5 ms·

I was under the impression that thorium-salt reactors have been tried in the past and not deemed "worth" from security and profitability point of view. What h

by zython 9y ago

I was under the impression that thorium-salt reactors have been tried in the past and not deemed "worth" from security and profitability point of view. What has changed about that ?

igravious 9y ago
I thought it was the other way around in fact. That they don't produce nuke-weapon-ready material meant that this avenue was not profitable from a security perspective. I may be recalling this incorrectly and I haven't re-checked but I think that's correct?
- philipkglass 9y ago
  No, that is incorrect, though it has often been repeated by less technically informed advocates of the thorium fuel cycle. The vast majority of the world's commercial nuclear reactors are light-water-moderated pressurized water reactors or boiling water reactors (PWR and BWR respectively). The actual military origins of these light water reactors is that they were originally researched for submarine and ship propulsion for the US Navy: https://en.wikipedia.org/wiki/Light-water_reactor https://en.wikipedia.org/wiki/Light-water_reactor https://en.wikipedia.org/wiki/Pressurized_water_reactor#History https://en.wikipedia.org/wiki/Pressurized_water_reactor#Hist... https://en.wikipedia.org/wiki/Boiling_water_reactor#Evolution https://en.wikipedia.org/wiki/Boiling_water_reactor#Evolutio... The United States and other nuclear weapons states never produced their weapons plutonium from light water reactors. Weapons grade plutonium has typically been produced from uranium in dedicated plutonium-production reactors moderated with heavy water or graphite. (The United States once had a single reactor that also produced commercial electricity along with weapons plutonium, https://en.wikipedia.org/wiki/N-Reactor https://en.wikipedia.org/wiki/N-Reactor, but it wasn't a light water reactor either.) Since uranium fueled light water reactors weren't used to make plutonium for weapons in the first place, the thorium-myth claim that commercial power reactors stuck with uranium so as to make weapons material is ridiculous. The military's early sponsorship of light water reactors for naval propulsion did give uranium-fueled LWRs a significant historical path dependency advantage. I speculate that thorium advocates who continue to repeat the myth about how uranium LWRs became dominant do so because it makes the dominant technology's dominance sound more sinister, hence thorium sound more attractive by contrast.
  - acidburnNSA 9y ago
    Oh my god thank you for understanding this and explaining it so well. I spend a lot of time trying to suppress the sinister-LWR myth. Real reasons MSRs declined include [1]: * The existing major industrial and utility commitments to the LWR, HTGR, and LMFBR. * The lack of incentive for industrial investment in supplying fuel cycle services, such as those required for solid fuel reactors. * The overwhelming manufacturing and operating experience with solid fuel reactors in contrast with the very limited involvement with fluid fueled reactors. * The less advanced state of MSBR technology and the lack of demonstrated solutions to the major technical problems associated with the MSBR concept. [1] http://www.energyfromthorium.com/pdf/WASH-1222.pdf http://www.energyfromthorium.com/pdf/WASH-1222.pdf
  - Recurecur 9y ago
    The issue wasn't "light water reactors" it was "uranium fuel cycle". Cheap uranium definitely benefited the US government.
    - igravious 9y ago
      And going back one step Recurecur, isn't a very large part of the the issue "fissionable plutonium" (because bombs) which motivates the "uranium fuel cycle" which means the "thorium fuel cycle" isn't half so interesting.
ChuckMcM 9y ago
They have different problems that pressured water reactors and are not as applicable to applications that the military would like to use them for. So the government sponsored research labs that were running and experimenting with them stopped doing so when research funds ran out. Add to the insane risk of investing in anything 'nuclear' and you don't have a lot of available capital. That said, the Chinese who invest in research for other reasons seem to have been working on a number of MSRs which could conceivably advance the state of the art significantly. Oddly enough, as an American, I am looking forward to the first thing that China builds that "we" American's cannot because we lack expertise and/or technology to do so.
- phkahler 9y ago
  >> Oddly enough, as an American, I am looking forward to the first thing that China builds that "we" American's cannot because we lack expertise and/or technology to do so. Or too much regulation or politics to allow.
  - mschuster91 9y ago
    > Or too much regulation or politics to allow. Or, as a German, too much regulation/politics to Get Shit Done. Just look what happened to Transrapid (maglev rail). All tech and IP went off to China, and we're stuck in 1980-and-earlier carriages for anything not an ICE or regio trains.
    - kuschku 9y ago
      > and we're stuck in 1980-and-earlier carriages for anything not an ICE or regio trains. Actually, the InterCity and EuroCity fleet was just entirely replaced. This means the entire fleet – S, Region, InterCity, EuroCity, InterCityExpress – is now replaced, or being replaced, with modern stock.
      - ChuckMcM 9y ago
        Offtopic but this means I am totally heading back to ride the new trains :-)

by zython 9y ago

I was under the impression that thorium-salt reactors have been tried in the past and not deemed "worth" from security and profitability point of view. What has changed about that ?

