Letter: Forever safe

LONG-LASTING radioactive wastes will have to be disposed of safely for 'all time', (Briefly, 13 February). Stringent safety requirements lay down a target that the annual risk to an individual from a deep underground repository will not exceed one in a million. This is a small fraction of the risk theoretically implied by natural background radiation.

Before disposal can be authorised, Nirex will also have to prove that it is impossible that amounts of plutonium, tiny in relation to the total mass of material in this repository, could migrate from stainless steel drums embedded in concrete and come together to cause a nuclear reaction.

Tom Curtin

Nirex

Didcot, Oxon