Performance of materials in the component cooling water systems of pressurized water reactors

The component cooling water (CCW) system provides cooling water to several important loads throughout the plant under all operating conditions. An aging assessment of CCW systems in pressurized water reactors (PWRs) was conducted as a part of Nuclear Plant Aging Research Program (NPAR) instituted by the U.S. Nuclear Regulatory Commission. This paper presents some of the results on the performance of materials in respect to their application in CCW systems. ALl the CCW system failures reported to the Nuclear Plant Reliability Data System (NPRDS) from January 1988 to June 1990 were reviewed; it is concluded that three of the main contributors to CCW system failures are valves, pumps, and heat exchangers. This study identified the modes and causes for the aging-related failures could be related to the performance of materials. Also, in this paper, the materials used for these components are reviewed, and their aging mechanisms under CCW system conditions are discussed