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3H monitoring in the river Vltava in the surroundings of NPP Temelín
ZEMAN, Karel
The State Office for Nuclear Safety (SÚJB) and the National Radiation Protection Institute (SÚRO) are involved in independent monitoring of the surroundings of nuclear power plants (NPPs) as stipulated by Czech legislation (Decree No. 319/2002 on Czech Radiation Monitoring Network, as amended by Decree No. 27/2006). This monitoring includes examination of samples from the hydrosphere, where any unusual presence of radionuclides can indicate radioactivity leaks from the NPP. Samples are taken weekly (2 sampling sites on the Vltava [Moldau] river downstream of the Temelín waste duct, viz. at Kořensko (downstream of the dam) and at Újezd) and monthly (from 5 sampling sites on the Vltava river {--} 2 upstream of the mouth of the duct and 3 downstream of the mouth of the duct {--} and 1 sampling site at the Býšov precipitation retention basin). A CANBERRA PACKARD TriCarb liquid scintillation beta spectrometer serves to measure the activity of tritium in surface waters in compliance with ČSN ISO 9698 (757635) standard. The aim of this work was to determine volume activity of point samples from the SÚJB monitoring sites in the Vltava river (with focus on Kořensko) and to examine tritium kinetics in dependence on factors such as the times of release from the NPP, flow rate through the Kořensko dam, Orlík basin level height, etc. The feasibility of back-tracing of the activity levels and times of release from the Temelín plant, which could serve SÚJB as a tool to check the data provided by the plant management, is discussed. The data of volume activity of tritium in watercourses in the vicinity of the NPP are in accordance with SÚJB{--}Temelín NPP interlaboratory comparisons. Linked to the known release times and amounts of effluents from the Temelín plant, the results of the measurements allow the propagation of tritium through the watercourse of the Vltava river to be assessed both in the time horizon and with respect to a quantitative estimate of dilution of the radioactivities in dependence on the flow rates. Owing to the fact that radioactivity in the surroundings of the NPP has been monitored for many years now, convincing evidence can be provided demonstrating that the operation of the plant does not endanger the health of the critical group of population living near the plant, that the radiological situation is stable, and that the requirements and conditions of authorized limits regarding the introduction of radionuclides into the environment are complied with.
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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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