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
National Atomic Energy Commission reactor was built (1957), the RA-1 Enrico Fermi. The 335-MWe Atucha I designed by Germany's (Siemens) was completed in 1974. In 1984 the 600-MWe Embalse designed by Canadian CANDU started its commercial operation. In 1995 CNEA's functions where divided into newly created separate organizations such as the Nuclear Regulatory Authority ("Autoridad Regulatoria Nuclear - ARN"), which supervises nuclear safety in the country, and the "Nucleoeléctrica Argentina - NASA", the company that operates the two completed nuclear power reactors. Today, CNEA mainly focuses on research and development of nuclear and related technologies. In 2001 the original 1956 Directory structure of a