Comment by PaulHoule

Nuclear power plants can vary their output faster than most people think, see

https://www.oecd-nea.org/upload/docs/application/pdf/2021-12...

   ... most of the modern light water nuclear reactors are capable (by design) 
   to operate in a load following mode, i.e. to change their power level once 
   or twice per day in the range of 100% to 50% (or even lower) of the rated   
   power, with a ramp rate of up to 5% (or even more) of rated power per minute.

One trouble is that changing the power output does put stress on components because of thermal expansion and contraction, potentially shortening their lifespan, but it something that can be designed for.