Estimation of Short Crack Growth Rate on PWSCC of Millannealed Alloy 600

Abstract

Understanding of short crack behaviors is essential to construct lifetime prediction models for light water reactor components. There is, however, no established method of directly measuring short crack behaviors. Therefore we need some interpolation or extrapolation technique to precisely evaluate the short crack growth rate. In this study, constant load tests were conducted to investigate a short crack growth rate on primary water stress corrosion cracking (PWSCC) for different mill annealed alloy 600 samples in primary water at 350°C. Maximum crack length was measured for each sample and then divided by relevant test duration to evaluate its crack growth rate. On the other hand, to determine the accurate crack growth rates, a crack growth simulation model which allowed for mechanical effects of grain boundaries on a crack kinked at the grain boundary triple point was developed. With this simulation model, the crack growth processes in the tests were reproduced using a computer and thereby the crack growth rate was evaluated.