Russia also said it would shut down its last plutonium-producing reactor.

ECONOMIST: Disarmament and counter-proliferation

It could also be possible to provide similarly enriched fuel, perhaps from France, for the Tehran Research Reactor (TRR) and LEU targets for producing medical isotopes in the reactor.

ECONOMIST: Iran and nuclear weapons

The existing reactor, which started producing electricity in 1971, will close by 2014.

BBC: Wales politics

That reactor type is not ideal for producing weapons-grade plutonium, but all reactors produce plutonium that could be used in a nuclear explosion.

BBC: Yongbyon restart: North Korea ramps up nuclear tension