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Composite materials with enhanced coefficient of linear attenuation of ionizing radiation
Novotný, Kamil ; Petruš, Josef (referee) ; Kučera, František (advisor)
Ionizing radiation has many useful applications in the fields of healthcare, food industry, nuclear energy and others but poses a hazard to human health in higher doses. In this work, composite materials with enhanced ionizing radiation attenuation properties were prepared. Unsaturated polyester resin was reinforced with inorganic fillers containing elements such as bismuth or barium. Morphology of the samples was studied using scanning electron microscopy. Theoretical values of mass attenuation coefficients were obtained for photon energies 662 keV and 1253 keV using the XCOM software. The attenuation of ionizing gamma radiation was experimentally measured using radioactive sources 137Cs and 60Co. Linear attenuation coefficients and half value layers of the materials were determined using the obtained data. Addition of the fillers improved the shielding properties of the matrix. Composite containing bismuth oxide achieved the highest values of linear and mass attenuation coefficients. The experimental results were found to be in good agreement with theoretical values. Moreover, influence of the fillers on impact toughness has been evaluated.
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Further developements in radiometric method for measurement of slurry density distribution in pipe flow
Krupička, Jan ; Matoušek, Václav ; Pěník, Vojtěch
Laboratory test loop for slurry pipe experiments at the Institute of Hydrodynamics is equipped with two prototypes of radiometric devices which are in permanent evolution as well as the radiometric method of measurement and data processing. Effect of usage of collimated gamma-ray source on the spatial resolution of the radiometric method is studied in this article. Up to now, four differend versions of image reconstruction methods were used to evaluate concentration distribution in a pipe cross-section. Comparison of these methods is presented based on experimental data.
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Determination of volume activity of gamma nuclide in environmental samples and assessment of influence of NPP Temelin on actual measured activity
DAVIDOVÁ, Lenka
In this thesis I target the assesment of a volume activity of gamma ray nuclides in the environment and the examination of the operation the Nuclear Power Station (NPS) Temelín in term of emitting the gamma ray nuclides and their environmental impact. There were collected data of several sorts of environmental samples for statistical analysis. The activity of gamma ray nuclides released by nuclear power plants to the environment after its initiation was compared to the activity of gamma ray nuclides contained it the environment before the initiation of the NPS. It was chosen five exemplary samples - , aerosoles, sediments, milk, soil and surface moisture, which have been scanning in years 1995 and 2005. In these samples, that have sufficient amount of data (sorts of milk, aerosoles and surface moisture) so the statistical analysis was relevant, it was proved, by the non-parametrical Mann-Whitney statistical testing, that there were no statistical difference between the data before and after the initiation of the NPS. The environmental impact wasn´t demonstrated. In these samples, that haven´t sufficient amount of data (sediments and soil), they were also tested (parametrical t. test) and it was proved that there were no statistical difference between the data before and after the initiation of the NPS. Because of very low quality of the testing, we have to use the box plot to ascertain the influence of NPS. In these plots the environmental impact wasn´t demonstrated as well.
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