Optimal Performance of Power Conversion Units and their Integration with Nuclear Reactors

The optimal thermodynamic performance of four power cycles is compared as a function of the working fluid temperature exiting the gas heater or steam generator that transfers reactor heat to the power generation turbines. This research is partially motivated by the desire to establish optimal designs for integrated, nuclear – renewable hybrid energy systems that must incorporate one of these power cycles. Research and development of these "hybrid" energy systems could lead to more efficient utilization of clean energy generation sources for both electricity generation and thermal energy applications. Achieving optimal performance for each subsystem, and the integration of those subsystems, will maximize the potential for these systems to meet the needs of the combined electricity, industrial manufacturing, and transportation sectors. The power cycles considered in this study include the steam Rankine cycle, the helium closed Brayton cycle, the supercritical carbon dioxide recompression cycle and the open air Brayton cycle. The relative thermodynamic performance of these cycles, integrated with four nuclear reactor types, respectively, is also compared to the theoretical optimal performance. The reactor types considered include a pressurized water reactor; a sodium-cooled, advanced fast reactor; a molten-salt-cooled advanced high temperature reactor; and a helium-cooled, very high temperature reactor. The study serves as a guide for evaluation of the basic power cycles for the four nuclear reactor types currently being evaluated by the U.S. Department of Energy (DOE) Advanced Reactor Technologies (ART) Program and provides information for the optimal design of integrated, hybrid energy systems that are also being developed under the ART Program. (author)