Dependence of neutron-induced swelling on nickel and chromium content in Fe-Ni-Cr ternary alloys

The steady-state swelling rate of EBR-II irradiated ternary alloys with less than or equal to 35% nickel appears to be approximately 5% per 1022 n cm-2 (E > 0.1 MeV) or 1%/dpa, independent of chromium and/or nickel content and also independent of the irradiation temperature in the range 400 to 6000C. The duration of the transient regime of swelling is sensitive to these three variables, however, tending to increase with increasing nickel or temperature or decreasing chromium content. A similar relative independence of the steady-state swelling rate on temperature has been also observed in commercial stainless steels, which also appear to be approaching a swelling rate of 1%/dpa at high fluence. There is some evidence that elemental segregation plays a role in the compositional dependence of swelling