Helium Entrapment In Liquid Metal Plasma-Facing Surfaces In Tokamak Fusion Reactors

Abstract

The ability to use liquids as plasma-facing components (PFCs) surfaces depends on their interaction with the plasma and the strong magnetic field. One important issue for the moving liquid is the ability to entrain particles that strike the surface while accommodating high heat loads. Particle entrapment could determine the viability of specific liquid candidates as successful renewable PFC surfaces. To study this problem, an analytical model is developed and implemented using the HEIGHTS package that takes into account the kinetics of particle injection, motion and interactions with the liquid lattice, and the ultimate release from the surface. An important question is whether He can also be pumped by the liquid rather than using the standard vacuum system approach. Impinging He particles at the low density at PFCs may be harder to pump using the standard pumping techniques. We find, in this analysis, a reasonable chance of adequate helium trapping in flowing lithium as PFC.