There are proliferation resistant design that can have quite good economics. You don't need breeders everywhere. Additionally, a Thorium breeder will produce U

There are proliferation resistant design that can have quite good economics. You don't need breeders everywhere. Additionally, a Thorium breeder will produce U-233 but it will be contaminated with U-232 making it a really unpractical material for nuclear bombs. And no nation has used it for that reason. In addition other elements produced make it absolutely trivial to measure and track. These nations could sign agreements of IEAE supervision and should anything happen the operator country can basically destroy the reactor with the push of a button. Reactors can also be off-shore, considering that 100s of millions of people in places like Indoneasia live on the coast. All in all, nations that really want nuclear reactors will mostly likely obtain it threw traditional means.