Every time I hear about Thorium I get a "Too good to be true" feeling but I don't know enough about the technology (and there aren't enough good sources about it) for me to make up my mind. This article cites that there are significant development costs for the first reactors and that few nuclear engineers are educated about them, but both of those are easily solvable problems for a smart team. What other negatives do Thorium reactors have?
Long story short, Th isn't actually fissable. It is fertile. You have to use something else (like U235/Pu/etc.) to create a stream of neutrons to turn Th into Pa which decays into U233 (iirc). which is then fissable. (and strangely enough, can be used to convert more Th...)
The problem is if the Pa absorbs another neutron, it no longer produces U233 and so it drops the yeild (and leads to other nasties, etc.).
This is, iirc. why the molten salt reactors are so appealing. You can run the reactor, continuously remove the Pa and let it decay into U233 which you then reintroduce into the reactor.
Well, the first issue is that there are no large-scale commercial Thorium reactors, which means alot of actual design and running flaws aren't known yet - PWR and BWR designs are an old, tested technology with it's flaws widely known and compesated (even through accidents like TMI).
However the biggest problem with Thorium MSRs is the political issue - MSRs produce Plutionum as a side-effect, which means Thorium power-plants produce nuclear WMD materials while operating. You can't do that with PWR/BWR designs, which is one of the reasons for their popularity - companies can export those reactors without fear of countries using them for WMD production.
lol minecraft and that, but a big part of the appeal of Thorium is that we have ridiculous amounts of it laying around already. It's a byproduct of other actinide mining, useless at present, and toxic enough that the safest thing to do is stockpile it.
Which the US has done, leaving us with enough to run reactors for decades / centuries at projected power loads.
Indeed too good to be true:
HEALTH
Thorium-232 is an alpha emitter very radiotoxic. For this isotope, the annual limit on intake (ALI) by inhalation of 90 Bq / year compared to that of plutonium 239, which is 300 Bq / year. It means that the thorium-232 is considered almost 3.3 times more radiotoxic that plutonium
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[ 2.9 ms ] story [ 23.9 ms ] threadThe problem is if the Pa absorbs another neutron, it no longer produces U233 and so it drops the yeild (and leads to other nasties, etc.).
This is, iirc. why the molten salt reactors are so appealing. You can run the reactor, continuously remove the Pa and let it decay into U233 which you then reintroduce into the reactor.
http://hal.archives-ouvertes.fr/docs/00/04/14/97/PDF/documen... is an interesting link discussing the feasibility of various reactor designs.
However the biggest problem with Thorium MSRs is the political issue - MSRs produce Plutionum as a side-effect, which means Thorium power-plants produce nuclear WMD materials while operating. You can't do that with PWR/BWR designs, which is one of the reasons for their popularity - companies can export those reactors without fear of countries using them for WMD production.
Which the US has done, leaving us with enough to run reactors for decades / centuries at projected power loads.