Obviously there is an interpretation that I hadn't considered. Is the original poster concerned with the total amount of heat being let out into the environment (the word "atmosphere"??) or is the original poster concerned only with heat emitted to atmosphere while pretending that heat emitted in other directions (e.g. seawater or lakewater), but which is nevertheless "there", doesn't exist?
If it's the latter, the question can't be answered, because there are examples of power plants regardless of power source that are cooled *directly* by varying combinations of seawater, lakewater, or atmosphere ... All that heat is going *somewhere*, though. One thing that can be stated is that the fossil fuel plants always have a chimney, and the nuclear plants don't (at least, not for the main power source).