Boiling water reactor
Also written BWR
Light water boils directly in the core and the steam drives the turbine: one loop instead of two, simpler but with an activated steam circuit. Water is again both coolant and moderator, and fuel is low-enriched uranium oxide, as in a PWR.
In the record: 4 companies, 0 laboratories and programmes, 3 reactors and 3 reactor designs.
Related approaches
Broader: Water-cooled
Companies 4
Reactors 3
Operating reactors first, then those being built or planned, then those shut down, suspended or cancelled.
- VK-50 Operating Research Institute of Atomic Reactors · RU · 1 measurement
- Darlington New Nuclear Project Unit 1 Under construction Ontario Power Generation · CA
- Clinch River Nuclear Site Unit 1 Planned Tennessee Valley Authority · US · 1 measurement
Reactor designs 3
Size class is worked out from the electrical output of one unit: up to 10 MWe is a microreactor, up to 300 MWe a small modular reactor. A design with no stated output is not classed.
| Design | Developer | Electrical output per unit | Size class | Licensing stage |
|---|---|---|---|---|
| Advanced Boiling Water Reactor (ABWR) ABWR | GE Vernova Hitachi Nuclear Energy | 1,350 to 1,460 MWe claimed | Large reactor | No milestone recorded |
| BWRX-300 | GE Vernova Hitachi Nuclear Energy | 300 MWe planned | Small modular reactor | Construction permit issued for one plant: CNSC licence to construct one BWRX-300 at the Darlington New Nuclear Project · Canadian Nuclear Safety Commission · 2025-04-04 |
| Economic Simplified Boiling Water Reactor (ESBWR) ESBWR | GE Vernova Hitachi Nuclear Energy | 1,520 MWe planned | Large reactor | No milestone recorded |
Measurements
2 reactors using this approach carry 2 measurements: 1 claimed, 1 planned. The values, each with its status and source, are on the benchmark and on each device's page. Most measured: VK-50 (1), Clinch River Nuclear Site Unit 1 (1).
Guides
- Reactor types explained The three questions that classify any fission reactor, and how pressurised water, boiling water, heavy water, gas-cooled, salt-cooled, molten-salt, sodium, lead and heat-pipe reactors each answer them.
Boiling water reactor in the glossary · Fission overview · All approaches