Not enough U235 to build a second bomb (it took like 140 lbs!) but there was enough Pu to build at least two.
I don’t think it works like that.
Much of the expense is in building & maintaining the plants to refine U-238 into U-235 or Plutonium. Once you’ve spent the money to build those plants, you need to run them continuously to try to accumulate enough fissile material for a bomb. It would save some operational expense to only run them for a month or two out of the year, but that’s an incredible waste of really expensive machinery. (And starting them up again after several months sitting idle might present problems.)
Plus there’s radioactive decay – I’m not sure the refined material would stay at ‘weapons-grade’ for years until they accumulated enough. I know the early US nuclear weapons were only functional for a few months – after that, they had to go back and have the nuclear fuel replaced with fresh ones, otherwise they might be a dud when used.
Remind me when that was?
The UK detonated a nuclear warhead in 1952, which was not an era of supercomputers and widespread understanding of nuclear weapons technology. France did it in 1960.
2016 is a very different time.
Again, of course, the time is dependent on will. A car assembly plant could be set up in sixty days or less - if an entire country was determined to do so without regard to the cost.
Right… ultimately the biggest hurdle is getting enough of the right fissile material, which is typically accomplished using centrifuges or through doing short-term burns in reactors and then chemically separating the plutonium. Neither of which is easy for a country without serious modern, heavy industry. But a country like Japan probably already produces the right kind of maraging steel centrifuges for other industrial purposes, and more impotrtantly, already has lots of reactors and high capacity fuel reprocessing plants which could be relatively easily tweaked to separate the plutonium from the uranium, as well as removing the waste, because after all, the PUREX process that they use for civilian purposes was actually developed by the Manhattan Project for separating plutonium for weapons purposes.
So at that point, once the Japanese decide they want a bomb, it’s a matter of just producing enough high quality plutonium, and then scheming up an implosion bomb system to go with it, which should be the easy part, since a lot of the conceptual stuff is readily available - stuff like the concept of explosive lenses made from two types of explosive, exploding wire detonators, etc… And there’s a lot more stuff developed since that could be included with little additional trouble- advanced wave shaping simulations to fine-tune the lenses, fusion boosting with tritium, external neutron initiators, etc…
Considering that the Japanese Rokkasho plant has a capacity of 8 TONS of Plutonium annually, getting 15-20 lbs for a crude implosion device should be trivial for them.
I don’t know how this can be answered at all. Is there an annual spending limit? Is it a country that has no uranium deposits? Or does?
I imagine that unless the country has had some export bans slapped on it by other countries, that they could buy everything needed except the nuclear material in a couple of days, and build/machine/assemble it within a few months. That is … if they could afford it.
I have no idea about the nuclear material side.
I think the OP was just trying to get a ballpark idea- for a country like say… Japan, it would be very easy, with the same being varying degrees of true for other developed countries like Germany, Netherlands, Italy, Spain and South Korea, with the main stumbling block being access to fissile raw material (natural uranium and/or having nuclear power reactors).
I was thinking about this last night, and another thing that came to mind is that in WWII, the physicists were actually discovering a lot of the nuclear physics involved in fission reactions as they went; the first nuclear chain reaction had only been started toward the end of 1942 by Enrico Fermi in Chicago, plutonium had only been discovered as an element in 1940, and nuclear fission itself had only been discovered in 1938! Today’s nuclear scientists have 70-some odd years of further research and testing to draw upon in the open literature, so they only have to concentrate on the parts specific to making a bomb, not on fission in general, or properties of nuclear materials.
How many bombs do you want? Enriched weapons-grade uranium adequate for at least a few bombs is available on the black market — very black. It would be a difficult intelligence operation to buy the uranium from those who want to sell it — preventing such transfers is a major priority of the world’s top spies — but if achieved, would be much faster and cheaper than trying to enrich uranium from scratch.
How many countries have started a nuclear program but abandoned the effort for budget or other reasons?