Thermodynamic Simulation of Supercritical Carbon Dioxide Brayton Cycle in an Advanced Nuclear Power Plant Equipped with a Heat Pipe Cooled Microreactor

One of the newest technologies in small nuclear power plants is using heat pipe cooled microreactors. In these power plants, several heat pipes transfer the heat produced in the microreactor core to the working fluid inside the main heat exchanger. In this paper the thermodynamic simulation of the Brayton gas cycle is conducted for a nuclear power plant equipped with a heat pipe cooled microreactor with a thermal power of 5 MW using the THERMOFLEX code. The considered working fluid in the Brayton cycle in this case is the supercritical carbon dioxide, and this cycle includes the main heat exchanger, turbine, main compressor, recompression compressor, pre-cooler and high and low-temperature recuperators. The results of the thermodynamic analysis of the studied cycle showed an efficiency of 36.508 % for the considered power plant. Besides that, as the pressure ratio of the main compressor increases up to 3.15, the efficiency of the power plant increases. Whereas, at higher pressure ratios, efficiency decreases. Also, the main compressor power in the cycle was obtained as 2030.1 kW. In addition, when the re-compression compressor is designed with a mass fraction of 23%, the cycle will achieve its highest efficiency. Besides that, the turbine expansion power and shaft power were calculated as 5091 kW and 5040 kW, respectively.