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If the portable reactors are thorium based - yey! If they are uranium based - nay! Thorium based reactors can't cause a meltdown and if something happens they

If the portable reactors are thorium based - yey! If they are uranium based - nay! Thorium based reactors can't cause a meltdown and if something happens they simply shut off, the reaction is self moderated, and if power goes off or it gets too hot the reaction slows down, unlike unranium based where they need control rods to NOT explode.

ansible 5y ago
Molten salt reactors in general can't cause a meltdown because they are designed to passively moderate in the event of a problem. That isn't something specific to thorium. And conversely, pressurized water reactors, especially older designs are not passively safe, and must go through a cool-down process which requires some of the control systems to be operating properly. In general I'd like to see more development work in the area of molten-salt reactors, especially those that can reprocess existing nuclear waste.
- ansible 5y ago
  Replying to myself, now narcissistic... > Molten salt reactors in general can't cause a meltdown because they are designed to passively moderate in the event of a problem. At least one design I've seen has a plug in the main salt loop that is made of lead or something with a relatively low melting point. It is actively cooled to keep it solid. If there is a total power failure, and nothing is running, the cooling system shuts off, the plug melts, and the main loop drains out into a containment pool. The MSR is just running at atmospheric pressure, not super-high pressure like a pressurized water reactor (hence the name). You can crack a pipe, and that's bad, but then the loop will drain out to the containment pool below the reactor. [1] Unlike a PWR, where cracking a pipe may well lead to a steam explosion. Even if initially contained, this is super bad. It is unfortunate that many of the reactor designs out there in operation now are not 100% passively safe. Having one or two backup systems (like a Fukushima Daiichi) sometimes just isn't enough. [1] Now note that recovering from such an emergency reactor shutdown on a MSR is no fun process, and will take a while to do cleanup and get things back up and running. A normal shutdown will not drain into the pool, as I understand it. (Edit: this is wrong, see reply.)
  - mnw21cam 5y ago
    The plug was just a bit of frozen fuel salt. The research group used to melt the plug to shut down the reactor when they wanted to go home after a day's work. Then in the morning they would heat up the containment pool to re-melt the fuel, and pump it back up into the reactor.
    - ansible 5y ago
      Even better. Thanks for the correction.
- lamontcg 5y ago
  If you can solve the molten salt problem, then you can hook that up instead to a concentrated solar power plant and you don't have to deal with nuclear waste or regulations at all.
mytailorisrich 5y ago
I'm sure they explode alright when hit by a missile. They can also be captured, which gives the enemy the ingredients for a dirty bomb and/or a nice bargaining chip. My understanding is also that "thorium-based" means U-233 as fuel [1], so that's what would be in the reactor. [1] https://en.wikipedia.org/wiki/Uranium-233 https://en.wikipedia.org/wiki/Uranium-233
- simplyinfinity 5y ago
  If they are to be deployed on battelfields I'm against it. But for domestic use, please, do it faster :)
  - iNane9000 5y ago
    I don’t think you can have one and not the other. I may be too pessimistic but I would guess other nations will steal this technology and not be so encumbered by their concerns for the environment.
    - simplyinfinity 5y ago
      The sooner everyone has source of clean energy, the sooner we can stop global warming. Yes, NK can steal the designs, but so what? Like something stopped them from making a nuke.
      - stuff4ben 5y ago
        LOL! That's actually a neat way to combat climate change. "Oh no, you've stolen my nuclear-powered, clean-energy reactor and you have to shut down your coal-fired plants because they're so inefficient now... anyways" Seriously though, from what I read, these can't be used to make weapons, so it's actually a win/win if they get used or stolen.
        iNane9000 5y ago
        “ these can't be used to make weapons, so it's actually a win/win if they get used or stolen.” I don’t know anything about it, but I worry about who is making those safety assessments and what their conflicts and incentives are. It seems like a lot of things can be weaponized or used to nefarious purposes. I can imagine a portable energy source having a lot of potential uses, say powering small sea craft or whatever.
mnw21cam 5y ago
That's a massive over-simplification, if not actually completely false. A lot of the benefits of the Thorium reactors that are being envisaged are because they are a molten salt design, not because they use Thorium. Molten salt reactors can't cause a meltdown, simply because they are already molten. Traditional reactors have the potential to explode because they are cooled by superheated pressurised water, not because they use Uranium. You can run standard Uranium through a molten salt reactor and get the safety benefits, and you can burn Thorium in more traditional reactors. Likewise, you can make self-regulating reactors that aren't molten salt reactors - it's just that molten salt reactors have one particular really neat mechanism for self-shutdown. Thorium does have some inherent advantages, two of which are plentiful supply and proliferation resistance.
- simplyinfinity 5y ago
  Of course it's oversimplified statement, it's 3 sentences in total, and that's for a reason : to get a point across not write 10 pages of details that nobody would read. A child commenter posted a bit more info with clarifications :)
LatteLazy 5y ago
Careful, we're on about our 5th generation of reactors that cannot meltdown. The last 4 melted down at various points.
nickik 5y ago
This is complete nonsense. Fuel choice has little to do with how safe a reactor is. Pretty much everything you say has to do with they type of reactor, and not the fuel. This is a common misconception (perpetuated by some pop-science youtube video stuff). You can build reactors with different fuels be passively safe. In fact most companies that would like to develop Thorium Breeders are in fact all starting with Uranium reactors but non are not passively save. Terrestrial Energy from Canada for example is party based out of a group that got to know each other at a Thorium conference, yet they are building a Uranium fast reactor. This reactor is passively save and doesn't need 'control rods' to not explode. Please stop perpetuating this sudo-science. There is basically s single real benefit to thorium. That is the ability to breed thorium in a thermal spectrum. U-233 that is the actual fissionable material in a thorium reactor generates 2.1 neutors in a thermal spectrum.

