Nuclear fission the Manhattan Project during World War II (September 1, 1939 – September 2, 1945) carried out most of the early scientific work on fission chain reactions, culminating in the three events involving fission bombs that occurred during the war. The first fission bomb, codenamed "The Gadget", was detonated during the Trinity Test in the desert of New Mexico on July 16, 1945. Two other fission bombs, codenamed "Little Boy" and "Fat Man", were used in combat against the Japanese cities of Hiroshima and Nagasaki in on August 6 and 9, 1945 respectively. Even the first fission bombs were thousands of
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