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FACTORS LIMITING LIFE TIME OF NUCLEAR POWER PLANTS WITH PRESSURIZED-WATER REACTORS
Křivánek, Robert ; Kolat, Pavel (referee) ; Liszka, Ervin (referee) ; Fiedler, Jan (advisor)
The aim of the thesis is to analyze the state of preparedness of nuclear power plants (NPP) for long term operation (LTO) based on the IAEA SALTO (Safety Aspects of Long Term Operation) peer review service, analysis of the most significant failures, accidents and operational experience with type reactors PWR/VVER focusing on cases caused by equipment ageing and identification of major structures and components limiting life time of PWR/VVER-type nuclear power plants, and possible measures to ensure their required service life. Based on the results of the IAEA SALTO peer review service, an analysis of the main deficiencies and measures of NPPs in preparation for a safe LTO was performed, focusing on topics whose deeper knowledge is important for the future more precise determination of technical factors limiting the lifetime of NPPs. The main deficiencies and measures in the preparatory phase for LTO and the most important technical measures are summarized in chapter 4.5. The main deficiencies and the most important technical corrective measures in the area of ageing management of structures and components are discussed separately. The history of major failures and operational experience of nuclear power plants with PWR/VVER reactors from the point of view of ageing of structures and components is analyzed in chapter 6.2. The result is a statistic analysis of ageing-related events, an overview of the most significant PWR/VVER reactor failures with an impact on their service life, a statistical overview and discussion of the most important degradation mechanisms, and other important findings from the history of major failures and operational experience. Chapter 6.3 analyzes factors limiting the operation of nuclear power plants with PWR/VVER reactors with focus on structures and components potentially limiting the life of PWR/VVER reactors and possible measures to ensure their required life. In conclusion, the main reasons of permanent shut down of NPPs (actual and potential) for 40, 60 and 80 years of operation and the measures to ensure their required life are summarized.
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The Effective and Ecological Burning of Biomass
Špiláček, Michal ; Kolat, Pavel (referee) ; Masaryk, Michal (referee) ; Skála, Zdeněk (advisor)
This work deals with the creation of a numerical model of a biomass combusting chamber on a grate. The research part of this work describes the basic properties of biomass important for its combustion and the biomass combustion process itself. For this process which it is necessary to know the dynamics of the chemical reactions and the overall mechanism of a grate combustion of fuels. It also describes the production of harmful emissions that can be generated by combustion of biomass and the emphasis is mainly on the production of nitrogen oxides. In the next part is described the combustion device itself and the basic mathematical model which incorporates the mechanisms of heat transfer, flow of fluids and transport of chemical species. The basic mathematical model is then extended to a complete mathematical model by determining the initial and boundary conditions. Subsequently, the results of the computer simulation of the mathematical model are presented and commented. The main focus are the emissions of nitrogen oxides and hydrocarbons. These results are used to design an improvement of the geometry of the combustion chamber.
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Design of a combined cycle electricity source
Kadáková, Nina ; Kolat, Pavel (referee) ; Milčák, Pavel (advisor)
A combined cycle is one of the thermal cycles used in thermal power plants. It consists of a combination of a gas and a steam turbine, where the waste heat from the gas turbine is used for steam generation in the heat recovery steam generator. The aim of the diploma thesis was the conceptual design of a combined cycle electricity source and the balance calculation of the cycle. The calculation is based on the thermodynamic properties of the substances and the basic knowledge of the Brayton and Rankin-Clausius cycle. The result is the amount and parameters of air, flue gases, and steam/water in individual places and the technological scheme of the source, in which these parameters are listed.
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Critical Heat Flux on Smooth and Modified Surfaces
Suk, Ladislav ; Kolat, Pavel (referee) ; Katovský, Karel (referee) ; Fiedler, Jan (advisor)
This thesis deals with the problem of critical heat flux (CHF) on technically smooth and treated surfaces at low pressures. The theoretical part presents the basic concepts of two-phase flow and an analysis of existing work on the influence of the surface on CHF. The main part of the work describes the built experimental apparatus for CHF research at low pressures of 100 -1500 kPa (1-15 bar) with a vertical internally heated annular test section. The internal annuli consists of an outer glass tube with an inner diameter of 14.8 mm and an inner tube made of Inconel ™ 625 / Optimized ZIRLO ™ with an outer diameter of 9.14 mm and a heated length of 380/365 mm. CHF experiments on technically smooth surface were performed at outlet pressures 120 kPa, 200 kPa and 300 kPa, at an inlet temperature of 64, 78 and 91 °C and at mass flux of 400, 500, 600 and 800 kg / m2s. The Inconel tubes were tested in two different surface modifications - abraded and bead blasted. Experiments were performed at mass flows of 400, 500 and 600 kg / m2s. The total number of 122 experimental runs were conducted and the results were compared with other literature experimental data. The maximum increase of CHF on abraded / bead blasted tube was 18.12% / 16.17%. The surface structure was analysed by laser microscopy. The wetting behaviour of the surface structures was measured by the sessile drop method. The elemental analysis of the surface was evaluated using the EDS method.
