Overall efficiency analysis of an innovative load-following nuclear power plant-thermal energy storage coupled cycle

An innovative thermal energy storage (TES)-nuclear power plant (NPP) coupled system is investigated. This system is intended to have a better ability to follow the grid demand. In this design, the phase change material (PCM)-based TES have a dual role in acting as a simple heat exchanger during optimal operation, or energy storage/supplier to overcome the fluctuating energy demand. To assess the coupling feasibility, the efficiency of overall system is examined using energy and exergy balances at different components for two designs of the power generation process: Rankine and supercritical carbon dioxide (SCO2) Brayton cycles. Results confirm that around 50% of the exergy is lost during plant operation in the reactor core. Most importantly, the losses in the TES are much smaller (< 10%) than the reactor core losses. Advanced (SCO2) Brayton cycle is more efficient than Rankine cycle and efficiency can reach 50% using high effectiveness and high-efficient components.