Diffusion of Xenon in Ceramic Oxides

Abstract

Postirradiation measurements were made at 700° to 1500°C of the release of ¹³³Xe recoiled into single‐crystal α‐Al₂O₃, BeO, MgO, and ZrO₂ crystals during neutron irradiation in contact with UO₂ powder. The release pattern from most of the specimens was identical: a high rate of loss of ¹³³Xe for several minutes followed by a slower release for which the cumulative fractional release was linear with the square root of the heating time. Diffusion coefficients for ¹³³Xe have been calculated from the slope of the release curve following the initial release. The magnitudes of the diffusion coefficients above 1100°C for α‐Al₂O₃, BeO, and MgO were nearly the same whereas the diffusion coefficients in ZrO₂ were ten to a hundred times larger. The activation energy for ¹³³Xe release from α‐Al₂O₃ above 1100°C was 64 kcal/g‐mole. The xenon release behavior has been compared to anion diffusion in these oxides.