Pressurized Water Reactor (PWR)

The pressurized water reactor (PWR) and its Russian modification, the VVER (an acronym based on the Russian words vodo-vodjanoj energetičeskij reaktor), is the most common nuclear reactor type in the world. There are about 265 operating PWRs in the world, which is 57% of all reactors. This type of reactor was developed in the USA and its design was later adopted and modified in Russia.

Ceramic pellets made of uranium enriched to 3.5%—5% are used as fuel. They are inserted into fuel rods that are assembled into fuel bundles 4 meters long. The reactor is a steel pressure vessel. The reactor core is 3.5 m high and has a 3 m diameter. This reactor is refueled once a year during reactor shutdown when one-quarter to one-third of the fuel bundles is replaced.

Ordinary water is used as both the moderator and the coolant (also referred to as a LWR, light water reactor). Water circulates in the primary circuit at a pressure of 15.7 MPa and its temperature is 300 °C when exiting the reactor. The thermal energy is transferred in a steam generator generating steam in the secondary circuit that drives a turbine. This type of power plant is a double-circuit power plant.

PWR schematic diagram.

PWR schematic diagram.

Video: View of the Watts Bar (USA) nuclear power plant with PWR type reactors manufactured by Westinghouse.

Nuclear block facility with PWR.

Nuclear block facility with PWR.

The San Onofre nuclear power plant in California is located on the Pacific Ocean coast and has three pressurized water reactors. The first and oldest is being decommissioned; the other two (PWR 1,200) are currently shutdown due to repairs of the steam generators. (Source: © iofoto / stock.adobe.com)
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The Trillo nuclear power plant in Spain is composed of a single PWR 1,000 pressurized water reactor that was commissioned in 1988. The construction of the second block was scrapped in 1983 when there was a change of government. (Source: © Jose / stock.adobe.com)
The Trojan nuclear power plant, constructed in Oregon, USA, was the only power plant with a pressurized water reactor. After 16 years, it was decommissioned due to persistent problems with the steam generators and the resistance of environmentalists. (Source: Wikipedia.org)
The Callaway power plant in Missouri, USA, is a nuclear power plant with a single PWR 1,200 reactor made by Westinghouse. The construction of an additional five, so-called small modular reactors, 200 MW each, is being considered. (Source: © spiritofamerica / stock.adobe.com)
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Some submarines and aircraft carriers are powered by PWR reactors.