The Manhattan Project Heritage Preservation Association, Inc.
"Preserving, Exhibiting, Interpreting and Teaching the History of the Manhattan Project"
|Home||Site Map||Contact Us||Feedback||Mission|
Become a 509th CG Collector - Find Out How HERE!
Above photos courtesy Bradbury Science Museum - "Click" on photo for enlargement
Fat Man Prints Available for Sale or Download HERE!
|"Fat Man" was the second plutonium, implosion-type
bomb. The first was the "gadget" detonated at the Trinity site on
July 16, 1945.
Keep in mind that an explosive nuclear chain reaction occurs when a sufficient quantity of nuclear fuel, such as uranium or plutonium, is brought together to form a critical mass. This is the minimum amount of fissionable material needed to start a chain reaction. The chain reaction starts when neutrons strike the heavy uranium or plutonium nucleus which splits releasing a tremendous amount of energy along with two or more neutrons which, in turn split more nuclei, and so on. In the implosion-type device, a core of sub-critical plutonium is surrounded by several thousand pounds of high-explosive designed in such a way that the explosive force of the HE is directed inwards thereby crushing the plutonium core into a super-critical state.
Dropped on the Japanese city of Nagasaki on August 9, 1945, it was the second nuclear weapon used in a war. Following are some approximate statistics for Fat Man. If you require more extensive information on this weapon, please contact us via feedback:
Official Test Count Commenced 3/22/02 -