Thorium itself cannot be used directly. Natural thorium is mostly composed of a single isotope, Th-232, that is only fertile, not fissile. Use of thorium in a power reactor or weapon requires that the natural Th-232 be transmuted within an already-operating reactor to U-233, which is fissile. This "breeding" of U-233 is analogous to the way plutonium is "bred" in a reactor from natural uranium.
The difference is that in addition to the merely-fertile U-238, natural uranium contains a nontrivial amount of fissile U-235 which can be extracted (at significant expense) and used directly to make weapons. With thorium, the only path to weapons-grade material requires an operating reactor to produce fertile U-233 by transmutation. This requirement for an operating reactor makes the process much easier for the international community to monitor, among other things. U-233 is known to be suitable for weapons use - there is one document example of the U.S. building and successfully detonating a weapon with a U-233 "pit" (bomb core). So it's false to say that the thorium fuel cycle is completely "weapons material clean." But I think it's true to say that the risk of weapons proliferation is lower compared to starting with U. I found this document which has everything you could ever want to know about this - although wikipedia seems good enough to answer almost any "lay person" question in this case. http://www-pub.iaea.org/mtcd/publications/pdf/te_1450_web.pdf Jeff On Sun, Nov 18, 2012 at 6:49 PM, Patrick Ellul <ellulpatr...@gmail.com>wrote: > Thanks Jeff. Can enriched Thorium also be used for nuclear weapons? > > > On Mon, Nov 19, 2012 at 1:46 PM, Jeff Berkowitz <pdx...@gmail.com> wrote: > >> I've looked at this a little. It's been under study for over 30 years, so >> the pros and cons are pretty well understood. The wikipedia page ("thorium >> fuel cycle") covers them. It's definitely feasible, probably an economic >> win for countries with a lot of thorium (e.g. India), and arguably a little >> safer. But for me, bottom line is that it doesn't change the fundamentals. >> There are still waste handling issues and reactor design issues and nuclear >> economy/proliferation issues. So moving from U to Th is a difference (in >> the technology sphere) that doesn't really make a difference (in the public >> policy sphere). >> >> Jeff >> >> >> On Sun, Nov 18, 2012 at 4:11 PM, Patrick Ellul <ellulpatr...@gmail.com>wrote: >> >>> Hello collective, >>> >>> Is Thorium really safer? And is it reallya a feasible solution? >>> >>> >>> http://www.newscientist.com/article/mg21628905.600-indias-thoriumbased-nuclear-dream-inches-closer.html?cmpid=RSS|NSNS|2012-GLOBAL|online-news >>> >>> Regards, >>> Patrick >>> >> >> > > > -- > Patrick > > www.tRacePerfect.com > The daily puzzle everyone can finish but not everyone can perfect! > The quickest puzzle ever! > >
