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Is it possible to design a nuclear reactor that’s resistant to widespread corruption and incompetence? In 2019, we have to consider that even advanced democrac

by neilk 7y ago

Is it possible to design a nuclear reactor that’s resistant to widespread corruption and incompetence? In 2019, we have to consider that even advanced democracies with great scientists and technologists might descend into some form of illiberal rule. Imagine if you could not depend on leaders to shut down a plant if problems are discovered, or if contracts were awarded based on cronyism, or if it was impossible to guarantee the quality of materials, or if whistleblowers were not protected. I'm not sure anyone can guarantee that any country will definitely remain stable over the lifetime of a nuclear reactor. Black Swans are out there.

baybal2 7y ago
If things descend to that, you have bigger issues than the possibility of a nuclear accident.
goda90 7y ago
There are reactor designs that can't be used to make weapons, and when they fail, passive systems prevent meltdown.
- acidburnNSA 7y ago
  Not that I'm aware of. All reactors, bar none, require safeguards to prevent the owner from making weapons-usable material on the sly. Civilian nuclear is a fairly impractical and round-about way to get weapons material (just use centrifuges... way easier), but if you think it's easier to get a nuke than a centrifuge, or if you are a corrupt leader who takes over a country that has nukes, you can generally make some pretty good U-233 or Pu-239 with any nuclear reactor. Yes, even Thorium reactors (they're the ones that make U-233). China, India, USA, Russia, France, UK, Pakistan, and Israel already have nuclear weapons. If you look at the fraction of world energy that that set of countries and their collective military allies uses (nevermind Israel), you can feel pretty good about transitioning more to nuclear even given a non-zero risk of proliferation.
  - garmaine 7y ago
    Thorium reactors can’t make weapons grade material. It’s just not part of the process. Thorium is also more abundant and easier to work with. The only reason why we have an uranium/plutonium nuclear industry is because those fuels permit dual-purpose (weapons generating) designs. Now it is just industrial* inertia. Edit: *industrial and regulatory.
    - acidburnNSA 7y ago
      Incorrect. Thorium reactors work by putting Th-232 into a neutron field, where it doesn't fission, but rather it absorbs neutrons to become unstable Th-233, which beta-decays into Pa-233 with a half-life of 21 minutes. Then Pa-233 in turn beta-decays to Uranium-233 with a half-life of 26.8 days. U-233 is fissile nuclear fuel, so when a neutron hits it, it will fission and release nuclear energy. All thorium-fueled reactors use this chain of events. But there's a problem. Pa-233 is a strong parasitic neutron absorber. So when it's sitting there for 26.8 days, if it were still in the nuclear core it would poison the chain reaction. So what people plan to do is to pull it out of the core chemically and put it into a holding cell outside the neutron flux where it can decay to U-233 in peace. Then the U-233 is added back to the core as it arrives. The U-233 is a potent nuclear weapons material and can be extracted from the decay tank in what are called in the non-proliferation industry "Significant Quantities". Faced with this issue, the ORNL folks created the Denatured MSR project in the death throes of the MSBR program (~1960s) which had U-238 mixed in to denature the WG U-233. Of course, then they were producing plutonium... The general claim is that U-232 is also produced in trace quantities, which has Tl-208 way down its decay chain, which emits a massive 2.6 MeV gamma ray that's hard to shield. Since it's way down the decay chain and U-232 has a 69 year half-life, every time you chemically purify your uranium you have pretty small amounts of gamma emitters. So you can purify, assemble a weapon, and drop it in a few weeks without worrying too much about Tl-208. The thorium-cant-make-bombs thing is a total myth. All nuclear reactors need safeguards, even thorium-fueled ones. This is doable and should not prevent us from making more carbon-free energy with any kind of nuclear reactor. More abundant: meh, not really. There's uranium dissolved in seawater in vast, practically infinite quantities. Easier to work with: definitely not. Higher melting temperatures for ceramics make solid-fuel thorium harder to fab, and the fluid fuel stuff is int he R&D stage. It also leads to lower-density fuels, which are crappier neutronically.
jyounker 7y ago
I think the issue is that nuclear reactors, because of the economic scale, are not resistant to small scale corruption and incompetence. (See Fukishima.) This is the number one thing that nuclear power advocates seem to ignore.
foxyv 7y ago
A lot of the modern molten salt thermal neutron designs are pretty much idiot proof. Aside from trying to breach the reactor vessel intentionally there isn't going to be a meltdown like pressurized designs. These are reactors that when they fail just kinda stop working. There isn't any need for active cooling since the nuclear reaction is thermally regulated. There isn't any pressurized water that can blow the top off a containment vessel. Even if there is a breach it doesn't blow waste across the countryside because there is no pressure difference between inside and outside the reactor.

