A4W reactor

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:

• A = Aircraft carrier platform
• 4 = Contractor's fourth core design generation
• W = Westinghouse, the contracted designer

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 MW_th 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]}

• A1B reactor
• Nimitz-class aircraft carrier

• [1] (correcting for the power output from 500 megawatts to 105.)