That's the average. But you'd need a few more for peak demand and a few more for when these are offline for maintenance, refuelling etc.
This is called demand response, https://www.energy.gov/oe/activities/technology-development/..., and it's probably as important of a component to future grid management as energy storage.
Bitcoin mining is commonly promoted as this kind of ideal electricity consumer. Hydrogen production could be another.
However, I think more interesting for this community would be to build some kind of demand response general computing datacenter. Basically, sell computing resources with poor availability guarantees, but at a cheaper rate than standard datacenters.
i.e. we'll run your batch jobs very cheaply, but we can't give you strong guarantees about how long it will take because we have to wait for excess grid electricity to have the energy to run them. Best case that's every night. Worst case we won't be able to run anything for weeks because Texas is going through another freak winter storm.
I think you misunderstood. The parent comment implied that excess electricity could be use to produce synthetic fuels (via carbon capture) to power conventional airplanes, ships or other machinery.
They'll probably shut the plant down, and have 500 workers come in to replace everything that needs to be replaced, and then power it up again within a few days, and let it run for another 6 months or so.
Everything will be planned on workplans, and most won't require specialist knowledge... Eg. "Replace pump 205 in building C with this pump. Required skills people: 2x plumber, 2x electrician".
Most reactor maintenance is already done during refueling so there isn't much more room to optimize that downtime. (though that may change the older a reactor gets)
Finland is actually somewhat known for running short (1 year) cycles with very very short (<10 days for refuelling is not unheard of) refuelling outages every other cycle alternating with slightly longer maintenance outages. A more typical scenario in the US would be 18 month cycles with a 30ish day outage. Some plants are moving to 24 month cycles with slightly longer outages.
Capacity factor for nuclear plants in the US is consistently around 93% (similar figures in many other countries as well), which is significantly higher than other generation sources.