Experimental investigation of Kr diffusion in UO2+: Slight deviations from stoichiometry, significant effects on diffusion kinetics and mechanisms

Diffusion of Xe and Kr implanted at low concentrations in UO2 as a function of temperature – An experimental study

“…4, although the corresponding studies agrees rather well on , is thus explained by slight and undiscernible variations on the uranium dioxide stoichiometry between studies (either from slightly different oxygen partial pressure conditions and/or impurity effects). This assumption is also supported by extended results to be published [62].…”

“…where R eva is the sublimation rate in kg/m 2 /s, P sat(T) (in Pa) is the saturated vapour pressure for UO 2 for a given temperature (P sat(T) data deduced from the work by Ackermann et al [61]), M W is the UO 2 molecular weight (0.270 kg/mol), R is the universal gas constant (8.134 J/K/mol) and T is the temperature in K. On another project [62], this predictive model and its associated P sat(T) input data was confronted with measurements of mass difference before and after annealing: the model and the weight measurement agree well with a difference of only ~15% erosion rate. The evaporation rate at 1300, 1350 and 1400°C is calculated at 0.13, 0.52 and 1.67 pm/s by the model.…”