Thermal Hydraulic Analysis of the MEGAPIE Target under Beam Wandering

For many decades, efforts have been made to reduce the amount of nuclear wastes. To incinerate the longlived radioactive nuclides, an accelerator driven system (ADS) is considered to be one of the most favorable solutions. In an ADS, a high energy proton beam is impinged on a heavy metal target to produce spallation neutrons which are multiplied in a sub-critical blanket. Therefore, the spallation target is one of the most important units in an ADS. One of the key issues in the target design is how to design an appropriate beam window and a LBE flow so that the system can sustain thermal and mechanical loads as well as radiation damage. In Europe, intensive research and development programs are now underway relating to the ADS technology. To gather practical experience relating to liquid metal targets, the pilot target MEGAPIE (MEGAwatt Pilot Experiment) has been designed and fabricated in Europe. The KAERI is actively involved in this project, especially in the thermalhydraulic design of the target. The present work is dealing with the thermal hydraulic analysis of the MEGAPIE target with a beam wondering. A series of numerical simulations to consider the consequences of beam wonderings away from the target axis have been performed using a computational fluid dynamics (CFD) code. The results achieved are presented and discussed