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The AmBe Laboratory Neutron Source Field Determination Using Experimental Stend
Jelínek, Martin ; Šťastný, Ondřej (referee) ; Katovský, Karel (advisor)
This master’s thesis provides a comprehensive overview of the conventional neutron sources from the perspective of reactions which lead to the production of neutrons, advantages, disadvantages, properties and their possible utilization. In the relation to the assembly of the laboratory neutron source and the unique experimental stand “Candle” basic methods of the neutron field analysis are outlined and two of them, the neutron activation analysis and the calculation using the MCNP software code are discussed in depth to apply and compare these methods. The experimental part deals with the realization of neutron activation analysis from its design itself, through gamma spectrometry to the cadmium ratio calculation. In compliance with the measurements, a calculation with MCNP code was run and both methods were evaluated and compared. The computation is complemented with the analysis of radiation situation on the borders of the supervised area, which is compared to the legal limit.
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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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Experimental and calculational salts' properties investigation for MSR reactors from nuclear data point-of-view
Burian, Jiří ; Ing. Miroslav Zeman, PhD., SÚJB RC Brno (referee) ; Katovský, Karel (advisor)
Nowadays there is research into molten salt reactors. The use of chlorine-based salts, which would be more available than known fluoride salts, is envisaged. The subject of research is not only the chemical and physical properties of chloride salts, but also their behavior in the neutron field and the influence of neutron balance inside the reactor. Many properties can also be determined using calculations that draw information from scientific nuclear libraries (endf). The purpose of this work is to compare important nuclear libraries with each other, and also to compare the reaction rates calculated from the library data with the reaction rates obtained by self-measurement. The preview will include a description of the necessary activities associated with the preparation of measurements, instructions for compiling the computer program NJOY and the process of the measurement itself. At the end of the work will be summarized the results and statements of which nuclear library is the closest in its values to the results of experiments.
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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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Experimental and calculational salts' properties investigation for MSR reactors from nuclear data point-of-view
Burian, Jiří ; Ing. Miroslav Zeman, PhD., SÚJB RC Brno (referee) ; Katovský, Karel (advisor)
Nowadays there is research into molten salt reactors. The use of chlorine-based salts, which would be more available than known fluoride salts, is envisaged. The subject of research is not only the chemical and physical properties of chloride salts, but also their behavior in the neutron field and the influence of neutron balance inside the reactor. Many properties can also be determined using calculations that draw information from scientific nuclear libraries (endf). The purpose of this work is to compare important nuclear libraries with each other, and also to compare the reaction rates calculated from the library data with the reaction rates obtained by self-measurement. The preview will include a description of the necessary activities associated with the preparation of measurements, instructions for compiling the computer program NJOY and the process of the measurement itself. At the end of the work will be summarized the results and statements of which nuclear library is the closest in its values to the results of experiments.
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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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Geological and geophysical exploration of the Kokonín fault for building constructions (Jablonec n. Nisou, Czech Republic)
Tumurkhuu, Gereltsetseg ; Goliáš, Viktor (advisor) ; Thinová, Lenka (referee)
Radioactivity is an important part of the environment. In the years 2014 - 2015 a survey on medicinal radioactive springs was carried out in the Tanvald granite body. During extensive radiohydrogeochemical exploration in the surrounding area of Schindler spring, the outcrop of U - mineralization has been found at a new construction site in the Kokonín fault. It is possible to find "hot" pieces of uranium ore fragments in the quaternary cover in this place. The occurrence of the hydrothermal (vein) type of uranium in the Krkonoše - Jizera is new as it hasn't been mentioned in literatures before. After an agreement with the owners, detailed radiometric survey proceeded in the surrounding area of two affected houses by using gamma spectrometry and emanometry at the dense net. There is a wider area between two houses with activities of 222 Rn over 1 MBq/m3 and on the ore outcrop was measured 3.3 MBq/m3 . A quaternary solifluction flow with an increased radioactivity creeps down under the House 1. The highest uranium contents reached up to 291 ppm eU (= 3 595 Bq/kg 226 Ra) on the uranium ore lens outcrop. The average of gamma dose rate is 85,6 nGy/h with maximem 261 nGy/h on the outcrop. A further radiometric survey through the entire Kokonín fault line was carried out in an area of roughly 0.25 x 1 km2...
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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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