On Sat, Dec 27, 2014 'Chris de Morsella' via Everything List < [email protected]> wrote:
> my principal concern. U-233 is a good bomb making material and the US > has in fact exploded a U-233 bomb. > Theoretically you can do it but it's hard to make a bomb with U-233, much harder than with Plutonium even if you avoid the U-232 contamination issue. As far as I know a U-233 bomb was attempted only twice, in 1955 the USA set off a plutonium-U233 composite bomb, it was expected to produce 33 kilotons but only managed 22; the only pure U-233 bomb I know of was set off in 1998 by India, but it was a fizzle, a complete flop, it produced a minuscule explosion of only 200 tons due to pre-detonation The critical mass of U-233 is 16 kilograms, that is slightly smaller than the critical mass for U235 but for Plutonium-239 its only 4.4 kilograms, and even in its purest most uncontaminated form the neutron density of U-233 due to spontaneous fissions is 3 times as high as Plutonium (which is higher than U-234) so it would be much harder to prevent pre-detonation than with Plutonium, and it’s hard to do with Plutonium. This means that making a bomb from U-233 would be much harder than making one from Pu-239 which is much harder than making one from U-235. To my knowledge in the 70 years since nuclear bombs were developed nobody has bothered to produce industrial quantities of U-233, much less U-233 with no U-232 contamination, and no nation has U-233 bombs in their stockpile and it’s not hard to figure out why, there are much easier and cheaper ways to blow something up. And it’s a bit late in the day to start worrying about nuclear proliferation, all Uranium reactors (but not Thorium reactors) produce lots of plutonium, a big power plant reactor will invariably produce many tons of it in its lifetime. There is already so much of it in existence, thousands of tons, that it's very hard to keep track of it all. The USA Energy Department has lost track of 5900 pounds of weapons grade U235 and Plutonium that it had shipped outside the USA, and both are far far easier to make a bomb out of than U233. So with all that fissile material floating around, not to mention fully functional H-bombs in Russia guarded by soldiers who can be bribed with a bottle of vodka, why would a terrorist bother with U-233? > LFTR reactors that have continuous fuel re-processing (which is highly > desirable for making them into efficient breeders) and the reactor molten > salt mix was removed from the active reactor before a significant portion > of the transmuted thorium-232 (e.g. the Pa-233) absorbed another neutron > transmuting into Pa-234 is an excellent means for producing highly pure > U-233 that is NOT contaminated with U-232 and thus is not especially hard > to handle. > That is possible but it would be difficult to produce significant quantities by that method, a sinister LFTR would require much more frequent and expensive continuous fuel re-processing than a peaceful LFTR. In a peaceful LFTR reactor about 1% of the U-233 would be contaminated with U-232 making it so radioactive it would be virtually impossible to work with. If you wanted to bring that 1% contamination figure down you’d have to go through a lot of additional costly and expensive steps. And normally all the U233 is completely burned up inside the LFTR reactor where its hard to steal, unlike existing reactors where used fuel rods must be shipped to distant reprocessing plants to extract the Plutonium. And Uranium reactors don’t need that Plutonium to keep going but Thorium reactors are not as neutron rich as the Uranium reactors we use today, LFTR's produce enough neutrons for a chain reaction to keep going but just barely; so if you start to siphon off more than a small amount of U-233 fuel for clandestine purposes the reaction will stop and the reactor will shut down. People tend to notice that sort of thing. So to sum up, what you say is possible, a LFTR could make a bomb, but it’s not practical. John K Clark -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
