Innovative Surfaces for Controlled Flow of Molten Lithium

The potential economic, environmental, and strategic benefits associated with the development of fusion energy are numerous. However, fusion technology cannot be realized without advanced materials that allow operation under the high heat flux conditions necessary for cost-competitive electric energy generation. In particular, a coating is needed to control the flow of molten lithium on the fusion reactor¿s plasma facing component. The liquid metal is a viable approach for accommodating continuous heat flux levels exceeding 10 MW/m. In this project, a high temperature microtextured coating, consisting of hundreds of thousands of pyramids per square millimeter, will be deposited onto a suitably radiation-tolerant substrate by chemical vapor deposition (CVD). The height and population density of the pyramids will be varied by varying the process conditions. The wicking properties of the resulting coatings will be measured and quantified by exposing the coatings to molten metals such as lithium, gallium, or tin, and the heat transfer and fluid flow characteristics will be modeled. If necessary, a thin coating of molybdenum can be applied to the textured surface to improve wetting. Commercial Applications and other Benefits as described by the awardee: Nuclear fusion offers a replacement for increasingly scarce fossil fuel energy sources. Alternatives to fossil fuels (e.g. wind, solar, geothermal) cannot generate sufficient energy to meet current needs. Fusion, with its low generation of radioactive waste, is ideal for large-scale energy production. Practical application is absolutely dependent on the development of advanced materials.