A Modular Approach for the Design of a Salt-to-Salt Heat Exchanger With 3-D-Printed Triply Periodic Minimal Surfaces for Future Fusion Machines

This study explores the preliminary design of a salt-to-salt heat exchanger (HX), focusing on the potential of Triply Periodic Minimal Surfaces (TPMSs) as the interface between the primary and secondary circuits in fusion machines. The hot fluid is a lithium–beryllium fluoride (FliBe) salt used as a liquid breeder, whereas the cold fluid is a conventional solar molten salt. Considering the high mass flow rates of molten salts required on both sides of the HX, the use of parallel circuits and an advanced modular design approach is required. This choice limits the dimension of the component, making TPMS-based designs feasible for 3-D printing. A methodology is presented to scale the requested performance to a single module. A scaled-down module is designed, adopting, among alternative TPMS, a diamond configuration. The prototype performance is assessed numerically, confirming the expectations.