Ultrasound Doppler velocimetry (UDV) was used to measure flow velocities at temperatures up to 620°C. To overcome the thermal restriction of the ultrasonic transducers an acoustic wave guide was used. The acoustic wave guide and the piezoelectric element are combined in the form of an integrated sensor. This approach allowed the first successful application of the ultrasound Doppler technique in liquid metals at temperatures above 200°C. The feasibility of this integrated sensor concept was demonstrated in experiments with metallic melts. Measurements were performed in a PbBi bubbly flow and in CuSn.

Velocity measurements at high temperatures by ultrasound Doppler velocimetry using an acoustic wave guide

Analysis and control of ﬂuid ﬂows, often subsidiary to industrial design issues,require measurements of the ﬂow ﬁeld. For classical transparent ﬂuids such aswater or gas a variety of well-developed techniques (laser Doppler and parti-cle image velocimetry, Schlieren optics, interferometric techniques, etc.) havebeen established. In contrast, the situation regardingopaque liquids still lacksalmost any commercial availability. Metallic and semiconductor melts oftenpose additional problems of high temperature and chemical aggressiveness,rendering any reliable determination of the ﬂow ﬁeld a challenging task. Thisreview intends to summarise diﬀerent approaches suitable for velocity mea-surements in liquid metal ﬂows and to discuss perspectives, particularly inview of some recent developments (ultrasound, magnetic tomography).Focus-ing mainly on local velocity measurements, it is subsequently distinguishedbetween invasive and non-invasive methods, leaving entirely aside the acqui-sition of temperature, pressure, and concentration, for which [1] may serve asa comprehensive reference.

Velocity Measurement Techniques for Liquid Metal Flows

This current report is a summary of information obtained in the "Information Capture" task of the US DOE-funded "Under Sodium Viewing (USV) Project" The goal of the multi-year USV project is to design, build, and demonstrate a state-of-the-art prototype ultrasonic viewing system tailored for periodic reactor core in-service monitoring and maintenance inspections The study seeks to optimize system parameters, improve performance, and re-establish this key technology area which will be required to support any new US liquid-metal cooled fast reactors

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Under-Sodium Viewing: A Review of Ultrasonic Imaging Technology for Liquid Metal Fast Reactors

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Assessment of Sensor Technologies for Advanced Reactors

Distributed temperature sensor testing in liquid sodium

An ultrasonic level measurement system which provides a continuous digital readout over a range of 3 to 180 inches, was tested in 500°F liquid sodium. The system proved to be accurate and reliable, required no initial warm-up period and experienced no long term drift. Modifications can extend the present operating temperatures to greater than 1200°F.

L. S. Boehmer

Papers

An Ultrasonic Instrument for Continuous Measurement of Sodium Levels in Fast Breeder Reactors