Performance Optimization of Power Generation System for Helium Gas/Lead Lithium Dual-coolant Blanket System

Helium gas (He-gas) / Lithium Lead (LiPb) Dual-cooled LiPb (DLL) blanket is one of the promising candidates for the DEMO fusion reactor for power generation. Brayton cycle based on He-gas has been used as the power generation system for the fusion and fission power reactors. In this work, a modified and efficient design of the power generation system with concept of two stage expansions and one intercooler named as Schematic-I has been proposed for the DLL blanket of Fusion Power Reactor (FDS-II) to increase the thermal performance (e.g. power density and efficiency) of the system and optimized the parameters of the system. The engineering equation solver tool was used to calculate the performance of the system. It is found that the use of more than one expansion stage with proper selection of intercooler is very effective as compared with either splitting the flow equally for the expansion in two turbines or a single stage expansion. The concept of two-stage expansions in the Schematic-I increased the thermal efficiency of the system up to 51%, which was 4% higher than previous design of DLL blanket power generation system. The main parameters of the system such as isentropic efficiency of turbine and compressor, pressure ratio, recuperator performance, the terminal temperature difference of the recuperator, the inlet temperature of DLL blanket and effect of different pressures on the system have all been analyzed and optimized to achieve high performance.