MHD pressure drop in ferritic pipes of fusion blankets

Magnetohydrodynamic flows in pipes of ferromagnetic material is an important issue for liquid metal blanket concepts using MANET as wall material. Fusion relevant magnetic fields of 4–8 T cause high pressure drop in the blanket header where a massive structure of ferromagnetic material exists. It is briefly outlined that in the blanket the reduction of pressure drop due to magnetic shielding is limited to about 10%. Remarkable reduction of pressure drop is possible by means of electrical insulation that prevents currents from short-circuiting through the very thick walls of the headers. Direct contact of the insulating material with the liquid metal is excluded by using metallic liners. Results are reported on the fabrication of such a test section and corresponding pressure drop measurements confirm the effective contribution of the electrical decoupling.