Component-Based Aging Management Roadmap

Abstract

A key consideration in a nuclear power plant operating life is the identification and tracking of all significant degradation mechanisms not only for life extension of existing plants but also in the design, construction, and commissioning phases of new builds.

During the design phases of today’s existing power plants, the operating life of major components was postulated on known degradation mechanisms using the best knowledge at that time. After decades of operation a much better understanding has been gained through well- established surveillance and monitoring programs. In most cases, what has been revealed are more significant rates of degradation than what was assumed in the original design. In addition, new mechanisms of degradation were discovered, most likely a result of limited knowledge of the effects of long-term operations on material properties.

This paper discusses the degradation mechanisms that should be considered in the design and life extension of safety-related nuclear plant components and suggests a practitioner’s checklist to assist in selecting applicable assessment methodologies and acceptance criteria. The end goal is to provide a component-based roadmap that incorporates modern guidelines and operating experience to produce a plausible list of degradation mechanisms and their associated rates of failure.