A Regulatory Analysis and Perspective Regarding Degradation of Materials in Light Water Reactors

Materials currently used in nuclear power plants are reliable and are generally resistant to environmental degradation.  However, occurrences of environmental degradation have been observed as the current fleet of reactors age.  Degradation of materials by mechanisms such as Intergranular Stress Corrosion Cracking (IGSCC) and Primary Water Stress Corrosion Cracking (PWSCC) create both technical and regulatory issues.  This paper provides an overview of the most significant technical and regulatory issues associated with materials degradation from the perspective of the Nuclear Regulatory Commission.  It also addresses the need for additional research to support regulation.