pressurized-water reactor

References

Images

Civaux nuclear power plant, western France

Cutaway diagram of a nuclear reactor core showing fuel assemblies inside a cylindrical reactor pressure vessel, with labeled components including control rod drive assembly, upper and lower grid plates, and a human figure for scale.

Cutaway diagram of a pressurized-water nuclear reactor showing labeled parts including control rods, control rod drive mechanism, fuel assemblies, coolant inlets and outlets, thermal shields, and baffle plate.

Diagram of a nuclear fuel assembly for a pressurized-water reactor, showing a vertical bundle of parallel fuel rods held by grid spacers, with control rods inserted among them, and labeled top and bottom nozzles.

Labeled diagram showing the process of a nuclear power plant with a pressurized-water reactor. Water circulates through the reactor core, heats to produce steam in a steam generator, which drives a turbine connected to an electric generator. Steam is then cooled in a condenser using water from a cooling tower, which releases nonradioactive water vapor. Control rods, pumps, and transmission lines are also indicated.

Diagram showing three types of power cycles in nuclear power plants: a single-loop cycle with one closed water circuit from reactor to turbine, a two-loop cycle with separate primary and secondary loops connected by a steam generator, and a three-loop cycle adding a tertiary loop and heat exchanger for extra separation between the reactor and turbine systems.

pressurized-water reactor

nuclear energy

Also known as: PWR

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Last updated

July 13, 2026

Quick Summary

Civaux nuclear power plant, western France — Civaux nuclear power plant, western France The Civaux nuclear power plant, using pressurized-water reactors, near Poitiers, western France.

A pressurized-water reactor (PWR) is a type of light-water reactor used for nuclear power generation. In a PWR, water under high pressure and temperature circulates through the reactor core, absorbing heat. This heated water then flows to a steam generator, where it transfers its heat to a secondary loop of water. The heat causes the water in the secondary loop to boil and produce steam, which drives turbines to generate electricity. PWRs operate at higher pressures and temperatures than boiling-water reactors (BWRs), leading to greater thermodynamic efficiency, though their pressure vessels are thicker.12

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nuclear reactor
PWRs and BWRs
…are two basic types: the pressurized-water reactor (PWR) and the boiling-water reactor (BWR). In the PWR, water at high pressure and temperature removes heat from the core and is transported to a steam generator. There the heat from the primary loop is transferred to a lower-pressure secondary loop also containing…
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…are two basic types: the pressurized-water reactor (PWR) and the boiling-water reactor (BWR). In the PWR, water at high pressure and temperature removes heat from the core and is transported to a steam generator. There the heat from the primary loop is transferred to a lower-pressure secondary loop also containing…
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nuclear engineering
Navy nuclear propulsion
…ships are similar to commercial pressurized-water reactors, except they are smaller and more rugged in order to withstand battle conditions such as torpedoes or depth charges or extreme loads such as the catapulting of jets off a carrier deck. Many of the functions carried out by nuclear engineers in working…
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…ships are similar to commercial pressurized-water reactors, except they are smaller and more rugged in order to withstand battle conditions such as torpedoes or depth charges or extreme loads such as the catapulting of jets off a carrier deck. Many of the functions carried out by nuclear engineers in working…
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nuclear power
World nuclear power
…types of power reactors are pressurized water reactors (PWRs) and boiling water reactors (BWRs), both of which are categorized as light water reactors (LWRs) because they use ordinary (light) water as a moderator and coolant. LWRs make up more than 80 percent of the world’s nuclear reactors, and more than…
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…types of power reactors are pressurized water reactors (PWRs) and boiling water reactors (BWRs), both of which are categorized as light water reactors (LWRs) because they use ordinary (light) water as a moderator and coolant. LWRs make up more than 80 percent of the world’s nuclear reactors, and more than…
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submarine
Reactors
…types of marine nuclear reactor: pressurized-water, natural-circulation, and liquid-metal.
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…types of marine nuclear reactor: pressurized-water, natural-circulation, and liquid-metal.
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