9 ms·

A floating nuclear plant sounds like of one the most dangerous things a society can do. One of the problematic aspects of atomic fission energy plants are their

by madez 8y ago

A floating nuclear plant sounds like of one the most dangerous things a society can do. One of the problematic aspects of atomic fission energy plants are their failure behaviour. One of the most important aspects there is the containment of the pollution (in Fukushima they literally freeze the ground water under the plant so it is contained from below, too). If you are free floating in water, possibly even an ocean, you are about as uncontained as you can possibly get.

azeotropic 8y ago
The U.S. Navy seems to operate a bunch of floating (and some submersible) nuclear power plants in the ocean without too much trouble.
- madez 8y ago
  Without too much trouble that we know of. And a small number of small reactors. I think it is extremely irresonsible to build military equipment with nuclear reactors. They are destroyed in conflict, polluting everything.
- fucking_tragedy 8y ago
  Correct me if I'm wrong, but I'm pretty sure the scale is much different.
  - acidburnNSA 8y ago
    Not too different. Subs can be a few hundred megawatts, vs. a few thousand in power plants.
    - bronson 8y ago
      Only an order of magnitude or two.
      - acidburnNSA 8y ago
        You can fit about 2 GW-scale AP1000 reactors on a big ship.
      - vonmoltke 8y ago
        There are no single reactors putting out tens of GW, so just one (at most).
- gricardo99 8y ago
  Here’s a list of sunken U.S. and Soviet nuclear submarines. And by “nuclear”, it means propulsion/reactor, not just nuclear warheads. https://en.m.wikipedia.org/wiki/List_of_sunken_nuclear_submarines https://en.m.wikipedia.org/wiki/List_of_sunken_nuclear_subma...
  - fovc 8y ago
    """ Of the nine sinkings, two were caused by fires, two by explosions of their weapons systems, two by flooding, one by bad weather, and one by scuttling due to a damaged nuclear reactor. """
    - garmaine 8y ago
      Well we all know the one scuttled due to damaged reactor was actually a cover story for defecting with first strike technology to the Americans...
      - dboreham 8y ago
        ...and to live in Montana, owning a pickup truck..
        garmaine 8y ago
        with two wives!
      - Fej 8y ago
        No one got the reference. Unfortunate. (for those looking, it's to the movie The Hunt for Red October)
  - RugnirViking 8y ago
    and yet despite that, we have yet to see significant effects on any of our daily lives from any of it.
    - 8y ago
- bronson 8y ago
  But what about scale? Sub reactors are tiny! Never more than a few hundred MW, with relatively little fuel. Typical powerplant reactors operate in the TWs.
  - acidburnNSA 8y ago
    *Typical power plants reactors operate in the GW, not TW. So there's about an order of magnitude difference between subs and power plants, not 4 orders of magnitude.
  - ChuckMcM 8y ago
    Your scale is off a bit. The Fukishima reactors were 484 MW to 1.1GW. Diablo Canyon, a fairly "new" (and now unused) Nuclear reactor setup in California were both units under 1.2GW. The reactors on the "Ford" class aircraft carriers are reported to produce about 700MW each.
    - bronson 8y ago
      Arg, I can't believe I brain-fumbled that. I meant to type GW. Wish I could still edit. Yes, it's 1-2 orders of magnitude.
sandworm101 8y ago
Water is a great radiation barrier. The "nuclear" failure option for a floating plant, sinking it, is reasonable. There are already a few reactors on the ocean floor (subs). That is far safer than having them in the atmosphere.
pathseeker 8y ago
Ah, the classic "this old power plant design had this failure mode, therefore all nuclear does this" argument. Do you know when Fukushima was built and what year the designs were drafted for it?
- fovc 8y ago
  I don't know enough here to comment on who's right, but when the magnitude of catastrophic failure is large enough, model error is appreciably important. So in those cases past experience is a very important input into the decision, even if not perfectly correlated. If anything, it proves that identifying all failure modes is challenging, and theoretically safe is not the same as practically safe.
  - bluGill 8y ago
    The magnitude of the error has been overstated though. There were issues, but a coal powerplant is worse for public health than the known disasters.
    - Teknoman117 8y ago
      Hydroelectic as well technically. A set of hydroelectric dam failures in China in 1975 killed more people directly from the event (171,000) than is estimated for the direct and future deaths caused from Chernobyl and Fukushima combined.
  - gh02t 8y ago
    "So in those cases past experience is a very important input into the decision, even if not perfectly correlated." Of course it is, which is why modern reactor designs have incorporated safety features based on these accidents and older designs have been retrofitted (with some exceptions that are legitimately concerning). It's entirely true that it is impossible to predict every mode of catastrophic failure, but that does not mean it's impossible to create designs that are resilient to unplanned disasters. No type of power plant can be perfectly safe, but for assessing practical safety records, in terms of deaths / TWh generated, even estimating conservatively nuclear power is safer than any other source of power (including wind and solar). Some references for this: https://www.statista.com/statistics/494425/death-rate-worldwide-by-energy-source/ https://www.statista.com/statistics/494425/death-rate-worldw... https://ourworldindata.org/what-is-the-safest-form-of-energy https://ourworldindata.org/what-is-the-safest-form-of-energy https://www.nextbigfuture.com/2008/03/deaths-per-twh-for-all-energy-sources.html https://www.nextbigfuture.com/2008/03/deaths-per-twh-for-all...
acidburnNSA 8y ago
That's a common reaction, but it doesn't stand to much scrutiny. Before radiation gets to the public, about 4 or 5 different barriers have to fail. The first is the fuel pin, then the cladding metal, then the coolant itself (which can often absorb problematic fission products), then the reactor vessel, then the containment, and then dispersal. You're focusing on containment/dispersal. But how do the first ones fail? The answer is that lack of decay heat removal allows the earlier barriers to heat up, melt, and fail. Well, if you have an intimate connection to an infinite heat sink (the sea), you don't ever lose decay heat cooling. You can't! So your fuel and clad stay intact in almost all scenarios. Earthquakes? No problem, the sea buffers you. Tsunamis? No problem, stay in moderately deep water and the wavelengths are so long that you'll barely notice them. Heavy weather? The world's largest ship (Prelude) is designed to stay operating (it's a LNG facility) during Cat 5 cyclones. Military attack? Sink and cool passively until a designed recovery operation can occur Ship collision? Stay out of shipping lanes; worse case, sink and don't leak. Also, keep people out of your exclusion zone by being a few km offshore. Honestly it's a pretty slick low-carbon rapid deployment scenario that improves construction cost and safety. Operation will likely be more expensive, but maintenance maybe not (since you can go home to the shipyard and be relieved by a spare).
- bronson 8y ago
  Most energy profit comes from externalizing the costs. Floating reactors would do that fantastically! Love the "sink and don't leak" requirement.
  - acidburnNSA 8y ago
    Better stated: sink and don't leak because you are intimately linked to a near-infinite heat sink, and heating up/melting are a prerequisite to leaking.
    - DoctorOetker 8y ago
      that doesn't discuss corrosion though, the ocean is full of salt, how many half-lives until corrosion prevents containment?
kenneth 8y ago
Floating nuclear power plants are already quite common and have a spotless track record in the past century. That's wht most of America's aircraft carriers and modern submarines are.
spricket 8y ago
This neglects the failure modes of nuclear power. The biggest danger, by far, is overheating, fire, and melting. Paradoxically, a nuclear plant could be made extremely safe if it just dumped all the fuel into the ocean at the first sign of trouble. With ulimited cooling the fuel can't melt so it will be safely contained within the rods/pellets. Yes the radiation near to the fuel would be insane, but water is so dense it would be safe to swim around maybe 50 feet away. There's never been a bad accident in spent fuel pools even though they contain orders of magnitude more fuel than operating reactors. This is just because it's really hard to melt something sitting in thousands of tons of water

