Production from world uranium mines now supplies only about 75% of the requirements of power utilities. Primary production from mines is supplemented by secondary supplies, principally by ex-military material and other inventories.
Uranium is a relatively common metal, found in rocks and seawater. Economic concentrations of it are not uncommon.
Uranium occurs in a number of different igneous, hydrothermal and sedimentary geological environments. The major primary ore mineral is uraninite or pitchblende, though a range of other uranium minerals exist.
Weapons-grade uranium and plutonium is being made available for use as civil fuel. Highly-enriched uranium from weapons stockpiles met about 13% of world reactor requirements through to 2013.
The basic fuel for a nuclear power reactor is uranium. Uranium occurs naturally in the Earth's crust and is mildly radioactive. Depleted uranium is a by-product from uranium enrichment.
Rock phosphate deposits contain many million tonnes of uranium, which may be extracted as a by-product of making fertilisers. The process because uneconomic in the 1990s, but process improvements and higher U prices may change this.
A large amount of uranium is in rare earths deposits, and may be extracted as a by-product. Higher uranium prices and geopolitical developments would enhance the economic potential for recovering these.
The Earth's uranium has been thought to be produced in one or more supernovae over 6 billion years ago. More recent research suggests it could also be created through the merger of neutron stars.