Thermodynamic Analysis of Combined Supercritical Carbon Dioxide Brayton Cycle Applied to Lead-cooled Fast Reactor

In this paper, the thermodynamic analysis of the lead-cooled fast reactor composing recompression supercritical carbon dioxide(S-CO2) Brayton cycle, steam Rankine cycle and He Brayton cycle as power block is introduced. The advantage of lead-cooled fast reactor composing recompression S-CO2 Brayton cycle is explored through comparing the optimal thermodynamic performance of recompression S-CO2 Brayton cycle with that of conventional power cycles. In order to improve the performance of S-CO2 cycle, the recompression supercritical carbon dioxide/transcritical carbon dioxide(S-CO2/T-CO2) combined cycle is primarily constructed by using T-CO2 as bottom cycle. The influences of the turbine inlet temperature, turbine inlet pressure and the compressor inlet temperature of the top cycle on the combined-cycle performance are further invesitgated. Finally, the performance of the S-CO2 cycle and that of S-CO2/T-CO2 combined cycle are compared. The results are indicated as follows. First, the lead-cooled fast reactor comprising recompression S-CO2 Brayton cycle has higher efficiency than the conventional systems. Second, the thermal efficiency and exergy efficiency of the S-CO2/T-CO2 combined-cycle can be maximally improved by 4.8% and 8.3% comparing to that of S-CO2 cycle, separately. Third, the thermal performance of the S-CO2 recompression cycle and that of S-CO2/T-CO2 combined cycle alter consistently with the changed crucial parameters of the top cycle. © 2020, Science Press. All right reserved.