Hydrogen Permeation through Walls with Laminar-Flow between Two Parallel Plate Walls

A tritium permeation window is an effective separation method for recovering hydrogen isotopes in the fuel cycle of a D-T fusion reactor. Hydrogen permeation through a plate type metal window has been analyzed numerically for laminar flow. The results obtained were summarized by a correlation between the local or mean Sherwood number and the reciprocal of the Graetz number. Longitudinal diffusion in the flow direction was also taken into account in the calculations. The contributions of the permeation parameter of walls and longitudinal diffusion in the flow direction to the Sherwood number was discussed. A set of equations which correlate the numerical results were proposed. Numerical calculations were performed for the selective permeation of tritium from tritium-helium mixtures in the D-T fuel cycle and from liquid Li blanket fluid. It was pointed out that both the diffusion resistances through the metallic wall and in the fluid in the vicinity of walls must be taken into consideration.