The Application of Multi-Channel Ultrasonic Flow Measurement Technology in the Measurement of Cooling Circulating Water in Nuclear Power Plants

To achieve accurate measurement of large-diameter cooling circulating water in nuclear power plants and provide data support for the safe, stable, and efficient operation of the system, this study focuses on multi-channel ultrasonic flow measurement technology and the correlation between seawater sound speed, temperature, and salinity. In terms of methods: First, the transducer replacement structure under non-stop flow and pressure of the multi-channel ultrasonic flow measurement device was optimized. Second, shielding, filtering, and data fusion technologies were introduced to process ultrasonic signals, thereby improving data reliability. Third, a correlation model between seawater sound speed, temperature, and salinity was established based on the Wilson formula. Experiments were conducted using a sound velocity meter, high-precision temperature sensor, and high-precision salinity sensor within the ranges of 14–29 °C (temperature) and 20–40‰ (salinity), and inversion was realized by combining the Newton iteration method. The results show that: (1) The measurement accuracy of the multi-channel ultrasonic flowmeter is stably controlled within ±0.5%, which can accurately measure low flow velocity and small flow rate, and detect issues such as pipe water leakage. (2) The average relative error between the calculated sound speed and the measured sound speed is 0.10%, while the average relative errors of temperature inversion and salinity inversion are 0.3% and 0.35%, respectively. (3) The non-stop flow maintenance of the transducer significantly reduces the construction difficulty. The conclusion indicates that this technology is superior to traditional methods in terms of measurement accuracy, stability, and adaptability to large-diameter pipelines, and can provide strong technical support for the safe operation and parameter optimization of the cooling circulating water system in nuclear power plants.