Irradiation-assisted stress corrosion cracking initiation tests have been completed on neutron-irradiated Type 347 stainless steel. The tests are being conducted using a miniature 4-point bend test technique, where the 4-point bend specimens have been extracted from the shanks of baffle-former bolts removed from service in pressurized water reactors. Very little laboratory crack initiation data exists on such material, though many Type 347 baffle-former bolts have failed in service. This small specimen technique allows for multiple tests of material extracted at nearly the same location, allowing for generation of a relatively large amount of data on a well-controlled set of specimens.
This study investigates the effects of stress, water chemistry (KOH vs. LiOH), and irradiation damage on IASCC initiation behavior to allow better understanding of IASCC in Type 347 stainless steel, with the objective of informing aging management practices to help mitigate IASCC. Based on the results to date, no difference in cracking behavior between the two environments is observed.