Conceptual design studies for the liquid metal target META:LIC

Abstract When the construction of ESS (European Spallation Source) in Sweden was initiated, the target station concept selection group decided to reevaluate a variety of target designs to respect new developments in their selection process. The META:LIC (MEgawatt TArget:Lead bIsmuth Cooled) target concept was developed following an extensive analysis of existing and new proposed designs and reached the level of proof of principle within only 2 years. ESS selected META:LIC as comparative target option for licensing purposes during the design update phase of ESS. The present work describes the design motivation of META:LIC referring to properties and design features of other targets. Therefore, META:LIC design is an evolutionary target which incorporates the extensive experience of liquid metal targets. The modular LBE (Lead Bismuth Eutectic) target concept with focus on the target module is introduced. Both, a window target option for the start of operation and a windowless option with extended lifetime are foreseen. Thermohydraulic simulations show that adequate window cooling can be realized. The stability of the free surface in the windowless option has been shown. Robust target module instrumentation based on free surface levels and the MEGAPIE experience is proposed for target control. Since the META:LIC concept foresees a horizontal extraction for both moderators and target from the monolith a safety concept based on the SNS and JSNS experience is proposed.