Coal and nuclear are both inflexible power sources, they are either on or off, and they are hard to turn on and off. Nuclear does have the benefit of being cheap after very high initial capital costs. Natural gas is a much better backup to renewables however, since it can turned on and off at will. Dam hydroelectric also has that nice quality (send water through the generator when you need it, otherwise let it stay in the reservoir).
Given nuclear’s inflexibility, doing untimely work when less electricity is needed for more timely needs is also a win.
Given nuclear’s inflexibility, doing untimely work when less electricity is needed for more timely needs is also a win.