Fracture mechanics testing of irradiated RPV steels by means of sub-sized specimens: FRACTESUS project

This work provides an overview of the FRACTESUS project (Euratom work programme 2019-2020). The European Union has defined clear short and long-term objectives to achieve its energy transition towards sustainable energy and a climate neutral economy by 2050. The success of this transition relies on the combination of energy efficiency and low carbon energy in all sectors of the economy. In all electricity mix scenarios up to 2050, one needs to rely on a combination of existing nuclear power plants, long-term operation, new nuclear build and future nuclear systems. The safety and operability of nuclear systems heavily rely on strategies where the integrity of structural materials plays an essential role. Due to material availability and/or irradiation constraints, the use of small sized specimens to obtain reliable measurements of the fracture resistance is needed by the nuclear industry to comply with safety directives. Measurement of fracture toughness using small-sized specimens has already been shown to be possible in both unirradiated and irradiated conditions. However, significant work is still required to achieve European regulatory acceptance. The goal of FRACTESUS is to join efforts to establish the foundation of small specimen fracture toughness validation and demonstration to address the different national regulatory authority concerns.