Pressurised Water Reactor.
In a PWR, the coolant is pumped under high pressure to the reactor core where it is heated by nuclear fission. This heated, high-pressure water circulates through a steam generator where it transfers its thermal energy to a lower-pressure secondary system where steam is generated to drive a turbine. The core outlet temperature of the coolant is at about 330°C and the pressure is about 15.5 MPa. These reactors represent half of the world’s installed capacity.