Prior to enrichment, uranium oxide must be converted to a fluoride so that it can be processed as a gas, at low temperature. Conversion plants are operating commercially in the USA, Canada, France, Russia and China.
Most of the commercial nuclear power reactors in the world today require uranium 'enriched' in the U-235 isotope for their fuel. The commercial process employed for this enrichment involves gaseous uranium hexafluoride in centrifuges.
Fuel fabrication is the final stage in nuclear fuel preparation prior to use in a reactor. Nuclear fuel assemblies are specifically designed for particular types of reactors and are made to exacting standards.