Characterization of the performance of a hybrid Small Modular Reactor and its interaction with the power grid

Hybrid energy systems with Small Modular Reactors (SMRs) offer a promising solution for combined electricity and heat production, enhancing nuclear plant flexibility and supporting energy decarbonization. This thesis explores this concept from a technical and economic perspective. The technical analysis proposes a conceptual design for the cogenerative secondary loop of a hybrid light-water SMR. Plant interaction with grid disturbances is then examined through multi-physics simulations, focusing on primary frequency regulation, an increasingly relevant aspect as renewable energy penetration grows. The economic assessment presents a methodology to estimate the overnight capital cost of nuclear power plants and compares the economic competitiveness of reactors producing electricity only, heat only and hybrid configurations. Results show that hybrid SMRs can regulate electrical power by diverting the mass flow rate to bypass the turbines, modulating heat output, and reducing disturbances to the steam generator. Finally, an economic assessment based on metrics such as Levelized Cost of Electricity (LCOE), Levelized Cost of Heat (LCOH) and Levelized Cost of Exergy (LCOEx) highlights the potential competitive advantages of hybrid SMRs over full-electrical and full-thermal configurations.