Preliminary Design of Water-Cooling System for Liquid Metal Divertor Target Test Module in EAST

Developing a robust, feasible, and reliable plasma-facing components (PFCs) is a key mission to realize the commercial fusion power reactor. The situation of the divertor targets will be particularly severe because of higher heat and particle flux in the future devices. In order to improve the power handling capacity and lifetime of the divertor target, a solution of covering the plasma-facing surface of the target with liquid metal was proposed owing to the ability of self-healing. However, liquid metal targets are still in early stages of development and there are many issues need to be explored, especially in the context of the plasma environment in a tokamak. Experimental Advanced Superconducting Tokamak (EAST), aiming to investigate scientific and engineering issues for fusion, provides a suitable environment to study the performance of liquid metal divertor. In this paper, the design of a water-cooling system for liquid metal divertor target test module in EAST is presented. It contains four circulation loops to deal with different accidents to ensure enough safety margin while minimizing the impact on the plasma discharge experiment. The corresponding system safety analyses have been performed and verified that the water-cooling system can meet the design requirements for the liquid metal target test under both normal condition and accidental events. Furthermore, the design of the water-cooling system is compatible with the constraints adopted for the high heat flux components, enhancing its potential for serving other test modules with similar water-cooling requirements in EAST.