by neilk 7y ago

baybal2 7y ago

If things descend to that, you have bigger issues than the possibility of a nuclear accident.

goda90 7y ago

There are reactor designs that can't be used to make weapons, and when they fail, passive systems prevent meltdown.

acidburnNSA 7y ago
Not that I'm aware of. All reactors, bar none, require safeguards to prevent the owner from making weapons-usable material on the sly. Civilian nuclear is a fairly impractical and round-about way to get weapons material (just use centrifuges... way easier), but if you think it's easier to get a nuke than a centrifuge, or if you are a corrupt leader who takes over a country that has nukes, you can generally make some pretty good U-233 or Pu-239 with any nuclear reactor. Yes, even Thorium reactors (they're the ones that make U-233). China, India, USA, Russia, France, UK, Pakistan, and Israel already have nuclear weapons. If you look at the fraction of world energy that that set of countries and their collective military allies uses (nevermind Israel), you can feel pretty good about transitioning more to nuclear even given a non-zero risk of proliferation.
- garmaine 7y ago
  Thorium reactors can’t make weapons grade material. It’s just not part of the process. Thorium is also more abundant and easier to work with. The only reason why we have an uranium/plutonium nuclear industry is because those fuels permit dual-purpose (weapons generating) designs. Now it is just industrial* inertia. Edit: *industrial and regulatory.
  - acidburnNSA 7y ago
    Incorrect. Thorium reactors work by putting Th-232 into a neutron field, where it doesn't fission, but rather it absorbs neutrons to become unstable Th-233, which beta-decays into Pa-233 with a half-life of 21 minutes. Then Pa-233 in turn beta-decays to Uranium-233 with a half-life of 26.8 days. U-233 is fissile nuclear fuel, so when a neutron hits it, it will fission and release nuclear energy. All thorium-fueled reactors use this chain of events. But there's a problem. Pa-233 is a strong parasitic neutron absorber. So when it's sitting there for 26.8 days, if it were still in the nuclear core it would poison the chain reaction. So what people plan to do is to pull it out of the core chemically and put it into a holding cell outside the neutron flux where it can decay to U-233 in peace. Then the U-233 is added back to the core as it arrives. The U-233 is a potent nuclear weapons material and can be extracted from the decay tank in what are called in the non-proliferation industry "Significant Quantities". Faced with this issue, the ORNL folks created the Denatured MSR project in the death throes of the MSBR program (~1960s) which had U-238 mixed in to denature the WG U-233. Of course, then they were producing plutonium... The general claim is that U-232 is also produced in trace quantities, which has Tl-208 way down its decay chain, which emits a massive 2.6 MeV gamma ray that's hard to shield. Since it's way down the decay chain and U-232 has a 69 year half-life, every time you chemically purify your uranium you have pretty small amounts of gamma emitters. So you can purify, assemble a weapon, and drop it in a few weeks without worrying too much about Tl-208. The thorium-cant-make-bombs thing is a total myth. All nuclear reactors need safeguards, even thorium-fueled ones. This is doable and should not prevent us from making more carbon-free energy with any kind of nuclear reactor. More abundant: meh, not really. There's uranium dissolved in seawater in vast, practically infinite quantities. Easier to work with: definitely not. Higher melting temperatures for ceramics make solid-fuel thorium harder to fab, and the fluid fuel stuff is int he R&D stage. It also leads to lower-density fuels, which are crappier neutronically.

jyounker 7y ago

I think the issue is that nuclear reactors, because of the economic scale, are not resistant to small scale corruption and incompetence. (See Fukishima.) This is the number one thing that nuclear power advocates seem to ignore.

foxyv 7y ago

A lot of the modern molten salt thermal neutron designs are pretty much idiot proof. Aside from trying to breach the reactor vessel intentionally there isn't going to be a meltdown like pressurized designs. These are reactors that when they fail just kinda stop working. There isn't any need for active cooling since the nuclear reaction is thermally regulated. There isn't any pressurized water that can blow the top off a containment vessel. Even if there is a breach it doesn't blow waste across the countryside because there is no pressure difference between inside and outside the reactor.