Testing and commissioning of Liquid Metal In-Vacuo Injection (LIVIn) System capable of evaluating hydraulic performance of capillary porous systems for liquid-metal plasma facing components*

Increasing the lifetime of plasma-facing components (PFC) is one of the necessities in developing long-pulsed fusion reactors. Among various approaches to this issue, liquid metal PFCs (LMPFC) show promising solutions as the constant replenishment facilitates efficient heat exhaust as well as inability to get damaged by radiation. However, studies have shown that free flowing liquid metal (LM) surface is prone to magnetohydrodynamic (MHD) instabilities. To avoid them, LMPFC with capillary porous systems (CPS) under stagnant/slow-flowing conditions have been proposed, but their true potential depends on many factors such as system geometry, material used, hydraulic performance, pore structure, permeability etc. Thus, after fabrication, further testing is required to determine the performance of these PFCs. The Liquid Metal In-Vacuo Injection (LIVIn) System associated with the IGNIS-2 facility is designed to test hydraulic performance of such LMPFC with CPS. The LIVIn system is compatible with UHV, and the LM flow path is fabricated with highly corrosion resistance material. Further, it is equipped with LM detector and a high-speed camera to detect LM levels while the in-vacuo LM seal in the system facilitates efficient sample swapping. Most importantly, since LIVIn system is integrated into IGNIS-2, all in-situ modification and characterization techniques in IGNIS-2 are available for LIVIn system. These include X-ray photoelectric spectroscopy (XPS) which enables us to monitor elemental composition variations of LM throughout the experiment. Continuing commissioning of the LIVIn system and system testing capabilities will be presented.