I wish I knew a bit more about how nuclear plants work, but I’m assuming that the river water, before being returned to the river, is cooled in the cooling towers using ambient air.
Besides the high input temperature of the water, are the higher air temperatures this time of the year also a contributing factor?
If they’re using cooling towers, undoubtedly so. The cooling towers won’t work as well, with higher temperature. Wet bulb is more important than dry bulb temperatures, but the wet bulb temps have been plenty high.
It depends on the power plant: Local enviro reg’s at some plants mean that “extra” cooling is done on the “river water” to get it closer to the “natural” temperatures before it is re-released to the river.
Don’t know if that is a requirement here.
You do lose a lot of cooling capacity at 90 inlet degrees compared to say 70 (nominal) or 45 (winter) inlet temps.