Innovative configuration of a hybrid nuclear-solar tower power plant

Abstract

This paper proposes a combination of a nuclear and a CSP plant and performs a thermodynamic analysis of the potential benefit. Most of today's operating nuclear reactor systems are producing saturated steam at relatively low pressure. This, in turn, limits their thermodynamic efficiency. Superheating of nuclear steam with solar thermal energy has the potential to overcome this drawback. Accordingly, an innovative configuration of a hybrid nuclear-CSP plant is assembled and simulated. It brings together pressurized water reactor and solar tower. The solar heat is transferred to nuclear steam to raise its temperature. Continuous superheating is provided through thermal energy storage. The results from design point calculations show that solar superheating has the potential to increase nuclear plant electric efficiency significantly, pushing it to around 37.5%. Solar heat to electricity conversion efficiency reaches unprecedented rates of 56.2%, approaching the effectiveness of the modern combined cycle gas turbine plants. Off-design model was used to simulate 24-h operation for one year by simulating 8760 cases. Due to implementation of thermal energy storage non-stop operation is manageable. The increased efficiency leads to solar tower island installed cost reductions of up to 25% compared to the standalone CSP plant, particularly driven by the smaller solar field.