Intergranular environmentally assisted cracking of Alloy 182 weld metal in simulated normal water chemistry of boiling water reactor

Following characterization of grain boundaries in Alloy 182 weld metal, intergranular environmentally assisted cracking (IGEAC) growth behavior of the alloy in simulated normal water chemistry (NWC) of boiling water reactor (BWR) was tested by employing a crack growth rate test. The grain boundary was found consist of about 72% random boundaries, 21% low-angle boundaries and a few coincident boundaries. The correlation between the grain boundary characters and IGEAC was discussed. Based on the IGEAC growth rates obtained in the test and evaluations of the crack tip strain rate, the parameter of the slip-dissolution/oxidation model that embodies the kinetics of oxidation/repassivation in the crack-tip environment of Alloy 182 in BWR-NWC was quantitatively determined.