Pressurised Water Reactor versus Boiling Water Reactor

Both Pressurised Water Reactor (PWR) and Boiling Water Reactor (BWR) use enriched Uranium as fuel and water as both coolant and moderator, to slow down neutrons. The major difference between these two types of reactors is PWR has water at over 300°C under pressure in its primary cooling/heat transfer circuit, and generates steam in a secondary circuit while BWR makes steam in the primary circuit above the reactor core.

Pressurised Water Reactors

The primary circuit to take reactor heat by water under pressure to the secondary circuit
The secondary circuit to raise steam for the turbine, steam condensed as water is returned to the steam generator

Boiling Water Reactors


A single circuit to take reactor heat and raise steam for the turbine
Steam condensed as water is returned to the reactor