THE DIFFUSION OF KRYPTON-85 FROM URANIUM DIOXIDE POWDER

The diffusion of Kr/sup 85/ in two UO/sub 2/ powders was studied by performing a series of post-irradiation anneals on the powders. The emanation data were analyzed by considering the effect of sintering as well as the effect of a distribution of particle sizes within the sample. Measurements were made at 900 to 1500 deg C. The time at a temperature was between 8 and 24 hours. The diffusion coefficients for Kr/sup 85/ in the two powders are represented by the equations: D = 2.65 x 10/sup -4/ exp - 65,500/RT for UO/sub 2/ prepared from crushed UO/sub 2/ pellets and, for a chemically prepared UO/sub 2/ powder, D = 4.9 x 10/sup -4/ exp - 73,800/RT. (auth