Steam generator (3D model).

A heat exchanger, used to convert feedwater into steam from heat produced in a thermal power plant. The heated coolant (usually ordinary water, but it can also be molten sodium, lead, or heavy water) passes through many thin tubes through a steam generator, where it transfers its heat to water at normal pressure. The water boils and produces steam, which is stripped of water droplets (dried) at the top of the steam generator and fed on to the turbine.