Not in the same instant but they were unavailable in overlapping succession such that the entire fleet was never close to completely online even when the grid was at maximum demand.

Of those 56 reactors in the entire of 2021 no more than 49 where on online at any time in the same day. 90% of the time it was 46 or less. 16% of days it was 36 or less bottoming out at 28, and everything didn’t suddenly start working in 2022.

https://www.worldnuclearreport.org/IMG/pdf/wnisr2022-figure2...

That’s the reality of “dependable” nuclear power, it wants to run 24/7 but can’t run 365.