New Velocity Measuring Techniques for Liquid Lead and LBE Flows

Liquid metal cooling or liquid metal targets belong to innovative reactor concepts such as fast reactor cooled by sodium or lead and the lead-bismuth target in a transmutation system. The safe and reliable operation of liquid metal systems requires corresponding measuring systems and control units, both for the liquid metal single-phase flow as well as for bubble-laden liquid metal two-phase flows. However, velocity measurements in opaque liquid metal flows still represent a challenging task as commercial measuring systems are not available for such fluids. During the last 15 years, considerable effort was spent at HZDR on the development and qualification of techniques to measure the velocity in metallic melts. Especially, significant progress has been achieved in the field of non-invasive measuring techniques. Recent reviews regarding the principles of different velocity measurement systems and their applicability have been published.
In general, measurement techniques are needed to determine flow rates, flow velocities, heat fluxes, pressures, and free surface levels. Within this paper we present some new developments comprising electromagnetic flow meters, ultrasonic Doppler measurements and a contactless inductive flow tomography. The capabilities of these measuring techniques have been verified by tests at HZDR using various liquid metal loops operating with lead, LBE, SnBi or sodium.