Simulation of hydrogen effect on equilibrium shape of gas bubbles in beryllium

摘要

In fusion environment hydrogen isotopes can be either produced inside beryllium bulk or adsorbed on beryllium surface. In the present work the effect of hydrogen surface concentration on the properties of five principal hexagonal close-packed beryllium surfaces (basal, prismatic type I and II, pyramidal type I and II) was studied by first-principle calculations. The configurations with high hydrogen coverage were studied for all considered surfaces. It was shown that the presence of adsorbed hydrogen atoms significantly changes the energy of all surfaces with except the prismatic type II surface. Influence of hydrogen surface concentration on the equilibrium shape of hydrogen covered bubbles was investigated by means of the Wulff polyhedron construction. (C) 2015 EURATOM. Published by Elsevier B.V. All rights reserved.