Studies of cesium and silver diffusion in reactor graphite were reported. The diffusant concentration distribution in samples after annealing was found to contradict that expected from Fick's laws. A model for diffusion through several types of sites (channels of migration) was proposed. Some features of diffusion sites were pointed out which may make the multichannel mechanism of migration evident in a short-duration diffusion experiment. The calculations performed indicate that the proposed mechanism conforms to the picture observed in experiment. Cesium diffusion parameters through three channels of migration in reactor graphite were given.

Diffusion of the Fission Metals Cesium and Silver in Reactor-Grade Graphite. Zherdev, F.F., Platonov, P.A.: Journal of Nuclear Materials C, 1991, 182, 223-9