Hydrogen isotope plasma-driven permeation through RAFM steel: isotope exchange and helium irradiation effect

Abstract Hydrogen isotope exchange in China low activation martensitic (CLAM) steel was investigated by plasma-driven permeation (PDP) measurements the temperature range of ∼670–920 K. It found that as H introduced into D plasma, flux HD increased while 2 decreased. The total flux, however, remained almost unchanged. Such a result allowed analysis replacement and showed reduction is balanced rise HD. In addition, formation to be closely related content plasma. isotopic effects on plasma dissociation/ionization rate incident were evaluated measuring parameters including electron density using triple Langmuir probe. correlation between ionization discussed. He pre-irradiation seeding during PDP also conducted investigate diffusion. reduced seeding. Data probe influenced Besides, under simultaneous + irradiation, atoms preferentially trapped at defects resulting shallower concentration gradient described observed decrease rate. reduce with much slower breakthrough reach steady-state. amount He-induced derived quantitatively from transient curves. believed bubbles formed near surface act trapping sites atoms, leading less effective diffusion coefficient an enhanced retention material.