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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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Nuclear Fuel and its Behavior during Burn-up
Matocha, Vítězslav ; Foral, Štěpán (referee) ; Katovský, Karel (advisor)
The point of this bachelor’s thesis is to characterize different types of nuclear fuels and their behaviour during the process of burning-up. Futher, basic types of nuclear reactors are mentioned, as well as their history and different kinds of nuclear fuels used in these reactors. Then there are pieces of information about fuel cycles and fuel burning-up. Furthermore, the thesis concentrates on the changes, which happen in the nuclear fuel during the process of burning-up, such as swelling and cracking. In its other parts, this bachelor’s thesis deals with fission products, mainly gas fission products are mentioned here. At the end of this thesis, a simple model of nuclear fuel burning-up is created. This model follows concentration of izotopes of uranium and plutonium during fuel burning-up.
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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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Sodium cooled fast reactors
Daňhel, Aleš ; Katovský, Karel (referee) ; Foral, Štěpán (advisor)
This bachelor’s thesis deals with the sodium-cooled fast reactors. It comprehensively describes the problem of sodium-cooled fast reactors. Attention was paid to the basic specifications and parameters of these reactors. There was briefly described nuclear reactions which are under way in core of sodium-cooled fast reactors but also chemical reactions which are linked to function of liquid sodium as a coolant and heat transfer substance. Attention was also paid to the differences in the reactor core configuration and to the machine device specific for sodium-cooled fast reactors. Further on this bachelor’s thesis puts on the overview of sodium-cooled fast reactors that have worked, are still working or are under construction in each country all over the world. There was briefly described generation IV nuclear reactors, particularly its history and reasons that originate generation IV. Under generation IV was also described nuclear reactor SFR and highlighted differences compared to existing sodium-cooled fast reactors. In the practical part of this bachelor’s thesis is easily made a calculation of the heat transfer from the fuel rod to the cooling sodium and there is also mentioned course of the heat transfer coefficient along the fuel rod. This calculation was made by computing program MATLAB.
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Uranium mineralization in the Krkonoše permian piedmont basin: Radioactive elements in the Rudník horizon near Vrchlabí
Novák, Dominik ; Goliáš, Viktor (advisor) ; Tuhý, Marek (referee)
This paper focuses on artificial outcrop of permian lacustrine sediments of the Rudník horizon (298-297 Ma) and red siltstones of the Vrchlabí formation near Vrchlabí, where increased concentrations of uranium and thorium radionuclides were observed during previous researches. Radionuclides are concentrated in a few layers of black, grey and red shales, which makes about 20 m of the whole 250 m long studied profile. Rock samples were collected from localised radioactive layers and studied for mineralogical compositions, concentrations of radionuclides and autoradiographic and microscopic study of uranium and thorium bonds in these rocks. Laboratory measurements confirmed increased concentrations of both uranium and thorium in collected samples. Highest amount of uranium was measured in anoxic black shale (106,9 ppm U), highest amount of thorium in anomalous sample of red siltstone (76,6 ppm Th). Shales and siltstones main contents are albite, analcime, calcite, dolomite, muscovite and potasium feldspars. Acording to the study it is assumed, that the main source of radionuclides were redeposited pyroclastics from the Krkonoše piedmont basin area or synchronous volcanic activity. It is likely, that during late tectonic development of the basin, these radionuclides were redistributed by hydrothermal...
