Engineered Surfaces for the Lithium Tokamak Experiment (LTX)

Reactor studies have identified liquid lithium walls as a promising solution to magnetic fusion energy (MFE) first wall problems. The difficulty of translating thick (0.1-1 mm) liquid metals into a full-wall solution has led to the pursuit of the "thin-film" approach (100-10,000 nm) for near-term applications such as the Lithium Tokamak experiment (LTX). However, thin lithium films can become saturated with hydrogen and form LiH, which is not attractive as a plasma facing component. A "thick" lithium film approach would enable hundreds of discharges without the formation of LiH. During this investigation, an engineered surface comprised of a porous refractory metal in which lithium is embedded is being developed to enable the evaluation of a thick lithium film approach for plasma facing components (PFCs). Innovative vacuum plasma spray forming techniques are being used to produce the porous refractory metal surface. Initial resistive heating tests have demonstrated the excellent wetting characteristics of the plasma spray formed porous deposits with liquid lithium. This paper will discuss the development of the engineered surfaces including resistive heating experiments of the porous surfaces with liquid lithium and the status of the effort to coat the full size LTX shell.