THE NEWEST 2-PHASE FLOW-CONTROL DEVICES IN LWR EQUIPMENT BASED ON ULTRASONIC AND WAT-TECHNOLOGY

This paper deals with new acoustic methods of two-phase flow diagnosti cs used to carry out research in the fields of nuclear power thermophy sics and nuclear power plant (NPP) technologies equipment control. All the designs are to be used under extreme conditions, characteristic f or water coolant, with temperature up to 350 degrees C and pressure 20 MPa. All the safety and reliability requirements are met. The methods use waveguide ultrasonic transducers for longitudinal and bending wav es, made according to specially designed technology (waveguide acousti c transducers-WAT technology). This paper deals with the operating pri nciples of transducers and processing device physical models as well a s some results on the practical use of this equipment. The method of a coustic impedance is based on measuring attenuation of a longitudinal or bending ultrasonic wave in a thin-walled tube diameter vapour fract ion or the level of the coolant in the tank. The waveguide transducers , designed by the centre, use bending waves of a surface type. They en able us to carry out diagnostics of the liquid film on the inner surfa ce of the tube or discover gas inclusions in the liquid flow. The pape r touches upon the method of acoustic emission for measuring moisture content in a steam flow.