A new versatile facility: Vehicle-1 for innovative PFC concepts evaluation and its first experiments on hydrogen recycling from solid and liquid lithium

A new plasma facility: Vehicle-1 has been built for the evaluation of innovative plasma-facing component concepts. This facility can conduct experiments in such a way that standing liquids in a tray are exposed to vertically flowing plasmas, or that flowing liquids on a slope are bombarded with horizontally directed plasmas. Vehicle-1 can generate steady state hydrogen plasmas with densities of the order of 1010 cm−3 and electron temperatures around 4 eV. Hydrogen recycling behavior has been observed in Vehicle-1, and the Arrhenius plot of rate constants exhibits a break at around 300 °C. The activation energies are −0.0096 eV and 0.17 eV, respectively, below and above the break. To understand the kinetics of hydrogen recycling, particles sticking coefficients have been measured. Results indicate that at temperatures below the break the sticking process appears to be rate-limiting, whereas above the break surface recombination is important. The sticking coefficients for plasma species have been found to be orders of magnitude larger than those for hydrogen molecules.