A. Hollingsworth M.-F. Barthe Z. Hu P. Desgardin M.Yu. Lavrentiev S.L. Dudarev P. Derlet D. Mason J. Hess S. Davies B. Thomas H. Salter E.F.J. Shelton K. Heinola K. Mizohata A. De Backer A. Baron-Wiechec I. Jepu E. Zayachuk A. Widdowson E. Meslin A. Morellec
Self-ion bombardment of pure tungsten with ion energies of 2 MeV is used to mimic the defects created by neutrons in a fusion reactor. Electron microscopy is used to characterize the microstructure of samples. Thermal Desorption Spectrometry (TDS) is performed on deuterium implanted samples in order to estimate deuterium inventory as function of…
Preprint PublishedJan Fikar Robin Schaeublin Daniel R. Mason Duc Nguyen-Manh
The vacancies produced in high energy collision cascades of irradiated tungsten can form vacancy clusters or prismatic vacancy dislocation loops. Moreover, vacancy loops can easily transform into planar vacancy clusters. We investigated the formation energies of these three types of vacancy defects as a function of the number of vacancies using thr…
PublishedDaniel R. Mason Andrew J. London
We present a morphological analysis of atom probe data of nanoscale microstructural features, using methods developed by the astrophysics community to describe the shape of superclusters of galaxies. We describe second-phase regions using Minkowski functionals, representing the regions’ volume, surface area, mean curvature and Euler characteristi…
Preprint PublishedDaniel R. Mason Duc Nguyen-Manh Mihai-Cosmin Marinica Rebecca Alexander Sergei L. Dudarev
The low energy structures of irradiation-induced defects have been studied in detail, as these determine the available modes by which a defect can diffuse or relax. As a result, there are many studies concerning the relative energies of possible defect structures, and empirical potentials are commonly fitted to or evaluated with respect to these en…
Preprint PublishedA. Hollingsworth M. Yu. Lavrentiev R. Watkins A. Davies S. Davies R. Smith D. R. Mason A. Baron-Wiechec Z. Kollo J. Hess I. Jepu K. Heinola J. Likonen K. Mizohata E. Meslin M.-F. Barthe A. Widdowson I. S. Grech K. Abraham A. McShee Y. Martynova M. Freisinger A. De Backer
A new facility to study the interaction of hydrogen isotopes with nuclear fusion relevant first wall materials, its retention and release, has been produced. The new facility allows implanting a range of gases into samples, including tritium. Accurate study of isotope effects, such as the isotopic exchange in damaged microstructure, has previously …
Preprint PublishedDaniel Mason Andrea Sand Sergei Dudarev
We describe the development of a new object kinetic Monte Carlo code where the elementary defect objects are off-lattice atomistic configurations. Atomic-level transitions are used to transform and translate objects, to split objects and to merge them together. This gradually constructs a database of atomic configurations- a set of relevant defect …
Preprint PublishedS. L. Dudarev D. R. Mason E. Tarleton P.-W. Ma A. E. Sand
Predicting strains, stresses and swelling in power plant components exposed to irradiation directly from the observed or computed defect and dislocation microstructure is a fundamental problem of fusion power plant design that has so far eluded a practical solution. We develop a model, free from parameters not accessible to direct evaluation or obs…
Preprint PublishedD.R. Mason X. Yi A.E. Sand S.L. Dudarev
We present a new analysis of nanoscale lattice defects observed after low-dose in situ self-ion irradiation of tungsten foils at cryogenic temperature. For decades, defect counts and size-frequency histograms have been the standard form of presenting a quantitative analysis of the nanoscale “black-dot” damage typical of such irradiations. Here …
Preprint PublishedA. De Backer D.R. Mason C. Domain D. Nguyen-Manh M.-C. Marinica L. Ventelon C.S. Becquart S.L. Dudarev
In a fusion tokamak, the plasma of hydrogen isotopes is in contact with tungsten at the surface of a divertor. In the bulk of the material, the hydrogen concentration profile tends towards dynamic equilibrium between the flux of incident ions and their trapping and release from defects, either native or produced by ion and neutron irradiation. The …
Preprint Published