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An automated system for motor-operated valve diagnostics

Journal Article · · Power Engineering; (United States)
OSTI ID:5403794
 [1];  [2]
  1. Imatran Voima Oy (IVO), Helsinki (Finland)
  2. Tennessee Univ., Knoxville, TN (United States)
This paper reports that proper performance of safety and control systems in nuclear power plants depends heavily on motor-operated valve (MOV) reliability. MOV operation also has an impact on plant availability. estimates indicate that valve-related problems in U.S. nuclear power plants result in 20% of unscheduled shutdowns. Predictive MOV maintenance avoids unscheduled outages and exposes unnecessary maintenance procedures that might otherwise take place during scheduled outages. For a predictive maintenance program, it is necessary that the degrading mechanical and electrical behavior of MOVs be detectable at an early stage and that the time to failure is predictable. Present testing practices do not fully address predictive MOV maintenance, but extensive research and development is underway to improve valve monitoring and diagnostics methods. Valve signature analysis appears to be the most promising new surveillance approach. This is a computer-aided testing method for measurement, management and analysis of MOV operation related time waveforms, such as motor current and valve stem thrust. Waveforms then are interpreted manually by a diagnostic expert.
OSTI ID:
5403794
Journal Information:
Power Engineering; (United States), Journal Name: Power Engineering; (United States) Vol. 95:12; ISSN POENA; ISSN 0032-5961
Country of Publication:
United States
Language:
English