Stress corrosion cracking in the heat affected zone of a stainless steel 308L-316L weld joint in primary water

Stress corrosion cracking (SCC) in the heat affected zone (HAZ) of a stainless steel 308L-316L weld joint in primary water of pressurized water reactor was investigated. Stress corrosion crack growth in the HAZ was observed in off-normal primary water chemistry with dissolved oxygen, but not in normal primary water chemistry with dissolved hydrogen. This suggests that it is unlikely a stress corrosion crack propagating in the HAZ could reach the fusion boundary and penetrate into the weld metal under normal primary water chemistry conditions. Microstructure analysis of the crack tip suggests that the SCC follows the slip-oxidation mechanism.