Bubble detection in sodium flow using EVFM and correlation coefficient calculation

Highlights: • The working principle of the EVFM primary instrument is analyzed. • The output signals of EVFM were collected at different injection flow rates. • Correlation coefficient calculation based signal processing method is proposed. • A secondary instrument was developed with DSP for EVFM. • The method and system are verified by using collected experimental data. - Abstract: In the sodium-cooled nuclear reactor, the steam generator (SG) is a heat exchange device between the sodium and water/steam. If it leaks, it will lead to the sodium-water reaction and affect the operational safety of the entire nuclear reactor. The electromagnetic vortex flow meter (EVFM) based on the principle of electromagnetic induction can be used to detect the SG leakage. The simulation experiment of the SG leakage is designed by injecting argon into the SG. The output signals of primary instrument of EVFM are collected under different gas injection flow rates, and the characteristics of the AC component in the output signals are analyzed in frequency and time domains, respectively. A signal processing method based on correlation coefficient calculation is proposed to detect the SG leakage. A secondary instrument of EVFM is developed with a DSP chip to realize the signal processing method in real time. The output signals of primary instrument of EVFM collected in the experiments are as the input signals for sending to the secondary instrument to perform verification experiments. The experimental results show that the proposed signal processing method can effectively identify the SG leakage signals, and the developed secondary instrument can detect the water/steam leakage of the SG down to 0.1 g/s with the response time being less than 1 s.