Swelling of cold-worked austenitic stainless steels irradiated in HFIR under spectrally tailored conditions

The effects of cold working and impurities on swelling behavior in austenitic stainless steels irradiated at 400 °C to 17.3 dpa under spectrally tailored conditions in the Oak Ridge research reactor and high flux isotope reactor were investigated. The specimens were 20% cold-worked JPCA, 316R, K (low carbon (0.02%)) and C (low carbon (0.02%) and doped with 0.08% niobium). The helium generation rate was about 15 appm He/dpa. Cavities, dislocation loops and carbides were formed by irradiation in these steels. The swelling in the JPCA-CW and 316-CW was 0.003% and 0.004%, respectively and in the C-CW and K-CW was 0.02% and 0.01%, respectively. Swelling in K and C steels was strongly reduced by 20% cold-work, and the swelling in JPCA-CW and 316R-CW steels was comparable to JPCA-SA and 316R-SA steels. The synergistic treatments of addition of some impurities and cold working are very effective for the suppression of swelling at 400 °C in austenitic stainless steels.