Time-resolved studies of deuterium release from lithium films exposed to water vapor

Highlights: • Li-D films rapidly react with water vapor at room temperature, increasing in mass 3 times and fully transforming into LiOH. • The dynamics of the film's mass can be well described using a diffusion driven model for the first 70% of the reaction and combined nucleation-diffusion based model fpr the whole reaction. • D remaining in the film after the exposure to water vapor is released in the form of hydrogen and water molecules at low temperatures up to about 540 K. - Abstract: In continuation of a previous study of Li-D films' interactions with atmospheric gases, dynamics of Li-D codeposit interaction with water vapor was studied. Li-D codeposits very actively react with water vapor, leading to formation of LiOH and release of major part of deuterium. The dynamics of the film mass (thickness of the reacted layer) was well described using a diffusion-based model at the early stage of the reaction and using a combined nucleation-diffusion based model in whole period of time. The most of D remaining in the film after exposure to water vapor is released during a heatup below 550 K, that is attributed to LiOH decomposition and occurs at lower temperatures than in the case of initial Li-D film.