Excerpt from the Wanderers list...
I'm surprised the US hasn't stepped up to the plate and volunteered to help with the uranium purification -- what better way to monitor than to be integral. Reciprocal agreements with Iranians, whereby the IAEA would be empowered to inspect US nuclear facilities, any time, would be a huge confidence building measure. Any administration at all serious about peace in the Middle East would be eagerly looking at non-proliferation by this means.
Of course Russia is closer, geographically, and already helps supply India with civilian-grade fissionable materials, so it makes sense that the US is backing Russia's overtures...