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[en] Monophase diffusion of 90Sr from radioactive wastes into bitumen, at approximately room temperature, is studied using the thin layer method. The diffusion couple absorbent-bitumen is considered as belonging to the semi-infinite type, with constant normalized concentration on the interface. The Matano-Boltzmann method is applied in order to find out the diffusion coefficients and their dependence on the normalized concentration. (orig.)
[en] The content of 90Sr was determined in samples of different subtropical soils taken from the depth of 0-10 sm. According to the decrease of 90Sr content, the soils can be arranged in the following order: alluvial sandy, terra rossa based on banded clay, yellow-brown gleyed > subtropical podsol > podsolized yellow soil > brown soil. The maximum concentration of 90Sr was found in 0-10 sm layer of alluvial sandy soil and terra rossa in citric plantations and the minimum concentration - in subtropical podsol and yellow-brown soil of tea plantations
[en] In the 2008 E-Area Performance Assessment (PA), each final disposal limit was constructed as the product of a preliminary disposal limit and a plume interaction factor. The following mathematical development demonstrates that performance objectives are generally expected to be satisfied with high confidence under practical PA scenarios using this method. However, radionuclides that experience significant decay between a disposal unit and the 100-meter boundary, such as H-3 and Sr-90, can challenge performance objectives, depending on the disposed-of waste composition, facility geometry, and the significance of the plume interaction factor. Pros and cons of analyzing single disposal units or multiple disposal units as a group in the preliminary disposal limits analysis are also identified.
[en] The radioactive contamination of omnivorous fish species (Cyprinus carpio, Hypophtalmictys nobilis Richardson), of herbivorous fish species (Hypophtalmictys molitrix Valenciennes) and carnivorous fish species (Silurus glanis L., Esox Lucius L.) has been investigated. Orientative data have been obtained by analyzing samples originating from various sites. Though differences appeared between the analyzed samples, no incorporations of outstanding nature have been observed. In accordance with experiences described in literature, the isotope Sr-90 is accumulated in an increased degree in the skeleton of fish living in ponds. This is valid in all cases when the vital processes are regulated artificially by fishery methods. A particularly important factor is that the individual fish living in ponds are 2-3 or at most 4 years of age i.e. from the aspect of their ontogenesis their organism is in a strongly build-up phase. Sr-90 proved to be accumulated in a relatively greater amount in the organisms of herbivorous fish. (P.J.)
[en] A case of internal contamination by 90Sr of a member of the public is described. An unauthorised person entered a low-activity waste storage placed in an abandoned sand mine, a barrel with marker for radioactive substances was found and manipulated with a tin labelled as ISOMET Sr90. The radiation protection authority was informed after 6 days and found surface contamination on his belongings. Whole-body counting with an HPGe detector and excretion analysis were performed. He was measured by whole-body counter 16 times from November 1990 to August 1992, 9 samples of urine and 6 samples of faeces were collected. For the estimation of the dose, the software CINDY with the biokinetic models of ICRP 30 was used. Single and continuous intakes were assumed. Intake was estimated to be about 3 MBq and committed effective dose 84 mSv. (author)