Radiation-induced material changes and susceptibility to intergranular failure of light-water-reactor core internals

Current understanding of radiation-induced material changes that occur in l ight-water-reactor (LWR) core components is critically reviewed and linked to intergranular failure processes. Although the basic science of radiation damage processes in metals is reasonably well established, accurate predic tion of microstructures, microchemistries and mechanical property changes i n complex stainless alloys during irradiation at LWR temperatures is not po ssible at present. Mechanistic understanding of these radiation-induced cha nges in commercial alloys is considered to be of paramount importance for t he mitigation of the intergranular environmental cracking that occurs in se rvice. Fundamental research is needed to define defect-solute interactions and microstructural evolution at intermediate temperatures and dose rates p ertinent to LWRs where transient effects often dominate behavior. In additi on, it is essential that radiation effects on matrix microstructure and mic rochemistry and grain boundary microchemistry be understood. Finally, a str onger emphasis on accurately quantifying radiation effects on environmental cracking mechanisms and kinetics is needed. (C) 1999 Published by Elsevier Science B.V. All rights reserved.