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Nuclear Fuel Margins Increasing at Nuclear Power Plant Dukovany
Vrábel, Radek ; ČEZ,, Ondřej Zlámal, (referee) ; Katovský, Karel (advisor)
This bachelor‘s thesis deals with power uprates and the extension of the nuclear fuel cycle at Czech nuclear power plants. The beginning of this thesis aims at improving the reader’s knowledge about nuclear reactors and nuclear fuel cycle. A whole chapter is dedicated to the development of nuclear fuel cycle at the nuclear power plant Dukovany. The progress in the field of nuclear fuels complements the development of the nuclear fuel cycle, thus providing visible benefits.
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Fuel element characterization
Halabuk, Dávid ; Suk, Ladislav (referee) ; Martinec, Jiří (advisor)
This bachelor thesis describes the fuel rods of VVER reactors. In addition to general description of fuel rod, there is also overview of the nuclear fuel used in the past and at present in Czech and Slovak nuclear power plants, as well as overview of the new trends in development of nuclear fuel. Big part of the thesis is focused on description of nuclear fuel and fuel cladding properties and the individual processes affecting fuel rod during fuel burnup. Next part describes in detail the causes of fuel failures occurring in VVER reactors. The last part of the thesis includes calculation of changes of deformations and stresses occurred in fuel cladding during pellet-cladding interaction. Calculation is done for four different shapes of fuel pellets and in addition to deformation and stress analysis, there are also calculated axial dilatations of fuel column and radial temperature distributions in fuel rod.
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Research and Development of Innovative Uranium Nuclear Fuel Matrices
Hrbáček, Tomáš ; Šťastný, Ondřej (referee) ; Katovský, Karel (advisor)
The bachelor thesis is focused on the issue of nuclear fuel used for nuclear reactors. It is dedicated to research of current trends in nuclear pellets. The qualitative parameters of nuclear fuels are described here, predominanly thermal conductivity and density of nuclear fuel. A special chaper of this thesis is devoted to the simulation and fuel additives during burnout. The final part of the bachelor thesis is dedicated to a specific design of material for a test research pellet.
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Analysis of possibilities for use of III. and IV. generation of nuclear reactors for the Czech Republic
Gajdzica, Lukáš ; Kopřiva, Radek (referee) ; Kopřiva, Radek (referee) ; Matal, Oldřich (advisor)
The thesis deals with the analysis of possibilities for use of III. and IV. generation of nuclear reactors for the Czech Republic. Introduction deals with basic principles of nuclear energetics and fuel cycle which is closely associated with the issue and its development and application in practice will have a significant effect both for choice of future types of nuclear reactors of IV. generation and the matter of settlement with spent nuclear fuel. In other parts the thesis deals with the present state of nuclear energetics in the Czech Republic, compares concrete chosen types of nuclear power plants of III. generation and generally describes nuclear reactors and power plants of IV. generation. Final part of the work is focused on questions concerning the possibility of construction of new blocks of nuclear power plants in the Czech Republic and presents concrete recommendation from author´s point of view.
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Simulation of nuclear fuel burn-up during whole fuel cycle
Smola, Luděk ; ČEZ,, Ondřej Zlámal, (referee) ; Katovský, Karel (advisor)
The main goal of this Bachelor’s thesis is to create a long-term kinetics model of a nuclear reactor – model, which simulates changes in nuclear fuel inside the reactor core during reactor operation. As the term long-term suggests, primarily the changes in whole five-year fuel cycle horizon are studied, which stands for changes in concentration of elements contained within fresh fuel as well as origination of new ones (with special focus on higher actinides and plutonium). This mathematical model is created using the MAPLE 14 software. Outputs from the model are displayed graphically and thoroughly analysed, so that comprehensive conclusions of problems can be made. Furthermore, the thesis contains theoretical and informational background that is necessary for understanding all the aspects of the model – historical development of nuclear reactors, their basic types, nuclear fuel description focusing on fuel for pressurized light-water reactors VVER (for which the model is primarily designed), MOX fuel and possibilities of its utilization, and last but not least – selected topics from nuclear physics.
