Site specific dependencies of hydrogen concentrations in zirconium hydrides

Abstract Zircaloy-4 specimens were H-charged up to 1230 wppmH. Intra-, inter- and trans-granular zirconium hydride precipitates (or ZrH 2− x where 1/(2 −  x ) is the Zr/H molar ratio) were observed throughout the α -Zr matrix. Transmission Electron Microscopy and electron diffraction confirmed that the ZrH 2− x precipitates were face-centred cubic structures consistent with the δ -ZrH 2− x phase. Electron Energy Loss Spectroscopy analysis of the δ -ZrH 2− x precipitates at three different nucleation spots displayed shifts in the plasmon energy loss peaks that can be attributed to local variations of the H content of the δ -ZrH 2− x precipitates rather than the presence of different ZrH 2− x phases as has previously been assumed.