Fracture toughness and Charpy impact properties of several RAFMS before and after irradiation in HFIR

Abstract

As part of the development of candidate reduced-activation ferritic steels for fusion applications, several steels, namely F82H, 9Cr–2WVTa steels and F82H weld metal, are being investigated in the joint DOE–JAEA collaboration program. Within this program, three capsules containing a variety of specimen designs were irradiated at two design temperatures in the ORNL High Flux Isotope Reactor (HFIR). Two capsules, RB-11J and RB-12J, were irradiated in the HFIR removable beryllium positions with europium oxide (Eu 2O 3) thermal neutron shields in place. Specimens were irradiated up to 5 dpa. Capsule JP25 was irradiated in the HFIR target position to 20 dpa. The design temperatures were 300 °C and 500 °C. Precracked third-sized V-notch Charpy (3.3 × 3.3 × 25.4 mm) and 0.18 T DC(T) specimens were tested to determine transition and ductile shelf fracture toughness before and after irradiation. The master curve methodology was applied to evaluate the fracture toughness transition temperature, T 0. Irradiation induced shifts of T 0 and reductions of J Q were compared with Charpy V-notch impact properties. Fracture toughness and Charpy shifts were also compared to hardening results.