Abstract
Stress corrosion cracking (SCC) tests were conducted under the supercritical-water cooled power reactor (SCPR) coolant conditions, which are predicted to consist of wide temperature range, extremely high pressure, and high dosage of neutron irradiation. This paper describes the results of SCC tests for austenitic stainless steels and a Ni base alloy. The susceptibility to intergranular stress corrosion cracking (IGSCC) was evaluated by slow strain rate tests (SSRTs), which were performed using a supercritical-water (SCW) test loop. The results for sensitized Type 304 SS indicated that the SCC susceptibility decreased with increasing temperature. The upper limit temperature of SCC susceptibility for sensitized type 304 SS existed at around 400°C, above which IGSCC did not occur in oxygenated supercritical water. No IGSCC of Type 316L SS and Alloy 600 was exhibited in fracture surface under SCPR conditions, even though small cracks were observed in side surface.