The flowing liquid surface retention experiment was designed to provide fundamental data on the retention and pumping of He, H and other species in flowing liquid surfaces. The flowing liquid surface retention experiment facility currently used an ion beam source, which injects ions into a flowing stream of liquid Li. Its design allows the liquid Li to flow between 2 vacuum chambers that became isolated from each other when the Li flowed. Flow velocities of between 0.5 and 3.0m/s down 2 ramps inside the upper vacuum chamber could be achieved. The ramps and lines where the liquid Li flowed were heated to between 250 and 500C in order to prevent any freezing. A dual residual gas analyzer system monitors the partial pressure of the implanted species in both vacuum chambers. The release rate of gas atoms in the second chamber was directly related to the mechanisms of transport within the metal bulk and also the process of desorption from the surface. For the case of He, the diffusion coefficient was calculated to be 4.5 x 10-3cm2/s at 250C. Helium retention coefficients of the order of 10-4 were obtained based on the experimental data.

Helium Retention and Diffusivity in Flowing Liquid Lithium. M.Nieto, D.N.Ruzic, J.P.Allain, M.D.Coventry, E.Vargas-Lopez: Journal of Nuclear Materials, 2003, 313-316, 646-50