Aging assessment of component cooling water systems in pressurized water reactors

A two-phase aging analysis of component cooling water (CCW) systems in pressurized water reactors (PWRs) was performed. In phase 1, the effects of aging on the CCW system are characterized, and the predominant failure modes, aging mechanisms, and components susceptible to aging degradation were identified. Failure rate trends were examined, and their effect on time-dependent system availability was investigated. In phase 2, which is the subject of this report, the methods used to manage aging degradation in the CCW system were studied. Information was collected and analyzed on inspection, surveillance, monitoring, and maintenance techniques from a survey of operating PWRs. The results are presented herein. Advanced techniques that may help detect and mitigate aging degradation also are included. A detailed examination of the materials of construction and their relationship to various aging mechanisms is discussed. In addition, the various standards, codes, and regulatory requirements that govern the design, construction, and operation of the CCW system were investigated. Recommendations to better manage aging degradation in component cooling water system are discussed.