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Fusion systems and their shielding
Roubal, Michal ; Katovský, Karel (referee) ; Král, Dušan (advisor)
This thesis is concerned with nuclear fusion and its use as a source of energy for humanity. In the first part of my thesis, I will briefly explore the research history of nuclear fusion. Next, I will investigate the various possible issues connected with achieving and sustaining nuclear fusion. I will briefly discuss the importance of mastering it. I will talk about existing and anticipated risks of radiation damage which can occur during nuclear fusion. Lastly, i will discuss the principles of tritium breeding.
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Neutron sources in science and industry
Andrýsek, Jan ; Zeman, Miroslav (referee) ; Král, Dušan (advisor)
This bachelor thesis is composed of literature review on the topic of neutron sources and experimental component discussing the reaction rate in an experimental model of a neutron source dependent on the isotope in used foil. The most used neutron sources in the world and in the Czech Republic are mentioned. The creation of neutrons in radionuclide sources in AmBe and PuBE, nuclear reactors, spallation sources and fusion neutron generators are described, together with their utilisation in research and industry. The practical part contains description of the design (\(\gamma \), n) of a neutron source in MCNP programme and its consecutive calculation using the Monte-Carlo method. The input for nuclear reaction are electrons accelerated onto energy of 70 MeV. These electrons strike the target, where the effect of braking radiation generates gamma rays. Radiation integrates with the nuclei of the convertor from beryllium oxide or lithium salt. The results analysed and discussed are used from experimental measurements in Yerevan for foils from isotopes 197-Au, 209-Bi and 59-Co. These foils were used in models with convertors from Beo and LiCl.
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Analysis of thermal power plants environmental impacts using radioanalytical methods
Král, Dušan ; Ing. Ondřej Huml, Ph.D., KJR FJFI ČVUT v Praze (referee) ; Katovský, Karel (advisor)
Operation of classical power sources, like coal fueled thermal power plants, causes more or less strong impact on surrounded environment. Beside to the generally discussed CO2 emissions, there are CO, SOx, NOx too; and also fly ash emissions containing various trace elements depending on coal quality. Heavy trace elements carried by fly ash generate locally distributed fallout and contaminate soil in the power plant neighborhood for many years. These elements may be detected in soil samples as well as in biomass. Objectives of this work are to find and quantify trace elements in soil samples near Oslavany hard coal fueled thermal plant, which was in operation from 1913 to 1993. Power plant did not use any advanced fly ash filters. Hard coal was used as a fuel for power plant and it was mined locally in Rosice-Oslavany coal district in very deep mines (up to 1428 m). Coal contained a lot of trace elements. A mine as well as power plant is for more than 20 year closed, but trace elements can be still find in the environment. Main goal is to find these elements using activation analysis and gamma-ray spectrometry methodology. We have assembled thirty six soil samples in square lattice drawn around Oslavany power plant brownfield. On behalf of cooperation with colleagues from the Czech Technical University in Prague and their Open-Access project, we irradiated samples in three vertical channels of VR-1 research nuclear reactor. Irradiated samples were transported to gamma spectroscopy & activation analysis laboratory and measured by HPGe detector. Gamma spectra were analyzed and some trace elements identified. We have determine relative and absolute concentration of found elements. We observe and determine activity and weight of As, U, Ba, La, Eu, Mn, K, V, Mg and Na only. Results show a real suspicion for increase of trace elements in soil samples of hard coal power plant surroundings.
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Investigation of Thorium Utilization in Accelerator Driven Nuclear Reactors
Král, Dušan ; ČR, Petr Chudoba, ÚJF AV (referee) ; Zeman, Miroslav (advisor)
This thesis deals with the idea of using accelerator driven systems for thorium transmutation into the fissile material, which can be utilized in the accelerator driven systems and in thermal nuclear reactors. Thorium occurs on Earth only in fertile isotope Th-232. It can be converted to fissile U-233 by neutron capture and subsequent beta decay. The experimental part handles the data measured by the irradiation of four thorium samples by the secondary neutrons in the QUINTA spallation target, which was irradiated with 660~MeV protons. Reaction rates for the fission and spallation products were estimated using gamma spectroscopy and activation techniques. Furthermore, Pa-233 production rates were also determined in all experimental samples. Pa-233 and fission production rates were calculated in all experimental samples using the MCNPX transport code and evaluated nuclear data for high-energy reactions. The experimental results are of a great importance for the future investigation of thorium in the accelerator driven system concept, validation of Monte-Carlo based calculation codes and validation of high-energy nuclear models.
