ABSTRACT
Pressurized water reactors (PWR) are the most common type of nuclear reactors in the world. A PWR core uses light water for both the moderator and the coolant, and it is kept under considerable pressure to prevent it from boiling. The core of a PWR is surrounded by a large, stainless steel container called a pressure vessel. The design pressure for most PWR pressure vessels is 17.25 MPa. In most PWRs, the majority of the pressure vessel is made from low-alloy carbon steel. In a large PWR, the core can contain 200 fuel assemblies arranged in square and/or rectangular arrays. A standard PWR pressure vessel in a 1000 MWE power plant has an inner diameter of approximately 5 m. A modern PWR has an average volumetric power generation rate of about 105 kW/L. In virtually all PWRs, the coolant enters the pressure vessel through a series of inlet nozzles and exits the core through a separate set of outlet nozzles.
