235U gaseous diffusion

Enrichment, Isotopic—An isotopic separation process by which the relative abundances of the isotopes of a given element are altered, thus producing a form of the element that has been enriched in one or more isotopes and depleted in others. In uranium enrichment, the percentage of uranium-235 in natural uranium can be increased from 0.7% to >90% in a gaseous diffusion process based on the different thermal velocities of the constituents of natural uranium (234U, 235U, 238U) in the molecular form UF6. 

Other important inorganic compounds of fluorine include uranium hexafluoride, UF6, a volatile substance that was used to separate 238U from the fissionable 235U by gaseous diffusion in the Manhattan Project. Sodium fluoride, NaF, is often added to drinking water and to toothpaste in order to reduce the incidence of tooth decay. 

The United States has three gaseous diffusion plants (18) for separating 235u located at Oak Ridge, Tenn., Paducah,... 

The S.W.U. provides a quantitative measure of the Isotope separation task for any conceivable process. For the task described In Figure 7, 227.3 kg S.W.U. are required per kg of 90% 235u. For gaseous diffusion, with (a-1) =. 0043, 98.2 million kg U must be pumped through the cascade in order to produce 1 kg of product. 

---