Key MHD Phenomena in the Poloidal Duct Flows of the Dual-Coolant Lead-Lithium Blanket

摘要

The Dual-Coolant Lead-Lithium (DCLL) blanket is considered in the US for testing in ITER and as a primary candidate for a DEMO reactor. In this blanket, eutectic alloy PbLi circulates as a breeder and coolant, while He is used for cooling the reduced activation ferritic steel structure. The key element of the DCLL concept is a flow channel insert (FCI) made of a silicon carbide composite (SiC_f/SiC) or possibly SiC foam, which is used to minimize a heat leakage from the breeder zone, to separate hot PbLi from the ferritic structure, and to reduce the pressure drop by decoupling electrically the liquid metal from the highly conducting structural walls (Fig. 1). The liquid metal motion in a strong reactor magnetic field induces an electric current, which in turn interacts with the magnetic field, resulting in the volumetric Lorentz force, which has a very strong effect on the flow field, and through modifications of the flow structure, on heat transfer. Such flows are known as magnetohydrodynamic (MHD) flows. The present study focuses on key MHD phenomena in the poloidal (vertical) ducts of the DCLL blanket, where the fusion energy associated with charged particles and neutrons from the reactor plasma is transformed into thermal energy, and thus, the MHD effects on heat transfer are of primary importance.