Putin is supplying the mullahs of Iran every nuclear technical requirement for the unthinkable. If for some reason the situation concerning Iran's nukes becomes very ugly and Putin is blamed for transferring the nuclear knowhow enabling the mullahs to undertake a threatening position, there could very well be a backlash inside Russia.
It's happened before in the land of the pogroms. I don't trust the damn Russians as far as I could thrown them.
No they are not - ever read a science text and understood it? The Russians are prividing nothing that can be turned into a nuclear weapon. They are even taking back spent all nuclear fuel. The issue is Iran develpoing the ability to enrich its own nuclear fuel - a technology the Russians are not selling Iran - the fear was that the refined Russian nuclear fuel would make it easier for Iran to take the enriched the uranium and turn it into weapons grade fuel. Russia is taking back all the fuel and thus is no longer part of the Iranian nuclear equation.
It is called reading.