EFFECT OF SPECIMEN SIZE AND PERCENT ENGAGEMENT ON SCC BEHAVIOR OF ALLOY 82 IN BWR ENVIRONMENTS

摘要

Ni-base Alloy 82 weld metal is widely used instructural components in BWRs. With its higher SCCresistance in BWR environments than Alloys 182 and 132,fewer crack incidents have been experienced in operatingBWR units. But recent crack incidents led to a commonrecognition: it is appropriate to develop an SCC growthrate disposition curve for Alloy 82 in BWR environmentsin order to properly evaluate the impact of possiblecracks in Alloy 82 on plant safety. Continued efforts havebeen made to properly evaluate the SCC growth behaviorof Ni-base weld metals in both PWR and BWRenvironments. However, some ambiguities specific tothose materials still remain in evaluating the relevance ofSCC data.In this study, considerations have been made on thesample size and the allowable K in an attempt toaccumulate SCC growth rate data of Alloy 82 in BWRenvironments at elevated K levels which is one of theimportant missing pieces in the disposition curvedevelopment.