4 ms·

Nuclear can do load following in France. According to this article (French), reactors can adjust power output by 80% in 30 minutes: https://www.lesechos.fr/2016

by Krssst 5y ago

Nuclear can do load following in France. According to this article (French), reactors can adjust power output by 80% in 30 minutes: https://www.lesechos.fr/2016/02/lelectricien-fait-de-plus-en-plus-varier-sa-production-nucleaire-210246 https://www.lesechos.fr/2016/02/lelectricien-fait-de-plus-en... (I am curious about more details since the figure lack context. It is not clear whether the 80% applies to nominal power.) Edit: the English wikipedia article on load following is actually much clearer: https://en.m.wikipedia.org/wiki/Load_following_power_plant#Nuclear_power_plants https://en.m.wikipedia.org/wiki/Load_following_power_plant#N... > Modern nuclear plants with light water reactors are designed to have maneuvering capabilities in the 30-100% range with 5%/minute slope.

pfdietz 5y ago
Load following with nuclear is hideously uneconomical though. Even in France they use non-nuclear for much of that, for example by selling or buying power to/from neighboring countries. In any case, the problem with nuclear is that existing nuclear technology does not decarbonize the world. World primary energy demand is 18 TW. This would require 6000 nuclear power plants (3GW(th) each), if today's reactors are used they'd consume (the 235U in) 1.5 million tonnes of natural uranium per year. Total world uranium resource is a shade over 6 million tonnes, so it would run out in four years. To power the world with nuclear one either needs seawater uranium extraction (scaled up by 12 orders of magnitude from what's been done so far; 170 km^2 of ocean area for each of those reactors; the power/area is much worse than PV) or breeder reactors (which France has given up on.)
- JamesBarney 5y ago
  Sure but surely we'll run into the same issues with rare earth metals when building out over 18,000,000 solar farms. The numbers you use for uranium resources, are the amount that is economically extractable right now at current prices. Given that only 14% of the cost of a nuclear plant is raw fuel we have lots of room to increase to increase the cost of extraction. And many places abandoned breeder reactors because the cost of uranium is cheap enough right now that fuel efficiency doesn't matter.
  - pfdietz 5y ago
    Solar farms don't use rare earth metals, so, no, it's not the same at all. France's abandonment of their breeder program is the tell that they don't think there's any significant chance that nuclear will scale to power the world anytime soon.
- ZeroGravitas 5y ago
  This is the same numerical sleight of hand that fossil fuel boosters use. Roughly half of the primary energy demand isn't actually used, it's just wasted as heat. Replacing fossil fuels with nuclear or renewables would mean that much less primary energy would be needed due to the efficiency gains of electrification. The real issue with nuclear is that it needs all the same stuff as renewables (better grid connections, pink hydrogen production, demand management, EVs, hydrogen based flight and shipping) in order to keep costs reasonable but still just costs more because solar and wind are much cheaper.
  - pfdietz 5y ago
    It's a ballpark figure. And it's an argument renewables handily pass, btw. It's not an argument that fossil fuels are essential. Of course the renewables are cheaper, but in addition to that argument the pro-nuclear argument is deceptive when it tries to portray existing nuclear technology as sufficient.
- LorenPechtel 5y ago
  Or breeder reactors. Use all the uranium, not just the .7% that is U235. Worried about terrorists? The reprocessing plant needs to leave a few isotopes in the fuel it produces. Things like Co-60. The spent rods have it--the reactors and the shipping systems are built to handle it. The terrorist can't handle it, though--while some are willing to engage in suicide missions they're not going to engage in futile suicide missions. Stealing the material will just get you dead before you can deliver it.
  - pfdietz 5y ago
    I'd worry more about state level proliferation. The blanket Pu from a fast breeder is super weapon grade, with very low higher isotope concentrations. In any case, breeders mean the claim that existing nuclear technology, and in particular France's existing nuclear technology, can do it are wrong. France's breeder effort was a spectacular failure that they've now abandoned.
nicoburns 5y ago
They can, but as most of the cost of nuclear is fixed costs, they're very expensive per unit of energy when used in this way (as you get less energy overall over the lifetime of the plant). As nuclear is already one of the most expensive forms of energy this quickly becomes prohibitive.

by Krssst 5y ago

pfdietz 5y ago

Load following with nuclear is hideously uneconomical though. Even in France they use non-nuclear for much of that, for example by selling or buying power to/from neighboring countries. In any case, the problem with nuclear is that existing nuclear technology does not decarbonize the world. World primary energy demand is 18 TW. This would require 6000 nuclear power plants (3GW(th) each), if today's reactors are used they'd consume (the 235U in) 1.5 million tonnes of natural uranium per year. Total world uranium resource is a shade over 6 million tonnes, so it would run out in four years. To power the world with nuclear one either needs seawater uranium extraction (scaled up by 12 orders of magnitude from what's been done so far; 170 km^2 of ocean area for each of those reactors; the power/area is much worse than PV) or breeder reactors (which France has given up on.)

JamesBarney 5y ago
Sure but surely we'll run into the same issues with rare earth metals when building out over 18,000,000 solar farms. The numbers you use for uranium resources, are the amount that is economically extractable right now at current prices. Given that only 14% of the cost of a nuclear plant is raw fuel we have lots of room to increase to increase the cost of extraction. And many places abandoned breeder reactors because the cost of uranium is cheap enough right now that fuel efficiency doesn't matter.
- pfdietz 5y ago
  Solar farms don't use rare earth metals, so, no, it's not the same at all. France's abandonment of their breeder program is the tell that they don't think there's any significant chance that nuclear will scale to power the world anytime soon.
ZeroGravitas 5y ago
This is the same numerical sleight of hand that fossil fuel boosters use. Roughly half of the primary energy demand isn't actually used, it's just wasted as heat. Replacing fossil fuels with nuclear or renewables would mean that much less primary energy would be needed due to the efficiency gains of electrification. The real issue with nuclear is that it needs all the same stuff as renewables (better grid connections, pink hydrogen production, demand management, EVs, hydrogen based flight and shipping) in order to keep costs reasonable but still just costs more because solar and wind are much cheaper.
- pfdietz 5y ago
  It's a ballpark figure. And it's an argument renewables handily pass, btw. It's not an argument that fossil fuels are essential. Of course the renewables are cheaper, but in addition to that argument the pro-nuclear argument is deceptive when it tries to portray existing nuclear technology as sufficient.
LorenPechtel 5y ago
Or breeder reactors. Use all the uranium, not just the .7% that is U235. Worried about terrorists? The reprocessing plant needs to leave a few isotopes in the fuel it produces. Things like Co-60. The spent rods have it--the reactors and the shipping systems are built to handle it. The terrorist can't handle it, though--while some are willing to engage in suicide missions they're not going to engage in futile suicide missions. Stealing the material will just get you dead before you can deliver it.
- pfdietz 5y ago
  I'd worry more about state level proliferation. The blanket Pu from a fast breeder is super weapon grade, with very low higher isotope concentrations. In any case, breeders mean the claim that existing nuclear technology, and in particular France's existing nuclear technology, can do it are wrong. France's breeder effort was a spectacular failure that they've now abandoned.

nicoburns 5y ago

They can, but as most of the cost of nuclear is fixed costs, they're very expensive per unit of energy when used in this way (as you get less energy overall over the lifetime of the plant). As nuclear is already one of the most expensive forms of energy this quickly becomes prohibitive.