Heat Storage as a Way to Increase Energy Efficiency and Flexibility of NPP in Isolated Power System

Abstract

This paper considers a thermal accumulator using phase transition materials as a way to increase the energy efficiency and maneuverability of nuclear power plants. A low-power nuclear power plant is the object of this study. Such nuclear power plants have a great potential for widespread implementation as sources of thermal and electrical energy for facilities of mineral and raw material as well as fuel and energy complexes located in distant regions. The main principles of development of low-power nuclear power plants are revealed. So, in the development of low-power nuclear power plants, experience in the creation and operation of shipboard nuclear power installations is widely used. The problems of NPP operation in daily maneuvering modes within an isolated power system are revealed. A method for improving the energy efficiency and maneuverability of nuclear power plants is proposed, in particular, through the use of thermal accumulators with a phase change material directly in the NPP circuit. A method of assessment of the dimensions of the heat accumulator and the amount of heat accumulating material is presented. A method of assessment of the efficiency of the accumulator application scheme is presented. The thermal scheme of a promising low-power nuclear power plant with an RITM-200 reactor is compiled. A scheme for switching on a heat accumulator with a phase change material to a scheme for regenerative heating of a turbine is proposed. The heat storage material selection is made, the main elements and characteristics of such an accumulator are determined, and the parameters of the heat transfer fluid’s movement through the accumulator are determined. A mathematical model of the heat exchange in an accumulator based on the finite difference method is compiled, and the simulation results are presented. The results of the experimental verification of the model are presented. As a result of the calculation of NPPs’ thermal schemes in the standard version and the version with a heat accumulator, the power increase in the turbine plant due to the application of accumulated heat in the accumulator discharge mode is determined.