Nuclear technology the element plutonium possesses an isotope that is sufficiently unstable for this process to be usable. Terrestrial plutonium does not currently occur naturally in sufficient quantities for such use, so it must be manufactured in a nuclear reactor. Ultimately, the Manhattan Project manufactured nuclear weapons based on each of these elements. They detonated the first nuclear weapon in a test code-named "Trinity", near Alamogordo, New Mexico, on July 16, 1945. The test was conducted to ensure that the implosion method of detonation would work, which it did. A uranium bomb, Little Boy, was dropped on the Japanese city Hiroshima on
B28 nuclear bomb several subsequent weapons. The B28 was the mainstay of SAC during the Cold War and have yet to be completely dismantled by the Defense Department (as of 2012). Nuclear researcher Chuck Hansen's research indicates that the Python primary was used in the US B28 nuclear bomb and the W28, W40, and W49 nuclear warheads. Four Mark 28 training variants (BDU-16/E) on their transporter (MHU-7/M) are on display in the Cold War Gallery at the National Museum of the United States Air Force in Dayton, Ohio. The Canadian War Museum, in Ottawa, holds a Mark 28RE training variant in its Cold