Abstract: Based on the turbine-driven pump manufacturing document and the design parameters of the operating auxiliary feedwater system, this paper proposes the measurement design for peak-over-threshold flow restriction of auxiliary feedwater turbine-driven pump. For the factors of the actual layout and system measurement requirements in Fuqing nuclear power plant, design optimization is also proposed. Through prototype test and on-the-spot debugging test, the feasibility of measurement design are verified. The measurement can completely meet the operational requirements of the system in nuclear power plant blackout accident.