Parameter-free quantitative simulation of high dose microstructure and hydrogen retention in ion-irradiated tungsten

Abstract

Hydrogen isotopes are retained in materials for fusion power applications, changing both hydrogen embrittlement and tritium inventory as the microstructure undergoes irradiation damage. But modelling of highly damaged materials - exposed to over 0.1 displacements per atom (dpa) - where asymptotic saturation is observed, for example tungsten facing the plasma in a fusion tokamak reactor, is difficult because a highly damaged microstructure cannot be treated as weakly interacting isolated defect traps. In this paper we develop computational techniques to find the defect content in highly irradiated materials without adjustable parameters. First we show how to generate converged high dose (>1 dpa) microstructures using a combination of the creation-relaxation algorithm and molecular dynamics simulations of collision cascades. Then we make robust estimates of point defects and void regions with simple developments of the Wigner-Seitz decomposition of lattice sites. We use our estimates of the void surface area to predict the deuterium retention capacity of tungsten as a function of dose. This is then compared to 3He nuclear reaction analysis (NRA) measurements of tungsten samples self-irradiated at 290 K to different damage doses and exposed to deuterium plasma at low energy at 370 K. We show that our simulated microstructures give an excellent match to the experimental data, with both model and experiment showing 1.5-2.0 at.% deuterium retained in tungsten in the limit of high dose.

preprint for submission to journal

References in corpus (10)

• Structure identification methods for atomistic simulations of crystalline materials
• High energy collision cascades in tungsten: dislocation loops structure and clustering scaling laws
• Elastic trapping of dislocation loops in cascades in ion-irradiated tungsten foils
• MMonCa: An Object Kinetic Monte Carlo simulator for damage irradiation evolution and defect diffusion
• Spatial ordering of nano-dislocation loops in ion-irradiated materials
• Observation of transient and asymptotic driven structural states of tungsten exposed to irradiation
• Evolution of small defect clusters in ion-irradiated 3C-SiC: combined cluster dynamics modeling and experimental study
• Hydrogen supersaturated layers in H/D plasma-loaded tungsten: A global model based on thermodynamics, kinetics and density functional theory data
• Self-optimized construction of transition rate matrices from accelerated atomistic simulations with Bayesian uncertainty quantification
• Atomistic-Object Kinetic Monte Carlo simulations of irradiation damage in tungsten

Cited by in corpus (9)

• Macroscopic elastic stress and strain produced by irradiation
• Dislocation density transients and saturation in irradiated zirconium
• Intense γ-photon and high-energy electron production by neutron irradiation: effects of nuclear excitations on reactor materials
• Volume of a dislocation network
• Comparative study on radiation resistance of WTaCrV high-entropy alloy and tungsten in helium-containing conditions
• Dependence of simulated radiation damage on crystal structure and atomic misfit in metals
• The effect of multi-occupancy traps on the diffusion and retention of multiple hydrogen isotopes in irradiated tungsten and vanadium
• Simulations of Nanocrystalline Iron Formation under High Shear Strain
• Atomic-level study of dose-dependent lattice thermal conductivity degradation in irradiated tungsten