|
|
|
|
|
|
by toast0
988 days ago
|
|
|
> I could never wrap my mind around how this makes sense. Nuclear has a fixed output, it doesn’t scale up and down the way fossil fuel plants do. Nuclear can and does regulate its output. And the fuel rods should last longer if you run at less than full output. But fuel cost is not a large component of nuclear energy cost, so it doesn't make a lot of economic sense to operate them far above or below their steady state maximum capacity. I agree that nuclear doesn't make a good backfill for intermittant sources; but it's not because they can't, it's because the economics aren't good. |
|
|
They do in France. You kind of have to, if you produce 70% of your power in nuke plants. But in the US, it's not done in any meaningful sense. All US plants run at 100% capacity all the time.
The reason for that is that it's incredibly complicated to ramp a nuke plant. If you take a reactor and reduce its heat output significantly, the currently active volume of fuel moves away from the decay product equilibrium - the reactor poisons its own fuel rods with neutron absorbing decay products. This makes a subsequent increase in output power extremely dangerous and thus impossible in practice. The only way to increase power safely is to wait for the radio poison to decay naturally, which can takes tens of days (and depends on by how much you reduced power).
The only reason the French can ramp the power of their nuclear plants up and down is that they have so many of them, and they are all controlled by a central authority. This means the reactors can take turns in reducing power, each night a different set of reactors poison their fuel and recover slowly over the next week or two.
There is also of course an economic side to this. In the US, nuclear power is so economically risky that planning a plant that is not trying as hard as it possibly can to recoup it's enormous investment would sound crazy to investors. It would make zero economic sense to not run at 100% all the time, and would probably make any newly build plant a billion dollar loss instantly.