6 ms·

Obviously it couldn’t melt through to China but AFAIK the way Czernobyl played out was that they had to somehow stop it from melting down to a flooded basement

Obviously it couldn’t melt through to China but AFAIK the way Czernobyl played out was that they had to somehow stop it from melting down to a flooded basement due to the fear of a long lasting series of hydrogen explosions that could have been truly disastrous for the region, if not Europe. Thus I think that the true worst case has so far never happened: A reactor without any of the modern safeguards (such as boronic sand pits) melting down to groundwater. Though, I guess subcritical core melts would not lead to hydrogen explosions, rather the creation of a lot of steam - it would be interesting to know how likely such a worst case would be and whether any of the world‘s reactors are configured to make this possible. Incredibly, 10 Chernobyl-type RBMK reactors are still in service.

petschge 8y ago
Part of that problem is that water is actually a decent moderator and neutron reflector, so it helps a lot in keeping a chain reaction with lots of energy output going. Some of the energy also goes into splitting water into hydrogen and oxygen. The hydrogen can then collect in some corner of the building until it reaches an concentration where it explodes rather easily. The explosion can then damage the building, ruining containment and scatter radioactive material around. Moral of the story? Keep your box of boronic sand nice and dry.
- logifail 8y ago
  > Moral of the story? Keep your box of boronic sand nice and dry. See also: "For every three units of energy produced by the reactor core of a U.S. nuclear power plants, two units are discharged to the environment as waste heat. Nuclear plants are built on the shores of lakes, rivers, and oceans because these bodies provide the large quantities of cooling water needed to handle the waste heat discharge."[0] [0] https://www.ucsusa.org/nuclear_power/nuclear_power_technology/got-water-nuclear-power.html https://www.ucsusa.org/nuclear_power/nuclear_power_technolog...
  - londons_explore 8y ago
    Pretty much every energy source has a lot of waste heat produced. Solar panels get hot, gas turbines have hot exhausts, coal plants have cooling towers etc. They all approximate a heat engine, and they must theoretically give off heat to the cold reservoir
    - logifail 8y ago
      > They all approximate a heat engine For each of those energy sources mentioned, what would happen if the generating station were to be completely inundated with water?
howard941 8y ago
Are there lessons we can take away from further studies on the ancient reactor at Oklo? (see https://www.scientificamerican.com/article/ancient-nuclear-reactor/ https://www.scientificamerican.com/article/ancient-nuclear-r... for ex)
eXpl0it3r 8y ago
The sad part is that the whole anti-nuclear politics often prevent building new and way safer reactors, yet they also don't manage to force shutdown all the dangers ones.
- afterburner 8y ago
  Building new reactors costs a massive amount of money, more than pro-nuclear advocates realize or are willing to admit. Shutting down reactors doesn't save much money; they've already been built. They also weren't built when renewable energy was developed into the very cost-effective solution it is today. The worst thing about building new reactors using existing technology (which would really no better than the existing ones) is the waste of money compared to alternatives, AND you get all the risk on top of that. Delicious government-subsidized risk.
  - kortilla 8y ago
    >Building new reactors costs a massive amount of money, more than pro-nuclear advocates realize or are willing to admit. Those costs are entirely political. Fear mongers have made it extremely difficult to get a nuclear project to completion (see the whole NRC approval process). Solar panels would be super expensive as well if each one had to go through a giant 30 year planning process that NIMBYs could easily disrupt. >They also weren't built when renewable energy was developed into the very cost-effective solution it is today. Renewable isn’t cost effective. That’s a lie told to placate people. In reality, renewable currently has no feasible way to replace enough fossil fuels to matter for global warming. Energy storage solutions to bring it into candidacy for base load are so far off the mark that they aren’t even deployed. Until we have a storage solution that doesn’t 10x+ the cost of renewables, which there is no promise of, we are signing up wholeheartedly for fossil fuels as our electricity backbone (and that doesn’t even address transportation energy where the picture is even more bleak). Reminder for anyone thinking renewables are so cost effective, here is the energy source breakdown in the US: https://www.eia.gov/energyexplained/images/charts/consumption-by-source-and-sector.png https://www.eia.gov/energyexplained/images/charts/consumptio...
    - 8y ago
afterburner 8y ago
Contaminating the groundwater is also a risk.
SampleBourgeois 8y ago
I believe the 'chernobyl nearly caused a series of hydrogen explosions' hypothesis is not true. I will find the links I have on this subject, later.

