Multiscale modeling of radiation damage in Fe-based alloys in the fusion environment

Modeling Microstructure and Irradiation Effects

“…[4]. The model also includes nonthermally activated events, such as the annihilation of a defect after encountering either a defect of opposite nature (i.e., a SIA encountering a vacancy) or a sink, as well as aggregation, either by adding a point defect to a cluster or by forming a complex.…”

“…Because of the Arrhenius dependence of Eq. [4], efforts are usually concentrated on the determination of the migration energies, i.e., the migration barrier the moving species have to go over, and the attempt frequencies are taken to be a constant of the order of the Debye frequency. The same reasoning is applied to the dissociation events, and efforts are then concentrated on the binding energies.…”

“…As a complete and thorough description of all the possible techniques applied to all the possible materials is out of reach and would require the writing of an entire book, the focus of this article is on the modeling of the microstructure of metals and metallic alloys and most examples provided pertain to the case of pressure vessel ferritic steels for fission reactors. The same techniques, however, can be applied to other structural materials (as well as other irradiation conditions [4] ), such as zirconium alloys, which hold the fuel; FeCr and oxide dispersion strengthened/nitride dispersion strengthened (ODS/NDS) alloys; austenitic alloys used for the internals; or tungsten, which is considered to coat the divertor in the International Thermonuclear Experimental Reactor (ITER).…”

In-Service Design & Performance Prediction of Advanced Fusion Material Systems by Computational Modeling and Simulation

“…These rate theory models are supported by molecular dynamics (MD) and Monte Carlo (MC) models of key mechanisms and material parameters. Key mechanisms include substitutional and interstitial helium diffusion and their interactions with self-interstitials and self-interstitial clusters, dislocations, grain boundaries and coherent precipitate interfaces [3,[7][8][9][10]. Key material parameters include the diffusion coefficients of the various migrating species, helium and vacancy binding energies with each other and with grain boundaries, dislocations/dislocation jogs and coherent interfaces.…”

“…A series of molecular statics and dynamics simulations, complemented by Lattice Monte Carlo Studies, were used to comprehensively characterize the configurations and energetics as well as the diffusion and interaction dynamics of self-interstitial atoms (SIA) and SIA clusters in Fe and simple Fe dilute Cu alloys [7,[14][15][16]. These studies were led by researchers at LLNL, and more recently UC Berkeley, but involved active collaborations with scientists at UCSB.…”