6 ms·

The thing you get in the sea is unlimited free cooling and radiation shielding. You could dump the core onto the seafloor and not really have to worry about any

The thing you get in the sea is unlimited free cooling and radiation shielding. You could dump the core onto the seafloor and not really have to worry about anything except the fuel elements eventually corroding and polluting a small area. There are 11 known reactors dumped into various oceans and nothing terrible has come about from them.

mechhacker 7y ago
Correct The major concerns seem to be hijacking/piracy, clearance to dock at ports, and the general umbrella of proliferation concerns. They don't want people taking these and using the material for bad things. If there was a way around that, then maybe they would be economical. The cheap fuel costs in the past made the NS Savannah non-competitive, but I doubt that's true now: https://en.wikipedia.org/wiki/NS_Savannah https://en.wikipedia.org/wiki/NS_Savannah
- djsumdog 7y ago
  That makes a lot of sense; probably why we only see nuclear reactors on military vessels.
  - loeg 7y ago
    I've thought about this somewhat. We only trust the military to run nuclear reactors; ok, can we work with that? The US military is already a grift and jobs program; maybe we can turn the Navy into a grift and jobs program that is also an electricity utility.
    - andromeduck 7y ago
      Make them power all the shipping, oceanic towboats.
  - srg0 7y ago
    Not true. The fleet of Russian icebreakers relies mostly on nuclear propulsion. Wikipedia lists four different cargo ships equipped with a nuclear reactor at some point of time. The regulations and infrastructure are lacking but the interest is there. Burning oil to move goods around the world is not a sustainable long term solution. Nuclear propulsion might be.
- missosoup 7y ago
  I wonder if we're over-reacting with anti proliferation. It takes 3 very difficult achievements to build a nuclear bomb. Access to reactor grade uranium is only one of them. I'm not sure the dangers of potential proliferation outweigh the tangible deaths per year that result from large ship pollution.
  - xorcist 7y ago
    Building a dirty bomb isn't difficult, if raw materials is readily available.
    - missosoup 7y ago
      Dirty bombs are cold war FUD. You could build a dirty bomb out of some smoke detectors. You could build a dirty bomb from the countless orphan sources scattered around the world with far less fuss than attacking a ship and causing an international incident. You could also build much more potent terror weapons without using any nuclear materials. https://en.wikipedia.org/wiki/Dirty_bomb https://en.wikipedia.org/wiki/Dirty_bomb The biggest threat a dirty bomb poses is fear. Meanwhile shipping pollution is estimated to be responsible for hundreds of thousands of deaths every year which we just take as a fact of life.
  - DennisP 7y ago
    Reactor-grade uranium isn't sufficient either. It's enriched to a maximum of 20% U235. A bomb requires over 90%, and getting to that requires the same kind of enrichment facilities you'd need if you started from uranium ore. But fission reactors also produce plutonium. Using that is another possibility, but you need very pure Pu239. Once the reactor has been running for over three months you start getting a lot of Pu240, which is a serious contaminant for bomb fuel. Separating those is not currently feasible. So one expedient for nuclear ships would be to run the reactors a few months in secure conditions before putting them to sea. Reactor-grade plutonium is still rigorously controlled, because it might be possible to make it explode, but nobody has ever done it. https://www.world-nuclear.org/information-library/nuclear-fuel-cycle/fuel-recycling/plutonium.aspx https://www.world-nuclear.org/information-library/nuclear-fu...
doh 7y ago
Godzilla? (It’s a joke of course. HN can be sometimes too serious)
- ben509 7y ago
  Seems like coastal real estate is fucked either way.
masklinn 7y ago
And there are already active civilian nuclear propulsion vessels, mostly russian: half a dozen icebreakers and the icebreaker cargo ship Sevmorput. A variant of the concept is the floating power plant Akademik Lomonosov, a barge housing 2x35MWe reactors. Though somewhat oddly it's not intended as a mobile power plant, it replaces a "normal" power plant being shut down in a far eastern autonomous district.
hwillis 7y ago
> You could dump the core onto the seafloor and not really have to worry about anything except the fuel elements eventually corroding and polluting a small area. Absolutely not. What you're saying is true for nuclear disposal- if you bury nuclear waste under the ocean floor there are no currents and no water table to disturb it, unlike on land where coolant water will rush towards drinking water, smoke does not diffuse evenly, and sediment does not naturally bury heavy isotopes. It is absolutely not true for an accident. Radionuclides from Fukushima are measurable anywhere in the Pacific ocean. They're all over the planet. That's key though, because such even distribution means that even very dangerous isotopes are very quickly reduced to safe concentrations, or at least lower than background radiation. On the other hand it is extremely difficult or impossible to save a priority environment if there is a real disaster. Convection will be driving far more radioactive material into the area than a land accident. You're not gonna ever have a meltdown (they already basically don't happen on land), but even a relatively small breach would have the potential to kill an entire area. Over most of the ocean that might be fine, but spawning areas or corals would be huge losses.
- missosoup 7y ago
  It doesn't matter. Because water is one of the most effective shields against radiation that you can possibly have. The effects are kept localised. Alpha to mm, Beta to cm, Gamma to 10s of m. To put things in perspective, you can take a swim in a spent fuel storage pond and be exposed to less radiation than outside it. The contamination from fukushima is detectable all over the planet just like all modern steel is detectably contaminated from 1960s nuclear testing[1]. It doesn't make it any kind of threat to the environment. We're talking about the same order of magnitude concentrations that are used in radiocarbon dating. And the very dangerous isotopes you speak of, they have a very short half-life. See also, the Oklo natural nuclear reactor complete with all the associated waste/contamination and the fact that it had little to no impact on the surrounding environment[2]. At the end of the day, there are 11 known and god knows how many unknown nuclear reactors dumped into the sea, and things have turned out pretty okay. One of them is even a popular dive site. [1]: https://en.wikipedia.org/wiki/Low-background_steel https://en.wikipedia.org/wiki/Low-background_steel [2]: https://en.wikipedia.org/wiki/Oklo https://en.wikipedia.org/wiki/Oklo

