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Investigation of Ionizing Radiation Infuence to the Communication Systems of Satellites
Golubev, Martin ; Kubíček, Michal (referee) ; Katovský, Karel (advisor)
This master thesis discuss about ionizing radiation, interaction with matter and effects on her. In the work is discussed differend types of interactions of directly ionizing radiation and indirectly ionizing radiation. Below is an overview of methods of shielding from all of types of ionizing radiation. Second part of this thesis discuss about single event effects in semiconductors which are cause by ionizing radiation. At the end is described design of measuring instrument included FPGA chips. This design is discused both from point of wiew hardware and software too.
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Design of nuclear ceramic materials with enhanced thermal conductivity
Roleček, Jakub ; Katovský, Karel (referee) ; Salamon, David (advisor)
Oxid uraničitý (UO2) je v současnosti nejčastěji používaným materiálem jakožto palivo v komerčních jaderných reaktorech. Největší nevýhodou UO2 je jeho velmi nízká tepelná vodivost, a protože se při štěpení UO2 v jaderném reaktoru vytváří velké množství tepla, vzniká v UO2 peletě velký teplotní gradient. Tento teplotní gradient způsobuje vznik velkého tepelného napětí uvnitř pelety, což následně vede k tvorbě trhlin. Tyto trhliny napomáhají k šíření štěpných plynů při vysoké míře vyhoření paliva. Tvorba trhlin a zvýšený vývin štěpného plynu posléze vede ke značnému snížení odolnosti jaderného paliva. Tato práce se zabývá problematikou zvyšování tepelné vodivosti jaderného paliva na modelu materiálu (CeO2). V této práci jsou studovány podobnosti chování CeO2 a UO2 při konvenčním slinováním a při „spark plasma sintering.“ Způsob jak zvýšit tepelnou vodivost použitý v této práci je včlenění vysoce tepelně vodivého materiálu, karbidu křemíku (SiC), do struktury CeO2 pelet. Od karbidu křemíku je očekáváno, že zvýší tok tepla z jádra pelety, a tím zvýší tepelnou vodivost CeO2. V této práci je také porovnávána podobnost chování SiC v CeO2 matrici s chováním SiC v UO2, které bylo popsáno v literatuře.
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Experimental Investigation of Accelerator Driven Nuclear Reactors for Thorium Based Nuclear Power
Zeman, Miroslav ; ČR,, Milan Štefánik, UJF AV (referee) ; Katovský, Karel (advisor)
The Master Thesis deals with the use of thorium nuclear fuel in accelerator driven systems. Basic principle of ADS, present situation and future possibilities are described in this work. The main goal of the work is determination of neutron flux in spallation target QUINTA. In December 2013, an experiment was performed at Joint Institute for Nuclear Research, Dubna. Samples of cobalt, situated at different positions in QUINTA target, were irradiated in secondary neutron field generated by deuteron beam of energies 2 AGeV and 4 AGeV and beam of C-12 with energy 2 AGeV. The samples were measured with the use of germanium semiconductor detectors and analysed using gamma-ray spectrometry. Reaction rates of Co-59 products were determined. Neutron flux was determined in setup QUINTA on the base of experimental reaction rates. Experimental reaction rates were compared with calcula1tion of MCNPX code.
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Performance of Composite Nuclear Fuels during Normal Operation and Nuclear Reactor Accidents
Foral, Štěpán ; Valach,, Mojmír (referee) ; Haščík,, Ján (referee) ; Katovský, Karel (advisor)
Tato práce se zabývá oblastí kompozitních jaderných paliv založených na UO2 . V práci je vyjmenováno několik materiálů vhodných jako aditivum ty jsou srovnány z několika různých hledisek. Byla vybrána kombinace UO2 + SiC pro detailní analýzu. Bylo zjištěno, že tato kombinace vykazuje dobré parametry v průběhu normálního provozu. Uvolňování plynných produktů štěpení je nižší společně s tepelně-mechanickým namáháním. Nicméně, je potřeba vyvinout nové modely chování kompozitních paliva. Analýza havárie blízké typu LOCA ukazuje, že palivo UO2 + SiC vykazuje poněkud lepší parametry ve srovnání s UO2 . Centrální teplota je nižší a mechanické namáhání je rovněž nižší. Na druhou stranu, analýza RIA havárie ukázala možné potíže. Například, zvýšená tepelná vodivost byla pravděpodobným důvodem zvýšené maximální teploty pokrytí a umocněné krize varu. Toto zjištění se pravděpodobně týká všech paliv založených UO2 , které mají zvýšenou tepelnou vodivost pomocí dopantů.
