Refueling and overhaul

To start ROH, operating procedures are used to shut down and cool down the propulsion power plant to bring it to desired temperatures, pressures, and other[further explanation needed] conditions.

During the ROH, ship's Navy crew stand shutdown watches, and civilian shipyard workers do much of the repair, maintenance, and installation work.

Land-based naval reactor prototype plants have also undergone similar refueling and overhauls, not at a shipyard but at whatever facility they are located.

Because it is so radioactive, removing a core with spent nuclear fuel from a reactor requires elaborate radiological handling precautions.

All materials that came in contact with the critical core, including the internal surfaces and coolant water, are considered radioactively contaminated and require special radiological handling and disposal precautions.

The overhaul commonly includes extensive maintenance and renovation work and checks of various systems and equipment aboard the ship.

At the same time a ship is refueled, it is given a complex overhaul in which broken, worn or obsolete parts are repaired or replaced and systems are modernized.

Given the size of an aircraft carrier and the number of systems and subsystems it has, an RCOH is extremely complex, costly (several billion dollars), and time-consuming.