Studies of Crack Growth Rates in Irradiated Stainless Steel Control Blade Materials Tested in High Temperature Water

摘要

Test program was conducted using CRB materials taken from BWRs and covering a fluence range of 2×10~(21) to 4×10~(21)n/cm~2 In this program. Irradiated tests conducted in good water chemistry: 1. 0.12 μS/cm in NWC and 0.09 μS/cm in HWC; 2. All tests exhibited a rapid change in ECP with water chemistry changes. HWC found to mitigate IASCC in stainless steel only at low and moderate K levels: little effect at higher K values: 1. The decrease in H_2 benefit at high K levels has also been observed in cold worked stainless steel. For the Type 316L tests, there was minimal HWC benefit: 1. Attributed to K test sequence used with a high K value at the test start. There was no clear fluence effect over the small range investigated: 1. Consistent with GE PLEDGE modeling: RIS and hardening saturated. Data was consistent with existing BWRVIP-99 data and curves: 1. Higher rates measured at higher K levels consistent with a higher K dependency.