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The Cesium-137 content in wild game in Šumava.
VENČOVSKÁ, Petra
Our territory was the artificial radionuclide cesium-137 (hereafter 137Cs) contaminated by radioactive contamination during nuclear testing in the atmosphere and to the largest nuclear accident occurring in Chernobyl. Contamination of the environment and its components 137Cs is still being monitored due to the long half-life of this radionuclide. The stated goal of the work is to compare the mass activity of 137Cs in the forest species from the Šumava region. This also results in the research question as to whether there is a difference in 137Cs in the mass of different animal species living in forests in the Šumava region. According to the availability of samples, the administrative districts of Vimperk and Horní Planá were selected. From these localities, there are also 14 measured samples of fur animals, which were provided for this research. Consequently, the content of 137Cs was determined by gamma semiconductor spectrometry, which, besides mentioned 137Cs, was also used for comparison with potassium-40 (hereinafter only 40K), which is the most widely used natural radionuclide. The measurement results also show that higher concentrations of 137Cs were in samples from the Vimperk region, and also that higher mass activity of 137Cs was measured in herbivores. The highest value of 40K was measured in both herbivores and omnivores. Effective dose ranges were calculated from the results obtained to express the level of contamination that would occur in the case of the consumption of contaminated meat. Calculated values of effective dose ranges due to internal contamination as well as other sources of radioactivity are not significant and their effect on the health of our population is negligible.
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History of serious accidents at nuclear facilities
DRAŽANOVÁ, Kristýna
The bachelor thesis maps all the accidents assessed by the INES scale level 5 and above. It is not only concerning events at nuclear power plants, but also at nuclear weapons production facilities, whose construction preceded the development of the nuclear power plants in several countries. An attention is paid also to the unfortunate event, which was originated as a result of unauthorized manipulation with a part of the radiotherapy device containing radioactive isotopes of caesium 137Cs. The theoretical part of the bachelor thesis explains the general concepts, such as radioactivity and ionizing radiation. It distinguishes the types and sources of ionizing radiations and describes its impact on human body. Next, it deals with the concept of nuclear safety, determined supervising authorities and its governing legislation. It also contains a description of the INES scale, which is an international scale used to assess nuclear incidents and accidents. The practical part of this thesis provides an overview of the accidents with a detailed description of their development, the circumstances that led to them and the consequences left behind. The development of the individual accidents is subsequently analysed with a view to discover the underlying causes, and finally compared in order to find possible identical features or similarities. The present thesis was intended to examine the following research question: Is human failure the most frequent cause of nuclear plant accidents?
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