Hydrogen isotope accumulation in fusion devices is an important question from the radiological safety perspective. Lithium is one of the perspective materials considered for use in plasma facing components. One of the channels for hydrogen isotope accumulation is codepositon with lithium. Lithium codepositon research is hindered by high chemical activity of lithium. A study of Li-D films codeposited in magnetron discharge with liquid cathode has been conducted. In situ TDS analysis of the films has been conducted. Additionally, a study of deuterium release from films due to contact with atmospheric gases and water vapor has been done.
As a result of the work, several conclusions can be made. Large amounts, at least several atomic percent, of hydrogen isotopes are accumulated in Li-D films. Deuterium content was estimated as D/Li=5-20%. Hydrogen isotope release occurs mainly in the form of H2, HD, D2.molecules, and not in the form of water molecules as could be expected if the film consisted of lithium hydroxide. There are two characteristic peaks at 710 K and 850 K, with 710 K peak being the dominant one. This allows us to speculate that there is a thin hydroxide layer on top of the film, as lithium hydroxide’s melting temperature is 730 K. Hydrogen isotopes are released from Li-D films on contact with atmospheric gases and water vapor. All deuterium leaves the film after three days of atmospheric exposure. At the same time, some deuterium remains in the film after interaction with water vapor.