> You need a nuclear reactor to supply the neutrons for transmutation into plutonium, so this isn't something you can do at home. Sure, but a simple graphite r

> You need a nuclear reactor to supply the neutrons for transmutation into plutonium, so this isn't something you can do at home. Sure, but a simple graphite reactor for Pu production, like what most current nuclear weapons states have used, isn't particularly complex. As you mention, the difficult and expensive part is apparently separating the Pu from the rest (PUREX). In the West, those plants go for $20 billion a pop, or about, although a would-be-proliferant could probably make do with something substantially cheaper. AFAICS the current thinking is that thanks to centrifuges, nowadays the easiest path for a rogue state to develop it's own weapon is to use enriched uranium. And yes, there's a lot of DU around. Except for kinetic warheads, counterweights in aircrafts, and such, there's not much use for it. Waiting for breeder reactors to be deployed on a large scale is the plan in practice, I suppose.