Temperature of the steam is not that important because it depends on the generator system each nuclear central has. Maybe a bigger nuclear central has lower steam temperature but higher flow so the important point is how many energy is generated in the reactor.

Even that number is not important because it depends again on the generator system. So the data to compare nuclear plants is not how many heat they generate but how many electricity they do generatei in a year (maintenance stops can be quite long).

Largest nuclear plant in 2019: "Tokyo Electric Power Co.’s (TEPCO) Kashiwazaki-Kariwa plant in Japan is currently the world’s largest nuclear power plant, with a net capacity of 7,965MW".

https://www.power-technology.com/features/feature-largest-nuclear-power-plants-world/