Engineered Surfaces for the Lithium Tokamak Experiment

75376B Reactor studies have identified liquid lithium walls as a promising solution to magnetic fusion energy first wall problems. For near-term applications, such as the Lithium Tokamak eXperiment (LTX), a thin-film approach has been pursued; 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. This project will develop engineered surfaces to enable the evaluation of a thick lithium film approach for plasma facing components. Phase I demonstrated the feasibility of plasma-spray-formed engineered surfaces for use with liquid lithium plasma facing components. Testing was performed to demonstrate the excellent wetting characteristics of the plasma-spray-formed porous deposits with liquid lithium ¿ plasma-sprayed porous Mo surfaces were wet at temperatures less than 300¿C. During Phase II, the engineered surface fabrication techniques will be optimized for full scale testing of a thick lithium plasma facing concept within LTX. Comparisons to thin films of liquid lithium adhered to a nonporous stainless steel surface by surface tension will be made. Commercial Applications and Other Benefits as described by the awardee: The thick film technology should have commercial application to heat pipes; thermal and electrical insulating coatings for the electronics industries; improved chemical compatibility for molten metal processing; and improved thermal protection systems for furnaces, turbines, incinerators, plasma torches, rocket engines, fuel injectors, hard coatings, plasma treating of materials, and thick film heaters.