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 Soviet atomic bomb project The Soviet atomic bomb project (Russian: Советский проект атомной бомбы, "Sovetskiy proyekt atomnoy bomby") was the classified research and development program that was authorized by Joseph Stalin in the Soviet Union to develop nuclear weapons during World War II. Although the Soviet scientific community discussed the possibility of an atomic bomb throughout the 1930s, going as far as making a concrete proposal to develop such a weapon in 1940, the full-scale program was initiated during World War II. Because of the conspicuous silence of the scientific publications on the subject of nuclear fission by German, American,