<P> On May 4, 1939 Joliot, Halban et Kowarski filed three patents . The first two described power production from a 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 . </P> <P> 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 . </P> <P> 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 a racquets court below the bleachers of Stagg Field at the University of Chicago . Fermi's experiments at the University of Chicago were part of Arthur H. Compton's Metallurgical Laboratory of the Manhattan Project; the lab was later renamed Argonne National Laboratory, and tasked with conducting research in harnessing fission for nuclear energy . </P> <P> In 1956, Paul Kuroda of the University of Arkansas postulated that a natural fission reactor may have once existed . Since nuclear chain reactions only require natural materials (such as water and uranium), it is possible to have these chain reactions occur where there is the right combination of materials within the Earth's crust . Kuroda's prediction was verified with the discovery of evidence of natural self - sustaining nuclear chain reactions in the past at Oklo in Gabon, Africa, in September 1972 . </P>

Who conducted the first controlled chain reaction releasing energy from nuclei
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