Crack Growth Behavior of Irradiated Type 316 SS in Low Dissolved Oxygen Environment

摘要

Cracking susceptibility of austenitic stainless steels is known to be affected by dissolved oxygen (DO) or corrosion potential. In low-DO environments, crack growth rate (CGR) is significantly lower than that in high-DO environments. A strong dependence of CGR on corrosion potential has also been seen in irradiated stainless steels. While it has been shown that reducing the potential can reduce the CGRs of irradiated SSs, some high-dose specimens have shown elevated CGRs even in low potential environments. Thus, it is not clear how irradiation affects the dependence of CGR on corrosion potential. In the present study, a disk-shaped compact tension specimen of Type 316 SS was tested in low-DO environment. The specimen had been irradiated in the BOR-60 reactor to 5 dpa at 320°C. Post-irradiation CGR tests were performed in a low-DO environment. The effect of unloading on crack growth behavior in low-DO environment is discussed.