Optimal system configuration and operation strategies of flexible hybrid nuclear-solar power plants

Nuclear power plants are commonly used for baseload power supply due to their high reliability, low variable costs, as well as relatively low thermal efficiencies and limited load-following capabilities; especially, in the case of light water reactors. At the same time, concentrating solar power (CSP) technology is gaining attention, but is still considered an intermittent source of power with a limited availability factor. In an effort to propose a very different performance characteristic for both technologies, a hybrid power system combining nuclear and CSP plants and integrated with a thermal energy storage system is considered in this paper. The integration of the technologies is achieved by adding an indirect solar superheater and a solar reheater to a small modular nuclear reactor (NuScale). The work includes modelling of the integrated hybrid system, thermodynamic performance analysis and operational optimization aimed at maximizing the profitability of such a hybrid power plant in Oman. The results show that the hybrid system has the potential to deliver more efficient and flexible power (operating between 55% and 100% of nominal load) with the nuclear reactor operated continuously at its full rated power. The hybridization concept can potentially produce a competitive levelized cost of electricity, especially with the integration of thermal energy storage. The study concludes that the installation of such a system in Oman is not yet economically viable unless electricity tariffs increase by 70% to UK levels