How does uranium become nuclear fuel?
Uranium, as it is mined from the ground, is not directly useable for power generation. Much processing must be carried out before uranium can be used efficiently to generate electricity. Uranium’s transformation from ore in the ground into nuclear fuel and ultimately the handling of waste products is described as the nuclear fuel cycle.
After a successful exploration program, uranium ore undergoes:
- Mining and milling to produce uranium oxide concentrate known as yellowcake (U308).
- Refining and conversion of the concentrated uranium into either uranium dioxide (UO2) for heavy water reactors or gaseous uranium hexafluoride (UF6) for light water reactors.
- Enrichment, which increases the proportion of the rarer "fissile" form of uranium, U-235, which is the essential component of nuclear fuel.
- Fuel manufacture, where the uranium is manufactured into fuel pellets.
- Electricity generation where nuclear fuel is loaded into a reactor and nuclear reactions generate electricity. After fuel is consumed, it is removed from the reactor and stored on-site for a number of years while its radioactivity and heat subside.
- Optional chemical reprocessing, after a period of storage, residual uranium or byproduct plutonium, both of which are still useful sources of energy, are recovered from the spent fuel elements and reprocessed. Alternatively, the spent fuel is stored for up to 50 years (while its radioactivity and heat subside) to allow the radioactivity to diminish; (while its radioactivity and heat subside).
- Disposal where, depending on the design of the disposal facility, the nuclear fuel may be recovered if needed again, or else remain permanently stored. At some point in the future the spent fuel will be encapsulated in sturdy, leach-resistant containers and permanently placed deep underground where it originated, thus completing the cycle.
Steps one to four are known as the front end of the fuel cycle; steps six and seven, the back end, refer to what happens after the fuel comes out of the reactor.
Nuclear Fuel Process
Cameco Corporation www.cameco.com/uranium_101/