3 ms·

One of the anti-proliferation points is that U233 (which is the isotope you're thinking of) is mixed with U232, which decays to products with high gamma output,

One of the anti-proliferation points is that U233 (which is the isotope you're thinking of) is mixed with U232, which decays to products with high gamma output, meaning that it's more dangerous to work with than the more typical fissionable materials, and much easier to detect. For a state this probably wouldn't be a significant barrier, but it's a fair point with respect to terrorist bombs. Of course, we haven't seen any of those, which implies that there's some non-obvious factor at work, here.

CWuestefeld 16y ago
From the OP: You will hear that we can’t make bombs out of U-233 because it is a virulent gamma-ray emitter. This is not true, and I find it curious that it is used as a reason. U-233 has a 158,000-year half-life. What they are referring to is the protactinium-233 contaminant, which has a 27-day half-life, beta-decaying into U-233 with gamma-ray involvement. Chemically scrub the protactinium, of course, or just wait a year and it will be gone.
- pjscott 16y ago
  No, that's wrong. The claim is that the bred U-233 will be contaminated with U-232, which is very hard to get rid of, and has the hard gamma emitter Thallium-208 in its decay chain.
  - tkeller 16y ago
    Where would the U-232 contamination come from, if it's bred U-233? Does thorium also just sometimes decay into the lighter isotope?
    - pjscott 16y ago
      Sometimes the thorium, when it absorbs a neutron, will emit two neutrons and turn into thorium-231, which decays (though a couple more isotopes) into U-232. It can also be formed when U-233 absorbs a neutron and emits two, forming U-232. How hard this would be to separate depends on the type of LFTR design you're using. However, you could also include some thorium-230 in the fuel mix to denature any protactinium produced, so there's really no way around having U-232 mixed with the bred U-233. Here's a blog post with more details on the entire process: http://energyfromthorium.com/2006/10/06/denaturing-thorium-with-ionium/ http://energyfromthorium.com/2006/10/06/denaturing-thorium-w...
      - ngvrnd 16y ago
        What about this? http://www.technologyreview.com/blog/arxiv/25855/?ref=rss http://www.technologyreview.com/blog/arxiv/25855/?ref=rss

CWuestefeld 16y ago

From the OP: You will hear that we can’t make bombs out of U-233 because it is a virulent gamma-ray emitter. This is not true, and I find it curious that it is used as a reason. U-233 has a 158,000-year half-life. What they are referring to is the protactinium-233 contaminant, which has a 27-day half-life, beta-decaying into U-233 with gamma-ray involvement. Chemically scrub the protactinium, of course, or just wait a year and it will be gone.

pjscott 16y ago
No, that's wrong. The claim is that the bred U-233 will be contaminated with U-232, which is very hard to get rid of, and has the hard gamma emitter Thallium-208 in its decay chain.
- tkeller 16y ago
  Where would the U-232 contamination come from, if it's bred U-233? Does thorium also just sometimes decay into the lighter isotope?
  - pjscott 16y ago
    Sometimes the thorium, when it absorbs a neutron, will emit two neutrons and turn into thorium-231, which decays (though a couple more isotopes) into U-232. It can also be formed when U-233 absorbs a neutron and emits two, forming U-232. How hard this would be to separate depends on the type of LFTR design you're using. However, you could also include some thorium-230 in the fuel mix to denature any protactinium produced, so there's really no way around having U-232 mixed with the bred U-233. Here's a blog post with more details on the entire process: http://energyfromthorium.com/2006/10/06/denaturing-thorium-with-ionium/ http://energyfromthorium.com/2006/10/06/denaturing-thorium-w...
    - ngvrnd 16y ago
      What about this? http://www.technologyreview.com/blog/arxiv/25855/?ref=rss http://www.technologyreview.com/blog/arxiv/25855/?ref=rss