Nuclear isn’t great for ‘peaker’/infrequent usage. The large up front capital costs means they require running at 90%+ utilization to be economic, and the way the radioactive decay chains work means they tend to take awhile (hours) to stabilize at their high power outputs, and hours to days to ramp down in actual effective power. Even a scrammed ‘hot’ reactor takes half a day to a couple days for daughter products to burn down to the point it doesn’t produce significant thermal power (hundred of megawatts to even half a gigawatt thermal).

That’s what got Fukushima btw - when they shut the reactor down and then the backup generators got destroyed, they lost their ability to pump water to cool the reactor (which requires significant electrical power), which proceeded to start to melt down the core, and causing massive hydrogen buildup, eventually blowing up the reactor building.

Some new designs allow more effective emergency passive cooling, but the issue remains - nuclear plants are great for baseline power, but they aren’t good for sub-day, hourly, or finer grained peaks. Both economically and technically. Think ‘fully loaded container ship’ or ‘multi-mile long train’.

Pumped storage, battery, or fossil fueled turbines are great for those faster reactions - and often can provide useful sub-second grid stability too. Think ‘speed boat’ or ‘passenger car’.