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Spent fuel pool accident simulation
Strieš, Jakub ; Foral, Štěpán (referee) ; Mičian, Peter (advisor)
The aim of the thesis is to provide a theoretical basis for simulating spent fuel pool accidents and to try to build a working model in the Melcor environment. The thesis is divided into four main parts. In the first part a description of the spent fuel pool is given. The processes that take place in nuclear fuel and thus lead to the formation of spent fuel are described. The reasons for the need to cool nuclear fuel after it has been in the reactor are described. For example, the generation of residual heat is described. This is followed by a description of the basic parts and purpose of a spent fuel pool. Structural parts, measuring systems or requirements for the pool itself are shown. Subsequently, an overview of accidents in spent fuel pools that have occurred in the past is also included in this chapter. Their causes and consequences are described, but especially their impact on the further development of nuclear safety, especially in the field of spent fuel pools. For both description and subsequent simulation, the two most studied ones, namely the loss-of-cooling failure and the loss-of-coolant failure, have been selected. The third section introduces the Melcor program which, is the main tool to create the simulation model. The chapter contains a basic description of the program as well as an introduction to the modules that are specifically designed for spent fuel pool simulations. The last part is a description of the model used, its creation, modification, problems in its creation and their solution. Finally, the results obtained are shown and described, together with a commentary to complete their understanding.
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Safety of the fuel stored in water pool
Mičian, Peter ; Novotný, Filip (referee) ; Foral, Štěpán (advisor)
This diploma thesis deals with storing the spent nuclear fuel and reviewing its safety. The theoretical part analyzes the processes taking place while the fuel is being used, such as fission, isotopic changes, fission gas release, cracking, swelling and densification of fuel pellet. The thesis is also focused on handling the spent fuel and on the way it makes from the reactor, through the spent fuel pool, the transportation, various kinds of storing, till the reprocessing and final deep geological repository. Furthermore, this part of the thesis briefly discusses computing code MCNP, its main characteristics, input files and using. The practical part of the work is focused on creating the model of the spent fuel pool located next to the nuclear reactor WWER 440/V213. This type was chosen, because it is the most used type of nuclear reactor in Czech Republic and Slovakia. With the help of the code MCNP, the multiplication factor of the main configurations of the fuel in the pool was calculated, and then the required safety regulations to ensure sufficient subcriticality, so its safety, were checked. Next, several analysis were performed using this model. These analyses were concerning the temperature of coolant, fuel and the use of various nuclear data libraries. In the future this model can be used to realize new analyses with new kinds of fuels, materials and data libraries.
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Design of equipment of spent nuclear fuel assemblies
Šimek, Ondřej ; Rausch, Ivan (referee) ; Vojáčková, Jitka (advisor)
The diploma thesis aim to the design of equipment for ŠKODA JS a.s., which is part of a new inspection stand (N-SIO). This equipment is an inspection column that provides the possibility to inspect spent fuel assemblies at the operation of the Temelín nuclear power plant. This master thesis is also a summary of the whole design of the new inspection stand and a description of the individual inspection components and devices. One of the parts of the thesis is also a basic strength analysis and a drawing of the main assembly of inspection equipment.
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Application possibilities of systems with heat accumulation in nuclear power
Sklenářová, Lenka ; Maar, Tomáš (referee) ; Martinec, Jiří (advisor)
This dissertation covers the application of heat accumulation systems in nuclear power engineering, namely in nuclear power plants. It is mainly a case of passive emergency systems, whose task is to accumulate the heat produced in the reactor’s active zone and in spent fuel pools during DBA (design-basis accidents) or beyond DBA. A particular example of heat accumulation is steam condensation after LOCA (loss of coolant accident). The primary circuit steam leakage increases containment pressure and has to be decreased by the steam condensation. This thesis deals with a theoretical substitute for ice condensers, which are used as a passive safety measure in some nuclear power plants. The substitute involves a choice of an alternative material, whose melting temperature (for heat accumulation) is closer to nuclear power plant operating temperatures. The other part of the dissertation discusses heat accumulation in spent fuel pools in case of all cooling systems failure.
