Nuclear doesn't scale quickly. It already adapts from 4GW to 7GW in Spain, but it does it slowly and ahead of weather conditions.
What is needed is more co-located battery storage, and more gravity (solid or water) storage.
Nuclear is never meant to scale, you want to run the plant at 100% as much as possible to recoup costs. It is baseload power and you deal with peaks using peaker plants and batteries.
Maybe I don’t understand the requirement, but can’t a constant-rate supply provide stored power for peak demand and support baseline consumption off-peak?