Variable research of the efficiency of a combined thermal storage system when used at NPPs with VVER

Abstract

The energy sector has the problem of covering the unevenness of daily energy consumption. Electric stations are unloaded during hours of reduced electrical load in the power system, which leads to a decrease in their economic efficiency and resource indicators. This problem is especially relevant for nuclear power plants. This is justified by their high cost with relatively cheap fuel, which makes it logical to fully load them. However, an increase in the number of nuclear installations in the energy system leads to the need to unload them. The authors developed a system for combining thermal accumulators (phase change accumulator and hot water tanks) with a nuclear power plant and an additional low-power steam turbine. An additional turbine makes it possible not to overload the main turbine of a nuclear power plant. In addition, when a nuclear power plant is de-energized, an additional turbine can provide power to the station’s own needs using only the decay heat energy of one reactor. The conditions for economic efficiency and payback of the accumulation system were studied in the work. Boundary values of the maximum net present value for three steam turbine power options for a range of operating conditions were obtained.