Rather than sit down with the six, it may be hoping to revive talks about a separate proposal for Russia, France, America and the IAEA to help it find replacement 20%-enriched fuel for a research reactor in Tehran that supplies medical isotopes.

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Nuclear reactor fuel is enriched to 3-5% Uranium-235.

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The idea was for Iran to ship 1, 200kg of its low-enriched uranium overseas to produce fuel for a research reactor, thus leaving the country for a while with too small a stockpile with which to make a bomb.

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U.S. and United Nations officials have documented what they describe as serious limitations in Iran's ability to quickly and efficiently produce the enriched uranium required to either fuel a nuclear power reactor or to build an atomic weapon.

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After Qom, Iran appeared to back off a bit by agreeing in principle to ship abroad much of its uranium stock (a bomb's worth or thereabouts if sufficiently re-enriched) for reworking to provide the needed reactor fuel.

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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.

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Under the proposal, Iran would get the fuel it needs for its research reactor in Tehran, but this would not be sufficiently enriched to make a bomb.

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Iran's stock of low-enriched uranium is bigger: only about half of it would be needed to produce the equivalent fuel load for the medical reactor.

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