10 ms·

This was with previous designs of fusion reactors. Read about proposed Ark and currently constructing Spark reactors. By using stronger superconductive magnets

by _0w8t 5y ago

This was with previous designs of fusion reactors. Read about proposed Ark and currently constructing Spark reactors. By using stronger superconductive magnets it was possible to reduce the size of the plant by order of magnitude. Spark even has a chance to get to Q>1 before ITER and it’s chamber is less than 2m in diameter. Plus it is possible to replace its parts without disassembling the whole reactor. [1] - https://en.m.wikipedia.org/wiki/SPARC_(tokamak) https://en.m.wikipedia.org/wiki/SPARC_(tokamak)

ncmncm 5y ago
That might be nice if they had solutions to the other problems not addressed (see above). But operating it will necessarily still be enormously more expensive than solar or wind, which cost practically nothing. Somebody with one leg can do a lot better in a race than somebody with none, but that is not the measure to consider when the competition is with two-legged runners. (Hint: they win.)
- _0w8t 5y ago
  In Europe after the last autumn when for months there were little wind and cloudy sky there is a realization that energy based purely on renewables will require much bigger storage and much more solar or at least significantly more expensive solar that works under clouds. Doable, but cost is non-trivial. So if any of fusion startups can make operating plant within the next 20 years, it can be used. But if that takes longer, then I agree that large-scale fusion will not happen.
  - pfdietz 5y ago
    Long term darkness/calm is solved with hydrogen. Europe has plenty of underground geology suitable for mass hydrogen storage (it's just like natural gas is stored.) Most of the energy still would go directly from solar/wind to the grid, or through efficient batteries, so the low round trip efficiency of power to gas to power doesn't matter much.
    - gmueckl 5y ago
      If hydrogen is produced from electricity at scale, it won't be used for energy storage. It'll get sold to chemical plants first. They'll pay good prices.
      - pfdietz 5y ago
        Yes, surely that will be a major market. It just makes the case easier for renewables, as that's a major source of dispatchable demand that can smooth variation in renewable output without having to pay a cost for turning it back to electric power later.
      - _0w8t 5y ago
        Or to steel smelters.
      - ncmncm 5y ago
        And, anywhere it is used, it will also be stockpiled. And sold back whenever the spot price rises.
    - tsimionescu 5y ago
      Electricity -> Hydrogen -> Electricity is insanely wasteful. If this is the only large scale long term storage we can come up with, we have a huge problem...
      - pfdietz 5y ago
        It would be a serious problem if hydrogen were used for diurnal storage. But for rare event backup, efficiency is really unimportant, since so little of the energy produced will go through that channel. What matters for use cases like that is minimizing capital cost, not maximizing efficiency. I'll add that the alternative proposal, excess renewables with curtailment, has 0% efficiency on the curtailed power. Using that power for anything at all, including making hydrogen, is more efficient that just dropping it on the ground.
      - ncmncm 5y ago
        Hydrogen is so useful for so many other things that its (present) poor round-trip efficiency doesn't matter much. And, that efficiency will only ever get better, not worse, and will get better faster the more of it there is. But hydrogen is very far from the only storage choice, it is just one that is attractive for numerous ancillary reasons: we need to make the hydrogen regardless, so might as well store it too.
panick21_ 5y ago
Compare that to a simple molten salt fission reactor. It will simply never be cheaper.
- _0w8t 5y ago
  Molten solt reactors do not solve the problem of nuclear waste. It is very expensive to deal with it as it has to be stored for hundreds of years unless some technology would appear to separate that cheaply. Fusion produce like order of magnitude less radioactive waste which will be short-lived. Plus a fusion plant can be very quick to start and shutdown or throttle down which is very useful for base load.
  - panick21_ 5y ago
    Molten salt reactors inherently don't. But you can burn up higher actinides resulting in waste that only needs to be stored a few 100 years and pose very little danger even in the most absurd scenarios. You don't need to separate all the different parts. You reprocess our old waste into fuel for modern reactors. In those reactors higher actinides will be burned up. And the resulting output does not have higher actinides and only needs to be stored as long. Moltex Energy is currently engaged with the Canadian regulator for such a facility, the process is called WATSS. Doing this is actually cheaper then the deep storage storage facilities proposed in many countries. Sadly because of political bullshit reprocessing has been made illegal in the US. Such things would have been doable decades ago, and the money for it is already on bank accounts in most countries. But politician force the 'dig a hole for everything' solutions instead. > Plus a fusion plant can be very quick to start and shutdown or throttle down which is very useful for base load. Next generation fusion would also be very reactive to changes. Far more then traditional. But the reality is you actually want to run full power as much as you can, no matter if fission or fusion.
  - pfdietz 5y ago
    Nuclear waste is not the major problem with fission, capital cost is. Fusion solves a minor problem of fission while making the major problem worse. It's a great example of misplaced focus. Cooling down the magnets of a fusion plant is not a quick process, btw. Hell, just getting a fusion plant built with RAFM steel up to operating temperature is a delicate process. Once irradiated, the temperature window that material can operate at is rather narrow (300 C to 550 C; below that it's too brittle and above that it creeps.)
pfdietz 5y ago
You are making a commonly seen mistake there. Yes, making magnetic fields stronger can give one higher power density than ITER. But one runs into a limit because of power density at the wall. Once you're at that limit, higher magnetic fields don't really help. ARC's volumetric thermal power density (volume of reactor, not of the plasma) is just 1/40th that of the primary reactor vessel of a commercial pressurized water fission reactor. 60% of the mass of an ARC reactor is in the steel structural supports for the magnets, so it's about at the upper limit for steady magnetic fields in a fusion reactor.

by _0w8t 5y ago

ncmncm 5y ago

That might be nice if they had solutions to the other problems not addressed (see above). But operating it will necessarily still be enormously more expensive than solar or wind, which cost practically nothing. Somebody with one leg can do a lot better in a race than somebody with none, but that is not the measure to consider when the competition is with two-legged runners. (Hint: they win.)

