Free surface liquid metal flow for fusion reactors

Abstract

Nuclear fusion has the potential to revolutionize energy production on Earth as both a clean and near-limitless source. Despite the promise of the idea of nuclear fusion as a source of energy there still exist serious physics and engineering questions and con- cerns that prevent actual commercialization of fusion as a source of energy. Amongst the engineering concerns is the handling of the extreme heat flux loads anticipated on the divertor region of the reactor. Reactors currently use solid divertor tiles and water cooling for the handling of heat flux, however for commercially viable reactors with heat flux pushing upwards of > 20[MW/m2] these systems will not be sufficient. The inability to remove heat quickly enough leads to reactors walls melting or deforming to the point where replacement is necessary, and the needs to shutdown and repair becomes unsustainable for energy production.

A proposed solution to this problem is covering the solid divertor with a flowing liquid metal that actively removes heat, and that also acts as a self-healing surface. Furthermore, liquid metal surfaces have been shown to improve the reactor plasma performance by creating a ”low-recycling” boundary condition. Amongst the liquid metal concepts are static/slow-flowing, and fast-flowing configurations. Many fast- flowing configurations have been largely discounted due to adverse magnetohydrody- namics effects that slow-flowing systems do not experience, however the slow-flowing systems do not solve the problem of heat removal and instead only offer the other advantages of a liquid metal wall. The goal of the research described in this disserta- tion was to investigate the uses and effects of user-imposed electromagnetic forces in the context of flowing liquid metal systems.