Comment Nuclear plants can load-follow (Score 2) 133
Cold-start takes forever, but once running, nuclear plants can load follow, adjusting output by several percent per minute. Generally they don't only for economic reasons: it makes more sense to throttle back everything else instead. However, if you run out of other things to shut down, nuke plants can load-follow just fine. France does this all the time.
Batteries are still useful in a bunch of ways, but you don't need nearly as many for a mostly-nuke grid as an mostly-renewables grid.
But if you turn OFF a light, the nuclear plant might meltdown.
They do not. If the grid can't accept the power, they just open the bypass valves and waste the extra heat while the reactor throttles down.