5 ms·

You can totally retrofit existing nuclear power plants for closed loop cooling. I'm not sure what the cost would be, though, but it might be worth doing.

moffkalast 2mo ago
Is it economically viable to run though? Natural draft towers or direct body of water cooling is used almost universally since it doesn't take any extra power. A large chunk of the powerplant's output would be running heat pump compressors to stop itself from exploding.
- emsign 2mo ago
  First of all you can't retrofit every npp with that, it's a lie. And eve; if you could, you are correct, it's financially not viable. Renewable energy is always the cheaper option by far.
- wongarsu 2mo ago
  Fully closed loop is probably not viable. But I suspect that's not the extreme GP might have meant. If for the sake or discussion we simplify cooling to four options: 1: just passing river water through a heat exchanger for cooling 2: ingesting river water, using it for cooling, then passing it through a cooling tower before returning it to the river 3: pass the water output from the cooling tower directly back in the cooling loop, only ingest enough water to replace evaporation 4: fully closed loop via direct heat exchange with air Then 4 is not very viable. But a lot of nuclear plants are stuck at 1 or 2, and each step up the ladder would allow them to operate in worse conditions. This one seems to be at version one
  - noduerme 2mo ago
    How do these things, whose sole purpose is to turn heat into electricity, end up with so much extra heat that it takes more energy than they produce to disperse it? Can't the excess heat in a closed loop system be captured and used to power the cooling? Sorry, maybe this is a stupid question.
    - Tade0 2mo ago
      The heat is spread out to a much larger volume. Heat engines are most efficient when the temperature difference between the hot and cold side is high, so you need to keep it that way to extract energy. A nuclear power plant achieves this by converting extreme heat from a small, but very angry rock to a huge lake of slightly warmer water. There exist reactor designs which operate at higher temperatures, thus increasing efficiency, but they're complicated as everything needs to be more heat-resistant.
      - noduerme 2mo ago
        okay but to maybe beat a dead horse, if you have these enormous cooling towers spewing out steam, is the steam coming out the top of those just not economically viable to use to run smaller generators or something?
        inigyou 2mo ago
        There are plants with multiple stages of turbines. You really do need high pressure, high temperature steam to make appreciable energy though. What comes off the top of a cooling tower will keep you warm, but it's had 99% of its energy already extracted.
    - dredmorbius 2mo ago
      Thermodynamics, specifically the Carnot Cycle. Heat engines do turn heat into mechanical energy (motion). What they don't do is do this with infinite efficiency. In practice, Carnot engines (heat engines) tend to operate at efficiencies between about 20 to 50%, with an average close to 30% percent. This means that most thermal electrical generation produces roughly three times as much heat as it does electricity. This applies across thermal mechanisms: diesel generators, gas turbines, coal-fired steam, and nuclear-powered steam plants. There's some room for increased efficiencies, and multi-pass systems, or systems with incorporated thermal applications (district space heat, industrial heat, food preparation) can achieve higher net efficiencies, though I believe the peak is around 60%, and that is rarely achieved. The other parts of the generating cycle are far more efficient. Generators typically operate well above 90% efficiency (mechanical energy in to electrical energy out), and distribution typically sees about 6% losses. But that first thermal step costs a lot. There's no such thing as a free lunch. <https://en.wikipedia.org/wiki/Carnot_cycle https://en.wikipedia.org/wiki/Carnot_cycle>
  - petre 2mo ago
    5. scrap 1..4 and build a gas cooled reactor instead. https://en.wikipedia.org/wiki/HTR-PM https://en.wikipedia.org/wiki/HTR-PM
Elfener 2mo ago
I've read that in the case of Paks a retrofit doesn't make sense because the entire thing is so old and needs to be rebuilt anyway. However, hopefully, they change the plans for (stalled project) Paks 2, because that would've used the same cooling system as the first one.
- deleted 2mo ago
  [deleted]
Pay08 2mo ago
I believe there was also a planned much cheaper retrofit to use pumps to increase force to necessary levels but it was scrapped.

