Uranium in its natural state is found in quantities that average about 4 grammes to every ton of rock. It is an extremely expensive process to extract this mineral from the rocks that contain it even when the deposits are relatively rich.

The best material for nuclear fission is Uranium 235, but natural uranium has only one atom of structure for every 140 atoms of Uranium 238. So even when the uranium has been extracted from the rocks, the element has to be further processed to get the portion with the atomic structure needed for nuclear reactors.

Once the atomic reaction has been set in motion, the energy which is released mostly takes the form of heat. This heat is led to a type of boiler where it generates steam that is later put to several uses. One kilogram of uranium yields as much energy as 3 million kilograms of coal.