mechhacker 7y ago

Correct The major concerns seem to be hijacking/piracy, clearance to dock at ports, and the general umbrella of proliferation concerns. They don't want people taking these and using the material for bad things. If there was a way around that, then maybe they would be economical. The cheap fuel costs in the past made the NS Savannah non-competitive, but I doubt that's true now: https://en.wikipedia.org/wiki/NS_Savannah https://en.wikipedia.org/wiki/NS_Savannah

djsumdog 7y ago
That makes a lot of sense; probably why we only see nuclear reactors on military vessels.
- loeg 7y ago
  I've thought about this somewhat. We only trust the military to run nuclear reactors; ok, can we work with that? The US military is already a grift and jobs program; maybe we can turn the Navy into a grift and jobs program that is also an electricity utility.
  - andromeduck 7y ago
    Make them power all the shipping, oceanic towboats.
- srg0 7y ago
  Not true. The fleet of Russian icebreakers relies mostly on nuclear propulsion. Wikipedia lists four different cargo ships equipped with a nuclear reactor at some point of time. The regulations and infrastructure are lacking but the interest is there. Burning oil to move goods around the world is not a sustainable long term solution. Nuclear propulsion might be.
missosoup 7y ago
I wonder if we're over-reacting with anti proliferation. It takes 3 very difficult achievements to build a nuclear bomb. Access to reactor grade uranium is only one of them. I'm not sure the dangers of potential proliferation outweigh the tangible deaths per year that result from large ship pollution.
- xorcist 7y ago
  Building a dirty bomb isn't difficult, if raw materials is readily available.
  - missosoup 7y ago
    Dirty bombs are cold war FUD. You could build a dirty bomb out of some smoke detectors. You could build a dirty bomb from the countless orphan sources scattered around the world with far less fuss than attacking a ship and causing an international incident. You could also build much more potent terror weapons without using any nuclear materials. https://en.wikipedia.org/wiki/Dirty_bomb https://en.wikipedia.org/wiki/Dirty_bomb The biggest threat a dirty bomb poses is fear. Meanwhile shipping pollution is estimated to be responsible for hundreds of thousands of deaths every year which we just take as a fact of life.
- DennisP 7y ago
  Reactor-grade uranium isn't sufficient either. It's enriched to a maximum of 20% U235. A bomb requires over 90%, and getting to that requires the same kind of enrichment facilities you'd need if you started from uranium ore. But fission reactors also produce plutonium. Using that is another possibility, but you need very pure Pu239. Once the reactor has been running for over three months you start getting a lot of Pu240, which is a serious contaminant for bomb fuel. Separating those is not currently feasible. So one expedient for nuclear ships would be to run the reactors a few months in secure conditions before putting them to sea. Reactor-grade plutonium is still rigorously controlled, because it might be possible to make it explode, but nobody has ever done it. https://www.world-nuclear.org/information-library/nuclear-fuel-cycle/fuel-recycling/plutonium.aspx https://www.world-nuclear.org/information-library/nuclear-fu...

