Abstract: The separation characteristics and pressure drop characteristics of the saturated wet steam through the corrugated plate separation element are verified under the actual operating conditions of the moisture separator reheater (MSR) for PWR nuclear power units. The saturated wet steam which meets the requirements are provided by using a large thermal hydraulic test bench, and the pressure drop and residual humidity are obtained when the wet steam flows through the test piece. The results show that the critical flow rate of re-entrainment is high, and when the inlet steam dryness is not greater than 86% and the inlet flowrate is less than the critical flowrate, the residual humidity is not greater than 0.1%, the separation efficiency is of 99% or more, and the pressure drop is not greater than 7 kPa. The design requirements of more than 99% steam dryness and less than 14kPa pressure drop are satisfied. It is with good separation and pressure drop characteristics.