PWR — Pressurized Water Reactor
The most widely deployed reactor type globally. Water is kept under high pressure (~155 bar) to prevent boiling in the primary circuit, then transfers heat via steam generators to a secondary loop that drives turbines. Light water serves as both coolant and moderator.
Key Stats
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PWR — Pressurized Water Reactor
Design Overview
The most widely deployed reactor type globally. Water is kept under high pressure (~155 bar) to prevent boiling in the primary circuit, then transfers heat via steam generators to a secondary loop that drives turbines. Light water serves as both coolant and moderator.
Key Specifications
Typical output: 900–1,800 MWe. Operating pressure: ~155 bar. Coolant temp: ~315°C outlet. Fuel: Low-enriched uranium (LEU) oxide pellets, ~3–5% U-235. Refueling cycle: 12–24 months.
Who Builds It
Westinghouse (AP1000), Framatome/EDF (EPR), KEPCO (APR-1400), Rosatom (VVER-1200), CNNC (HPR-1000/Hualong One)
Where It's Deployed
USA, France, China, South Korea, Russia, Japan, UK, and most nuclear nations
Advantages
Proven technology with 60+ years of operational data. High reliability, strong safety record, well-understood fuel cycle.
Disadvantages
Complex two-loop system. High capital cost. Requires large volumes of cooling water. Low thermodynamic efficiency (~33%).
Technology reference note · Second Atomic Age Nuclear Wiki Last updated: 2026-05-10
Sources
- IAEA - Nuclear Power Reactors [UNVERIFIED] — Overview of nuclear reactor technologies, including PWRs, from the International Atomic Energy Agency.
- World Nuclear Association - Pressurized Water Reactors [UNVERIFIED] — Detailed technical and operational information on PWRs.
- Wikipedia - Pressurized Water Reactor — General encyclopedia entry covering design, history, and deployment of PWRs.
- Westinghouse - AP1000 — Information on the AP1000, a modern PWR design by a leading vendor.
Sources (1)
Related Notes
SMR — Small Modular Reactor
Factory-fabricated reactors typically under 300 MWe designed for modular deployment. Various designs span PWR, BWR, molten salt, high-temperature gas, and fast neutron variants. Most are in licensing or early construction phases as of 2025.
technologiesGen IV HTGR — Generation IV High-Temperature Gas-Cooled Reactor
Uses helium as coolant and graphite as moderator. Operates at very high temperatures (750–950°C outlet), enabling industrial process heat, hydrogen production, and high thermodynamic efficiency. TRISO fuel particles provide inherent safety — fuel cannot melt.
technologiesCANDU — Canada Deuterium Uranium Reactor
Uses heavy water (D₂O) as both moderator and coolant under pressure. Unique ability to use natural uranium fuel (no enrichment needed). Can be refueled on-line without shutdown.
technologiesGen IV SFR — Generation IV Sodium-Cooled Fast Reactor
Uses liquid sodium coolant (no moderator) enabling fast neutron spectrum. Can breed plutonium from U-238 (breeder reactor) or burn actinide waste. Sodium coolant enables high operating temperatures at low pressure.
technologiesRBMK — Reactor Bolshoy Moshchnosti Kanalnyy (High-Power Channel-Type Reactor)
Soviet-era graphite-moderated, light-water-cooled channel reactor. No containment vessel. Positive void coefficient at low power created dangerous instability — root cause of the Chernobyl disaster. All remaining units are in Russia.
technologiesVVER — Vodo-Vodyanoy Energetichesky Reaktor (Water-Water Power Reactor)
Russian pressurized water reactor design, analogous to Western PWRs but with distinct engineering choices: hexagonal fuel assemblies, horizontal steam generators, and no liner in the pressure vessel. Modern VVER-1200 (Gen III+) features passive safety systems.