Hydrogen interaction with point defects in tungsten

Abstract

First-principles calculations were used in determining the binding and trapping properties of hydrogen to point defects in tungsten. Hydrogen zero-point vibrations were taken into account. It was concluded that the monovacancy can hold up to five hydrogen atoms at room temperature. The hydrogen was found to distort the self-interstitial atom configuration geometry. The interaction of hydrogen with the transmutation reaction impurities Re and Os were studied. It was found that the substitutional Re and Os have a negligible effect on the hydrogen trapping whereas the interstitial Os may increase the hydrogen inventory in tungsten.

Numerical analysis of TDS spectra under high and low flux plasma exposure conditions

“…Ab initio and Molecular Dynamics simulations showed that H tends to occupy off-centred position in a vacancy, experiencing weak attraction to W atoms [18,19]. This implies that H atoms, when filling a void, first should occupy the inner surface positions and then fill the centre.…”

Recent progress in research on tungsten materials for nuclear fusion applications in Europe

“…The primary D-W irradiation-induced collision statistics were determined by binary collision approximation calculations with SRIM and the W collision cascades by Molecular Dynamics (MD) [65] simulations. The activation energies needed for detrapping of D from the resulted irradiation-induced trap sites were determined with first-principles calculations using electron density functional theory (DFT) [64]. A full, detailed description of the present RE method and its inputs from MD and DFT calculations have been published recently [66a] The validated RE code is suitable for simulating hydrogen implantations into W with fluences below the blistering threshold.…”

Interaction of hydrogen with dislocations in tungsten: An atomistic study

“…For the EAM1 potential, emphasis was put on a quantitative reproduction of ab initio data for the binding between H-H, He-He and H-He pairs [11]. The off-center position of a H atom in a vacancy as predicted by DFT [14] was not considered, and therefore both H and He are described by pair potentials only. For the EAM2 potential, the focus was made on the stabilizing H in an off-center position in the vacancy and therefore an embedding function was added for H. Both types of the potentials predict the tetrahedral position for a H atom as the most favorable in bulk W, which is important for this work as we focus on the calculation of the binding between H atoms and defects.…”