petschge 8y ago

Part of that problem is that water is actually a decent moderator and neutron reflector, so it helps a lot in keeping a chain reaction with lots of energy output going. Some of the energy also goes into splitting water into hydrogen and oxygen. The hydrogen can then collect in some corner of the building until it reaches an concentration where it explodes rather easily. The explosion can then damage the building, ruining containment and scatter radioactive material around. Moral of the story? Keep your box of boronic sand nice and dry.

logifail 8y ago
> Moral of the story? Keep your box of boronic sand nice and dry. See also: "For every three units of energy produced by the reactor core of a U.S. nuclear power plants, two units are discharged to the environment as waste heat. Nuclear plants are built on the shores of lakes, rivers, and oceans because these bodies provide the large quantities of cooling water needed to handle the waste heat discharge."[0] [0] https://www.ucsusa.org/nuclear_power/nuclear_power_technology/got-water-nuclear-power.html https://www.ucsusa.org/nuclear_power/nuclear_power_technolog...
- londons_explore 8y ago
  Pretty much every energy source has a lot of waste heat produced. Solar panels get hot, gas turbines have hot exhausts, coal plants have cooling towers etc. They all approximate a heat engine, and they must theoretically give off heat to the cold reservoir
  - logifail 8y ago
    > They all approximate a heat engine For each of those energy sources mentioned, what would happen if the generating station were to be completely inundated with water?

howard941 8y ago

Are there lessons we can take away from further studies on the ancient reactor at Oklo? (see https://www.scientificamerican.com/article/ancient-nuclear-reactor/ https://www.scientificamerican.com/article/ancient-nuclear-r... for ex)

eXpl0it3r 8y ago

The sad part is that the whole anti-nuclear politics often prevent building new and way safer reactors, yet they also don't manage to force shutdown all the dangers ones.

afterburner 8y ago
Building new reactors costs a massive amount of money, more than pro-nuclear advocates realize or are willing to admit. Shutting down reactors doesn't save much money; they've already been built. They also weren't built when renewable energy was developed into the very cost-effective solution it is today. The worst thing about building new reactors using existing technology (which would really no better than the existing ones) is the waste of money compared to alternatives, AND you get all the risk on top of that. Delicious government-subsidized risk.
- kortilla 8y ago
  >Building new reactors costs a massive amount of money, more than pro-nuclear advocates realize or are willing to admit. Those costs are entirely political. Fear mongers have made it extremely difficult to get a nuclear project to completion (see the whole NRC approval process). Solar panels would be super expensive as well if each one had to go through a giant 30 year planning process that NIMBYs could easily disrupt. >They also weren't built when renewable energy was developed into the very cost-effective solution it is today. Renewable isn’t cost effective. That’s a lie told to placate people. In reality, renewable currently has no feasible way to replace enough fossil fuels to matter for global warming. Energy storage solutions to bring it into candidacy for base load are so far off the mark that they aren’t even deployed. Until we have a storage solution that doesn’t 10x+ the cost of renewables, which there is no promise of, we are signing up wholeheartedly for fossil fuels as our electricity backbone (and that doesn’t even address transportation energy where the picture is even more bleak). Reminder for anyone thinking renewables are so cost effective, here is the energy source breakdown in the US: https://www.eia.gov/energyexplained/images/charts/consumption-by-source-and-sector.png https://www.eia.gov/energyexplained/images/charts/consumptio...
  - 8y ago

afterburner 8y ago

Contaminating the groundwater is also a risk.

SampleBourgeois 8y ago

I believe the 'chernobyl nearly caused a series of hydrogen explosions' hypothesis is not true. I will find the links I have on this subject, later.