Liquid Li/V alloy blanket

Page 1 : Problems in Liquid Li/V-alloy blanket

Page 2 : Three-surface and multi-layer coated channel
Page 3 : Numerical analysis and experiments
Page 4 : Published Papers

Problems in Liquid Li/V-alloy blanket

MHD pressure drop reduction is an important issue in the Li/V blanket. The MHD pressure drop is caused by both generation of electromagnetic force working as resistance force and increase of friction force due to flattened velocity distribution by the electromagnetic force. Since the electromagnetic force is proportional to square of the magnetic filed while the friction force changes linearly against the field, suppressing electromagnetic force becomes important for MHD pressure drop reduction.

Several ideas have been proposed to decrease the electromagnetic force. Especially, insulating coating can reduce the MHD pressure drop dramatically because electromagnetic force comes out even. However, current paths to the channel wall, which induces the electromagnetic force, are easily formed by liquid lithium invasion to the conducting wall through cracks in insulator caused by difference in thermal expansion between the conducting wall and insulator. In addition, insulating material having low thermal conductivity is not suitable to apply on the first wall exposed to high heat flux from main plasma.

MHD pressure drop