So the power supply used to change the speed of nuclear warships from bare steerageway to 30+kts rather quickly is not responsive to changes in demand? Friend you seem to have some conceptual errors.
There is a lot of things you need to do if you take a plant out of operation, and there is a significant amount of decay heat from fission products that does require external power (basically what caused fukashima's fires) to cool over days if you turn a plant off, but you are oversimplifying solved engineering challenges to present them as intractable challenges.
There is a lot of things you need to do if you take a plant out of operation, and there is a significant amount of decay heat from fission products that does require external power (basically what caused fukashima's fires) to cool over days if you turn a plant off, but you are oversimplifying solved engineering challenges to present them as intractable challenges.