The A4W reactor is a naval reactor used by the United States Navy to propel warships and generate onboard electricity.
The A4W designation stands for:
These nuclear fission pressurized water reactors (PWRs) were jointly designed by Bettis Atomic Power Laboratory and Knolls Atomic Power Laboratory[1][failed verification] and built by Westinghouse Electric Company. Their reactor cores are expected to operate for about 25 years before refueling is required.[1] The only ships to use these nuclear reactors are the Nimitz-class supercarriers, which have two reactors rated at 550 MWth each. These generate enough steam to produce 140,000 shaft horsepower (104 MW) for each pair of the ship's four shafts[2] – two per propulsion plant – plus approximately 100 MW of electricity.[citation needed]