Measurement of Sodium Flow With Ultrasonic Flow Meter

Liquid Sodium is the best coolant for Fast Breeder Reactors. Flow of liquid sodium has to be measured in Fast Breeder Reactor circuits and in experimental facilities. Magnetic flow meters based on Faraday's Law of induction are used normally to measure the flow. Calibrated magnetic flow meters are welded at the required location during the construction of the sodium system and are difficult to remove from the system for recalibration during service life if required. For pipes with larger diameters the magnet assembly of the flow meter becomes larger, making the flow meter bulky and heavy. For in-situ calibration of magnetic flow meters and for measurement of flow in large pipes ultrasonic method is considered. An industrial clamp-on type ultrasonic flow meter (USFM), based on the principle of transit time measurement, was procured and tested in a liquid sodium system to measure the flow rate. To establish the reliability, the USFM was installed in various sodium systems where magnetic flow meters exist and output compared with the existing flow meters. The results are encouraging and the perspective is that this flow meter can be used in sodium systems to measure flow. This paper describes testing of USFM in various sodium systems and its performance.