For reference: nuclear power plants can do load following: https://en.wikipedia.org/wiki/Load-following_power_plant#Nuclear_power_plants https://en.wikipedia.or

For reference: nuclear power plants can do load following: https://en.wikipedia.org/wiki/Load-following_power_plant#Nuclear_power_plants https://en.wikipedia.org/wiki/Load-following_power_plant#Nuc... It's more cost efficient to keep them running all the time since most of the cost of nuclear is building the power plant, but power output can be adjusted if needed.