Open surface MHD flow of liquid metal coolant in a rotating divertor target of a Tokamak fusion reactor

E. V. Muraviev

Russian Scientific Center, Kurchatov Institute, 123182 Moscow, Russia

Abstract
A new divertor concept where the liquid metal (LM) (Ga) is to be used as a coolant has been proposed by the author with colleagues. In the Russian DEMO fusion reactor project this concept was further developed for the conditions of extremely high peak thermal loads to the divertor targets (up to 500 MW/m2). The proposed divertor target was a rotating drum with the outer surface facing the plasma and the inner surface cooled by free LM flow. The LM coolant is sprayed into ring grooves from several mouthpieces distributed around the drum circumference and taken out by a corresponding number of scoops. The LM in the cooling groove is accelerated by the moving walls due to friction and MHD interaction though it does not gain the full linear velocity of the rotating drum before getting into the nearest scoop. For this system a quasi-one-dimensional MHD flow model has been developed which allowed us to determine the LM velocity distribution depending on the conditions of LM feeding in and out. Iterative calculations were performed to achieve self-consistent solutions/or the closed circular flow in the cooling groove. The obtained results can be used for calculations of heat transfer coefficients.