Transient phenomena and their consideration in load-following control of nuclear power plants

Abstract

Radical changes have been happening on the source side of the electricity system due to the rolling back of large-sized fossil-fueled power plants and the coming to the front of uncontrollable renewables. As a worldwide consequence, to ensure the permanent balance of the grid, even big-sized units have to be operated in load-following mode, including also nuclear power plants. This mode is conducted by the control system, which must also consider the side effects of this rather dynamic operating mode. In this report, we show up all components of such a control system, including the process model, structural integrity assessment, and control algorithm. All the aforementioned elements are discussed on the basis of a concrete example, and the resulting control behavior of the entire system is also shown. The results demonstrated that a significant reduction in the caused thermal stresses could be achieved while keeping the control quality practically unchanged.