Bi-Directional Hydrogen Isotopes Permeation through the First Wall of a Magnetic Fusion Power Reactor

Plasma-driven permeation (PDP) and gas-driven permeation (GDP) through a first wall candidate material F82H have been investigated using a laboratory-scale steady state plasma facility. Experiments indicate that GDP may take place in the opposite direction of PDP, which then results in an unwanted increase in edge plasma density. A hydrogen flow from the plasma side to the gas side has also been identified. A one-dimensional diffusion analysis code, DIFFUSE, has been utilized to simulate the experiments. Multiple hydrogen isotopes (D/T) bi-directional permeation has been studied by DIFFUSE-code modelling as well. The two isotopic (D/T) flows appear to be independent of each other, driven by their own concentration gradients.