Flux and composition dependence of irradiation creep of austenitic alloys irradiated in PFR at ∼420°C

Swelling and irradiation creep of five austenitic stainless steel alloys irradiated at similar to 420 degrees C in the Prototypic Fast Reactor (PFR) were examined. The specimens were in the form of pressurized creep tubes, constructed in the USA and irradiated in PFR in a joint USA/UK experiment. The alloy compositions varied greatly, with the greatest elemental variation in the nickel content, which ranged from 15% to 40% over the five alloys. For each alloy, at least two identical sets of tubes were constructed. Each tube-set was irradiated at a different neutron flux level. Swelling was observed to vary with both alloy composition and flux. Irradiation creep was examined from the perspective of the (B) over bar = (<(epsilon)over bar>) over dot/<(sigma)over bar> = B-0 + D(S) over dot creep model. The values of both creep coefficients, B-0 and D, were typical for austenitic stainless steels and were found to be insensitive to flux over the range of fluxes in this experiment. However, the creep coefficients may be mildly sensitive to alloy composition. (C) 1998 Elsevier Science B.V. All rights reserved.