by madez 8y ago

azeotropic 8y ago

The U.S. Navy seems to operate a bunch of floating (and some submersible) nuclear power plants in the ocean without too much trouble.

madez 8y ago
Without too much trouble that we know of. And a small number of small reactors. I think it is extremely irresonsible to build military equipment with nuclear reactors. They are destroyed in conflict, polluting everything.
fucking_tragedy 8y ago
Correct me if I'm wrong, but I'm pretty sure the scale is much different.
- acidburnNSA 8y ago
  Not too different. Subs can be a few hundred megawatts, vs. a few thousand in power plants.
  - bronson 8y ago
    Only an order of magnitude or two.
    - acidburnNSA 8y ago
      You can fit about 2 GW-scale AP1000 reactors on a big ship.
    - vonmoltke 8y ago
      There are no single reactors putting out tens of GW, so just one (at most).
gricardo99 8y ago
Here’s a list of sunken U.S. and Soviet nuclear submarines. And by “nuclear”, it means propulsion/reactor, not just nuclear warheads. https://en.m.wikipedia.org/wiki/List_of_sunken_nuclear_submarines https://en.m.wikipedia.org/wiki/List_of_sunken_nuclear_subma...
- fovc 8y ago
  """ Of the nine sinkings, two were caused by fires, two by explosions of their weapons systems, two by flooding, one by bad weather, and one by scuttling due to a damaged nuclear reactor. """
  - garmaine 8y ago
    Well we all know the one scuttled due to damaged reactor was actually a cover story for defecting with first strike technology to the Americans...
    - dboreham 8y ago
      ...and to live in Montana, owning a pickup truck..
      - garmaine 8y ago
        with two wives!
    - Fej 8y ago
      No one got the reference. Unfortunate. (for those looking, it's to the movie The Hunt for Red October)
- RugnirViking 8y ago
  and yet despite that, we have yet to see significant effects on any of our daily lives from any of it.
  - 8y ago
bronson 8y ago
But what about scale? Sub reactors are tiny! Never more than a few hundred MW, with relatively little fuel. Typical powerplant reactors operate in the TWs.
- acidburnNSA 8y ago
  *Typical power plants reactors operate in the GW, not TW. So there's about an order of magnitude difference between subs and power plants, not 4 orders of magnitude.
- ChuckMcM 8y ago
  Your scale is off a bit. The Fukishima reactors were 484 MW to 1.1GW. Diablo Canyon, a fairly "new" (and now unused) Nuclear reactor setup in California were both units under 1.2GW. The reactors on the "Ford" class aircraft carriers are reported to produce about 700MW each.
  - bronson 8y ago
    Arg, I can't believe I brain-fumbled that. I meant to type GW. Wish I could still edit. Yes, it's 1-2 orders of magnitude.

