K-25
K-25 was the codename given by the Manhattan Project during World War II for the project to produce enriched uranium for atomic bombs using the gaseous diffusion method. Originally the codename for the product, over time it came to refer to the project, the production facility located at the Clinton Engineer Works in Oak Ridge, Tennessee, the main gaseous diffusion building, and ultimately the site. When it was built in 1944, the four-story K-25 gaseous diffusion plant was the world's largest building, with over 1,640,000 square feet (152,000 m2) of floor space and a volume of 97,500,000 cubic feet (2,760,000 m3).
Gaseous diffusion is based on Graham's law, which states that the rate of effusion of a gas is inversely proportional to the square root of its molecular mass. The highly corrosive uranium hexafluoride (UF
6) was the only known compound of uranium sufficiently volatile to be used in this process. Before this could be done, the SAM Laboratories at Columbia University and the Kellex Corporation had to overcome formidable difficulties to develop a suitable barrier.
Construction of the K-25 facility was undertaken by J.A. Jones Construction. At the height of construction, over 25,000 workers were employed on the site. Gaseous diffusion was but one of three enrichment technologies used by the Manhattan Project. Slightly enriched product from the S-50 thermal diffusion plant was fed into the K-25 gaseous diffusion plant. Its product in turn was fed into the Y-12 electromagnetic plant. The enriched uranium was used in the Little Boy atomic bomb used in the atomic bombing of Hiroshima. In 1946, the K-25 gaseous diffusion plant became capable of producing highly enriched product.
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