Fracture Toughness Characterization in the Transition and Ductile Regime of an A508 Type Weld Metal With the Mini-CT Geometry Before and After Irradiation

The mini-CT geometry is being adopted worldwide for application to measure the fracture toughness properties. This geometry is particularly adapted for irradiated materials given the limited space available for irradiation in high flux material test reactors such as the BR2 reactor. A series of twenty (20) mini-CT specimens taken from an A508-type weld were irradiated in the BR2 reactor at 290 °C to a fluence level of ∼5 × 10¹⁹ n/cm², E > 1MeV. They were precracked and 20 % side grooved before irradiation. In parallel, twenty four (24) unirradiated mini-CT specimens were available for testing.

The main objective of this paper is to measure fracture toughness in the transition and ductile regime before and after irradiation and to compare the results with low flux surveillance data.