[illiarian]

> Nuclear reactors are not only slow to switch power output

This is not true

> On top of that, running nuclear reactors on average significantly below maximum output drives the cost up further.

It doesn't

[bayesian_horse]

Of course running below maximum output drives up cost. Are you disagreeing with basic math? Consumption of fuel is not the main cost of a nuclear power plant, and even if you shut it down completely, it still needs external power for the cooling.