Technical Specification action statements requiring shutdown. A risk perspective with application to the RHR/SSW systems of a BWR
- Avaplan Oy, Espoo (Finland)
- Brookhaven National Lab., Upton, NY (United States)
When safety systems fail during power operation, the limiting conditions for operation (LCOs) and associated action statements of technical specifications typically require that the plant be shut down within the limits of allowed outage time (AOT). However, when a system needed to remove decay heat, such as the residual heat removal (RHR) system, is inoperable or degraded, shutting down the plant may not necessarily be preferable, from a risk perspective, to continuing power operation over a usual repair time, giving priority to the repairs. The risk impact of the basic operational alternatives, i.e., continued operation or shutdown, was evaluated for failures in the RHR and standby service water (SSW) systems of a boiling-water reactor (BWR) nuclear power plant. A complete or partial failure of the SSW system fails or degrades not only the RHR system but other front-line safety systems supported by the SSW system. This report presents the methodology to evaluate the risk impact of LCOs and associated AOT; the results of risk evaluation from its application to the RHR and SSW systems of a BWR; the findings from the risk-sensitivity analyses to identify alternative operational policies; and the major insights and recommendations to improve the technical specifications action statements.
- Research Organization:
- Nuclear Regulatory Commission, Washington, DC (United States). Div. of Systems Research; Avaplan Oy, Espoo (Finland); Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (United States)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 10106753
- Report Number(s):
- NUREG/CR-5995; BNL-NUREG-52364; ON: TI94003823; TRN: 94:000885
- Resource Relation:
- Other Information: PBD: Nov 1993
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
BWR TYPE REACTORS
REACTOR COOLING SYSTEMS
AFTER-HEAT REMOVAL
FAILURES
RISK ASSESSMENT
ENGINEERED SAFETY SYSTEMS
SENSITIVITY ANALYSIS
REACTOR SAFETY
HEAT TRANSFER
HYDRAULICS
220900
210100
POWER REACTORS
NONBREEDING
LIGHT-WATER MODERATED
BOILING WATER COOLED