From the series Atom and industrialisation of science
The course of the war between Germany and the Soviet Union, from Operation Barbarossa — the German attack of June 22nd, 1941 — up to the Battle of Stalingrad between the summer of 1942 and February 2nd, 1943, set the timeframes of the Russian nuclear programme.
The Battle of Stalingrad
The Battle of Stalingrad was the turning point of the Second World War on the Eastern Front. We quote The New York Times of February 3rd, 1943, to illustrate the climate of the period, within which we need to contextualise Soviet decisions about the nuclear bomb. The daily cited a Moscow bulletin, according to which the Red Army had completely destroyed the elite of Adolf Hitler’s army, trapping 330,000 soldiers.
On the basis of Russian announcements, since mid-November 1942, a total of 503,650 soldiers of the Axis powers (Germany, Italy, and Japan) had been killed or captured. This figure excluded Axis losses in the previous three months of fierce fighting which had raged along the Volga and at Stalingrad. German radio broadcasts acknowledged the demise of the trapped Nazi army but stated that the battle had cost the Russians more than 300,000 men. Beyond the Russians’ huge territorial progress, the destruction of the Axis troops and equipment was considered even more important by the Allies (the USSR, the UK, and the US) for bringing the Nazis to their knees. These facts are all drawn from the reports of The New York Times.
In this scenario, the Soviet government had to decide how to proceed in developing its nuclear industry. David Holloway writes in his book Stalin and the Bomb [1994] that, when Igor Vasilyevich Kurchatov [1903-1960] was called to Moscow on October 22nd to discuss his appointment as director of its nuclear programme, the Red Army was still fighting desperately to defend Stalingrad. The government’s original idea was to appoint Abram Ioffe [1880-1960], but he rejected the offer, because he believed himself too old at 63 to take on such a role. Ioffe, together with Vice-Premier and People’s Commissar for the Chemical Industry (dedicated to nuclear research) Mikhail Pervukhin [1904-1978], strongly backed Kurchatov’s appointment. On February 2nd, 1943, the German army surrendered at Stalingrad. On March 10th, Kurchatov was confirmed as the scientific director of the Soviet nuclear project.
The moment of choices
In January 1943, Kurchatov had expressed to Pervukhin his doubts regarding whether the Soviet Union could build a nuclear bomb before the end of the war. In Holloway’s opinion, in 1943 Stalin knew about the Anglo-American nuclear programmes through his network of spies, but he did not yet believe the Soviet project to be crucial in the final outcome of the war against Germany. He launched the programme not to build a nuclear bomb in the immediate term, but as an investment against the future uncertainties of relations with the other powers. His vision went beyond the war, even if, in the immediate future, it was necessary to concentrate all the Soviet Union’s resources on defeating Germany.
After the German attack, the State Defence Committee had been created on June 30th, 1941, under Stalin’s chairmanship, with Vyacheslav Mikhaylovich Molotov appointed as vice-chairman. In February 1943, Kurchatov told Molotov he was unsure about the possibility of building the atomic bomb because there were many issues that he still did not understand. Molotov recalls that it was thus decided to provide Kurchatov with the intelligence Soviet spies had gathered in England.
Kurchatov spent several days studying the material and wrote two memoranda for Pervukhin. What struck him most was the possibility of a chain reaction using natural uranium and heavy water, according to the experiments conducted in Cambridge. This pointed to an alternative to enriching U-235, because a natural uranium and heavy water reactor could produce the fissile element 94 — plutonium. The British findings demonstrated that, through the production of plutonium, the timeline for developing the bomb would be shorter than what had been calculated by the Soviet scientists. At that moment, Kurchatov was still unaware of Enrico Fermi’s previous December success in Chicago, when he achieved the first atomic pile in history, based on natural uranium and graphite. Kurchatov’s reading of the covertly obtained documents led him to follow the plutonium route as the most promising path, without, however, abandoning the pursuit of enriched uranium.
Molotov introduced Kurchatov to Stalin, who promised him all the support he needed. On April 12th, following the State Defence Committee’s decision to formally launch the nuclear project, the Academy of Sciences issued secret instructions to build a new laboratory for Kurchatov, designated Laboratory N° 2. Although formally part of the Academy, the laboratory actually reported directly to Pervukhin, with whom Kurchatov dealt directly. The latter met his closest colleagues to decide upon the lines of research to follow and took responsibility for planning and building an experimental pile for the production of element 94.
