Nuclear power plants are designed to produce electricity steadily for 24 hours a day. But now that nuclear power plants share the electric grid with renewable energy sources that fluctuate based on the weather and time of day, their design is mismatched with modern operational needs. Rather than running constantly, nuclear power plants need to have greater flexibility in when they produce energy and when they pause.
A group of researchers at the UCF Center for Advanced Turbomachinery and Energy Research (CATER) believe the solution to this challenge lies in thermal energy storage (TES), a technology system that collects and stores heat produced by nuclear reactor until it is needed.
Their research on TES integration with nuclear power plants was recently published in the Journal of Energy Resources Technology, Part A: Sustainable and Renewable Energy. Their study, titled "Molten Salt Reactor Dispatch Optimization via Thermal Energy Storage: Coupled Thermodynamic Modeling and Rolling-Horizon Economic Analysis," combines thermodynamic modeling with an economic analysis of how nuclear power plants can financially operate in a changing energy market.
The authors of the study are doctoral research assistants Augusto Delavald Marques and Abhilash Prasad, Postdoctoral Scholar Shinjan Ghosh, Associate Professor Erik Fernandez, alumnus Marcel Otto, and CATER Director Jayanta Kapat.
"Nuclear power needs to be flexible while nuclear reactors operate at a steady pace because grid demand varies throughout the day, and this is especially pronounced in grids with high solar penetration, which typically peaks around noon and diminishes toward night," Marques says. "This is a challenge for power plants because they must adjust quickly to meet grid demand."
Traditional nuclear power plants aren't designed to rapidly cycle on and off, so they must deliberately lower their output, which can stress the equipment, or continue to produce power when it isn't needed.
But TES systems could alleviate this problem by absorbing excess heat produced by the nuclear reactor and regulating the amount of heat sent to the grid. The stored energy in the TES can then run the power grid during times of lower energy demand.
Another issue that the UCF researchers believe a TES can solve is that of price. Electricity prices can vary throughout the day as supply and demand changes. By storing the energy when demand and prices are low and using it when demand and prices increase, Ghosh says it can increase the value of the electricity produced.
"As renewable power generation grows, the need for flexibility in nuclear plants has become more important," Marques says. "The deployment of next-generation nuclear reactors in the US over the next few years, such as molten salt reactors, is an opportunity to incorporate TES and improve the integration of nuclear and renewable energy on the same grid."
