Aging effects in component failure and downtime data and impacts on plant risk

The status results of two related projects are described in this presentation. The first part of the presentation, corresponding to the first project, is entitled Evaluation of Aging Effects in Component Failure and Downtime Data. The second part of the presentation, corresponding to the second project, is entitled Evaluation of Core Melt Frequency Effects Due to Component Aging and Maintenance. The work performed to evaluate aging effects in component failure and maintenance downtime data has resulted in an analysis procedure and personal computer software being developed. The procedure has been applied to diesel data circuit breaker data, controller data and starter data. Significant aging effects have been preliminarily identified. The work performed to evaluate core melt frequency impacts from component aging has resulted in approaches and software being developed. The applications to two NUREG 1150 probabilistic risk assessments show the dramatic effects aging and different maintenance programs can have. The detailed contributions which are produced allows the aging contributors to be effectively prioritized. Multiple aging effects are often the dominant contributors. These results are also preliminary and are under review