SCC Initiation Behavior of Alloy 182 in PWR Primary Water

摘要

SCC initiation behavior of 15% CF specimens cut from four different alloy 182 weldments was investigated in 360 °C simulated PWR primary water under constant load at the yield stress using direct current potential drop to perform in situ monitoring of SCC initiation time. Within each weldment, one or more specimens underwent SCC initiation within 24 h of reaching full load while some specimens had much longer initiation times, in a few cases exceeding 2500 h. Detailed examinations were conducted on these specimens with a focus on different microstructural features such as preexisting defects, grain orientation and second phases, highlighting an important role of microstructure in crack initiation of alloy 182.