Thin Man (nuclear bomb) Thin Man (nuclear bomb) "Thin Man" was the code name for a proposed plutonium gun-type nuclear bomb using plutonium-239 which the United States was developing during the Manhattan Project. They aborted its development when they discovered that the spontaneous fission rate of their nuclear reactor-bred plutonium was too high for use in a gun-type design, due to the high concentration of the isotope plutonium-240. In 1942, prior to the Army taking over wartime atomic research, Robert Oppenheimer held conferences in Chicago in June and Berkeley, California, in July at which various engineers and physicists discussed nuclear bomb design issues. A
Soviet atomic bomb project control of the atomic bomb project by establishing a special committee to oversee the development of nuclear weapons as soon as possible. On 9 April 1946, the Council of Ministers created KB–11 ('Design Bureau-11) that worked towards mapping the first nuclear weapon design, primarily based on American approach and detonated with weapon-grade plutonium. From this point, the work on the program was carried out quickly, resulting in the first nuclear reactor near Moscow on 25 October 1946. From 1941–46, the Soviet Union's Ministry of Foreign Affairs handled the logistics of the atomic bomb project, with Foreign Minister Vyacheslav Molotov controlling