Nuclear can dial down/up 80% on hourly basis

You still need the same number of staff supervising. Still the same interest costs on the huge bank loan to build it. Still the same maintenance intervals, etc.

Might as well leave it at full power if there is any use whatsoever for the produced energy. Even if there isn't, using the energy to warm up the ocean avoids thermal cycling of the reactor core and therefore reduces maintenance.

This should kill combined cycle role in the electricity mix to counterbalance renewables swings ? am I missing something ?