On Sun, Apr 5, 2015 at 4:39 PM, meekerdb <meeke...@verizon.net> wrote:
> The reason LFTRs have been touted as proliferation resistant is that the > U233 is mixed with U232 which makes its use in a weapons almost impossible. The intense gamma rays given off by U232 is one reason no nation has a U233 bomb in its stockpile but it's not the only reason. Even in its purest most uncontaminated form the free neutron density of U-233 due to spontaneous fissions is 3 times as high as in U235, and it would be far higher than that if it had any U232 contamination. And the higher the neutron density the greater the pre-detonation problem. So if you had enough U235 it would be relatively easy for a shade tree mechanic to cobble something together that would bring 2 sub critical pieces of U235 together fast enough to make a crude bomb, but that would be much too slow to prevent pre-detonation with U233, you'd need a method that was far more sophisticated than that to make a bomb from U233, and that's even assuming your U233 was absolutely pure and uncontaminated with 232. Even the professional bomb makers aren't very good at making U233 bombs, the USA, the USSR and India have all tried it and all found the results to be very disappointing. For example in 1955 the USA exploded a composite Plutonium U233 bomb but the blast was no bigger than if had just the plutonium in it, the U233 ended up doing virtually nothing. In 1998 India made a pure U233 bomb but it was a embarrassing dud with a blast of just 200 tons. Pre-detonation is a serious problem in U233 bombs even if you have the resources of a nation state at your disposal.. And unlike existing Uranium power reactors which constantly increases the amount of Plutonium on the planet a legal LFTR would burn up all of its U233. > the proliferation problem for a LFTR is that Proactinium can be > chemically remove from the cycle, which prevents the accumulation of U232. That's possible but not probable, and certainly a standard LFTR operation would not have the equipment to do that. And although Protactinium is part of the most important chain that leads to U232 there are other pathways that don't involve Protactinium at all so you'd still have some U232 contamination giving off deadly gamma rays and releasing neutrons making pre-detonation more likely. Forget about terrorists, it's too difficult and expensive for even countries to make a U233 bomb; if you want to worry about something worry about the thousands of fully functional H-bombs floating around the world. > Then the U233 can be siphoned off and used. A 2GW LFTR is expected to > produce about 60Kg of excess U233 per year; enough for 7 to 8 nuclear > weapons. I question that figure. Even theoretically the best (or worst depending on how you look at it) a LFTR could do is make 9% more U233 than it burns up, but much more realistically it would be closer to 1%, you try to steal more than that and the reactor grinds to a halt. And the critical mass of U233 is 15 kg so even if that number was correct I don't see how you could make 7 or 8 bombs with just 60 Kg of U233 unless you compressed the metal to more than normal density, and that would take mega sophistication. John K Clark i -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
