Iran Focus

Thanks to Laura Rozen at War and Piece, I find a discussion of an deal offered to Iran concerning the nuclear issue.  The EU, the five members of the Security Council and Germany are behind it.  The full text of the offer to Iran is available online.

One part jumped out at me, something I don't see why the Iranians would accept: "Provision of legally binding nuclear fuel supply guarantees."  Legally binding by whom?  Legally enforced by whom?  Wouldn't it be more rational for a state like Iran, constantly under verbal assault from America, to rely on themselves as much as possible?  Doesn't it provide some additional basis for national pride to be self-sufficient?  Not to mention the benefit they would get by getting to do advanced science and engineering themselves?