A liquid metal cooled RFP fusion core is designed in this study. In order to attain high cooling ability of the first wall without an excessive MHD pressure drop, the return paths of eddy currents induced in the coolant are minimized. Because there are no computer codes capable of analyzing the three-dimensional MHD problems in the blanket, the effects of toroidal field and poloidal field are estimated separately with the assumed streamlines. The total pressure drop through the fusion power core is calculated at only 1 MPa, while the heat transfer coefficient on the first wall is above 25 kW/m2. The stress in the first wall is reasonably low. An MHD coil concept, a toroidal field amplifier by the MHD effect, is proposed and showed to be feasible.