In recent years the multi-scale modelling approach (MMA) has become increasingly important to complement experiments in the search for new structural materials for nuclear applications such as fusion, accelerated driven system and Gen IV reactors. Multi-scale modelling is also having an increasingly important role in support of the surveillance programmes of currently existing nuclear power plants, as samples of their pressure vessels are becoming rare and their life extension can only be managed via a deeper understanding of radiation damage mechanisms. Within the MMA, ab initio obtained data are generally transferred into interatomic potentials used for large scale molecular dynamics and Monte Carlo simulations of radiation damage production and subsequent microstructural and microchemical evolution. Eventually, the information thereby obtained can be transferred to mesoscopic models, such as other Monte Carlo or rate theory approaches for microstructural and microchemical evolution, or dislocation dynamics, for the description of the plastic behaviour. Finally, a bridge to macro-scales, treated by means of finite element techniques, is built. Results at the meso and macroscopic scales are generally suitable for direct comparison with experimental observations.
Worldwide, a lot of both scattered and co-ordinated work applying an MMA to a number of structural nuclear materials (SNMs) has been carried out in the last couple of decades, with diverse outcomes. In order to define the next steps to be taken towards the development of integrated multi-scale modelling frameworks of practical use for nuclear applications and to enlarge the number of possible contributors to this long-term activity, it is important to provide a critical and complete reference review of the state-of-the-art. This review should highlight weak and strong points of the applied approaches and evidence, as much as possible, to what extent the existing work contributes to enhancing our understanding of radiation damage processes in SNMs and bears the promise of providing, in the future, predictive tools. Based on this review, some conclusions about the priorities in the field should be also drawn.
Within the scope stated above, under the guidance of the Nuclear Science Committee (NSC) and under the mandate of the Working Party on Multi-scale Modelling of Fuel and Structural Materials for Nuclear Systems (WPMM), the objective of the Expert Group on Structural Materials Modelling (SMM) is to provide a critical review of the state-of-the-art concerning the use of a MMA to describe the changes induced by irradiation in SNMs.
In more detail, the objectives of the expert group are to:
This expert group is expected to work closely with the WPMM Expert Group on Multi-scale Modelling Methods (EGM3), especially concerning points 4 and 5.
The Working Party on Multi-scale Modelling of Fuels and Structural Material for Nuclear Systems (WPMM) was established to deal with the scientific and engineering aspects of fuels and structural materials, aiming at establishing multi-scale models and simulations as validated predictive tools for the design of nuclear systems, fuel fabrication and performance.
Under the guidance of the Nuclear Science Committee (NSC) and under the mandate of the Working Party on Multi-scale Modelling of Materials (WPMM), the scope of the Expert Group on Multi-scale Modelling Methods (EGM3) is to provide an overview of the various methods and levels of models used for modelling materials for the nuclear industry (fuels and structural materials).
Under the guidance of the Nuclear Science Committee (NSC) and under the mandate of the Working Party on Multi-scale Modelling of Fuels and Structural Materials for Nuclear Systems (WPMM), the objective of the Expert Group on Multiscale Modelling of Fuel (EGM2F) is to share and support the development of a multi-scale modelling approach of fuels in support of current fuel optimisation programmes and innovative fuel design.
The main objectives of this expert group are to assess the limitations of the NRT-dpa standard, in the light of both atomistic simulations and known experimental discrepancies; and to revisit the NRT-dpa standard and examine the possibility of proposing a new improved standard of primary damage characteristics.
The objectives of the expert group are to assess the accuracy and calculation time of the various first principle tools applied in the assessment of the properties of the nuclear materials; assess the accuracy and calculation time of the various classical molecular dynamic tools applied in the assessment of the properties of the nuclear materials; and define the needs for the development of the tools applied in the benchmarks.