Technical specification action requirements for AFW system failures: Method development and application to four PWR plants
- Avaplan Oy, Espoo (Finland)
- Brookhaven National Lab., Upton, NY (United States)
Failures in the auxiliary feedwater (AFW) system of pressurized water reactors (PWRs) are considered to involve substantial risk whether a decision is made to either continue power operation while repair is being done, or to shut down the plant to undertake repairs. Technical specification action requirements usually require immediate plant shutdown in the case of multiple failures in the system (in some cases, immediate repair of one train is required when all AFW trains fail). This paper presents a probabilistic risk assessment-based method to quantitatively evaluate and compare both the risks of continued power operation and of shutting the plant down, given known failures in the system. The method is applied to the AFW system for four different PWRs. Results show that the risk of continued power operation and plant shutdown both are substantial, but the latter is larger than the former over the usual repair time. This was proven for four plants with different designs: two operating Westinghouse plants, one operating Asea-Brown Boveri Combustion Engineering Plant, and one of evolutionary design. The method can be used to analyze individual plant design and to improve AFW action requirements using risk-informed evaluations.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (United States)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 373769
- Report Number(s):
- BNL-NUREG-63222; CONF-960912-32; ON: TI96013472; TRN: 96:024889
- Resource Relation:
- Conference: International topical meeting on probabilistic safety assessment - moving toward risk based regulation, Park City, UT (United States), 29 Sep - 3 Oct 1996; Other Information: PBD: [1996]
- Country of Publication:
- United States
- Language:
- English
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