ansible 5y ago

Molten salt reactors in general can't cause a meltdown because they are designed to passively moderate in the event of a problem. That isn't something specific to thorium. And conversely, pressurized water reactors, especially older designs are not passively safe, and must go through a cool-down process which requires some of the control systems to be operating properly. In general I'd like to see more development work in the area of molten-salt reactors, especially those that can reprocess existing nuclear waste.

ansible 5y ago
Replying to myself, now narcissistic... > Molten salt reactors in general can't cause a meltdown because they are designed to passively moderate in the event of a problem. At least one design I've seen has a plug in the main salt loop that is made of lead or something with a relatively low melting point. It is actively cooled to keep it solid. If there is a total power failure, and nothing is running, the cooling system shuts off, the plug melts, and the main loop drains out into a containment pool. The MSR is just running at atmospheric pressure, not super-high pressure like a pressurized water reactor (hence the name). You can crack a pipe, and that's bad, but then the loop will drain out to the containment pool below the reactor. [1] Unlike a PWR, where cracking a pipe may well lead to a steam explosion. Even if initially contained, this is super bad. It is unfortunate that many of the reactor designs out there in operation now are not 100% passively safe. Having one or two backup systems (like a Fukushima Daiichi) sometimes just isn't enough. [1] Now note that recovering from such an emergency reactor shutdown on a MSR is no fun process, and will take a while to do cleanup and get things back up and running. A normal shutdown will not drain into the pool, as I understand it. (Edit: this is wrong, see reply.)
- mnw21cam 5y ago
  The plug was just a bit of frozen fuel salt. The research group used to melt the plug to shut down the reactor when they wanted to go home after a day's work. Then in the morning they would heat up the containment pool to re-melt the fuel, and pump it back up into the reactor.
  - ansible 5y ago
    Even better. Thanks for the correction.
lamontcg 5y ago
If you can solve the molten salt problem, then you can hook that up instead to a concentrated solar power plant and you don't have to deal with nuclear waste or regulations at all.

mytailorisrich 5y ago

I'm sure they explode alright when hit by a missile. They can also be captured, which gives the enemy the ingredients for a dirty bomb and/or a nice bargaining chip. My understanding is also that "thorium-based" means U-233 as fuel [1], so that's what would be in the reactor. [1] https://en.wikipedia.org/wiki/Uranium-233 https://en.wikipedia.org/wiki/Uranium-233

simplyinfinity 5y ago
If they are to be deployed on battelfields I'm against it. But for domestic use, please, do it faster :)
- iNane9000 5y ago
  I don’t think you can have one and not the other. I may be too pessimistic but I would guess other nations will steal this technology and not be so encumbered by their concerns for the environment.
  - simplyinfinity 5y ago
    The sooner everyone has source of clean energy, the sooner we can stop global warming. Yes, NK can steal the designs, but so what? Like something stopped them from making a nuke.
    - stuff4ben 5y ago
      LOL! That's actually a neat way to combat climate change. "Oh no, you've stolen my nuclear-powered, clean-energy reactor and you have to shut down your coal-fired plants because they're so inefficient now... anyways" Seriously though, from what I read, these can't be used to make weapons, so it's actually a win/win if they get used or stolen.
      - iNane9000 5y ago
        “ these can't be used to make weapons, so it's actually a win/win if they get used or stolen.” I don’t know anything about it, but I worry about who is making those safety assessments and what their conflicts and incentives are. It seems like a lot of things can be weaponized or used to nefarious purposes. I can imagine a portable energy source having a lot of potential uses, say powering small sea craft or whatever.

mnw21cam 5y ago

That's a massive over-simplification, if not actually completely false. A lot of the benefits of the Thorium reactors that are being envisaged are because they are a molten salt design, not because they use Thorium. Molten salt reactors can't cause a meltdown, simply because they are already molten. Traditional reactors have the potential to explode because they are cooled by superheated pressurised water, not because they use Uranium. You can run standard Uranium through a molten salt reactor and get the safety benefits, and you can burn Thorium in more traditional reactors. Likewise, you can make self-regulating reactors that aren't molten salt reactors - it's just that molten salt reactors have one particular really neat mechanism for self-shutdown. Thorium does have some inherent advantages, two of which are plentiful supply and proliferation resistance.

simplyinfinity 5y ago
Of course it's oversimplified statement, it's 3 sentences in total, and that's for a reason : to get a point across not write 10 pages of details that nobody would read. A child commenter posted a bit more info with clarifications :)

LatteLazy 5y ago

Careful, we're on about our 5th generation of reactors that cannot meltdown. The last 4 melted down at various points.

nickik 5y ago

This is complete nonsense. Fuel choice has little to do with how safe a reactor is. Pretty much everything you say has to do with they type of reactor, and not the fuel. This is a common misconception (perpetuated by some pop-science youtube video stuff). You can build reactors with different fuels be passively safe. In fact most companies that would like to develop Thorium Breeders are in fact all starting with Uranium reactors but non are not passively save. Terrestrial Energy from Canada for example is party based out of a group that got to know each other at a Thorium conference, yet they are building a Uranium fast reactor. This reactor is passively save and doesn't need 'control rods' to not explode. Please stop perpetuating this sudo-science. There is basically s single real benefit to thorium. That is the ability to breed thorium in a thermal spectrum. U-233 that is the actual fissionable material in a thorium reactor generates 2.1 neutors in a thermal spectrum.