Supercritical CO2 Power Cycle for Small Modular Reactor

Abstract

Most Gen IV reactors have high operating temperature to increase power plant efficiency as well as for hydrogen production. The widely used steam Rankine cycle is not suitable for Gen IV Reactors because of low turbine inlet temperature or high turbine inlet temperature (649 °C) with extreme high pressure (34 MPa) by using ultra-supercritical (USC) steam cycle. Supercritical CO2 recompressing cycle can achieve a competitively high thermal efficiency with turbine inlet temperature at 500–600 °C and turbine inlet pressure at 20 MPa. However, this operating pressure is still too high to limit its application in power cycle of nuclear power plant. A combined recompressing cycle and dual expansion turbine technology is employed to reduce the operating pressure for nuclear power plant and increase thermal efficiency. Besides, sensitive analysis is performed for three kinds of S-CO2 power cycle. The results show that the combined recompressing cycle and dual expansion turbine technology is effective and suitable for Gen IV reactors with relatively lower reactor operating pressure (10–15MPa) and high thermal efficiency.