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Boiling Water Reactor (BWR)

Light Water family · Generation II / III+ · Commercial

Settled science

Water boils directly in the core and the steam drives the turbine — simpler than a PWR but the turbine loop is mildly radioactive.

How it works — schematic
🚧 Diagram in progress
Containment Reactor vessel Core Steam Turbine G ⚡ grid Condenser
Direct cycle — steam is made right in the core.

Simplified schematic for orientation, not an engineering drawing — we're actively refining these for accuracy.

Key specs

Coolant
Boiling water
Moderator
Water
Fuel
Low-enriched UO₂
Spectrum
Thermal
Outlet temp
~285 °C
Status
Commercial

Real-world examples

  • • Fukushima Daiichi (older BWRs)
  • • GE BWRX-300 (SMR successor)
Strengths
  • + Simpler, lower pressure than PWR
  • + Direct cycle efficiency
Trade-offs
  • – Radioactive turbine loop
  • – Complex in-core flow