_0w8t 5y ago
In Europe after the last autumn when for months there were little wind and cloudy sky there is a realization that energy based purely on renewables will require much bigger storage and much more solar or at least significantly more expensive solar that works under clouds. Doable, but cost is non-trivial. So if any of fusion startups can make operating plant within the next 20 years, it can be used. But if that takes longer, then I agree that large-scale fusion will not happen.
- pfdietz 5y ago
  Long term darkness/calm is solved with hydrogen. Europe has plenty of underground geology suitable for mass hydrogen storage (it's just like natural gas is stored.) Most of the energy still would go directly from solar/wind to the grid, or through efficient batteries, so the low round trip efficiency of power to gas to power doesn't matter much.
  - gmueckl 5y ago
    If hydrogen is produced from electricity at scale, it won't be used for energy storage. It'll get sold to chemical plants first. They'll pay good prices.
    - pfdietz 5y ago
      Yes, surely that will be a major market. It just makes the case easier for renewables, as that's a major source of dispatchable demand that can smooth variation in renewable output without having to pay a cost for turning it back to electric power later.
    - _0w8t 5y ago
      Or to steel smelters.
    - ncmncm 5y ago
      And, anywhere it is used, it will also be stockpiled. And sold back whenever the spot price rises.
  - tsimionescu 5y ago
    Electricity -> Hydrogen -> Electricity is insanely wasteful. If this is the only large scale long term storage we can come up with, we have a huge problem...
    - pfdietz 5y ago
      It would be a serious problem if hydrogen were used for diurnal storage. But for rare event backup, efficiency is really unimportant, since so little of the energy produced will go through that channel. What matters for use cases like that is minimizing capital cost, not maximizing efficiency. I'll add that the alternative proposal, excess renewables with curtailment, has 0% efficiency on the curtailed power. Using that power for anything at all, including making hydrogen, is more efficient that just dropping it on the ground.
    - ncmncm 5y ago
      Hydrogen is so useful for so many other things that its (present) poor round-trip efficiency doesn't matter much. And, that efficiency will only ever get better, not worse, and will get better faster the more of it there is. But hydrogen is very far from the only storage choice, it is just one that is attractive for numerous ancillary reasons: we need to make the hydrogen regardless, so might as well store it too.

panick21_ 5y ago

Compare that to a simple molten salt fission reactor. It will simply never be cheaper.

_0w8t 5y ago
Molten solt reactors do not solve the problem of nuclear waste. It is very expensive to deal with it as it has to be stored for hundreds of years unless some technology would appear to separate that cheaply. Fusion produce like order of magnitude less radioactive waste which will be short-lived. Plus a fusion plant can be very quick to start and shutdown or throttle down which is very useful for base load.
- panick21_ 5y ago
  Molten salt reactors inherently don't. But you can burn up higher actinides resulting in waste that only needs to be stored a few 100 years and pose very little danger even in the most absurd scenarios. You don't need to separate all the different parts. You reprocess our old waste into fuel for modern reactors. In those reactors higher actinides will be burned up. And the resulting output does not have higher actinides and only needs to be stored as long. Moltex Energy is currently engaged with the Canadian regulator for such a facility, the process is called WATSS. Doing this is actually cheaper then the deep storage storage facilities proposed in many countries. Sadly because of political bullshit reprocessing has been made illegal in the US. Such things would have been doable decades ago, and the money for it is already on bank accounts in most countries. But politician force the 'dig a hole for everything' solutions instead. > Plus a fusion plant can be very quick to start and shutdown or throttle down which is very useful for base load. Next generation fusion would also be very reactive to changes. Far more then traditional. But the reality is you actually want to run full power as much as you can, no matter if fission or fusion.
- pfdietz 5y ago
  Nuclear waste is not the major problem with fission, capital cost is. Fusion solves a minor problem of fission while making the major problem worse. It's a great example of misplaced focus. Cooling down the magnets of a fusion plant is not a quick process, btw. Hell, just getting a fusion plant built with RAFM steel up to operating temperature is a delicate process. Once irradiated, the temperature window that material can operate at is rather narrow (300 C to 550 C; below that it's too brittle and above that it creeps.)

pfdietz 5y ago

You are making a commonly seen mistake there. Yes, making magnetic fields stronger can give one higher power density than ITER. But one runs into a limit because of power density at the wall. Once you're at that limit, higher magnetic fields don't really help. ARC's volumetric thermal power density (volume of reactor, not of the plasma) is just 1/40th that of the primary reactor vessel of a commercial pressurized water fission reactor. 60% of the mass of an ARC reactor is in the steel structural supports for the magnets, so it's about at the upper limit for steady magnetic fields in a fusion reactor.