NRC's material aging research program

The US Nuclear Regulatory Commission (NRC) is conducting an aggressive program of research to evaluate the potential effects of plant aging on the integrity and reliability of key systems, structures, and components. The research results contribute to NRC evaluations of a variety of issues related to operating plants and to license renewal. The overall aging research program includes research that addresses materials aging considerations, aging of various electrical and mechanical components, and aging of other structures and components, including the containment and civil structures. This paper focuses on the materials aging research program. The materials aging research program addresses degradation of materials due to the plant operating environment, and the impact of that degradation on the structural integrity of the primary pressure boundary and other critical structures and components, e.g., reactor internals. Additionally, the materials aging research program includes research to evaluate the capabilities of current nondestructive examination systems. The materials aging research program is a vital part of NRC's overall regulatory program. The research provides the technical bases for many of the current-day regulatory decisions, and provides longer term confirmation of broader policies and regulations promulgated based on engineering judgment or limited data sets. The research program also includes some exploratory research wherein research is conducted to better evaluate the safety significance of an issue, or to increase NRC's understanding in an area of potential safety significance