Uranium enrichment

Uranium found in nature consists largely of two isotopes, U-235 and U-238. The production of energy in nuclear reactors is from the 'fission' or splitting of the U-235 atoms, a process which releases energy in the form of heat. U-235 is the main fissile isotope of uranium.

Enrichment processes require uranium to be in a gaseous form at relatively low temperature, hence uranium oxide from the mine is converted to uranium hexafluoride in a preliminary process, at a separate conversion plant.

There is significant over-supply of enrichment capacity worldwide, much of which has been used to diminish uranium demand or supplement uranium supply. The ability of enrichment to substitute for uranium (see description of underfeeding below) has become more significant as centrifuge technology has taken over, since this means both lower SWU costs and the need to keep the centrifuges running, so capacity remains on line even as demand drops away.

• Most of the 500 commercial nuclear power reactors operating or under construction 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 in centrifuges. An Australian process based on laser excitation is under development.
• Prior to enrichment, uranium oxide must be converted to a fluoride so that it can be processed as a gas, at low temperature.
• From a non-proliferation standpoint, uranium enrichment is a sensitive technology needing to be subject to tight international control.
• There is a significant surplus of world enrichment capacity.