Optimization of Weight and Size Characteristics and Unification of Heaters of the Regeneration System of NPP Turbine Units

When designing new nuclear power plants, it is important to ensure cost-effective electricity production while complying with safety, reliability, and environmental protection requirements. One of the directions for solving this problem is to improve the equipment of nuclear power plants, in particular the search for the most suitable technical solutions for regenerative high- and low-pressure heaters (HPH and LPH) of steam turbine units (STU). Optimization of water subcooling to the saturation temperature of the heating steam (hereinafter referred to as subcooling) in the STU regeneration stages makes it possible to increase the power of the power unit or reduce the metal intensity of the heaters, depending on the expected economic indicators of the nuclear power plant, which leads to a reduction in the estimated cost of generated electricity. Unification of heaters will make it possible to simplify the processes of design, manufacturing, repair, and transportation of serially produced heat-transfer equipment, improve the layout of the turbine building, and reduce equipment development costs. The article presents the results of calculations of the technical and economic indicators of the heat-transfer equipment of the STU regeneration system type K-1200-6.8/50 LMZ, and draws conclusions about the possibility of finding a preferable solution based on the criterion of annual economic effect. A special feature of the methodology used is the determination of the most appropriate values of water subcooling in surface heaters of the STU regeneration system depending on operating conditions, the situation on the electricity and equipment market, as well as economic policy. The possibility of increasing the economic efficiency of the power unit by optimizing the weight and size characteristics and unifying the heat-transfer equipment of the regeneration system is shown. An additional economic effect can be obtained by using chamber-type heaters in a horizontal design, combining two heating stages in one housing. A promising layout option is that in which the entire LPH group is represented by unified surface-type devices in a horizontal design located in the condenser hood of a half-speed STU.