IASCC Initiation in Highly Irradiated Stainless Steels under Uniaxial Constant Load Conditions

Uniaxial constant load tests in 320°C simulated PWR primary water were conducted for cold-worked SUS316 stainless steels irradiated to 30–73 dpa. IASCC failure occurred within ∼100 h at applied stresses of 470–752MPa. The time-to-failure decreased with increasing neutron dose and applied stress. A compilation of literature data obtained using ring compression tests indicated that the results of ring compression tests for IASCC initiation were similar to those of uniaxial tensile tests. The border stress for IASCC failure decreased with increasing dose and saturated at ∼400 MPa at ∼30 dpa. This behavior was similar to that of radiation-induced material changes, such as hardness or grain boundary segregation.