The release of T from neutron-irradiated monocrystalline particles (0.15 to 0.84mm) was measured during isothermal annealing. Diffusion data (table 134) were deduced from the results by considering the time-dependence of diffusion in a solid sphere. The diffusivity of T at temperatures of between 573 and 950K was found to be described by:

D (cm2/s) = 0.116 exp[-101(kJ/mol)/RT]

T.Tanifuji, K.Noda, T.Takahashi, H.Watanabe: Journal of Nuclear Materials, 1987, 149, 227-32