The A1W reactor is a prototype nuclear reactor used by the United States Navy to provide electricity generation and propulsion on warships. The A1W designation stands for: * A = Aircraft carrier platform * 1 = First generation core designed by the contractor * W = Westinghouse was the contracted designer This nuclear reactor was the prototype for the A2W reactor used in the world's first nuclear-powered aircraft carrier, the USS Enterprise (CVN-65). The A1W prototype was used to train nuclear-qualified sailors for almost 34 years until its reactor plants were shut down on January 26, 1994.