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Spent nuclear fuel and its properties
Jestřáb, Tomáš ; Řež,, Martina Malá, Centrum výzkumu (referee) ; Katovský, Karel (advisor)
The main goal of this Bachelor’s thesis is to develop fuel depletion models of a nuclear fuel used at Nuclear Power Plant Dukovany – originally designed nonprofiled fuel used in a three-year cycle, inovated profiled fuel used in a four-year cycle and currently used fuel Gd-2M+ used in a five year fuel cycle. Models are created by computational code UWB1 providing fast calculation of nuclear fuel depletion. Outputs of these models are in thesis graphically displayed and analyzed from the point of view of fuel depletion, enrichment or irradiation time spent in reactor core. These analyses are based on theory including information about the nuclear fuel cycle focusing on its middle part and the back end of the nuclear fuel cycle.
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Design of equipment of spent nuclear fuel assemblies
Šimek, Ondřej ; Rausch, Ivan (referee) ; Vojáčková, Jitka (advisor)
The diploma thesis aim to the design of equipment for ŠKODA JS a.s., which is part of a new inspection stand (N-SIO). This equipment is an inspection column that provides the possibility to inspect spent fuel assemblies at the operation of the Temelín nuclear power plant. This master thesis is also a summary of the whole design of the new inspection stand and a description of the individual inspection components and devices. One of the parts of the thesis is also a basic strength analysis and a drawing of the main assembly of inspection equipment.
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Safety of the fuel stored in water pool
Mičian, Peter ; Novotný, Filip (referee) ; Foral, Štěpán (advisor)
This diploma thesis deals with storing the spent nuclear fuel and reviewing its safety. The theoretical part analyzes the processes taking place while the fuel is being used, such as fission, isotopic changes, fission gas release, cracking, swelling and densification of fuel pellet. The thesis is also focused on handling the spent fuel and on the way it makes from the reactor, through the spent fuel pool, the transportation, various kinds of storing, till the reprocessing and final deep geological repository. Furthermore, this part of the thesis briefly discusses computing code MCNP, its main characteristics, input files and using. The practical part of the work is focused on creating the model of the spent fuel pool located next to the nuclear reactor WWER 440/V213. This type was chosen, because it is the most used type of nuclear reactor in Czech Republic and Slovakia. With the help of the code MCNP, the multiplication factor of the main configurations of the fuel in the pool was calculated, and then the required safety regulations to ensure sufficient subcriticality, so its safety, were checked. Next, several analysis were performed using this model. These analyses were concerning the temperature of coolant, fuel and the use of various nuclear data libraries. In the future this model can be used to realize new analyses with new kinds of fuels, materials and data libraries.
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Spent nuclear fuel and its properties
Jestřáb, Tomáš ; Řež,, Martina Malá, Centrum výzkumu (referee) ; Katovský, Karel (advisor)
The main goal of this Bachelor’s thesis is to develop fuel depletion models of a nuclear fuel used at Nuclear Power Plant Dukovany – originally designed nonprofiled fuel used in a three-year cycle, inovated profiled fuel used in a four-year cycle and currently used fuel Gd-2M+ used in a five year fuel cycle. Models are created by computational code UWB1 providing fast calculation of nuclear fuel depletion. Outputs of these models are in thesis graphically displayed and analyzed from the point of view of fuel depletion, enrichment or irradiation time spent in reactor core. These analyses are based on theory including information about the nuclear fuel cycle focusing on its middle part and the back end of the nuclear fuel cycle.
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Application possibilities of systems with heat accumulation in nuclear power
Sklenářová, Lenka ; Maar, Tomáš (referee) ; Martinec, Jiří (advisor)
This dissertation covers the application of heat accumulation systems in nuclear power engineering, namely in nuclear power plants. It is mainly a case of passive emergency systems, whose task is to accumulate the heat produced in the reactor’s active zone and in spent fuel pools during DBA (design-basis accidents) or beyond DBA. A particular example of heat accumulation is steam condensation after LOCA (loss of coolant accident). The primary circuit steam leakage increases containment pressure and has to be decreased by the steam condensation. This thesis deals with a theoretical substitute for ice condensers, which are used as a passive safety measure in some nuclear power plants. The substitute involves a choice of an alternative material, whose melting temperature (for heat accumulation) is closer to nuclear power plant operating temperatures. The other part of the dissertation discusses heat accumulation in spent fuel pools in case of all cooling systems failure.
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