Fracture mechanics testing of irradiated RPV steels by means of sub-sized specimens (FRACTESUS). The European Union has defined clear short and long term objectives to achieve its energy transition towards sustainable energy and 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 particular, the industry and transport sector will need to rely more heavily on electricity to achieve this goal. In all electricity mix scenarios up to 2050, one needs to rely on one or a combination of existing nuclear power plants, long term operation, new nuclear build and future nuclear systems. Safety and operability of any nuclear systems heavily relies on a defense in depth strategy where the integrity of structural material plays an essential role. Due to material availability and/or irradiation constraints, the use of small size specimen to obtain reliable measurement of the resistance to fracture is needed by the nuclear industry to comply with the amended Nuclear Safety Directive. Small size specimen fracture toughness measurement has already been shown possible. However, some effort is still requested to achieve European regulatory acceptance of this approach. The goal of this project is to join European and International effort to establish the foundation of small specimen fracture toughness validation and demonstration to achieve change in code and standards allowing to address the various national regulatory authority concerns. FRACTESUS is involving in a very early stage regulatory bodies, code and standardization committee, the industry and the international community in order for the consortium to optimize available resources and expertise.

ENTENTE "European Database for Multiscale Modelling of Radiation Damage" aims to design a new European experimental/modelling materials database to collect and store pedigree data on radiation damage of RPV steels, according to FAIR (Findability, Accessibility, Interoperability, and Reusability) principles. The project can be seen as three interconnected blocks: DATABASE Design - Multi-disciplinary teams (materials scientists, engineers, software developers) for the definition of new effective data formats suitable for microstructural and modelling data, and interfaces needed to ensure interoperability. - Interface the SOTERIA platform with the ENTENTE database so that experimental data and metadata could be retrieved and post processed in order to correctly parametrize modelling tools ADVANCED experiments/models - Microstructural characterization, linked with appropriate models, by means of advanced (S)TEM techniques, APT, -XRD and in-situ TEM for mapping the radiation induced defects and associated strain-stress fields - In-depth analysis of segregation and structural, chemical nature and strength of grain boundaries to study hardening and non-hardening embrittlement INNOVATIVE data analysis and hybrid models - Simulation tools that enable the description of radiation damage up to space and time scales that are comparable with those reached in experiments on RPV steels. Accelerated physically informed fracture laws with a reasonable predicting capability on heterogeneous microstructures. - First application of ICME (Integrated Computational Materials Engineering) approaches to enable virtual studies of alternative neutron embrittlement scenarios -Machine learning and artificial neural networks approaches to support atomistic modeling as well as to predict hardening and/or embrittlement Target data will be those generated during previous EURATOM projects (LONGLIFE, PERFORM, SOTERIA, TAREG, PHARE) on RPV steels.