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Radioactivity of granitoids of the Krkonoše-Jizera pluton
Černík, Tomáš ; Goliáš, Viktor (advisor) ; Matolín, Milan (referee)
2. SUMMARY This thesis is focused on the natural radioactivity of the Krkonoše pluton, which is divided in 6 particular types of granite: the Jizera, the Liberec, the Fojtka, the Tanvald, the Harrachov, the Krkonoše ones. The goal of the thesis was to compare these values and find out whether there was an unlike element (U, Th, K) content difference. Based on literature data about the Czech and Polish part of pluton, there was assigned data of the analysed samples (of contents of K, U, Th) to each type of granite. The literature data was refined on the base of the current knowledge. The localized collection points were assigned to the particular types of the Krkonoše - Jizera granitoids. The analytic data collection was statistically evaluated. On the base of the statistic data evaluation significant differences of the radioactive element content of the particular types of granite was proved. The most radioactive one is the Harrachov granite. The Tanvald one has a distinctively anomalous ratio of U to Th higher than 1. The other types of granite have only an average level of radioactivity. There was also checked a significant aerial gamaspectrometric anomaly in the south - west direction of Hejnice. There was made a field gamaspectrometric measurement, which did not prove the significant increase in an...
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Uranium content in macrofungi
Kubrová, Jaroslava ; Borovička, Jan (advisor) ; Řanda, Zdeněk (referee)
In the leading part of this work I presented general information on the kingdom of fungi and fungal ecology focused on marofungi (macromycetes). Furthermore, I reviewed the phenomenon of trace elements accumulation in macrofungal fruit-bodies, particularly focused on uranium and its biogeochemistry. In the experimental part, results of my own research are presented. I determined concentrations of uranium, thorium, silver and lead by use of HR- ICP-MS and ENAA. The macrofungal samples were collected 1/ in clean areas with diverse geological bedrock, 2/ in uranium-polluted area in vicinity of Příbram (Central Bohemia, Czech Republic). Furthermore, selected trace elements were determined also in underlying soils by use of the both analytical methods. For investigation of trace elements mobility, the BCR sequential extraction was applied.
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Thorium as an environment stressor for plant growth.
Hrdinová, Aneta ; Lhotáková, Zuzana (advisor) ; Podlipná, Radka (referee)
Thorium is an element belonging to heavy metals, which is characterized by its radioactivity similarly to uranium and radon. Thorium is not commonly used in industry, but becouse of its radioactive properties it has a great potentional for future use in nuclear energetics. Thus, increasing release of Th into the soil, water and atmosphere can be expected in near future and through plant biomass it could become a part of food chains and webs and, thus, to represent a considerable health risks to humans. Studies devoted to research on thorium and its effects on plants has not been published much yet. The majority of these studies focus mainly only on plant abilities to accumulate thorium and/or monitoring distribution of thorium in plant body. But till now, a study is still missing, which would monitor the effect of thorium on the physiological characteristics of plants. Plants of Nicotiana glutinosa (L.) medium Thorium accumulatin were hydroponically cultivated Hoagland nutrient media differedin the presence of thorium, tartaric acid, putrescine and phosphates. In first part of the present study I monitored accumulation of thorium by tobacco plants under the influence of the above-mentioned modifications of media. In the second part, I studied the Th effect on the photosynthetic apparatus (contents...
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Thorium accumulation and study of stress responces of plants on thorium presence
Kufner, Daniel ; Soudek, Petr (advisor) ; Petrová, Šárka (referee)
The ability of the accumulation of thorium and study of the stress responses on his presence was tested on a selected cultivar of tobacco, La Burley 21. Plants were cultivated in Hoagland's hydroponic medium under artificial light. Except to the ability of accumulation and distribution of thorium in the all parts of plant was investigated the effect of selected organic and inorganic additions on accumulation. Among organic substances included citric acid, tartaric and oxalic acid in their presence was observed the increase of thorium in all parts of the plant. Were also tested products from the diamine and polyamines (putrescine, cadaverine, spermine and spermidin). These substances, also known for their antioxidant activity in plants, had an impact on reducing the accumulation of thorium, especially in the root system of plants. The most important factor influencing the accumulation of thorium was the absence of phosphate ions in a hydroponic medium, which caused the rise of the concentration of thorium about several levels in all parts of the plants. The initial decrease of pH after additions of organic acids or addition of high concentrations of thorium and the gradual increase of pH during cultivation had proved significant. It was also compared the uptake of accumulation and distribution of...
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