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The Manhattan Project was the codename for an Allied project conducted during World War II to develop the first atomic bomb, before Germany or Japan. The project was led by the United States, and included participation from the United Kingdom and Canada. From 1942 to 1946 the project was under the command of Major General Leslie R. Groves, Jr. of the U.S. Army Corps of Engineers. The Army component of the project was officially designated the Manhattan District, U.S. Engineer Department, but was usually referred to as the Manhattan Engineer District (MED). The project’s roots began in 1939 when at the urging of Leó Szilárd, Albert Einstein signed the Einstein–Szilárd letter to President Franklin D. Roosevelt expressing concerns that Nazi Germany might develop nuclear weapons. The Manhattan Project, which began as a small research program that year, eventually employed more than 130,000 people and cost nearly US$2 billion ($22 billion in present day value). It resulted in the creation of several research and production sites whose construction and operations were secret. Research took place at more than 30 sites, including universities across the United States, Canada, and the United Kingdom. The three primary research and production sites of the project were the plutonium-production facility at the Hanford Site in eastern Washington state; the uranium enrichment facilities at Oak Ridge, Tennessee; and the weapons research and design laboratory at Los Alamos, New Mexico. The Little Boy gun-type fission weapon was made from uranium-235, an isotope of uranium that makes up only 0.7% of natural uranium and is chemically identical to the 99.3% uranium-238. Three physical methods were employed for uranium enrichment, most of the work was performed at Oak Ridge. Electromagnetic separation was employed at Y-12; gaseous diffusion was carried out at K-25; and thermal diffusion was used at S-50. The three enrichment processes were run in series, with S-50 as the first stage, enriching from 0.71% to 0.89%. This material was fed into the gaseous diffusion process in the K-25 plant, which produced a product enriched to about 23%. This was, in turn, fed into Y-12, which boosted it to about 85%, sufficient for nuclear weapons. The more complex plutonium core Fat Man implosion-type nuclear weapon required a concerted effort from Los Alamos scientists to design and construct. The first was detonated at the Trinity test in July 1945. Bombs developed by the project were used in the Atomic bombings of Hiroshima and Nagasaki. The Manhattan Project was also charged with gathering intelligence on the German nuclear energy project. Through its Operation Alsos it gathered nuclear materials and rounded up German scientists. The MED maintained control over American atomic weapons production until the formation of the United States Atomic Energy Commission in January 1947.
From Wikipedia, the free encyclopedia : Project |
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