little outing”; they flew part of the way “in order that she might have this [new] experience.”) He traveled on to Montreal alone and left Montreal for England in a British bomber on June 28. The British flew rather than shipped Fuchs home because they wanted him promptly at Harwell. A former Royal Air Force Base located south of Oxford on the Berkshire Downs, Harwell was being reactivated as a research center; the British were preparing secretly to build their own atomic bomb, and
