Effects of dissolved hydrogen on IASCC behavior

Uniaxial constant load SCC (Stress Corrosion Cracking) tests at stress levels of 376 to 752 MPa, corresponding to normalized stress of 0.4 to 0.8 {sigma}{sub y} ({sigma}{sub y}: yield strength) were conducted on cold-worked SUS316 stainless steel specimens irradiated to 38 dpa in 320 C simulated PWR primary water containing 500 ppm B and 2 ppm Li while changing dissolved hydrogen (DH) concentration of 0.5 ppm (5 cc/kg-H{sub 2}O) and 4 ppm (45 cc/kg-H{sub 2}O). Failure - non failure border stress was identified to be (0.7 - 0.8)*{sigma}{sub y} at 0.5 ppm, and (0.4 - 0.5)*{sigma}{sub y} at 4 ppm. It was confirmed from these findings and the previously obtained border stress of (0.5 - 0.6)*{sigma}{sub y} at 2.8 ppm (30 cc/kg-H{sub 2}O) that the border stress for IASCC initiation decreases as the DH concentration increases. (authors)