Nuclear chain reaction the last one called ""Perfectionnement aux charges explosives"" was the first patent for the atomic bomb and is filed as patent n°445686 by the Caisse nationale de Recherche Scientifique. In parallel, Szilárd and Enrico Fermi in New York made the same analysis. This discovery prompted the letter from Szilárd and signed by Albert Einstein to President Franklin D. Roosevelt, warning of the possibility that Nazi Germany might be attempting to build an atomic bomb. On December 2, 1942, a team led by Enrico Fermi produced the first artificial self-sustaining nuclear chain reaction with the Chicago Pile-1 (CP-1) experimental reactor in
R4 nuclear reactor of the plant was later used as an oil-fired plant, but the large building remains an unused structure to this day. The reactor was later used to test nuclear safety equipment, as well as the behavior of nuclear reactors. R4 nuclear reactor R4 nuclear reactor was a nuclear reactor built at Marviken and the fourth nuclear reactor built in Sweden. It was heavy water moderated and intended for the dual role of 130MWe of power generation as well as plutonium production. It had a central role in the Swedish nuclear weapon programme. During the mid 1960s, the social democratic government