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
R1 (nuclear reactor) R1 (nuclear reactor) R1 was the first nuclear reactor of Sweden. It was a research reactor located at the Royal Institute of Technology (KTH) campus at Valhallavägen in central Stockholm, in the rock beneath the current-day Q buildings. The reactor was active from July 13, 1954 to June 6, 1970. The reactor was dismantled, and there is nothing left of it today; the reactor hall however still exists. The capacity of the reactor was originally 300 kW but was later increased to 1 MW. In 2016, the reactor hall was used to film the music video for Alan Walker's song