[23p-E103-1~10] Plasma-Liquid Interaction - Recent Trends of their Fundamentals and Applications -

[23p-E103-6] Liquid metal plasma-facing components for a steady-state magnetic fusion reactor

〇Yoshihiko Hirooka¹ (1.Chubu Univ. Grad. Sch. Eng.)

Keywords:liquid metal, magnetic fusion reactor, plasma-wall interactions

Most of the existing confinement devices and power reactor designs employ tungsten for the divertor, a key plasma-facing component (to be referred to as PFC) for power and particle handling due to its high thermal resistance and low sputtering characteristics. In fact, the International Thermonuclear Experimental Reactor (ITER) is envisaged to use tungsten as the divertor surface material. In the current divertor design, tungsten backed with an actively cooled heat sink made of a material with a high thermal conductivity, such as copper alloys, could handle heat fluxes up to 20MW/m², which may be sufficient for fusion devices with the heating power up to 50MW. However, this limit may not apply for the first DEMO and following commercial reactors to which the heating power would easily exceed 100MW. In addition, the ductile-brittle transition temperature (DBTT) for commercially available tungsten materials is typically around 400^oC, either prepared by powder metallurgy or chemical vapor deposition. Because the ITER divertor will be operated at around 1000^oC, temperature cycles associated with reactor start-up and shutdown would cross DBTT repeatedly, which could then induce thermo-mechanical cracking on the divertor surface.To resolve these technical issues with tungsten PFCs, the use of liquid metals has been proposed and a variety of proof-of-principle experiments have been conducted, the data from which will be reviewed in this presentation.