5 ms·

If you mean "protect these units from bad guys so they don't threaten our electrical system," that's kind of the point of having a decentralized system of small

by Tcepsa 13y ago

If you mean "protect these units from bad guys so they don't threaten our electrical system," that's kind of the point of having a decentralized system of smaller reactors: if one or two get sabotaged, others in the system can easily pick up the slack. If you mean "protect these units from bad guys so they don't steal the thorium and weaponize it," that's one of the great things about thorium reactors: thorium and its byproducts are very hard to weaponize. [1] [1] https://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor#Safety https://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reacto...

hga 13y ago
To which I say BS, at least for the reason cited. Sure, the U-232 contaminated U-233 is nasty, but as long as it doesn't make it impractical to make a nuclear warhead it's quantitatively different from the uranium cycle, where after a few months at most plutonium is impossibly contaminated with two even more undesirable isotopes (one is very hot, I've seen estimates of 100kW for a bomb sized quantity (it's used for RTGs in deep space probes), the other precludes much of a bang and required the Manhattan Project to go with an implosion design). Despite the gamma ray emission drawbacks, it could still be the easiest way to get lots of weapons grade fissionables from civilian power plants.
- fnordfnordfnord 13y ago
  These folks seem to think the problem is solvable by adding U-238 http://www.coal2nuclear.com/MSR%20-%20Denatured%20-%20CNSLeBlanc2010revised.pdf http://www.coal2nuclear.com/MSR%20-%20Denatured%20-%20CNSLeB...
  - hga 13y ago
    Yeah, that solves it neatly. Reduces to a protoactinium problem, it decays to U-233 with a half-life of 27 days. The article claims there's so little protoactinium in the total mass of salt and stuff that it's not practical to isolate it, at least not without detection, and failing that, not quickly. This gets into fine details beyond my level of expertise, but I agree the problem is much reduced. Although very possibly still greater than for current LEU designs.
kintamanimatt 13y ago
What about the health impact following a release of materials?
- tehwalrus 13y ago
  Molten salt thorium reactors are "continuous reprocessing" ones, which means they burn all the (active) waste they create for more energy. Solid thorium reactors mix Th with the existing waste piles of Plutonium sitting in cooling pools and burn that up for us[1]. There's no waste materials to release from either of these reactors. [1] http://www.extremetech.com/extreme/160131-thorium-nuclear-reactor-trial-begins-could-provide-cleaner-safer-almost-waste-free-energy http://www.extremetech.com/extreme/160131-thorium-nuclear-re...
  - hga 13y ago
    Waste != Materials. These reactors by definition have a fair amount of very "hot" materials; it hardly matters if none of them are declared "waste" if they'll still kill you in a few minutes of direct exposure.
    - tehwalrus 13y ago
      ... molten salt reactors (the kind in the comment at the top of this thread) are at atmospheric pressure, and are designed with a drain plug which isolates the (very hot) materials from the neutron source, after which they cool down happily on their own in a separate but similarly shielded compartment. release of materials is one of the most unlikely outcomes ever.
      - hga 13y ago
        You really can't imagine a release of materials outcome in the context of active sabotage? (Which is relevant in the context of massive distributed ones; current nuclear power systems mitigate this by being few in number such that they can be well guarded.)

by Tcepsa 13y ago

hga 13y ago

To which I say BS, at least for the reason cited. Sure, the U-232 contaminated U-233 is nasty, but as long as it doesn't make it impractical to make a nuclear warhead it's quantitatively different from the uranium cycle, where after a few months at most plutonium is impossibly contaminated with two even more undesirable isotopes (one is very hot, I've seen estimates of 100kW for a bomb sized quantity (it's used for RTGs in deep space probes), the other precludes much of a bang and required the Manhattan Project to go with an implosion design). Despite the gamma ray emission drawbacks, it could still be the easiest way to get lots of weapons grade fissionables from civilian power plants.

fnordfnordfnord 13y ago
These folks seem to think the problem is solvable by adding U-238 http://www.coal2nuclear.com/MSR%20-%20Denatured%20-%20CNSLeBlanc2010revised.pdf http://www.coal2nuclear.com/MSR%20-%20Denatured%20-%20CNSLeB...
- hga 13y ago
  Yeah, that solves it neatly. Reduces to a protoactinium problem, it decays to U-233 with a half-life of 27 days. The article claims there's so little protoactinium in the total mass of salt and stuff that it's not practical to isolate it, at least not without detection, and failing that, not quickly. This gets into fine details beyond my level of expertise, but I agree the problem is much reduced. Although very possibly still greater than for current LEU designs.

kintamanimatt 13y ago

What about the health impact following a release of materials?

tehwalrus 13y ago
Molten salt thorium reactors are "continuous reprocessing" ones, which means they burn all the (active) waste they create for more energy. Solid thorium reactors mix Th with the existing waste piles of Plutonium sitting in cooling pools and burn that up for us[1]. There's no waste materials to release from either of these reactors. [1] http://www.extremetech.com/extreme/160131-thorium-nuclear-reactor-trial-begins-could-provide-cleaner-safer-almost-waste-free-energy http://www.extremetech.com/extreme/160131-thorium-nuclear-re...
- hga 13y ago
  Waste != Materials. These reactors by definition have a fair amount of very "hot" materials; it hardly matters if none of them are declared "waste" if they'll still kill you in a few minutes of direct exposure.
  - tehwalrus 13y ago
    ... molten salt reactors (the kind in the comment at the top of this thread) are at atmospheric pressure, and are designed with a drain plug which isolates the (very hot) materials from the neutron source, after which they cool down happily on their own in a separate but similarly shielded compartment. release of materials is one of the most unlikely outcomes ever.
    - hga 13y ago
      You really can't imagine a release of materials outcome in the context of active sabotage? (Which is relevant in the context of massive distributed ones; current nuclear power systems mitigate this by being few in number such that they can be well guarded.)