The MHD pressure drop in the second wall orifice which connects the first wall cooling channel and the header in one of the BCSS blankets is discussed. Though the second wall is thin, the pressure drop in the orifice can be very large because of leakage current effects. If eddy currents leak and do not have to pass through thin walls, the resistivity of the current path may be low and the current intensity may be high, which induces a high pressure drop. The presence of leakage current greatly affects the MHD pressure drop in fusion reactor blankets.