TEMPERATURE MONITORING OF LEAD BISMUTH EUTECTIC FLOW IN THE MEGAPIE TARGET

Introduction. An Electromagnetic Pumps System 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 within the Euratom 5 Framework Programme as an implementation of transmutation technology [1]. The EMPS operates being submerged in lead bismuth eutectic (LBE), whose temperature fluctuates depending on the proton beam trip in the range 220–380◦C with the temperature changing rate 5–10◦C/s. The electromagnetic pump system is responsible for the lead bismuth eutectic flow in the MEGAPIE target. Stop of the flow, e.g., as a result of the channel plugging with He bubbles, leads to local overheating of the proton beam inlet window and very likely to its disintegration. Therefore, monitoring of the flow during the target operation is a very important task. Results of original electrodynamics and thermo hydraulic calculations of the electromagnetic pump system are presented in the report. These results assume the procedure of lead bismuth eutectic flow monitoring through electrical regimes for electromagnetic pumps and lead bismuth eutectic temperatures measurements. The procedure is based on the strong correlation between the lead bismuth eutectic temperature at the EMPS inlet and outlet, the flow rate and the electrical regime for the pump. A special PC code, which allows controlling the intensity of the lead bismuth eutectic flow in the EMPS channel at steady and transient temperature regimes of the target operation, has been developed and proposed. There are recommendations on the PC code adoption for the MEGAPIE target control system at the end of the presentation.