Fine, than they can go a bit lower still. But for a grid mainly powered by renewables, they would have to be able to go all the way down to 0, what is really no

Fine, than they can go a bit lower still. But for a grid mainly powered by renewables, they would have to be able to go all the way down to 0, what is really not a practical option for nuclear reactors. But there is another catch: nuclear is extremely expensive, even when run most of the time close to 100%. But any time you throttle the reactor, you are driving the costs up. Because most of the costs are in building and operating the reactor, less so in fuel.