LIMET- a test bed for liquid metal targets

As the most delicate component of the lower target container is the Beam Entrance Window (BEW), it is necessary to demonstrate that the structural integrity of the window would be maintained under a variety of operational and accident-scenario conditions. It is of crucial safety importance that the BEW is adequately cooled. In the actual MEGAPIE (Megawatt Pilot Experiment) design, unidirectional flow across the window was affected by a jet exiting from a bypass nozzle in order to provide sufficient window cooling. As the use of an additional bypass pump increased significantly the complexity and costs of the system, the idea of having a reliable configuration without additional bypass flow directed the design efforts. Therefore, the main objective of the activities, which comprise extensive experimental and computational studies and are coordinated under project LIMET (Liquid Metal Target test bed), is to investigate various designs and cooling capabilities of the lower target region without a using bypass flow nozzle and to analyse hydraulic, structural and thermal behaviour of the target mock- up. The preliminary computations have been performed for water and LBE (Lead Bismuth Eutectic) as working fluids and for various geometrical parameters. The optimization of these geometrical parameters is planned to be achieved by combining experimental investigations with computational studies.Two experimental series have been planned: water (LIMETW) and liquid metal experiments (LIMETLBE). A goal of the water experiments (LIMETW) is to investigate several geometries of the riser tube end geometries that should provide adequate cooling of the BEW. They will be subsequently investigated during the second session named LIMETLBE.