The study of the active zone of channel water-water reactors.

Students Name: Hilianchuk Kateryna Volodymyrivna
Qualification Level: magister
Speciality: Nuclear Рower Еngineering
Institute: Institute of Power Engineering and Control Systems
Mode of Study: full
Academic Year: 2022-2023 н.р.
Language of Defence: ukrainian
Abstract: Hilianchuk K. V., Semerak M. M. (head). Investigation of the core of pressurized water reactors. Master’s qualification thesis. - Lviv Polytechnic National University, Lviv, 2022 The bachelor’s thesis consists of 91 pages of explanatory note and five sheets of graphic part of A1 format, made in the program "COMPASS". 30 literary sources were used in the bachelor’s thesis. The object of study of this master’s qualification work is the core of water-water reactors. The subject of research is modeling the law of dependence of the temperature field and deformation of the fuel element on thermophysical parameters. The purpose of the study is mathematical modeling of the law of change of thermal processes in the fuel element depending on its thermophysical parameters. The following tasks are performed in the work: to determine the change in the temperature of the fuel pellet rod fuel element along the radius r depending on the change in heat release and thermal conductivity coefficient; to determine the change in the displacement of the radius points relative to the center of the fuel pellet caused by the heating of the fuel element. In the theoretical part of this master’s qualification work, water-water reactors are considered, namely: their purpose, features and disadvantages are described; the characteristics and design of VVER-1000 reactors are analyzed; the reactor core is considered, namely, the design and characteristics of fuel elements and fuel assemblies are described. The work is aimed at studying the thermal deformation of the rod fuel element, which can lead to cracking of fuel pellets in the fuel element and its cladding, which leads to accidents. By the method of mathematical modeling with the use of differential equations of heat conduction and displacement, analytical expressions for the study of the temperature field and deformation of a solid fuel pellet of a rod fuel element were found. On the basis of these expressions the influence of thermophysical parameters of fuel on the change of thermal processes in it is investigated. In the technical and economic part the methodology is analyzed and the cost of electricity is calculated, where the cost of 1 kWh of supplied electricity and heat is determined - 0.6981 UAH. The annual output, salary costs, depreciation and other expenses are determined. In the last section of the thesis developed a functional diagram of automatic control, alarm and regulation of the deaerator, as well as a specification for automatic control and regulation of parameters in the deaerator, made on the basis of a local complex of regulating equipment of the system "Cascade-2". Key words - fuel element, pressurized water reactor, temperature, displacement.