The diffusion of cesium in graphite was recognized as being a process which could be described by a conventional grain boundary diffusion model. The phenomenon of fast movement on the "grain" surfaces and slow movement in the "grains" was demonstrated, and an attempt was made to evaluate the governing transport coefficients. The grain boundary diffusion model was extended to include an evaluation of a system for the permeation of a membrane and the coincidental loading up of this membrane. Universal solutions were given for fluxes and loadings as a function of time, transport coefficients, and appropriate other properties, provided that certain assumptions were made

Diffusion of Cesium through Graphite. Chandra, D., Norman, J.H.: Journal of Nuclear Materials, 1976, 62[2-3], 293-310