Frequency fluctuation coefficient based bubbles detection method in sodium flow with electromagnetic vortex flowmeter

The electromagnetic vortex flowmeter is a new type of instrument for detecting the steam generator leakage in sodium-cooled fast reactor for the operational safety of the entire nuclear power plant, and its performance is determined by the signal processing method. However, the existing signal processing methods pay more at-tention to the amplitude of the signal, and there are many factors that affect the amplitude of the signal, in-cluding the strength of the magnetic field, the flow rate of liquid sodium, and the magnification of the con-ditioning circuit. Therefore, a signal processing method of bubbles detection in sodium is studied from the perspective of frequency. It is found that the bubbles will cause a distorted waveform in the output signal of the OSOES 1 , thereby affecting the frequency calculation result of the OSOES. The flow signal cycle is used as the time unit to calculate the frequency of the OSOES, and the frequency fluctuation coefficient is defined. The relationship between the frequency fluctuation coefficient and the number of flow signal cycles is established to provide a strategy for studying how to highlight the effect of bubbles on the OSOES. A frequency fluctuation coefficient based bubbles detection method in sodium flow is proposed. It is implemented on DSP-based hard-ware system in real-time, and the verification experiments show that this method can detect the minimum water leak rate in the SG as low as 0.1 g/s.