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Power plants designed to be only power plants rather than also fast breeders for military doomsday weapons would certainly help. Molten salt reactors and Candu

Power plants designed to be only power plants rather than also fast breeders for military doomsday weapons would certainly help. Molten salt reactors and Candu reactors neither one fail the same way as Fukushima and Chernobyl. Fusion plants, once commercially viable, also will not fail the same way. New light water reactors should probably not be built considering the options.

Aachen 6y ago
Didn't bill gates fund this traveling wave reactor that has this property? I checked Wikipedia but it doesn't say either way. I don't remember for sure but I think this is a thing now, just nobody wants him to build it because brrr scary nuclear let's rather stop advancement of the field.
- marcosdumay 6y ago
  Fast breeders are scary. That Wikipedia page does not mention any breakthrough in passive stability, and unless somebody mentions it, the safe thing to assume is that any fast breeder has none. What means that it can basically blow like the Chernobyl reactor or worse due to failure of equipment.
  - Aachen 6y ago
    I'm no physicist, is this traveling wave reactor a "fast breeder" that you're talking about? From what I read, the stability comes from it not being a runaway reaction that needs active brakes. If something fails, the reaction will stop on its own rather than having a meltdown or explosion. But I'm just parroting what I read in the past (not sure where), I don't do nuclear physics and can't say whether it's snake oil or real.
    - marcosdumay 6y ago
      I'm not an expert. My knowledge of nuclear physics is limited to some liquid model theory at university (what is basically the simplest model you can find and completely useless), and some empiric data. I also just met this design. But I do know some general principles. The Wiki page claims very briefly this is a fast breeder design where it says it uses fast neutrons, also, it doesn't mention moderation, that is the process that converts fast neutrons into slow ones. Now, the thing that makes slow neutron reactions safer is that nothing happens unless the neutrons goes into the moderation medium, so if things deviate from the design, the reaction stops. Fast neutron reactions do not have this property, so any stability must be designed into it. That does not mean that you can't get some passive stability built into it, what it does mean is that it must be actively put into the project, and you must correctly account for any possible failure mode. Thus, a good rule of thumb is that if somebody is talking about fast reactors and doesn't take 90% of the time talking about safety, then that somebody does not have a viable idea.
  - HPsquared 6y ago
    Fast reactors usually have a strong negative temperature coefficient of reactivity. This is inherent to the temperature of the fuel and responds instantly. The Integral Fast Reactor, for instance, was designed to tolerate loss of coolant flow without even needing to insert the control rods to shutdown, with no core damage. https://www.ne.anl.gov/About/hn/logos-winter02-psr.shtml https://www.ne.anl.gov/About/hn/logos-winter02-psr.shtml The main issue I have with fast reactors is the liquid sodium coolants typically used, very hazardous stuff if it was to leak. Molten salts are a nice alternative.
- cestith 6y ago
  I'm not familiar enough with Gate's investments nor his foundation's investments to say, and "traveling wave reactor" is something I've read once or twice before but not looked much into. CANDU reactors have an excellent safety record and fail in a much safer way than light water reactors. I've been looking more into those recently. MSRs, and especially molten thorium salt reactors, I've read about and watch documentaries about quite a bit. Still, I'm just an interested layperson in this discussion. I used to date someone who was planning to be a nuclear engineer, but she ultimately ended up in software, too.
- jasonwatkinspdx 6y ago
  The traveling wave reactor concept failed to pan out, and no it was not because of "brrr scary." Gate's project switched to a different design they were going to build in China, but that got caught up in the bluster between Xi and Trump. In any case it's clear his startup has failed to come up with anything novel that significantly changes the cost math with nuclear, which is the actual problem.
  - Aachen 6y ago
    That's not what he writes in his book that came out iirc last month, specifically the "we moved to another design because this idea failed" I mean, but I didn't dive into it much further so I could be wrong.

Aachen 6y ago

Didn't bill gates fund this traveling wave reactor that has this property? I checked Wikipedia but it doesn't say either way. I don't remember for sure but I think this is a thing now, just nobody wants him to build it because brrr scary nuclear let's rather stop advancement of the field.

marcosdumay 6y ago
Fast breeders are scary. That Wikipedia page does not mention any breakthrough in passive stability, and unless somebody mentions it, the safe thing to assume is that any fast breeder has none. What means that it can basically blow like the Chernobyl reactor or worse due to failure of equipment.
- Aachen 6y ago
  I'm no physicist, is this traveling wave reactor a "fast breeder" that you're talking about? From what I read, the stability comes from it not being a runaway reaction that needs active brakes. If something fails, the reaction will stop on its own rather than having a meltdown or explosion. But I'm just parroting what I read in the past (not sure where), I don't do nuclear physics and can't say whether it's snake oil or real.
  - marcosdumay 6y ago
    I'm not an expert. My knowledge of nuclear physics is limited to some liquid model theory at university (what is basically the simplest model you can find and completely useless), and some empiric data. I also just met this design. But I do know some general principles. The Wiki page claims very briefly this is a fast breeder design where it says it uses fast neutrons, also, it doesn't mention moderation, that is the process that converts fast neutrons into slow ones. Now, the thing that makes slow neutron reactions safer is that nothing happens unless the neutrons goes into the moderation medium, so if things deviate from the design, the reaction stops. Fast neutron reactions do not have this property, so any stability must be designed into it. That does not mean that you can't get some passive stability built into it, what it does mean is that it must be actively put into the project, and you must correctly account for any possible failure mode. Thus, a good rule of thumb is that if somebody is talking about fast reactors and doesn't take 90% of the time talking about safety, then that somebody does not have a viable idea.
- HPsquared 6y ago
  Fast reactors usually have a strong negative temperature coefficient of reactivity. This is inherent to the temperature of the fuel and responds instantly. The Integral Fast Reactor, for instance, was designed to tolerate loss of coolant flow without even needing to insert the control rods to shutdown, with no core damage. https://www.ne.anl.gov/About/hn/logos-winter02-psr.shtml https://www.ne.anl.gov/About/hn/logos-winter02-psr.shtml The main issue I have with fast reactors is the liquid sodium coolants typically used, very hazardous stuff if it was to leak. Molten salts are a nice alternative.
cestith 6y ago
I'm not familiar enough with Gate's investments nor his foundation's investments to say, and "traveling wave reactor" is something I've read once or twice before but not looked much into. CANDU reactors have an excellent safety record and fail in a much safer way than light water reactors. I've been looking more into those recently. MSRs, and especially molten thorium salt reactors, I've read about and watch documentaries about quite a bit. Still, I'm just an interested layperson in this discussion. I used to date someone who was planning to be a nuclear engineer, but she ultimately ended up in software, too.
jasonwatkinspdx 6y ago
The traveling wave reactor concept failed to pan out, and no it was not because of "brrr scary." Gate's project switched to a different design they were going to build in China, but that got caught up in the bluster between Xi and Trump. In any case it's clear his startup has failed to come up with anything novel that significantly changes the cost math with nuclear, which is the actual problem.
- Aachen 6y ago
  That's not what he writes in his book that came out iirc last month, specifically the "we moved to another design because this idea failed" I mean, but I didn't dive into it much further so I could be wrong.