First principles study of the behavior of hydrogen atoms in a W monovacancy

Object kinetic Monte Carlo simulations of irradiated tungsten for nuclear fusion reactors

“…Binding energies for H atoms to V m and H n V m clusters are summarized in Table 3.8. In the case of H trapped in a single vacancy (H n V), the results [128] are in good agreement with previously published data [122,[130][131][132][133] as observed in Figure 3.4. [128]) are compared to those obtained by Johnson et al [131], Heinola et al [132], Ohsawa et al [133], Liu et al [130] and Fernandez et al [122].…”

“…Los resultados mostraron que, de nuevo, la densidad de bordes de grano tiene un claro efecto en la aniquilación entre vacantes y átomos intersticiales de W. Más aún, de la comparativa entre los experimentos y las simulaciones en el caso de NW, se infirió que los bordes de grano actúan como caminos preferenciales para la difusión de hidrógeno. Los estudios tanto de helio como de hidrógeno [128]) are compared to those obtained by…”

“…Formation energies (E f ) for a system of a certain number of W and H atoms, N W and N H , respectively, were calculated using the equation [128]:…”

“…where E tot is the final total energy, E(W) is the atomic energy of one W atom inside the pure bulk when a 5 × 5 × 5 supercell is used and E(H) is the half of the energy of the isolated H 2 molecule [128][129][130], located inside an otherwise empty 5 × 5 × 5 supercell with sides equal to the equilibrium lattice parameter of the pure W.…”

“…[122,123,128,[130][131][132][133], show a binding energy of a H atom to a vacancy higher than 1 eV (see Figure 3.5). Nanostructured materials have a large density of grain boundaries (GBs) which, depending on the irradiation conditions, have a clear influence on the distribution of both FPs and light species such as H [49].…”