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
Enrico Fermi Nuclear Generating Station was achieved on August 23, 1963. On October 5, 1966 Fermi 1 suffered a partial fuel meltdown. Two of the 92 fuel assemblies were partially damaged. According to the United States Nuclear Regulatory Commission, there was no abnormal radioactivity released to the environment. Fermi 1 was a liquid metal (sodium) cooled fast breeder reactor design. It was capable of producing 200 megawatts thermal (MWt) power or 69 MW electrical power with 26% enriched metallic uranium fuel. The enriched uranium section of the reactor (core) was a 30 inch in diameter cylinder by 30 inches high and contained 92 fuel assemblies.