Evaluation of the mitigation effect of hydrogen water chemistry in BWRs on the low-frequency corrosion fatigue crack growth in low-alloy steels

The mitigation effect of hydrogen water chemistry (HWC) on the low-frequency corrosion fatigue crack growth behaviour of low-alloy steels was investigated under those critical boiling water reactor (BWR) system conditions, where fast corrosion fatigue crack growth significantly above the ASME XI 'wet' reference fatigue crack growth curves was observed under normal water chemistry conditions (NWC). The experiments were performed under simulated BWR conditions at temperatures of 250, 274 or 288 °C. Modern high-temperature water loops, on-line crack growth monitoring (DCPD) and fractographical analysis by scanning electron microscope were used to quantify the cracking response. HWC resulted in a significant drop of low-frequency corrosion fatigue crack growth rates by at least one order of magnitude with respect to NWC conditions and is therefore a promising and powerful mitigation method.