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Sensitivy analysis of the influence of manufacturing inaccuracies on the nuclear fuel reactivity
Sedlák, Martin ; Katovský, Karel (referee) ; Novotný, Filip (advisor)
This thesis deals with a sensitivity analysis of the influence of manufacturing inaccuracies on the reactivity of nuclear fuel. Sensitivity analysis has been done for fuel assembly TVSA-T, for nuclear reactors VVER-1000. Particularly, for fuel rod of type tvel - without burnable absorbers. Thirty three combinations of maximal and minimal of manufacturing parameters were simulated in SCALE environment. Changes of multiplication coefficient in dependence on burnup for 5 combinations have been also studied. It has been found that the most significant influence on the reactivity has the accuracy of enrichment and outer diameter of cladding. It has also been found that influence of manufacturing inaccuracies is not constant during burnup. The benefit of the thesis is determining the effects of individual inaccuracies on the reactivity and the fact that their influence is not constant during burnup.
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Radiation damage of VVER-440 based Dukovany NPP reactor pressure vessel investigation
Říha, Tomáš ; Martinec, Jiří (referee) ; Šen, Hugo (advisor)
This master‘s thesis deals with radiation damage of reactor pressure vessels, specifically of NPP Dukovany Unit No. 3. In general damage mechanisms of reactor steels are described and possibilities of monitoring of material degradation and its recovery used at NPP’s all over the world are mentioned as well. A practical part of the thesis is focused on interpretation of analyses carried out with the assistance of MOBY DICK code. The ground of these analyses is a neutron fluence value development on different locations of RPV for the whole life of operation up to 24th cycle. The analyses results are put into context with performed in-service inspections. The thesis follows up with neutron fluence computation for the future cycles containing new types of nuclear fuel up to 34th cycle. The outcome of practical part of the master‘s thesis is a comparison between new types of nuclear fuel with respect to radiation damage of RPV’s.
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Nuclear Fuel Innovation
Mičian, Peter ; Zeman, Miroslav (referee) ; Katovský, Karel (advisor)
This bachelor thesis deals with the latest findings about nuclear fuel, especially fuels for pressurized water reactors. The thesis provides an overview of the latest research in the field of fuel cladding, which separates the fuel from coolant. Part is focused on burnable absorbers, which helps to reduce neutron flux during the first year of new fuel assembly. Furthermore, the thesis briefly discusses transmutation fuel cycles. the main empahsis is focused on ATF fuels, in the form of fuels with enhanced thermal conductivity. Develompment in this field could increase the safety and usage of the nuclear energy. The latest part is focused on applications of computational program FEMAXI-6 and analyze its outputs. This program deals with calculations of behavior of high-burnup fuel elements. As data for inputs were used real data from the nuclear power plant Dukovany.
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Front end of the fuel cycle
Sedlák, Miroslav ; Katovský, Karel (referee) ; Foral, Štěpán (advisor)
Bachelor thesis will work of the front of the fuel cycle. Summarize and describe the current knowledge related to uranium, the phase transformation of unemployable chemical element for mankind significant energy source. Understanding the process of processing uranium to energy source is invaluable importance for the future of energy. The use of uranium as fuel only brings advantages inherent in the usability element for humanity, but also the disadvantege of environmental threats and the threat of negative censequences to the environment in case of accidents. A thorough knowledge of the various stages of the fuel cycle contributes to increasing the safety of use of this chemical element for mankind and increasing efficiency in the conversion of uranium ore, thereby creating still more favorable conditions for the development of nuclear energy.
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Front and Back End of the Nuclear Fuel Cycle
Winterová, Radka ; Mastný, Petr (referee) ; Katovský, Karel (advisor)
In this bachelor thesis author deals with the topic of nuclear power fuel cycle and the particular differences that are typical for each nuclear reactor types. The author aims to describe in detail both - the front and especially the back end of the nuclear fuel cycle, fuel fabrication for light water nuclear reactors, fuel reprocessing and recycling, and consequently fuel production based on REPU and MOX. Thesis should also get familiar with global approaches to fuel cycle, especially the back end.
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