A Pressurized Water Reactor (PWR) is a type of nuclear reactor that uses water as both a coolant and a neutron moderator. In a PWR, water is kept under high pressure to prevent it from boiling, even at high temperatures. This pressurized water circulates through the reactor core, where it absorbs heat generated from nuclear fission of uranium fuel. The heated water then flows to a steam generator, where it transfers its heat to a secondary water loop, producing steam. This steam drives a turbine connected to a generator, producing electricity. PWRs are widely used in commercial nuclear power plants around the world due to their reliability and safety features.