Temperature monitoring of the lead bismuth eutectic flow in the MEGAPIE target

S. Ivanov¹ - S. Dementjev²

¹ Institute of Physics, University of Latvia, 32 Miera 32, LV-2169 Salaspils, Latvia
² Spallation Neutron Source Division, PSI, CH-5232 Villigen PSI, Switzerland

Abstract
An Electromagnetic Pump System (EMPS) for the MEGAPIE target has been developed, produced and tested at the Institute of Physics, University of Latvia, during the recent two years in the framework of the MEGAPIE-TEST Project (MEGAWatt Pilot Experiment - TESTing) funded by the Euratom 5^th Framework Programme as an implementation of transmutation technology . The EMPS operates when submerged in the lead bismuth eutectic (LBE), with its temperature ranging within 220-380\degC (the temperature changing rate 5-10\degC/s), depending on the proton beam trip. The electromagnetic pump system is responsible for the lead bismuth eutectic flow in the MEGAPIE target. Discontinue of the by-pass flow, as the result of the channel blockage by helium bubbles, could lead, under certain conditions, to undesirable consequences, including even disintegration of the beam entrance window. Therefore, monitoring of the flow during the target operation is very important. The results of the original electrodynamic and thermohydraulic calculations of the electromagnetic pump system are presented in the paper. These results assume the monitoring of the lead bismuth eutectic flow through electric regimes for electromagnetic pumps and LBE temperature measurements. The procedure rests upon the strong correlation between the LBE temperature at the EMPS inlet and outlet, the flow rate and the electric regime for the pump operation. A special PC code, which allows to control the intensity of the LBE flow in the EMPS channel at steady and transient temperature regimes of the target operation, has been developed and used. There are presented recommendations on the PC code adoption for the MEGAPIE target control system at the end of the paper. Figs 10, Refs 4.