Diffusion kinetics of N in UO2 pellets were determined experimentally at 1000 to 1600C. The fraction of nitrogen liberated from uniformly dispersed uranium nitride particles in UO2 was measured on carefully characterized pellets. The diffusion coefficient for nitrogen in UO2 could be represented by:

D(cm2/s) = 2.25 x 10-9 exp[-33400/RT]

H.M.Ferrari: Journal of Nuclear Materials, 1964, 12[2], 142-4