Light water reactor
Collective term for all H2O moderated and
cooled reactors; See 'boiling water
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.