Nope, they're only good for base loads except in places like Northfield Mountain where there's amenable geology to support pumped hydro. Running them hotter and wasting the energy at night isn't viable, the quantity of thermal energy requiring dispersion can decimate the local ecology. Storing a significant portion of the overnight generation of a nuke plant is no small feat; the Hornsdale power reserve in Australian (Tesla) stores 129 MWh total.. a single reactor easily produces a gigawatt or more, and typically there are 2+ reactors, so Hornsdale would store less than 1/10 of one hour's generation. Highly reactive sources like rooftop solar or wind farms are going to be required until/unless there's enough storage to smooth out the demand. Right now variable generation (solar, wind) is cheaper than battery storage.
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