Designing of cooling water system for a pyro-breaker utilized in superconductive fusion facility

Abstract Pyro-breaker used as a backup breaker in Quench Protection System (QPS) guarantees the safety of a superconductive fusion facility. High current flows through the pyro-breaker and great amount of heat flux will be brought into the breaker due to the structure and mechanism of the Pyro-breaker. Requirement of each subsystem is crucial for the overall designing of the entire Cooling Water System (CWS). In this paper an optimized design of the CWS for Pyro-breaker is presented. Theoretical calculation and Computational Fluid Dynamics (CFD) are used to analysis the heat transfer coefficient of the cooling system. Thermal-electrical simulation is performed on the model and the result is verified by experiment on a prototype. It can be concluded that the presented Pyro-breaker model has the current capacity of 40kA with the coolant velocity of 1 m/s. Optimization of the CWS is made based on the verified method and a set of required coolant velocities is proposed when the current capacity reaches up to 80kA. The pressure drop, which is an important factor for the entire CWS, is calculated in ANSYS CFX when the breaker is applied under 80kA.