Diffusion of tritium in pseudo-monocrystal graphite samples was observed using a tritium imaging camera. Samples implanted with tritium were annealed for hour-long intervals at 375 to 1975K and tritium images were photographically recorded after each anneal. Diffusion lengths of about 20μm in the basal plane of the sample were recorded, implying a diffusion coefficient of about 2 x 1010cm2/s at temperatures of about 1800K. An unexpectedly large amount of tritium was retained in the near surface of the samples even after prolonged annealing to 1975K.

Tritium Diffusion in Pseudo-Monocrystal Graphite, Observed with a Tritium Imaging Camera. Kushita, K.N., Youle, I., Haasz, A.A., Sawicki, J.A.: Journal of Nuclear Materials, 1991, 179-181[1], 235-8