The effect of helium (He)-induced surface microstructure on D plasma-driven permeation through a reduced activation ferritic/martensitic (RAFM) steel CLF-1 has been studied. The CLF-1 steel is pre-exposed by He plasma with ion fluence of 1022-1024 He m-2 and an incident energy of 100 eV at 708 K. The following D plasma driven permeation (PDP) experiment is performed at 693 K. Steady-state D permeation flux decreases with the increase of He ion fluence. D diffusion coefficient is found not to be significantly affected by He pre-damage, while D reflection coefficient increases with the enhance of He ion fluence. Scanning electron microscope (SEM) and transmission electron microscope (TEM) analyses clearly reveal the evolutions of surface roughness and the He bubbles layer after He exposures. Elastic recoil detection (ERD) is used to identify He concentration depth profiles in the samples. Both the surface microstructure modification and the He bubble layer formation contribute to the reduction of D permeation.
Experiments concerning the effect of helium (He) plasma exposure on deuterium (D) plasma-driven permeation (PDP) through tungsten (W) foils in a linear plasma facility has been performed. 0.05 mm thick W foils were exposed to ~2×1020 m-2s-1 He plasma with various fluences at 883 K. After He irradiating, D permeation tests were performed for the samples and retention was also measured by high-resolution thermal desorption spectroscopy (TDS). It was observed that He pre-irradiation resulted in a significant reduction of D permeation and retention in W. Microstructure observation indicated that the surfaces of samples after He irradiation turned rough and He nanobubbles were formed near the surface. The defective structure including He nanobubbles very likely enhances D reemission and accordingly reduces the permeation and retention in He pre-irradiated W.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.