Comment by acidburnNSA

Today's nuclear reactors run constantly because the fuel is so cheap compared to the rest of the operations. They want to be selling kWh as much as possible because kWh is money. To convince nuclear operators to do backup, there would have to be some kind of market for their on-demand carbon-free characteristics. This would require market changes.

Of course, it's very possible for nuclear reactors to load follow from a physical point of view. Naval reactors load follow into battle mode quite impressively, and power stations could do the same, again if there were a market for it.

Even traditional reactors can couple to some kind of thermal energy storage system to allow them to stay mostly at 100% while the whole system load follows very nicely.

There are many exciting possibilities in on-demand, low-footprint, low-carbon energy with nuclear technology.