Nuclear fission Mexico, which was the scientific hub for research on bomb development and design. Other sites, notably the Berkeley Radiation Laboratory and the Metallurgical Laboratory at the University of Chicago, played important contributing roles. Overall scientific direction of the project was managed by the physicist J. Robert Oppenheimer. In July 1945, the first atomic explosive device, dubbed "Trinity", was detonated in the New Mexico desert. It was fueled by plutonium created at Hanford. In August 1945, two more atomic devices – "Little Boy", a uranium-235 bomb, and "Fat Man", a plutonium bomb – were used against the Japanese cities of Hiroshima
B83 nuclear bomb in the Grenadier Tierra nuclear weapon test on 15 December 1984, at a reduced yield of 80 kilotonnes due to the Threshold Test Ban Treaty. With the dismantling of the last B53 bomb in 2011, the B83 became the highest yield nuclear weapon in the U.S. arsenal. The bomb is long, with a diameter of . The actual nuclear explosive package, judging from published drawings, occupies some in the forward part of the bomb case. The bomb weighs approximately . The location of the lifting lugs shows that the greater part of the total mass is contained in the nuclear