I just looked this up–diesel locomtive engines can be several MW and clearly convert most of their fuel into waste heat, yet they are air-cooled, that is their radiators are. Why could not a FF reactor just have an air-cooled radiator? No water flow is needed, in fact you might just have the helium in the radiator. This would be an environmental gain.
I can see you can’t just dump the heat in the sewer. In NYC just 1.5 GW of cooling would raise the water temperature to 100F.
