Uranium is an element found in the Earth’s crust. Uranium is approximately as common as tin and is about 35 times more common than silver. Uranium is a trace constituent of most rocks, dirt, and of the oceans but can only be mined economically where there is a large concentration ore. At today’s prices, there is enough mineable uranium to supply reactor fuel for another century.

Uranium ore is processed into yellowcake and converted to uranium hexafluoride, which is then enriched using various techniques. At this point, the enriched uranium, containing more than 0.7% U-235, is used to make rods of the proper composition and geometry for the particular reactor that the fuel is destined for.

The fuel rods typically spend 5-6 years inside the reactor until about 3% of their uranium has been fissioned. The spent rods are then moved to a spent fuel pool where the short-lived isotopes can decay away. After about 5 years in a cooling pond, the spent fuel is radioactively and thermally cool enough to handle, and it can be moved to dry storage casks or reprocessed.