Aging and service wear of electric motor-operated valves used in engineered safety-feature systems of nuclear power plants: Aging assessments and monitoring method evaluations
Motor-operated valves (MOVs) are located in almost all plant fluid systems. Their failures have resulted in significant plant maintenance efforts. More important, the operational readiness if nuclear plant safety-related systems has often been affected by MOV degradation and failure. Thus, in recent years MOVs have received considerable attention by the Nuclear Regulatory Commission and the nuclear power industry and were identified as a component for study by the Nuclear Plant Aging Research (NPAR) Program. In support of the NPAR Program, a comprehensive Phase II aging assessment on MOVs was performed by the Oak Ridge National Laboratory (ORNL), and the results of this study are presented in this report. An evaluation of commercially available MOV monitoring methods was carried out, as well as an assessment of other potentially useful techniques. These assessments led to the identification of an effective, nonintrusive, and remote technique, namely, motor current signature analysis (MCSA). The capabilities of monitoring methods (especially MCSA) for detecting changes in operating conditions and MOV degradation were investigated in controlled laboratory tests at ORNL, in situ MOV tests at a neighboring nuclear power plant, and the Gate Valve Flow Interruption Blowdown test in Huntsville, Alabama. 17 refs., 121 figs., 10 tabs.
- Research Organization:
- Nuclear Regulatory Commission, Washington, DC (USA). Div. of Engineering; Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5684053
- Report Number(s):
- NUREG/CR-4234-Vol.2; ORNL-6170/V2; ON: TI89015547
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ENGINEERED SAFETY SYSTEMS
VALVES
NUCLEAR POWER PLANTS
WEAR
AGING
BLOWDOWN
ELECTRIC CURRENTS
ELECTRIC MOTORS
FAILURES
INSPECTION
LUBRICATION
MONITORING
REACTOR SAFETY
RECOMMENDATIONS
CONTROL EQUIPMENT
CURRENTS
EQUIPMENT
FLOW REGULATORS
MOTORS
NUCLEAR FACILITIES
POWER PLANTS
SAFETY
THERMAL POWER PLANTS
220900* - Nuclear Reactor Technology- Reactor Safety
220200 - Nuclear Reactor Technology- Components & Accessories