Development of the performance evaluation technique for motor-operated valves

It is required to monitor periodically the operability of the safety-related Motor-Operated Valves(MOVs) in the nuclear power plants. However, acquiring the diagnostic signals at the valve is very difficult and requires a lot of time, effort and expenditure. In this paper, a new method is introduced to remotely evaluate the performance of the MOVs accurately and economically. The technique to be utilized includes electrical measurements and signal processing to estimate the motor torque and the stem thrust, which are recommended as two most effective parameters in diagnosing MOVs by US NRC (Nuclear Regulatory Commission)