But that's the point, really. Nuclear reactors are not economical if you're not really going for it, so in an environment where you are relying heavily on nuclear reactors, suddenly your entire endeavor is not very practical without massive state aid.
This is less of a problem in other places that have less nuclear power setup because they can be used to cover the baseline. Now, EDF is turning off reactors over the weekend cuz the power isn't needed, and in periods of high demand EDF doesn't actually have the capacity, because they don't have much peak generation!
Building more nuclear plants to cover peaks would make everything even more expensive, And decomissioning reactors entirely would cause their own massive issues because, again, electricity generation is not fungible.
One would (correctly!) point that most renewables don't help with peak generation either, and you would be right. But if you're planning on decomissioning a nuclear power plant, replacing some of that capacity with renewables at least gets your operating costs down. And energy storage solutions that are more fungible... well... you walk and chew bubble gum. Use what you have, and build what makes sense. Just in 2023 your choices for clean power generation for energy storage are vast.