Flowing Liquid Lithium Walls Using Engineered Surfaces

75376-Reactor studies have identified liquid lithium walls as a promising solution to magnetic fusion energy (MFE) first-wall problems. However, the implementation of a flowing liquid lithium first wall in a fusion experiment is complicated by magnetohydrodynamic (MHD) effects produced in fast-flowing bulk liquid metals in a magnetic field, and the practical concerns of dealing with hundreds of liters of fast flowing liquid metals. To overcome these problems, this project will develop slow flowing ¿thick film¿ liquid lithium walls using engineered surfaces. During Phase I, fabrication techniques will be developed to produce engineered surfaces comprised of: (1) a high thermal conductivity substrate, (2) an electrically insulating coating, (3) a lithium barrier to prevent attack of the underlying substrate, and (4) a porous tungsten layer for embedding the ¿thick-film¿ lithium. Tests will be performed using liquid lithium to determine wetting characteristics, the amount of penetration in the porous layer, chemical compatibility, and coating stability. Techniques for restraining the liquid lithium and controlling the flow direction will also be investigated. In Phase II, engineered surfaces using slow flowing ¿thick film¿ liquid lithium will be produced for testing in an operating spherical torus such as the Lithium Tokamak Experiment (LTX) or the National Spherical Torus Experiment (NSTX). 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 and rocket engines.