Wow, that's pretty fast. So 12 minutes worst case. TIL.
Still, I wonder if the economics don't favor running near 100%. You've already paid the high up-front cost of the equipment, and fuel costs are low, so I assume you're better off selling excess power when possible.
Of course. Though with increasing deployment of intermittent sources like wind and solar, occasionally the wholesale price can drop lower than the marginal cost of the nuclear plant (or even negative, if said power sources receive production subsidies regardless of the wholesale price), in which case it makes sense to throttle down.
Future grids with more intermittent renewables will have increasingly volatile prices, but not necessarily lower on average. So generators that can produce during high price periods (e.g. if wind and solar aren't producing much) can make a lot of money then, compensating for less income during low price periods.
I'd be willing to bet there are some significant thermal efficiency losses at 100% that would push you down closer to (made up number incoming) 80% at idle
Still, I wonder if the economics don't favor running near 100%. You've already paid the high up-front cost of the equipment, and fuel costs are low, so I assume you're better off selling excess power when possible.