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Experimental analysis focused on the effect of chloride salt on neutron flux with different energy levels
Slančík, Tomáš ; Števanka, Kamil (referee) ; Katovský, Karel (advisor)
Master’s thesis focuses on the history and current progress in research of molten salt reactors around the world, with an emphasis placed on the properties of molten salts and the problems associated with their use. In relation to the practical part, one chapter is devoted to the creation of input file in the MCNP software. The practical part deals with neutron activation analysis of graphite prism experiment, which is filled with powder NaCl salt. This experiment is focused on the effect of salt on neutron flux with different energy levels. The whole problem was also simulated in the MCNP environment along with the experiment. At the end of the thesis, the individual methods are compared and evaluated.
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Depletion calculation of VVER 1000 reactor fuel using KENO code
Janošek, Radek ; Katovský, Karel (referee) ; Novotný, Filip (advisor)
The introduction to operational nuclear reactors focusing on light-water pressurized reactor VVER 1000 is in the beginning of this Master´s thesis. This thesis covers basic technology of VVER 1000 reactor with focus on reactor core and nuclear fuel TVSA-T. A significant part of the thesis deal with basic concepts of nuclear safety and its methods. The main goal is to create a model of VVER 1000 reactor, which can be used in nuclear burn-up calculations using KENO code. Therefore a part of this thesis deals with explanation of statistical Monte Carlo method and the KENO code.
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Reseach of Molten Salt Cooled Nuclear Reactor Behavior
Kostečka, Jan ; Števanka, Kamil (referee) ; Katovský, Karel (advisor)
The master ‘s thesis deals with the studying behavior of nuclear reactors cooled by liquid salts and with application of liquid salts for IV. Generation of nuclear reactors. For the use of liquid salts, it’s necessary to change the concept of the structure of nuclear reactors. There are new ways to use new fuel in a liquid state. Each salt compound or a set thereof is original in its nature. Therefore, it is necessary to consider a suitable compound for the purposes employed. These points are discussed in the theoretical part. The thesis examines particularly chloride salts, with which there is not much experience. The practical part monitors and verifies the nuclear properties of chloride salts, in our case it is a solid-state chloride sodium chloride’s compound. In addition to the experimental measurement, the MCNP simulation program is used also.
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Description and Utilization of Small and Medium Sized Nuclear Reactors
Novotný, Filip ; Sklenka,, Ľubomír (referee) ; Katovský, Karel (advisor)
This Bachelor’s thesis examines the area of small- and medium-sized nuclear reactors and their roles in the early development of nuclear energy. The work covers current small- and medium-sized reactors in operation and considers future developments in this area. Included is an analysis of the possibilities for their use and applications in various areas of human activity. The work focuses on new projects of small- and medium-sized reactors, especially on projects considered for the near future. They are evaluated for nuclear weapons proliferation resistance, as well as their economic and technical advantages. Furthermore, an analysis was carried out of the possible uses of small reactors in propulsion of spaceships, and their use in various geographic areas. Knowledge acquired from this analysis applies to the situation in the Czech Republic. Both unrealized projects, and projects which may be realized in the future, have been described.
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Simulation of Accelerator Driven Nuclear Reactor for Spent Nuclear Fuel Transmutation
Jarchovský, Petr ; Ing. Antonín Krása, Ph.D., SCK.CEN Mol (referee) ; Katovský, Karel (advisor)
This master’s thesis deals with usage of burn-up (spent) nuclear fuel in nuclear power plants of next generation – accelerator driven transmutation plants which is produced in current nuclear power plants. This system could significantly reduce the volume of dangerous long-lived radioisotopes and moreover they would be able to take advantage of its great energy potential due to fast neutron spectrum. In the introduction are listed basic knowledge and aspects of spent nuclear fuel along with its reprocessing and the possibility of further use while minimizing environmental impact. As another point detailed description of accelerator driven systems is described together with its basic components. In addition this search is followed by individual chronological enumeration of projects of global significance concerning their current development. Emphasis is placed on SAD and MYRRHA projects, which are used like base for calculations. This last, computational part, deals with the creation of the geometry of subcritical transmutation reactor driven by accelerator and subsequent evaluation which assembly is the most effective for transmutation and energy purposes along with changing of target, nuclear fuel and coolant/moderator.
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Subchannel analysis of VVER-100 reactor core
Bednář, Michal ; Petrosyan, Taron (referee) ; Katovský, Karel (advisor)
This master’s thesis deals with boiling crisis and with departure from nucleate boiling ratio. This thesis explains terms like the boiling crisis in nuclear reactors and the thesis deals with individual parameters of the reactor core, which have an impact on departure from nucleate boiling ratio. After that, the thesis deals with subchannel analysis and describes basic mathematical and physical models of the chosen subchannel program. The thesis then processes, with the ALTHAMC12 subchannel program, the chosen parameters and their impact on departure from nucleate boiling ratio. The conclusion of the diploma thesis deals with the evaluation of the best and worst calculated combination.
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