PPPL cleans porous tungsten fusion wall tiles in vacuum with neon plasma and heat

Researchers from the U.S. Department of Energy's Princeton Plasma Physics Laboratory, Princeton University and Pennsylvania State University reported a way to clean porous tungsten tiles after they are installed inside a fusion system. Fusion concepts that protect walls with liquid lithium held in sponge-like tungsten can be clogged when manufacturing contaminants such as carbon and oxygen react with lithium. Even cleaned tiles can be recontaminated when exposed to air during installation, according to a phys.org write-up of the work. In experiments inside PPPL's Lithium Tokamak Experiment-Beta, highly contaminated porous tungsten samples were exposed to a neon glow discharge and heated to roughly 800°C (1,470°F). Combined heat and plasma cleaned more effectively than plasma alone, with samples changing from dull dark gray to metallic silver. The results are published in Nuclear Materials and Energy (DOI: 10.1016/j.nme.2026.102123). Camila López Pérez led the research. The method aims to let future systems clean tiles under vacuum after installation rather than only before they enter the chamber.