sandworm101 8y ago

Water is a great radiation barrier. The "nuclear" failure option for a floating plant, sinking it, is reasonable. There are already a few reactors on the ocean floor (subs). That is far safer than having them in the atmosphere.

pathseeker 8y ago

Ah, the classic "this old power plant design had this failure mode, therefore all nuclear does this" argument. Do you know when Fukushima was built and what year the designs were drafted for it?

fovc 8y ago
I don't know enough here to comment on who's right, but when the magnitude of catastrophic failure is large enough, model error is appreciably important. So in those cases past experience is a very important input into the decision, even if not perfectly correlated. If anything, it proves that identifying all failure modes is challenging, and theoretically safe is not the same as practically safe.
- bluGill 8y ago
  The magnitude of the error has been overstated though. There were issues, but a coal powerplant is worse for public health than the known disasters.
  - Teknoman117 8y ago
    Hydroelectic as well technically. A set of hydroelectric dam failures in China in 1975 killed more people directly from the event (171,000) than is estimated for the direct and future deaths caused from Chernobyl and Fukushima combined.
- gh02t 8y ago
  "So in those cases past experience is a very important input into the decision, even if not perfectly correlated." Of course it is, which is why modern reactor designs have incorporated safety features based on these accidents and older designs have been retrofitted (with some exceptions that are legitimately concerning). It's entirely true that it is impossible to predict every mode of catastrophic failure, but that does not mean it's impossible to create designs that are resilient to unplanned disasters. No type of power plant can be perfectly safe, but for assessing practical safety records, in terms of deaths / TWh generated, even estimating conservatively nuclear power is safer than any other source of power (including wind and solar). Some references for this: https://www.statista.com/statistics/494425/death-rate-worldwide-by-energy-source/ https://www.statista.com/statistics/494425/death-rate-worldw... https://ourworldindata.org/what-is-the-safest-form-of-energy https://ourworldindata.org/what-is-the-safest-form-of-energy https://www.nextbigfuture.com/2008/03/deaths-per-twh-for-all-energy-sources.html https://www.nextbigfuture.com/2008/03/deaths-per-twh-for-all...

acidburnNSA 8y ago

That's a common reaction, but it doesn't stand to much scrutiny. Before radiation gets to the public, about 4 or 5 different barriers have to fail. The first is the fuel pin, then the cladding metal, then the coolant itself (which can often absorb problematic fission products), then the reactor vessel, then the containment, and then dispersal. You're focusing on containment/dispersal. But how do the first ones fail? The answer is that lack of decay heat removal allows the earlier barriers to heat up, melt, and fail. Well, if you have an intimate connection to an infinite heat sink (the sea), you don't ever lose decay heat cooling. You can't! So your fuel and clad stay intact in almost all scenarios. Earthquakes? No problem, the sea buffers you. Tsunamis? No problem, stay in moderately deep water and the wavelengths are so long that you'll barely notice them. Heavy weather? The world's largest ship (Prelude) is designed to stay operating (it's a LNG facility) during Cat 5 cyclones. Military attack? Sink and cool passively until a designed recovery operation can occur Ship collision? Stay out of shipping lanes; worse case, sink and don't leak. Also, keep people out of your exclusion zone by being a few km offshore. Honestly it's a pretty slick low-carbon rapid deployment scenario that improves construction cost and safety. Operation will likely be more expensive, but maintenance maybe not (since you can go home to the shipyard and be relieved by a spare).

bronson 8y ago
Most energy profit comes from externalizing the costs. Floating reactors would do that fantastically! Love the "sink and don't leak" requirement.
- acidburnNSA 8y ago
  Better stated: sink and don't leak because you are intimately linked to a near-infinite heat sink, and heating up/melting are a prerequisite to leaking.
  - DoctorOetker 8y ago
    that doesn't discuss corrosion though, the ocean is full of salt, how many half-lives until corrosion prevents containment?

kenneth 8y ago

Floating nuclear power plants are already quite common and have a spotless track record in the past century. That's wht most of America's aircraft carriers and modern submarines are.

spricket 8y ago

This neglects the failure modes of nuclear power. The biggest danger, by far, is overheating, fire, and melting. Paradoxically, a nuclear plant could be made extremely safe if it just dumped all the fuel into the ocean at the first sign of trouble. With ulimited cooling the fuel can't melt so it will be safely contained within the rods/pellets. Yes the radiation near to the fuel would be insane, but water is so dense it would be safe to swim around maybe 50 feet away. There's never been a bad accident in spent fuel pools even though they contain orders of magnitude more fuel than operating reactors. This is just because it's really hard to melt something sitting in thousands of tons of water