In April, in his report to Pervukhin, Kurchatov estimated they would need 15 tonnes of heavy water and 2 tonnes of natural uranium for a heavy water reactor, or 500-1,000 tonnes of graphite and 50-100 tonnes of uranium for a graphite reactor. The heavy water reactor needed less uranium, but heavy water was very difficult to procure. None of the materials Kurchatov needed were available at the time in the Soviet Union. In March 1943, he had asked Leonid Nemenov [1905-1980], who had worked at Ioffe’s Institute before the war, to build a cyclotron in order to obtain samples of element 94 (plutonium) to study. He gave him 16 months to complete it. It was not until 1946 that Kurchatov was able to start studying the small quantities of plutonium obtained from the uranium irradiated in the cyclotron. In April 1944, only 25 scientists were working in Laboratory N° 2, compared to the hundreds who were working at Los Alamos on the Manhattan Project.
The most formidable problem for Kurchatov was sourcing uranium and graphite. Only at the end of the summer of 1945 did pure graphite become available, produced by the Moscow Electrode Plant. The quantity of uranium needed for the experimental reactor was not yet available. It would be found only later, in Eastern Europe, following Germany’s defeat.
The spy network
According to Holloway, the Soviet Union had world-class scientists capable of developing a nuclear bomb independently. However, a pivotal role was also played by the extensive spy network in Britain and in the United States, saving the Soviets a year or two in the development of the bomb, since it meant Kurchatov could choose to follow the Anglo-Americans down proven scientific pathways.
In his book Dark Sun [1996], Richard Rhodes, the American historian of the nuclear and the hydrogen bomb, writes that the most productive espionage cell in the history of Soviet spying emerged at the University of Cambridge in the 1930s. While the physicists of the Cavendish Laboratory were exploring atomic nuclei, a group of young intellectuals at Trinity College, Cambridge, had embraced socialist ideas.
Even if his description is ideologically biased, expressing a negative judgement about people who, from an American viewpoint, had betrayed the West, Rhodes tells us that between the two world wars, socialist and communist ideas had spread among students at British universities. These idealistic youths, seeking an alternative to Anglo-Saxon capitalism and German Nazism, betrayed their own country in order not to betray the human race, whose future, they thought, was in the hands of those who had carried out the Bolshevik Revolution. Their personal tragedy was that they would in turn be manipulated and betrayed by the Stalinist counterrevolution. Michael Straight [1916-2004], an American student and Soviet spy, reports that there were 600 students with socialist ideas at Cambridge. It was among these that the Soviets recruited their assets.
An important figure was John Cairncross [1913-1995]. He had graduated from Glasgow University in 1933 in French and German. He then studied modern languages at the Sorbonne in Paris and subsequently at Trinity College, Cambridge. There, he frequented left-wing circles and met other members of the future spy ring. Cairncross entered the British Foreign Office in 1936, after passing its entrance exam with top grades. Shortly afterwards, he was presented to James Klugmann [1912-1977], a fellow Soviet spy in Cambridge, who recruited him into the antifascist movement and enrolled him as an agent. Cairncross was transferred to the Treasury in 1938, and in 1941 became the private secretary of Lord Hankey [1877-1963], a minister without portfolio of the War Cabinet and chairman of the Cabinet Scientific Advisory Committee. Hankey chaired the Defence Services Panel to which the work of the MAUD Committee (the British nuclear project) was subordinate.
The MAUD Report in Soviet hands
According to Rhodes, Cairncross’s position allowed him to pass the Soviets a copy of the July 1941 MAUD REPORT, which outlined the prospects of Britain building a nuclear bomb. We wrote about this report in September 2022 [Rivalità atomiche tra alleati
, Lotta Comunista].
In 1942, Cairncross was appointed as a German translator at Bletchley Park, a government codebreaking centre north of London, where German encrypted military communications were deciphered and sent to the secret services. Cairncross clandestinely sent many decrypted communiqués to the Soviets, including vital messages about the movements of the German army on the Eastern Front. These helped the Red Army to prepare itself for the massive German attack on the Russian front. It is through Cairncross that the NKVD, the interior ministry and secret police of the Soviet Union, acquired a complete copy of the MAUD Report. Moscow now knew that the British government had decided to build a nuclear bomb and that the British scientists had calculated a timeframe of between two and five years.
The dates are important: in 1941-42, the information supplied by their spy ring did not have an immediate effect on the policy of the Soviet government, whose urgent priority was resisting the German troops’ attack. The development of the nuclear bomb required a colossal commitment of government funds, which could not be diverted from conventional forces during the height of the war.
The Soviets had all the necessary information thanks to their spy ring, and nuclear physicists able to build the nuclear bomb; but in the midst of war, they did not have the industrial capacity to realise the project. After Stalingrad, Stalin decided to go ahead with the nuclear project as a secondary priority. Only after Germany’s surrender in May 1945, and, crucially, after the Hiroshima bomb in August of the same year, did he decide to commit the full weight of Soviet industry to the development of the nuclear bomb.