The impact of specific surface area on the retention of deuterium in carbon fiber composite materials

Abstract

a b s t r a c tIn this study, the PISCES-A linear plasma instrument has been used to characterize retention in several carbon fiber composites in order to better understand the factors which lead to elevated retention levels in these materials. The PISCES instrument is capable of subjecting materials to intense fluxes (up to 10 22 m −2 s −1 ) of low energy (150 eV) D + ions, producing conditions similar to those encountered by plasma facing components in a fusion reactor. In this investigation, three CFCs (fabricated with different manufacturing processes) are compared with the N11 composite used in the Tore Supra reactor. The specific surface areas for these materials were within the range of 0.14-0.55 m 2 /g. The plasma bombardment conditions were adjusted to provide doses on the order of 10 25 -10 26 m −2 at a sample temperature of 200 • C. After removal from PISCES-A, the amount of D retained in the sample surface was determined via thermal desorption spectroscopy. The measured retention showed a strong correlation with the type of material used and the corresponding BET surface area. By using a CFC with a lower internal porosity, one could expect a reduction in retention by a factor of 5 or more.