moffkalast 2mo ago

Is it economically viable to run though? Natural draft towers or direct body of water cooling is used almost universally since it doesn't take any extra power. A large chunk of the powerplant's output would be running heat pump compressors to stop itself from exploding.

emsign 2mo ago
First of all you can't retrofit every npp with that, it's a lie. And eve; if you could, you are correct, it's financially not viable. Renewable energy is always the cheaper option by far.
wongarsu 2mo ago
Fully closed loop is probably not viable. But I suspect that's not the extreme GP might have meant. If for the sake or discussion we simplify cooling to four options: 1: just passing river water through a heat exchanger for cooling 2: ingesting river water, using it for cooling, then passing it through a cooling tower before returning it to the river 3: pass the water output from the cooling tower directly back in the cooling loop, only ingest enough water to replace evaporation 4: fully closed loop via direct heat exchange with air Then 4 is not very viable. But a lot of nuclear plants are stuck at 1 or 2, and each step up the ladder would allow them to operate in worse conditions. This one seems to be at version one
- noduerme 2mo ago
  How do these things, whose sole purpose is to turn heat into electricity, end up with so much extra heat that it takes more energy than they produce to disperse it? Can't the excess heat in a closed loop system be captured and used to power the cooling? Sorry, maybe this is a stupid question.
  - Tade0 2mo ago
    The heat is spread out to a much larger volume. Heat engines are most efficient when the temperature difference between the hot and cold side is high, so you need to keep it that way to extract energy. A nuclear power plant achieves this by converting extreme heat from a small, but very angry rock to a huge lake of slightly warmer water. There exist reactor designs which operate at higher temperatures, thus increasing efficiency, but they're complicated as everything needs to be more heat-resistant.
    - noduerme 2mo ago
      okay but to maybe beat a dead horse, if you have these enormous cooling towers spewing out steam, is the steam coming out the top of those just not economically viable to use to run smaller generators or something?
      - inigyou 2mo ago
        There are plants with multiple stages of turbines. You really do need high pressure, high temperature steam to make appreciable energy though. What comes off the top of a cooling tower will keep you warm, but it's had 99% of its energy already extracted.
  - dredmorbius 2mo ago
    Thermodynamics, specifically the Carnot Cycle. Heat engines do turn heat into mechanical energy (motion). What they don't do is do this with infinite efficiency. In practice, Carnot engines (heat engines) tend to operate at efficiencies between about 20 to 50%, with an average close to 30% percent. This means that most thermal electrical generation produces roughly three times as much heat as it does electricity. This applies across thermal mechanisms: diesel generators, gas turbines, coal-fired steam, and nuclear-powered steam plants. There's some room for increased efficiencies, and multi-pass systems, or systems with incorporated thermal applications (district space heat, industrial heat, food preparation) can achieve higher net efficiencies, though I believe the peak is around 60%, and that is rarely achieved. The other parts of the generating cycle are far more efficient. Generators typically operate well above 90% efficiency (mechanical energy in to electrical energy out), and distribution typically sees about 6% losses. But that first thermal step costs a lot. There's no such thing as a free lunch. <https://en.wikipedia.org/wiki/Carnot_cycle https://en.wikipedia.org/wiki/Carnot_cycle>
- petre 2mo ago
  5. scrap 1..4 and build a gas cooled reactor instead. https://en.wikipedia.org/wiki/HTR-PM https://en.wikipedia.org/wiki/HTR-PM

Elfener 2mo ago

I've read that in the case of Paks a retrofit doesn't make sense because the entire thing is so old and needs to be rebuilt anyway. However, hopefully, they change the plans for (stalled project) Paks 2, because that would've used the same cooling system as the first one.

deleted 2mo ago
[deleted]

Pay08 2mo ago

I believe there was also a planned much cheaper retrofit to use pumps to increase force to necessary levels but it was scrapped.