[dogma1138]

I don't really know those numbers (not sure if anyone does, and you know various treaties make any numbers published debatable because the official should be 0 or very close to it) officially they aren't supposed to make any new weapons and they have to disassemble existing ones and to dilute their highly enriched uranium stockpiles (Strategic Arms Reduction Treaty, probably some others too). Uranium enrichment is usually measured in SWU's that's separation work units which basically means your capacity to separate Uranium with 1 ton of raw Uranium as the feeding source. Basically to get 90% or higher enriched uranium you need about 1000-1200 SWU's which will produce 5-6kg* of weapons grade uranium from 1 ton of raw feed. If you have en enrichment capacity of 20,000,000 SWU you should be able to produce about 100,000 tons of weapons grade uranium per year (enough for about 2000* non salted/boosted bombs)

As for books don't have anything on top of my head but this is a good source of info http://www.world-nuclear.org/info/nuclear-fuel-cycle/convers... The association of american scientists and similar organizations should also have plenty of nuclear related information. As I had to Google this earlier, and you might do it now, may I be the 1st one to welcome you to the watch list.

* may vary based on your enrichment process

* based on common publicly known weapon designs (50kg per fissile core) not sure how low an Uranium fissile core can get once you start getting into salting and multi staged fission.

Edit: Just to elaborate on the previous comment.

The difference in effort required between weapons grade and fuel grade uranium is almost negligible (this is why breakout is so easy for nuclear powered states). A 1000SWU on average will produce 5KG of weapons grade Uranium and about 100-120KG of reactor grade uranium. A 1000MW nuclear power plant needs about 75 tons of fuel per year (or upto 18 months depending on the burn rate), a bomb needs under 50kg of Uranium.