Hydrogen permeation and retention in deuterium plasma exposed 316L ITER steel

Abstract

Fuel permeation and retention in fusion reactor wall materials are important issues for plasma operation and safety reasons in ITER. The austenitic stainless steel 316L(N)-IG will be used as structural material in the first wall components in ITER. The impact of deuterium plasma exposure on the deuterium permeation and retention was studied. Polished 316L(N)-IG steel samples were deuterium plasma exposed with an ion energy of 200 eV and at two different fluences. Deuterium gas-driven permeation and thermal desorption spectroscopy measurements were performed afterwards. By comparison of the exposed samples to an unexposed sample, it is concluded that the surface roughness due to plasma exposure has no significant influence on the deuterium permeation through the samples. The first results of thermal desorption spectroscopy analysis show that the main release of retained deuterium is between 600∘C and 900∘C and the release temperature increases by increasing the plasma fluence.

Keywords

• ITER grade 316L(N)-IG steel
• Deuterium plasma exposure
• Hydrogen permeation and retention
• Gas-driven deuterium permeation measurement
• Thermal desorption spectroscopy
• Surface roughness