Thermal overload protection for electric motors on safety-related motor-operated valves: Generic Issue II. E. 6. 1
NRC regulatory positions, as stated in Regulatory Guide 1.106, Revision 1, have been identified by the Office for Analysis and Evaluation of Operational Data (AEOD) as potential contributors to valve motor burnout. AEOD is particularly concerned about the allowed policy of bypassing thermal overload devices during normal or accident conditions. Regulatory Guide 1.106 favors compromising the function of thermal overload devices in favor of completing the safety-related action of valves. The purpose of this study was to determine if the guidance contained in Regulatory Guide 1.106 is appropriate and, if not, to recommend the necessary changes. This report describes thermal overload devices commonly used to protect safety-related valve operator motors. The regulatory guidelines stated in Regulatory Guide 1.106 along with the limitations of thermal overload protection are discussed. Supplements and alternatives to thermal overload protection are also described. Findings and conclusions of several AEOD reports are discussed. Information obtained from the standard review plan, standard technical specifications, technical specifications from representative plants, and several papers are cited.
- Research Organization:
- US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Div. of Engineering
- OSTI ID:
- 6913252
- Report Number(s):
- NUREG-1296; ON: TI88012943; TRN: 88-027760
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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29 ENERGY PLANNING
POLICY AND ECONOMY
NUCLEAR POWER PLANTS
EQUIPMENT PROTECTION DEVICES
VALVES
DESIGN
ENGINEERED SAFETY SYSTEMS
MOTORS
REACTOR SAFETY
RECOMMENDATIONS
REGULATIONS
THERMAL STRESSES
US NRC
CONTROL EQUIPMENT
EQUIPMENT
FLOW REGULATORS
NATIONAL ORGANIZATIONS
NUCLEAR FACILITIES
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SAFETY
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THERMAL POWER PLANTS
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