Repair of Materials Degradation in Light Water Reactor Components

Corrosion induced degradation of material components in the harsh environment of light water reactor can impact reactor reliability, availability, safe operation and eventually life. A possible remedy could be to replace the replaceable components at appropriate moments which may not be economically favorable. Thus there is a need to develop technologies to repair degraded materials. STATEMENT OF HOW THIS PROBLEM IS BEING ADDRESSED Corrosion resistant weld overlays are currently being used to improve the service life of material components made with corrosion prone material. However, the welding technology has serious issues such as dilution and susceptibility to cracking. In this program a novel technology will be developed that will not have the issues associated with the currently utilized welding process. WHAT IS TO BE DONE IN PHASE I In this Phase I STTR work samples appropriate for testing in light water reactor environment will be fabricated and treated with the proposed technology. The relevant performance of the as- treated samples will be evaluated in light water reactor environment. Based on the performance data the feasibility of the proposed technology will be demonstrated. COMMERCIAL APPLICATIONS AND OTHER BENEFITS Given limits on new nuclear reactor builds imposed by economics and industrial capacity, the extended service of the existing fleet will be essential. The proposed technical approach to increase the life of the existing nuclear reactors consists of the repair of the degraded materials. This approach is expected to minimize the new builds with concomitant economic benefit. The proposed technology can be easily utilized in many other non-nuclear commercial applications involving restoration of metallic components having corrosion related damage. KEY WORDS Light water reactor, Stainless steel, Ni base alloys, Stress corrosion cracking, Repair, Welding SUMMARY FOR MEMBERS OF CONGRESS The life of nuclear reactor can be seriously impacted by the degradation of material components in the harsh environment of reactor. The proposed technology is expected to extend the service life of the existing nuclear reactor fleet through damage repair/mitigation of reactors metallic components.