Background. Nuclear power engineering faces the problem of low maneuverability of power plants, which makes it difficult to adapt to changing energy consumption modes. There is a need to develop technical solutions that increase the flexibility of nuclear power plants without significant design changes to reactor plants. One of the promising areas to solve this problem is the introduction of heat storage systems that allow us to accumulate excess energy during periods of low consumption and use it during peak load hours.
Materials and methods. The study has been conducted using MBIR research reactor, as well as the material of published articles on heat accumulation. The authors have used the methods to analyze existing schemes of thermal accumulation for nuclear power plants, as well as methods to model and select operating modes of heat accumulator. A design option for implementation of a heat accumulator using four circulation pumps and a two-tank coolant storage tank has been considered.
Results. A concept for using a two-tank heat accumulator with a nitrate-nitrite salt coolant for the MBIR nuclear research reactor has been developed. This concept includes three operating modes: charging, discharging, and nominal condition. The choice of coolant is justified by its high heat capacity compared to sodium and, crucially, increased safety in case of possible contact with water, which reduces the risks during integration with the steam-water circuit. The proposed heat accumulator design consists of a discharge tank, a charging tank, four heat accumulator pumps (HAPs), and shutoff valves.
Conclusions. The proposed concept of a heat accumulator for the MBIR research reactor ensures more efficient use of the reactor thermal energy, allows the turbine to operate in a semi-peak mode, and can be adapted for use at industry-based nuclear power plants. The use of a heat accumulator offers an opportunity for energy storage and increased maneuverability of the power plant. The proposed concept can be applied in the future for industry-based nuclear power plants.