Deuterium trapping and release in Be(0001), Be(11–20) and polycrystalline beryllium

Abstract

The atomistic understanding of retention and release processes of deuterium in beryllium is reached by comparing well-defined experiments on Be(0001) and [11][12][13][14][15][16][17][18][19][20] single crystals, as well as polycrystalline Be to simulations. The experimental desorption spectra are modelled as a coupled reaction diffusion system (CRDS). The single atomistic steps are described by a set of rate equations. Activation energies for the single processes are calculated from density functional theory. (0001) is attributed to anisotropic self-interstitial diffusion influencing the availability of monovacancy traps during implantation. Additionally, desorption spectra with various temperature ramps recorded on polycrystalline Be were successfully reproduced with the CRDS code. D 2 release from polycrystalline Be occurs at lower temperatures than from the single crystals. This is attributed to fast D diffusion along grain boundaries.

Hydrogen in beryllium oxide investigated by DFT: on the relative stability of charged-state atomic versus molecular hydrogen

“…Using equations (10) and (11) The corresponding diffusion coefficients are plotted in Figure 9. As the data from Macaulay-Newcombe et al [34] were obtained with deuterium, they were rescaled with the square root of the mass ratio between deuterium and hydrogen.…”

Hydrogen retention and diffusion in tungsten beryllide

“…We have elsewhere given our quantum contribution to the investigation of the very complex physics lying behind hydrogen retention, diffusion, and release in beryllium [16][17][18]. These phenomena are very complex and subtle, and quantum ab initio investigations are of great help in elucidating them.…”

Analytical model of hydrogen inventory saturation in the subsurface of the wall material and comparison to Reaction-Diffusion simulations

“…This system describes the implantation of HIs, their diffusion and trapping at defects into the materials. Since then, the R-D model has been numerically solved to study the interaction of HI with various fusion relevant materials: tungsten[3,4,5,6,7,8], beryllium[9,10], steel[11,12], aluminium[13] to mention just a few examples. However, in a tokamak, the implantation conditions vary widely as a function of the location on the wall; this complicates the full modelling of HI retention and the interpretation of the simulation results.…”