Nuclear plant service water system aging degradation assessment. Volume 2, Phase 2
- Pacific Northwest Lab., Richland, WA (United States)
This report discusses the second phase of the aging assessment of nuclear plant service water systems (SWSs) which was performed by the Pacific Northwest Laboratory (PNL) to support the US Nuclear Regulatory Commission`s (NRC`s) Nuclear Plant Aging Research (NPAR) program. The SWS was selected for study because of its essential role in the mitigation of and recovery from accident scenarios involving the potential for core-melt, and because it is subject to a variety of aging mechanisms. The objectives of the SWS task under the NPAR program are to identify and characterize the principal age-related degradation mechanisms relevant to this system, to assess the impact of aging degradation on operational readiness, and to provide a methodology for the management of aging on the service water aspect of nuclear plant safety. The primary degradation mechanism in the SWSs as stated in the Phase I assessment and confirmed by the analysis in Phase II, is corrosion compounded by biologic and inorganic accumulation. It then follows that the most effective means for mitigating degradation in these systems is to pursue appropriate programs to effectively control the water chemistry properties when possible and to use biocidal agents where necessary. A methodology for producing a complete root-cause analysis was developed as a result of needs identified in the Phase I assessment for a more formal procedure that would lend itself to a generic, standardized approach. It is recommended that this, or a similar methodology, be required as a part of the documentation for corrective maintenance performed on the safety-related portions of SWSs to provide an accurate focus for effective management of aging.
- Research Organization:
- Nuclear Regulatory Commission, Washington, DC (United States); Pacific Northwest Lab., Richland, WA (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 10104007
- Report Number(s):
- NUREG/CR-5379-Vol.2; PNL-7916-Vol.2; ON: TI93003172
- Resource Relation:
- Other Information: PBD: Oct 1992
- Country of Publication:
- United States
- Language:
- English
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