Understanding the short crack behavior is important to construct lifetime prediction models for light water reactor components. There are, however, limitted methods 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 the primary water stress corrosion cracking (PWSCC) short crack growth rate on for different mill annealed alloy 600 samples 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 more 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 rate, when a crack grows along grain boundaries and affected by these, was evaluated. Keywords: mill annealed alloy 600, PWSCC, short crack, estimation of crack growth rate, weibull distribution, crack growth simulation