Heating of water by nuclear power stations

Certain unresolved difficulties lead at the moment to a preference for wet coolants, where the latent heat of water enables power to be evacuated with an air flow of 30,000 m3/s. Most of the calories, instead of heating the surrounding air, convert the water into steam. In the wet coolant almost 70% of the heat transfer takes place by evaporation: the air is heated and takes up water vapour as it passes through the coolant; at the outlet the water vapour often condenses and produces a more or less heavy visible plume. The air flow in the coolant is obtained either by means of a high stack which produces a so-called natural draft by chimney effect, or by the use of ventilators which avoid the need to built stacks but sometimes raise awkward acoustical problems. The following will concentrate exclusively on wet coolants with natural draft