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Transmutation of spent nuclear fuel with using accelerator driven systems
Máca, Pavel ; Král, Dušan (referee) ; Zeman, Miroslav (advisor)
This bachelor thesis deals with the analysis of neutron spectra in the reactors with liquid salts. The teoretical part contains a brief description of the nuclear fuel cycles. In the theoretical are further described the reactors of IV. generations. Here are the reactors on the basis of liquid salts described in detail. The practical part of the bachelor thesis is focused on the analysis of neutron spectra in set-ups performer from solid salt. Concretly, the salts NaCl and KCl were analysed by means of the computational codes TALYS and MCNP.
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Characterization of the neutron AmBe source using threshold activation detectors
Burian, Jiří ; Zeman, Miroslav (referee) ; Král, Dušan (advisor)
Neutron activation analysis is used to characterize an unknown neutron field source or material of unknown composition. Using known reactions that take place in the activation detector due to the action of the neutron field, their measurement and evaluation, we can describe the composition of the source if we know the material composition of the activation detector, or, conversely, if we do not know the materials from which the activation detector is made, we can find out if we put this detector of unknown composition into the action of neutron radiation of known origin.
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Determination of nuclear reactions' microscopic cross-sections using an accelerator-driven neutron source
Filová, Vendula ; Šťastný, Ondřej (referee) ; Král, Dušan (advisor)
Tato práce se věnuje určení mikroskopických účinných průřezů interakcí neutronů s indiem. Teoretická část shrnuje neutronové zdroje používané ve vědě i průmyslu, popisuje princip jejich fungování a představuje příklady jejich aplikací. Praktická část obsahuje postup vyhodnocování velikostí účinných průřezů včetně jednotlivých provedených korekcí. Byly vyhodnocována data celkem ze tří experimentů, při kterých byly produkovány neutrony interakcí protonů s tenkým lithiovým terčem. Kvazi monoenergetickým neutronům byly vystaveny sendviče folií včetně foile z india, produkty interakcí byly měřeny pomocí gamma spektrometrie. Výsledné mikroskopické účinné průřezy jsou porovnány s daty z knihoven evaluovaných dat a z knihovny EXFOR.
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Determination of nuclear reactions' microscopic cross-sections using an accelerator-driven neutron source
Filová, Vendula ; Šťastný, Ondřej (referee) ; Král, Dušan (advisor)
Tato práce se věnuje určení mikroskopických účinných průřezů interakcí neutronů s indiem. Teoretická část shrnuje neutronové zdroje používané ve vědě i průmyslu, popisuje princip jejich fungování a představuje příklady jejich aplikací. Praktická část obsahuje postup vyhodnocování velikostí účinných průřezů včetně jednotlivých provedených korekcí. Byly vyhodnocována data celkem ze tří experimentů, při kterých byly produkovány neutrony interakcí protonů s tenkým lithiovým terčem. Kvazi monoenergetickým neutronům byly vystaveny sendviče folií včetně foile z india, produkty interakcí byly měřeny pomocí gamma spektrometrie. Výsledné mikroskopické účinné průřezy jsou porovnány s daty z knihoven evaluovaných dat a z knihovny EXFOR.
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Fusion systems and their shielding
Roubal, Michal ; Katovský, Karel (referee) ; Král, Dušan (advisor)
This thesis is concerned with nuclear fusion and its use as a source of energy for humanity. In the first part of my thesis, I will briefly explore the research history of nuclear fusion. Next, I will investigate the various possible issues connected with achieving and sustaining nuclear fusion. I will briefly discuss the importance of mastering it. I will talk about existing and anticipated risks of radiation damage which can occur during nuclear fusion. Lastly, i will discuss the principles of tritium breeding.
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Transmutation of spent nuclear fuel with using accelerator driven systems
Máca, Pavel ; Král, Dušan (referee) ; Zeman, Miroslav (advisor)
This bachelor thesis deals with the analysis of neutron spectra in the reactors with liquid salts. The teoretical part contains a brief description of the nuclear fuel cycles. In the theoretical are further described the reactors of IV. generations. Here are the reactors on the basis of liquid salts described in detail. The practical part of the bachelor thesis is focused on the analysis of neutron spectra in set-ups performer from solid salt. Concretly, the salts NaCl and KCl were analysed by means of the computational codes TALYS and MCNP.
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