Comment by wombatpm

Water used for nuclear reactor cooling can only be returned to the environment if its temperature is within 0.5 deg F of the local source temperature. I live near a facility that is on the river with several man made cooling lakes. During the winter, there is constant fog and ice by the roads. So much so, that the road to the facility itself has covered bridge crossing one of the lakes.

During drought, the capacity of the plant is reduced due to lack of cooling capacity.

And remember, the reactor is used to generate high pressure steam which produces electricity, hot water and low grade steam. Even with high efficiency gas turbines and heat integration, there is a significant amount of steam that needs to be condensed before it can be feed back into the reactor.