STRESS CORROSION CRACK INITIATION SUSCEPTIBILITY OF IRRADIATED AUSTENITIC STAINLESS STEELS

摘要

The susceptibility of neutron irradiated austenitic stainless steels to the initiation of irradiation-assisted stress corrosion cracking (IASCC) was assessed. Solution annealed (SA), high purity (HP) type 304 stainless steel with and without additions of Mo and Si, and HP type 316L +Hf were strained by constant extension rate testing (CERT) in simulated 288°C BWR NWC at a rate of 3.5 × 10~(-7)/s. CERT test data and fracture analysis showed that IASCC susceptibility increased in order of HP304, HP304+Mo, HP316L+Hf, and HP304+Si. This trend was also observed when comparing fracture surfaces of the same alloys tested by CERT in BWR NWC after proton irradiation. Differences were insignificant among reported crack growth rate (CGR) values for the same neutron irradiated alloys, and no connection between crack initiation and CGR was confirmed from the alloys tested.