Help please: thorium reactors

I\’ve been contacted by a very major investor type who wants to know more about thorium reactors.

Before I go back to him with what I know (essentially, they work, but it\’s a regulatory thing….that\’s about as much as I know) I want to throw it out to you guys.

Details and specifics of thorium reactors: what are they good/bad for, why aren\’t we using them?

14 comments on “Help please: thorium reactors

  1. Is it because the recent worldwide concern over the limit of Uranium availability has made Thorium reactors more of an economical proposition than before? Good job, wikipedia…

    Are you back in residence now?


  2. Good: there’s lotsa thorium, and they’re intrinsically safer, since you need a particle accelerator fo fission the fuel, and if you pull the plug on that the reaction dies almost immediately. You can use them as breeder reactors to get more fuel out of the cycle.

    Bad: no-one’s made one yet, and you need a particle accelerator, so they’ll probably be very expensive.

  3. As governments reconsider nuclear power, we’ll discover whether public hysteria about it will be sustained in the absence of Moscow gold to support it. Unless, of course, oil and gas-rich Moscow decides to try again.

  4. Coincidently i happen to be doing a presentation on throium fission for uni on thursday so hopefully i know at least a bit about it.

    Thorium Breeder reactors seem to be much better than U-235 traditional reactors and still significantly better than U-238 breeders.

    They seem to be more economical, produce less waste and less dangerous waste, there harder to make a bomb fromand there are huge amounts of fuel for it relative to other forms of nuclear power (unless anyone happens to invent fusion in the next decade or so).

    It could well be as Kay says that the reasons they are not in use are historical plus there is always the massive dislike people particularly in the UK have of nuclear power.

    One of the few disadvantages i can think of is that extra heavy shielding is required as U-233 is produced as a by product and its a high intensity gamma emmiter but its not that significant a disadvantage as far as im aware plus after fuel processing i belive it can be reused for other purposes.

    Now i cant say im excatly an expert, (only a first year physics student so basically i know nothing yet) but it does seem a pretty sound technology to me.

    Also i refer you to this pdf its quite helpful in getting your head round some of the advantages:

  5. sorry talking nonsense U-232 is the undesired side product U-233 is an essential part of the process and im still not sure wheather it can be reprocessed usefully or not but it does have a fairly short half life~70 years

  6. plus there is always the massive dislike people particularly in the UK have of nuclear power.

    I think “particularly not in France” would be more accurate. Most of the rest of mainland Europe, and the other English-speaking countries, have a similar raging phobia to the British public’s.

  7. I’m sure you can find plenty on the interwebs Tim, but my brief summary is: There was one working in the USA for a number of years at Oak Ridge ( a molten salt reactor) but closed a few years ago (actually in 1969 I believe) as there was no support. There are issues with finding good materials to resist attack by molten halides but a Nickel alloy proved OK, and one has to remove as much of the Xe 131 fission product as it poisons the reaction rapidly.

    Although in theory one can produce nuclear weapons using U233 (instead of U235), only one was made that we know of, by the USA (Operation teapot in 1955, Test MET on 15 April, a composite Pu/U233 core) and the yield was well below expectations. A major issue with U233 is that it is rapidly contaminated by U232 which is a high energy gamma emitter, making it very hard to handle without heavy shielding, and making it easily detected. Other decay products “poison” the fission reaction unless controlled. that’s relatively easy in a reactor, hard in a bomb. So it is generally (although not universally) presumed that U233 has a lower proliferation risk than Pu.

    India is still doing research, not much elsewhere although there are some enthusiastic private groups in the USA.

    Ref (I know it’s Wiki but not a bad summary) at

    FWIW, very, very, promising and IMHO very definitely worth investing in, although like with all things nuclear, very high costs and risks.

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