Computational modelling enables to study materials response in extreme environments,
such as nuclear reactor, safely and, also, reduce the costs associated with
carrying out multiple experimental studies to map out wide operational conditions.
Therefore, we can effectively use these methods to gain new insights into
processes happening at the atomic level and determine the most important ones
affecting for example the degradation of the material under irradiation
conditions. Due to the large lengthscales, necessary to contain a collision
cascade, classical molecular dynamics has to be used to study radiation damage
events. These methods often neglect the role of electronic stopping which can
contribute to about 20% energy loss by the energetic particles. We have
developed a novel model that is able to capture the energy losses to electrons in
collision cascade simulations and are going to employ the method in this
proposal.
Austenitic steels is one of the main types of materials used in nuclear
reactors. The electronic losses have often been neglected in the computational
research studying the radiation damage in these materials. Moreover, our
previous work, among others, has shown that the inclusion of electrons can
significantly affect the defect production in the material due to irradiation
damage. This work will be part of the ANITA project funded by Energimyndiheten,
industry and Uppsala university where small modular reactor (SMR) concepts are studied.
Our project aims at studying the radiation damage in FeCrNi austenitic steel
as a model system and expanded to FeCrAl steel. We will employ the
state-of-the-art models to include all the necessary physics taking place in
the extreme events. We have developed the parameterisation for the
electron-ion interaction and will be using available
interatomic potentials for FeCrNi compound. We will carry out the simulations
using LAMMPS software and our electron-ion interaction model.
In the project we will carry out simulations
at multiple damage energies (10-100 keV). For each energy we will gather
statistical averages by running many simulations with different initial
conditions and will gather information on the surviving defects which can be
compared to available experimental data. Furthermore, we will study the
electronic effects in FeCrAl steel by first running time-dependent density
functional theory calculations to map the energy transfer from energetic ions
to electrons from first principles. This data will be used in the development
of the electron-ion coupling model that can be used in classical MD
simulations. After, the parameterisation of the model we will carry out
similar radiation damage simulations as for FeCrNi compound.