Light water reactor

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Collective term for all H₂O moderated and cooled reactors; See 'boiling water reactor', 'pressurized water reactor' (H₂O = "light" water, in contrast to D₂O = "heavy" water). The light water reactor produces heat by controlled nuclear fission. The reactor core consisting of fuel and control elements is enclosed by a water-filled steel pressure vessel. The heat generated by the fission heats the water which evaporates in the pressure vessel in a boiling water reactor but, in the pressurized water reactor, the steam evaporates in a steam generator of a secondary circuit. The steam energy is converted into rotary motion of the turbine to which a generator for the generation of electricity is connected. After flowing through the turbine, the steam condenses into water in the condenser and is recirculated to the pressure vessel or steam generator. The water required to cool the condenser is taken from a river and refed into the river in warmed condition or the heat is dissipated via a cooling tower into the atmosphere.

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