Hydrogen gas driven permeation through the fine-grain graphites MPG-8 and

R5710, and through CFC NB31 in two main directions was investigated for sample

thicknesses of 1–7mm and pressures from 10−2 to 10Pa. The gas driven permeation

occurred through the carbon-base materials by the hydrogen molecular gas flow

through the internal porosity network rather than hydrogen atom diffusion through

the graphite lattice. The permeabilities of MPG-8 and Nb31 were of the same

order, while the permeability of R5710 was two orders of magnitude less. The

specific bulk conductivity was about 5 x 1015molecules/smPa for MPG-8; 8 x

1013molecules/smPa for R5710; 1016molecules/smPa for Nb31 along ex-pitch (x)

fibers after taking into account the perforated surface layer and 8 x

1015molecules/smPa for Nb31 along needled (z) fibers.

Gas-Driven Hydrogen Isotopes Permeation Through Different Carbon Materials.

A.V.Spitsyn, A.V.Golubeva, M.Mayer, A.A.Skovorod: Journal of Nuclear

Materials, 2009, 390-391, 701-4