Tensile Properties and Swelling of 20% Cold-Worked Type 316 Stainless Steel Irradiated in a High-Flux Isotope Reactor (HFIR)

Abstract

Immersion density and elevated-temperature tensile properties were determined on 20% cold-worked Type 316 stainless steel irradiated in the High-Flux Isotope Reactor (HFIR) at approximately 285, 370,470, 560, and 620°C to fluences of 1.8 to 6.2 × 1026 neutrons (n)/m2 (>0.1 MeV), which resulted in displacement damage levels of 16 to 54 displacements per atom (dpa) and helium concentrations of 900 to 3300 atomic parts per million (appm). Tension tests were done at temperatures near the estimated irradiation temperatures. Swelling increased with increasing irradiation temperature to a maximum of 2.1% at 620°C. Irradiation at the lowest temperatures (285 and 370°C) increased the strength. At the higher irradiation temperatures, the strength decreased during irradiation. Ductility generally reflected the strength behavior: an increase in strength resulted in a decrease in ductility. When the present data are compared with previously published data, there is good agreement with one exception. Previous experiments showed a large decrease in ductility when irradiated at 600°C and tested at 575°C that was not observed in the present tests. There was also good agreement between HFIR-irradiated steel and literature data for Experimental Breeder Reactor-II (EBR-II)-irradiated steel.