Definition of boiling-water reactor in US English:

boiling-water reactor

(also BWR)


  • A nuclear reactor in which the fuel is uranium oxide clad in zircaloy and the coolant and moderator is water, which is boiled to produce steam for driving turbines.

    • ‘Activists said that the reactor, an advanced boiling-water reactor, was used by a nuclear power plant in Japan, where several nuclear accidents have occurred.’
    • ‘Light-water reactors are classified as either pressurized-water reactors or boiling-water reactors, depending on whether the coolant water is kept under pressure or not.’
    • ‘Two advanced boiling-water reactors are being built in Japan.’
    • ‘RBMK-reactors (pressure-tube boiling-water reactors), which are cooled with light water and moderated with graphite, are now less commonly operated in some former Soviet Union bloc countries.’
    • ‘The fraction of the reactor's fuel core replaced during refueling is typically one-fourth for a boiling-water reactor and one-third for a pressurized-water reactor.’


boiling-water reactor

/ˈwädər rēˈaktər/