The process of increasing the abundance in uranium of the fissile isotope uranium-235, typically to make it suitable for use in nuclear power or nuclear weapons; frequently attributive.
Natural uranium is made up of about 0.72% uranium-235. Enriched uranium used in nuclear power generation typically contains 3–5% uranium-235; that used in nuclear weapons typically contains over 85% uranium-235. The chief methods used for uranium enrichment are gaseous diffusion and gas centrifugation of uranium hexafluoride.
1950s; earliest use found in Chemical Week.