Browsing by Subject "FISSION-PRODUCTS"

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  • Salminen-Paatero, Susanna; Thölix, Laura E; Kivi, Rigel; Paatero, Jussi (2019)
    Radionuclides 137Cs and 90Sr and total beta activity were determined from air filters collected in Rovaniemi (Finnish Lapland) in1965–2011. Nuclear contamination sources present in the air filter samples as well as temporal changes in radionuclide concentrations were examined. Ozone observations and meteorological modeling were used in combination with radionuclide analyses to study the reasons behind the observed seasonal concentration variation. In general, the magnitude and variation in activity concentrations of 137Cs and 90Sr and total beta activity in the surface air of Rovaniemi in 1965–2011 corresponded well with values from other countries. However, the obtained results prove in practice that hardly any refractory or intermediate radionuclides from the destroyed Chernobyl reactor fuel were introduced to Finnish Lapland. The main source of 137Cs and 90Sr and total beta activity in the surface air of Rovaniemi in 1965–2011 has been intense atmospheric nuclear weapon testing in 1950s–1960s and later tests performed in 1965–1980, as well as leakages from underground nuclear tests in Semipalatinsk, 1966, and Novaya Zemlya, 1987. For 137Cs and total beta activity, the influence of Chernobyl and Fukushima accidents was detected.
  • Rice, S.; Algora, A.; Tain, J. L.; Valencia, E.; Agramunt, J.; Rubio, B.; Gelletly, W.; Regan, P. H.; Zakari-Issoufou, A. -A.; Fallot, M.; Porta, A.; Rissanen, J.; Eronen, T.; Äystö, J.; Batist, L.; Bowry, M.; Bui, V. M.; Caballero-Folch, R.; Cano-Ou, D.; Elomaa, V. -V.; Estevez, E.; Farrelly, G. F.; Garcia, A. R.; Gomez-Hornillos, B.; Gorlychev, V.; Hakala, J.; Jordan, M. D.; Jokinen, A.; Kolhinen, V. S.; Kondev, F. G.; Martinez, T.; Mason, P.; Mendoza, E.; Moore, I.; Penttilä, H.; Podolyak, Zs.; Reponen, M.; Sonnenschein, V.; Sonzogni, A. A.; Sarriguren, P. (2017)
    The beta decays of Br-86 and Rb-91 have been studied using the total absorption spectroscopy technique. The radioactive nuclei were produced at the Ion Guide Isotope Separator On-Line facility in Jyvaskyla and further purified using the JYFLTRAP. Br-86 and Rb-91 are considered to be major contributors to the decay heat in reactors. In addition, Rb-91 was used as a normalization point in direct measurements of mean gamma energies released in the beta decay of fission products by Rudstam et al. assuming that this decaywas well known from high-resolution measurements. Our results show that both decays were suffering from the Pandemonium effect and that the results of Rudstam et al. should be renormalized. The relative impact of the studied decays in the prediction of the decay heat and antineutrino spectrum from reactors has been evaluated.