Testing and analysis of MOV

Motor Operated Valves (MOVs) are vital components of Nuclear Power Plants, as they facilitate remote and quick operation of plant process systems. MOVs consist primarily of two parts- the actuator and the valve. The motor operator (actuator) provides the torque required for closing/opening of the valve. Limit switch (LS) and Torque switch (TS) are incorporated to control valve operations. Failure of any of the components of the MOV can render it inoperable resulting in impairment of safety functions and increased plant downtime for repairs. Therefore, inspection and testing of these valves for timely detection of degradation is of paramount importance. This paper focuses on various examinations, inspections and testings of MOVs during in-manufacture, pre-service and in-service stages. An effort is also made to highlight the condition monitoring of MOVs. (author)