COMPARATIVE ANALYSIS OF TECHNICAL, ECONOMIC, WEIGHT, AND SIZE CHARACTERISTICS OF HORIZONTAL AND VERTICAL STEAM GENERATORS FOR 1000 MW NUCLEAR POWER PLANT UNITS
Authors: Yefimov Olexandr , Pylypenko Mykola , Kavertsev Valerii , Harkusha Tatyana , Sydorkin Igor , Chyzhyk Oleksandr 
Published: November 2024

A comparative analysis of the technical characteristics and parameters of horizontal and vertical steam generators for reactorinstallations with water coolant in modern 1000 MW NPP power units has been conducted. It is noted that the peculiarities of thedesign schemes and constructions of steam generators in NPP power units with water coolants are significantly influenced by thestrong dependence between the coolant temperature at the steam generator inlet and the pressure in the reactor circuit. Thedependencies of coolant and working substance temperature changes and the amount of heat transferred in steam generatorelements have been considered. The t-Q diagram of a steam generator with a water coolant featuring a non-boiling economizer,evaporator, and superheater is presented. The parameters of water coolants and working substances in nuclear power plant steamgenerators are provided. The t-Q diagram for steam generators without a superheater section is shown, because in modern 1000MW nuclear power plant units with steam generators which use water as the working substance in the steam-turbine cycle,saturated steam without superheating is used. This is because minor superheating of the steam does not significantly increase theefficiency of the steam-turbine cycle but requires significant complexity in the design of the steam generators. It is noted that thecorrect choice of their structural schemes is crucial in the creation of steam generators with water coolants. It has been proven thatthe characteristics determining the structural schemes of steam generators with water coolants are: the scheme of washing the heatexchange surface with the coolant, the form of the heat exchange surface, the layout of steam generator elements, the principle ofworking substance movement, and others. The technical characteristics of a horizontal-type steam generator for 1000 MW nuclearpower plant units are presented, which have proven to be quite effective in operation. However, their designs and characteristicslimit the potential for further improvement of the technical and economic indicators of nuclear power plants. It is noted thatimproving the technical and economic efficiency of 1000 MW nuclear power plant units while simultaneously reducing capitalcosts for their construction is possible by increasing the unit capacity of powerful vertical-type steam generators installed on them.Compared to horizontal steam generators, vertical steam generators allow for a more rational layout of the primary circuitequipment in the reactor department, thus reducing the volume and cost of construction and installation works. The maindimensions and weight characteristics of possible designs of vertical steam generators for nuclear power plants with VVER-1000reactors are provided. It is concluded that once-through vertical steam generators with spiral wound heat exchange tubes and watercoolant in the first circuit tubes weigh approximately 1.5 to 2 times less than vertical steam generators with natural circulation. It isdetermined that once-through vertical steam generators with a hydraulic scheme involving the movement of the working substancein the tubes and the water coolant in the inter-tube space significantly lag behind once-through vertical steam generators with watercoolant in the tubes in terms of dimensional and weight characteristics and also vertical steam generators with natural circulation interms of weight. It is concluded that for VVER-1000 nuclear power plants, the most promising of all options are vertical once-through steam generators with the movement of the water coolant in spiral wound heat exchanger tube bundles. These steamgenerators occupy approximately four times less area in the reactor department than horizontal ones with the same steamproduction, which significantly reduces construction costs for nuclear power plants.