Expediting Fusion Energy Development via Sheared-Flow-Stabilized Z-Pinches and Liquid Metal Walls

Zap Energy Inc. (ZEI) is on the path to commercialization of a sheared-flow-stabilized (SFS) Z-Pinch plasma discharge fusion system. The SFS Z-pinch concept, developed at the University of Washington with LLNL collaborators, offers the promise of a compact fusion device owing to its simple geometry and absence of external magnetic field coils. Recent experiments corroborate expected thermonuclear fusion reaction rates, as the discharge current is scaled towards compact reactor conditions.

ZEI envisages the use of an advanced liquid metal blanket as a primary plasma facing material for tritium breeding, building upon the well characterized Pb-17Li eutectic alloy. Other important functions of the liquid metal, besides T-breeding, are cooling and heat transfer, plasma radiation shielding, and other applications specific to the SFS Z-pinch reactor architecture to enable its use under high vacuum and high current service. Liquid metals have rapidly emerged as some of the most attractive coolants for heat transfer enhancement in fusion reactor technologies. They possess excellent physical properties, including low melting point, high boiling point, high thermal conductivity, low viscosity, among others. The Lead-Lithium alloy is also an adequate radiation shield owing to lead’s high atomic number which results in a high stopping power of ionizing radiation. Utilization of a liquid metal as plasma facing material, instead of a solid component, solves many of the radiation degradation challenges observed on crystalline materials, since there is no such ordered atomic structure in liquids due to its inherent amorphous nature. It also enables easier tritium separation, as opposed to Li-containing ceramic liners.