A. De Backer

Sink strength calculations of dislocations and loops using OKMC

Abstract We calculate the sink strength of dislocations and toroidal absorbers using Object Kinetic Monte Carlo and compare with the theoretical expressions. We get good agreement for dislocations and loop-shaped absorbers of 3D migrating defects, provided that the volume fraction is low, and fair agreements for dislocations with 1D migrating defects. The master curve for the 3D to 1D transition is well reproduced with loop-shaped absorbers and fairly well with dislocations. We conclude that, on the one hand, the master curve is correct for a wide range of sinks and that, on the other, OKMC techniques inherently take correctly into account the strengths of sinks of any shape, provided that an effective way of appropriately inserting the sinks to be studied can be found.

Modelling radiation damage and He production in tungsten

Tungsten is a candidate material for the divertor and for first wall armor of future thermonuclear fusion reactors (ITER and DEMO). In such irradiation conditions, it is well known that the microstructure, and as a result the properties of the materials, will evolve. In this perspective, the fate of irradiation-induced defects (helium atoms, vacancies, self-interstitials and the complexes they can form) has to be understood. In particular, He migration properties are of fundamental as well as practical interest, as they can affect the microstructure evolution and eventually influence physical and mechanical properties, the most significant example being high-temperature helium embrittlement. In this work, we show how our ab initio parameterized object kinetic Monte Carlo code LAKIMOCA can model the evolution, during implantation, of the point defect population in the track region of 800 keV 3He atoms implanted in W samples. We also discuss possible improvements of the model.

Cascade fragmentation: deviation from power law in primary radiation damage

ABSTRACT The sizes of defect clusters, produced in materials by energetic ion or neutron impacts, are critically important input for models describing microstructural evolution of irradiated materials. We propose a model for the distribution of sizes of vacancy and self-interstitial defect clusters formed by high-energy impacts in tungsten, and provide new data from in situ ion irradiation experiments to validate the model. The model predicts the statistics of sub-cascade splitting and the resulting distribution of primary defects extending over the entire range of cluster sizes, and is able to provide initial conditions for quantitative multi-scale simulations of microstructural evolution. GRAPHICAL ABSTRACT IMPACT STATEMENT We present a model, parameterized for tungsten, for the distribution of defect sizes in primary radiation damage, as an essential step in multi-scale modelling of microstructural evolution in irradiated materials.

Deuterium trapping and release in JET ITER-like wall divertor tiles

A selected set of samples from JET-ILW divertor tiles exposed in 2011-2012 has been analysed using thermal desorption spectrometry (TDS). The highest amount of deuterium was found on the regions wi ...

Subcascade formation and defect cluster size scaling in high-energy collision events in metals

Please note that terms and conditions apply. You may also be interested in: High-energy collision cascades in tungsten: Dislocation loops structure and clustering scaling laws A. E. Sand, S. L. Dudarev and K. Nordlund Cascade morphology transition in bcc metals Wahyu Setyawan, Aaron P Selby, Niklas Juslin et al. Simulation of defects in fusion plasma first wall materials Troev T, Nankov N and Yoshiie T Primary damage in tungsten using the binary collision approximation, molecular dynamic simulations and the density functional theory A De Backer, A Sand, C J Ortiz et al. Electronic excitations in atomistic models of radiation damage C P Race, D R Mason, M W Finnis et al. Electronic effects in high-energy radiation damage in tungsten E Zarkadoula, D M Duffy, K Nordlund et al. Variability in atomic collision cascade distributions