Lets see...give them options that would allow for us to follow their nuclear material very closely. The special nuclear materials could be monitored to the point where every single ounce of Uranium 235 is accounted for. If it is ever unaccounted for, find it. If it can't be located, shut them down. Hell, it probably be best if we could get them to shut down their enriching program. we could do so by offering them really really cheap fuel. If we were to offer that and they rejected, then we have some pretty good reasons to kick the shit out of them(by any means, economically or whatever) cause their is no incentive to make your own fuel if you could get it cheaper unless you wanted to do some shady stuff. If they accepted our fuel, we could keep strict tabs on its location. Monitor it going into the reactor. Monitor reactor power. Monitor refuels. Basically be the nuclear watchdogs. It would sure make that whole shebang a little easier to deal with.