Post exposure time dependence of deuterium retention in lithium and lithium compounds. (May 2019) - Yang, Y.
Highlights: The amount of deuterium retained in Li film decreased by 45% after 16 h. The amount of deuterium retained in composite LiO films decreased at the same rate compared to Li films. Amount of deuterium retained in LiCO film is independent of time up to 3 days. Abstract: Lithium (Li) coating of plasma-facing components (PFC) has led to improved plasma performance in fusion experiments due to the effectiveness of Li in retaining hydrogen (H) isotopes and thus reducing recycling. Since Li readily reacts with background gases present in fusion experiments, it is important to understand and parameterize the time dependence of deuterium (D) retention in Li and Li compounds for applications of Li under future long-pulse plasma conditions. D retention in pure Li and composite LiO and LiCO films was studied as a function of time after these films were exposed to 450 eV D2 + ion irradiation. The amount of deuterium retained in both Li and LiO films at 300 K decreased at the same rate by 45% after 16 h. The amount of D retained in LiCO films was found to be independent of time up to 3 days. Increasing the temperature of a pure Li film to 420 K increased this rate of decrease by 50%, while increasing the thickness of the lithium film from 3 to 16 monolayers had no effect on the decrease rate.