Development of Ultrasonic Flowmeter for Sodium-Cooled Fast Breeder Reactor

- Applicability Verification of Multi-Path Ultrasonic Flowmeter -

Abstract

   In a conceptual design study on a commercial Fast Breeder Reactor, a large-diameter high-chrome steel piping was introduced to shorten the length of the piping. Ordinarily, an electromagnetic flowmeter (EMF) is applied to measure the flow rate of liquid metal such as sodium. However, because the EMF is not well suited to magnetic material, such as high-chrome steel, an ultrasonic flowmeter is being developed to measure the flow rate of sodium. An ultrasonic transit-time method is applied to flow rate measurement. Water-flow tests were carried out using a 1/4 scale model in order to evaluate the effect of the number of ultrasonic propagation paths on applicability to measurement and development requirements. As a result, it was confirmed that linearity of flow rate and measurement response time requirements were satisfied with 2- and 4-paths. Also, it was found that flow rate measured by the ultrasonic flowmeter in the 4-path did not depend on the installation position of the transducer in a piping system with upstream pipe from 3.0 to 3.6 times the piping inner diameter. From the above results, it was verified that the ultrasonic flowmeter is applicable to a commercial FBR by adopting the multi-path system.