A primitive bomb could be made with 35 kilograms of plutonium dioxide, or terrorists could use hydrofluoric acid to precipitate out the pure metal, Barnaby says. Only 13 kilograms of pure metal would be needed to create an explosion with a yield of 100 tonnes of TNT - 50 times the size of the largest terrorist bomb to date, in Oklahoma City six years ago. Hard to steal BNFL points out, however, that MOX fuel would be difficult to steal because it travels under armed guard. We are 100 per cent confident in the physical protection measures we have. The company points out that turning plutonium into MOX fuel and burning it in reactors could reduce the threat of nuclear weapons proliferation by cutting plutonium stockpiles.
Some plutonium also has to be returned to foreign customers because they own it.