doh 7y ago

Godzilla? (It’s a joke of course. HN can be sometimes too serious)

ben509 7y ago
Seems like coastal real estate is fucked either way.

masklinn 7y ago

And there are already active civilian nuclear propulsion vessels, mostly russian: half a dozen icebreakers and the icebreaker cargo ship Sevmorput. A variant of the concept is the floating power plant Akademik Lomonosov, a barge housing 2x35MWe reactors. Though somewhat oddly it's not intended as a mobile power plant, it replaces a "normal" power plant being shut down in a far eastern autonomous district.

hwillis 7y ago

> You could dump the core onto the seafloor and not really have to worry about anything except the fuel elements eventually corroding and polluting a small area. Absolutely not. What you're saying is true for nuclear disposal- if you bury nuclear waste under the ocean floor there are no currents and no water table to disturb it, unlike on land where coolant water will rush towards drinking water, smoke does not diffuse evenly, and sediment does not naturally bury heavy isotopes. It is absolutely not true for an accident. Radionuclides from Fukushima are measurable anywhere in the Pacific ocean. They're all over the planet. That's key though, because such even distribution means that even very dangerous isotopes are very quickly reduced to safe concentrations, or at least lower than background radiation. On the other hand it is extremely difficult or impossible to save a priority environment if there is a real disaster. Convection will be driving far more radioactive material into the area than a land accident. You're not gonna ever have a meltdown (they already basically don't happen on land), but even a relatively small breach would have the potential to kill an entire area. Over most of the ocean that might be fine, but spawning areas or corals would be huge losses.

missosoup 7y ago
It doesn't matter. Because water is one of the most effective shields against radiation that you can possibly have. The effects are kept localised. Alpha to mm, Beta to cm, Gamma to 10s of m. To put things in perspective, you can take a swim in a spent fuel storage pond and be exposed to less radiation than outside it. The contamination from fukushima is detectable all over the planet just like all modern steel is detectably contaminated from 1960s nuclear testing[1]. It doesn't make it any kind of threat to the environment. We're talking about the same order of magnitude concentrations that are used in radiocarbon dating. And the very dangerous isotopes you speak of, they have a very short half-life. See also, the Oklo natural nuclear reactor complete with all the associated waste/contamination and the fact that it had little to no impact on the surrounding environment[2]. At the end of the day, there are 11 known and god knows how many unknown nuclear reactors dumped into the sea, and things have turned out pretty okay. One of them is even a popular dive site. [1]: https://en.wikipedia.org/wiki/Low-background_steel https://en.wikipedia.org/wiki/Low-background_steel [2]: https://en.wikipedia.org/wiki/Oklo https://en.wikipedia.org/wiki/Oklo