Reactor pressure vessel

A reactor pressure vessel (RPV) in a nuclear power plant is the pressure vessel containing the nuclear reactor coolant, core shroud, and the reactor core. A reactor pressure vessel (RPV) in a nuclear power plant is the pressure vessel containing the nuclear reactor coolant, core shroud, and the reactor core. Not all power reactors have a reactor pressure vessel. Power reactors are generally classified by the type of coolant rather than by the configuration of the reactor vessel used to contain the coolant. The classifications are: Of the main classes of reactor with a pressure vessel, the pressurized water reactor is unique in that the pressure vessel suffers significant neutron irradiation (called fluence) during operation, and may become brittle over time as a result. In particular, the larger pressure vessel of the boiling water reactor is better shielded from the neutron flux, so although more expensive to manufacture in the first place because of this extra size, it has an advantage in not needing annealing to extend its life. Annealing of pressurized water reactor vessels to extend their working life is a complex and high-value technology being actively developed by both nuclear service providers (AREVA) and operators of pressurized water reactors.