Welding of Irradiated Steels: State of the Art, Near-Term Needs, and Remaining Technical Gaps

Abstract

Aging of LWRs and HWRs leads to degradation of critical components, which requires repairs if the plant is to continue producing power. Repair techniques will often employ welding, which can be challenged by irradiation-induced changes in the materials requiring repair. This paper reviews the state of the art of welding irradiated materials, discusses examples of repairs that will be needed in the near term, and identifies technical gaps that still remain in the implementation of available welding repair technologies. Practical examples will be presented that are relevant to BWR, PWR, and CANDU designs (for example, core shrouds, core barrel welds, and calandria relief ducts). Technical challenges that are design-specific will be distinguished from those that are design- agnostic, identifying areas where collaboration is most productive.