Two reactors drive two turbine generators and then three electric motors that power the propellers, producing a propulsive power of 60 MW. The replenishment cycle is quoted at 6-7 years, or with a capacity factor of 65%, the replenishment is every 7-10 years, the revision at 20 years, for a lifespan of 60 years. In the United States Navy, refueling and reconditioning (ROH) refers to a lengthy reconditioning process or procedure performed on nuclear-powered naval vessels, involving the replacement of spent nuclear fuel with new fuel and general maintenance repair, refurbishment, and often modernization of the entire ship. In theory, such a process could simply involve just refueling or just a review, but in practice, nuclear refueling is always combined with a review.
An ROH usually takes one to two years for submarines and up to almost three years for an aircraft carrier, made in a naval shipyard. Time periods between RoHS on a ship have historically varied from approximately 5 to 20 years (for submarines) to 25 years (for Nimitz class aircraft carriers). For modern submarines and aircraft carriers, RoHs are generally carried out about half their useful life. There are also shorter maintenance arrangements called availability for ships periodically in shipyards.
A particularly lengthy refueling, maintenance and modernization process for a nuclear aircraft carrier can last up to almost three years and is known as a refueling complex (RCOH) overhaul. Because it is so radioactive, removing a core with spent nuclear fuel from a reactor requires elaborate radiological handling precautions. As the ship is ready, towards the end of the ROH, the power plant heats up or restarts to the desired operating temperature and pressure so that it can start up when it is ready. Once a reactor core has become critical, meaning that it has been used during the operation of a reactor, highly radioactive nuclear fission products have formed in the core, and the core has become highly radioactive.
Complex Replenishment and Overhaul (RCOH) is a process for refueling and upgrading nuclear-powered aircraft carriers in the U.S. UU. The reactors aboard the George Washington contain enough nuclear fuel to fully power the ship and all its needs on board for approximately 20 years. Refueling the USS George Washington is a very costly task because the aircraft carrier is powered by two A4W nuclear reactors.
These two reactors, according to The Encyclopedia of Ships, drive four propellers that produce a maximum speed of 30 knots. The nuclear reactors that power some aircraft carriers typically consume their nuclear fuel at about half of their desired 50-year lifespan. In a nuclear-powered ship, nuclear fuel is essentially a solid inside the core of a reactor that is inside the ship's nuclear reactor. Refueling involves taking the spent core out of the reactor and putting in a new core with new nuclear fuel.
Naval onshore reactor prototype plants have also undergone similar refueling and overhauls, not at a shipyard, but at whatever facility they are in.