igravious 9y ago

I thought it was the other way around in fact. That they don't produce nuke-weapon-ready material meant that this avenue was not profitable from a security perspective. I may be recalling this incorrectly and I haven't re-checked but I think that's correct?

philipkglass 9y ago
No, that is incorrect, though it has often been repeated by less technically informed advocates of the thorium fuel cycle. The vast majority of the world's commercial nuclear reactors are light-water-moderated pressurized water reactors or boiling water reactors (PWR and BWR respectively). The actual military origins of these light water reactors is that they were originally researched for submarine and ship propulsion for the US Navy: https://en.wikipedia.org/wiki/Light-water_reactor https://en.wikipedia.org/wiki/Light-water_reactor https://en.wikipedia.org/wiki/Pressurized_water_reactor#History https://en.wikipedia.org/wiki/Pressurized_water_reactor#Hist... https://en.wikipedia.org/wiki/Boiling_water_reactor#Evolution https://en.wikipedia.org/wiki/Boiling_water_reactor#Evolutio... The United States and other nuclear weapons states never produced their weapons plutonium from light water reactors. Weapons grade plutonium has typically been produced from uranium in dedicated plutonium-production reactors moderated with heavy water or graphite. (The United States once had a single reactor that also produced commercial electricity along with weapons plutonium, https://en.wikipedia.org/wiki/N-Reactor https://en.wikipedia.org/wiki/N-Reactor, but it wasn't a light water reactor either.) Since uranium fueled light water reactors weren't used to make plutonium for weapons in the first place, the thorium-myth claim that commercial power reactors stuck with uranium so as to make weapons material is ridiculous. The military's early sponsorship of light water reactors for naval propulsion did give uranium-fueled LWRs a significant historical path dependency advantage. I speculate that thorium advocates who continue to repeat the myth about how uranium LWRs became dominant do so because it makes the dominant technology's dominance sound more sinister, hence thorium sound more attractive by contrast.
- acidburnNSA 9y ago
  Oh my god thank you for understanding this and explaining it so well. I spend a lot of time trying to suppress the sinister-LWR myth. Real reasons MSRs declined include [1]: * The existing major industrial and utility commitments to the LWR, HTGR, and LMFBR. * The lack of incentive for industrial investment in supplying fuel cycle services, such as those required for solid fuel reactors. * The overwhelming manufacturing and operating experience with solid fuel reactors in contrast with the very limited involvement with fluid fueled reactors. * The less advanced state of MSBR technology and the lack of demonstrated solutions to the major technical problems associated with the MSBR concept. [1] http://www.energyfromthorium.com/pdf/WASH-1222.pdf http://www.energyfromthorium.com/pdf/WASH-1222.pdf
- Recurecur 9y ago
  The issue wasn't "light water reactors" it was "uranium fuel cycle". Cheap uranium definitely benefited the US government.
  - igravious 9y ago
    And going back one step Recurecur, isn't a very large part of the the issue "fissionable plutonium" (because bombs) which motivates the "uranium fuel cycle" which means the "thorium fuel cycle" isn't half so interesting.

ChuckMcM 9y ago

They have different problems that pressured water reactors and are not as applicable to applications that the military would like to use them for. So the government sponsored research labs that were running and experimenting with them stopped doing so when research funds ran out. Add to the insane risk of investing in anything 'nuclear' and you don't have a lot of available capital. That said, the Chinese who invest in research for other reasons seem to have been working on a number of MSRs which could conceivably advance the state of the art significantly. Oddly enough, as an American, I am looking forward to the first thing that China builds that "we" American's cannot because we lack expertise and/or technology to do so.

phkahler 9y ago
>> Oddly enough, as an American, I am looking forward to the first thing that China builds that "we" American's cannot because we lack expertise and/or technology to do so. Or too much regulation or politics to allow.
- mschuster91 9y ago
  > Or too much regulation or politics to allow. Or, as a German, too much regulation/politics to Get Shit Done. Just look what happened to Transrapid (maglev rail). All tech and IP went off to China, and we're stuck in 1980-and-earlier carriages for anything not an ICE or regio trains.
  - kuschku 9y ago
    > and we're stuck in 1980-and-earlier carriages for anything not an ICE or regio trains. Actually, the InterCity and EuroCity fleet was just entirely replaced. This means the entire fleet – S, Region, InterCity, EuroCity, InterCityExpress – is now replaced, or being replaced, with modern stock.
    - ChuckMcM 9y ago
      Offtopic but this means I am totally heading back to ride the new trains :-)