The analysis of methods of equipment deactivation and dismantling during decommission of nuclear power units at a Nuclear Power Plant.
Students Name: Demianiuk Yaroslav Oleksandrovych
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: In the near future, the number of decommissioned power units will increase steadily, the problem of rational organization of the process of utilization of materials and equipment is quite relevant. It is necessary to solve not only the task of processing scrap metal contaminated with radionuclides, but also metal with different degrees of radioactive contamination. The desire to use radioactive metal will be great, as heavily contaminated parts dismantled during decommissioning are made mainly of corrosion-resistant steels, alloys and other valuable metals. A lot of research work has been devoted to the search for rational ways to decontaminate metal. At present, mainly chemical and electrochemical methods of decontamination are used, but they require a large consumption of acids, alkalis, surfactants. These methods are time consuming and lead to the formation of a significant amount of liquid radwaste. The main sources of surface contamination in NPP premises are radioactive corrosion products 51Сr, 54Мn, 58Со, 60Со, 59Fe, ll0Ag and a small fraction of fission products 103Ru, 134Cs, 140La, l44Ceand others. In terms of nuclear power plants, the radionuclides l37Cs, 90Sr, 238-241Рu, 24lAm, 244Cmare also of practical importance from the point of view of radiation safety. Decontamination is the main operation during decommissioning, the objectives of which may be to reduce occupational exposure, reduce the possibility of releases of radioactive substances into the environment, reuse materials, and also simplify the processing of radwaste. The object of research is the equipment for decommissioning of nuclear power installations. Subject of research - methods of decontamination and dismantling of equipment during decommissioning of nuclear power installations. The purpose and objectives of research. 10 The aim of the work is to analyze the methods of decontamination and dismantling of equipment during decommissioning of nuclear power installations. To achieve this goal it was necessary to perform the following tasks: - analyze the decontamination process; - to analyze physical and chemical processes of radioactive contamination; - analyze the sources and levels of radioactive contamination of nuclear power installation equipment surfaces and premises; - to analyze the main methods of the decontamination process; - to analyze the specifics of decommissioning and dismantling of reactor equipment. In this master’s qualification work the process of decontamination during decommissioning of nuclear power installation of NPPs is investigated. A review of the decontamination process during the decommissioning of nuclear power plants and the issue of planning, a description of modern technologies. Based on the analysis of international and domestic experience, the issues of radioactive waste management, methods of decontamination, dismantling of equipment, as well as estimates of costs of decommissioning are considered. In the section of economics, economic indicators are calculated, which show the expediency of decontamination of radwaste. The automation section describes the measures for the automation of the turbine plant. Since it is impossible to measure the vapor pressure by directly connecting the manometer to the steam line due to the high temperature of the medium, therefore a condensing vessel should be provided. Secondary intermediate devices are selected taking into account their unified input/output signals. Actuators must ensure appropriate speed of regulation. Key words: decontamination, dismantling of equipment, decommissioning, nuclear power installation, radioactive waste.