Natural uranium is a blend of two types : U-235 and U-238.

At a uranium enrichment plant, the concentration of U-235 is increased by discarding some U-238.

The cast-off uranium (mainly U-238), called ”depleted uranium”, has virtually no commercial value.

But there are several important military uses for depleted uranium :

1. when placed in a reactor, it breeds plutonium — a powerful nuclear explosive;
2. when incorporated into an H-bomb, it doubles the explosive power of the weapon;
3. when used to coat conventional bullets and shells, it makes them armour-piercing;
4. when used as a metallic alloy in tanks and other vehicles, it provides armour-plating.

Containers of depleted uranium.
Photo by Robert Del Tredici