Void Swelling Screening Criteria for Stainless Steels in PWR Systems

Abstract

Most of the available void swelling (VS) data are from fast reactors rather than PWRs, but there are indications that the saturation VS rate for PWR-relevant conditions is at least an order of magnitude smaller than that observed in fast reactors. In 2005, VS screening criteria (temperatures ≥320 °C (608 °F) and fluence ≥20 dpa) were calculated. Since publication of these initial screening criteria, a physics-based model has been developed for the prediction of VS in irradiated austenitic stainless steel components. Comparisons between experimental data derived from density measurements and transmission electron microscopy (TEM) characterizations suggest that the Cluster Dynamics model is capable of predicting the evolution of the irradiated microstructure under PWR conditions. The Cluster Dynamics model estimates <1.5% VS for solution-annealed or cold-worked austenitic stainless steel at temperatures below 320 °C (608 °F) and doses <20 dpa for all displacement rates. Therefore, the previous conservative screening criteria originally calculated in 2005 are retained.