Demand following for nuclear is possible (after all, if you produce 10X but the demand suddenly drops to 7X, what you can always do is to "dump" 3X worth of steam instead of injecting it in the turbine), but because the cost of nuclear is mainly upfront, it is not cost efficient at all.

If it costs 10X dollars upfront to build a nuclear central that can produce 10X energy, then if you run it at 100%, it will cost 1 dollar per 1 unit of energy. If you follow the demand, you will not produce 10X, but let's say to illustrate maybe 5X, and it will cost 2 dollars per 1 unit of energy.

You are right about storage as a way to help with demand following, but if you build enough storage capacity, then you basically have solved "for free" a big part of the problem linked to the intermittence of renewables. In this case, you have the choice between building an expensive nuclear central and a distributed cheaper renewable generation.

I'm not saying it demonstrate renewables are better, but that it is true that nuclear is not the obvious winner it looks like before we look into the practical details.