GRAIN-BOUNDARY DIFFUSION IN URANIUM-DIOXIDE - CORRELATION BETWEEN SINTERING AND CREEP AND A REINTERPRETATION OF CREEP MECHANISM

Previously published data on the final stage sintering kinetics of stoichiometric uranium dioxide are correlated with a reinterpretation of low-stress creep behaviour of identical material (data on both processes by the present authors). For both processes the rate-controlling diffusional flux is considered to be that of uranium ions along grain boundaries. The effective diffusion coefficient for uranium ion diffusion along grain boundaries, DGB, is estimated to be: DGB = 1.38(÷x5) × 10-6 exp - [(2.39 ± 0.8) × 105/8.31T] m2/s. Comparisons are made between this value and those previously measured by radio-tracer methods. © 1979.