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Critical Heat Flux on Smooth and Modified Surfaces
Suk, Ladislav ; Kolat, Pavel (referee) ; Katovský, Karel (referee) ; Fiedler, Jan (advisor)
This thesis deals with the problem of critical heat flux (CHF) on technically smooth and treated surfaces at low pressures. The theoretical part presents the basic concepts of two-phase flow and an analysis of existing work on the influence of the surface on CHF. The main part of the work describes the built experimental apparatus for CHF research at low pressures of 100 -1500 kPa (1-15 bar) with a vertical internally heated annular test section. The internal annuli consists of an outer glass tube with an inner diameter of 14.8 mm and an inner tube made of Inconel ™ 625 / Optimized ZIRLO ™ with an outer diameter of 9.14 mm and a heated length of 380/365 mm. CHF experiments on technically smooth surface were performed at outlet pressures 120 kPa, 200 kPa and 300 kPa, at an inlet temperature of 64, 78 and 91 °C and at mass flux of 400, 500, 600 and 800 kg / m2s. The Inconel tubes were tested in two different surface modifications - abraded and bead blasted. Experiments were performed at mass flows of 400, 500 and 600 kg / m2s. The total number of 122 experimental runs were conducted and the results were compared with other literature experimental data. The maximum increase of CHF on abraded / bead blasted tube was 18.12% / 16.17%. The surface structure was analysed by laser microscopy. The wetting behaviour of the surface structures was measured by the sessile drop method. The elemental analysis of the surface was evaluated using the EDS method.
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Design of a combined cycle electricity source
Kadáková, Nina ; Kolat, Pavel (referee) ; Milčák, Pavel (advisor)
A combined cycle is one of the thermal cycles used in thermal power plants. It consists of a combination of a gas and a steam turbine, where the waste heat from the gas turbine is used for steam generation in the heat recovery steam generator. The aim of the diploma thesis was the conceptual design of a combined cycle electricity source and the balance calculation of the cycle. The calculation is based on the thermodynamic properties of the substances and the basic knowledge of the Brayton and Rankin-Clausius cycle. The result is the amount and parameters of air, flue gases, and steam/water in individual places and the technological scheme of the source, in which these parameters are listed.
|
|
|
The Effective and Ecological Burning of Biomass
Špiláček, Michal ; Kolat, Pavel (referee) ; Masaryk, Michal (referee) ; Skála, Zdeněk (advisor)
This work deals with the creation of a numerical model of a biomass combusting chamber on a grate. The research part of this work describes the basic properties of biomass important for its combustion and the biomass combustion process itself. For this process which it is necessary to know the dynamics of the chemical reactions and the overall mechanism of a grate combustion of fuels. It also describes the production of harmful emissions that can be generated by combustion of biomass and the emphasis is mainly on the production of nitrogen oxides. In the next part is described the combustion device itself and the basic mathematical model which incorporates the mechanisms of heat transfer, flow of fluids and transport of chemical species. The basic mathematical model is then extended to a complete mathematical model by determining the initial and boundary conditions. Subsequently, the results of the computer simulation of the mathematical model are presented and commented. The main focus are the emissions of nitrogen oxides and hydrocarbons. These results are used to design an improvement of the geometry of the combustion chamber.
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FACTORS LIMITING LIFE TIME OF NUCLEAR POWER PLANTS WITH PRESSURIZED-WATER REACTORS
Křivánek, Robert ; Kolat, Pavel (referee) ; Liszka, Ervin (referee) ; Fiedler, Jan (advisor)
The aim of the thesis is to analyze the state of preparedness of nuclear power plants (NPP) for long term operation (LTO) based on the IAEA SALTO (Safety Aspects of Long Term Operation) peer review service, analysis of the most significant failures, accidents and operational experience with type reactors PWR/VVER focusing on cases caused by equipment ageing and identification of major structures and components limiting life time of PWR/VVER-type nuclear power plants, and possible measures to ensure their required service life. Based on the results of the IAEA SALTO peer review service, an analysis of the main deficiencies and measures of NPPs in preparation for a safe LTO was performed, focusing on topics whose deeper knowledge is important for the future more precise determination of technical factors limiting the lifetime of NPPs. The main deficiencies and measures in the preparatory phase for LTO and the most important technical measures are summarized in chapter 4.5. The main deficiencies and the most important technical corrective measures in the area of ageing management of structures and components are discussed separately. The history of major failures and operational experience of nuclear power plants with PWR/VVER reactors from the point of view of ageing of structures and components is analyzed in chapter 6.2. The result is a statistic analysis of ageing-related events, an overview of the most significant PWR/VVER reactor failures with an impact on their service life, a statistical overview and discussion of the most important degradation mechanisms, and other important findings from the history of major failures and operational experience. Chapter 6.3 analyzes factors limiting the operation of nuclear power plants with PWR/VVER reactors with focus on structures and components potentially limiting the life of PWR/VVER reactors and possible measures to ensure their required life. In conclusion, the main reasons of permanent shut down of NPPs (actual and potential) for 40, 60 and 80 years of operation and the measures to ensure their required life are summarized.
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