Naslov
14C in biological samples from the vicinity of NPP Krško

Autori
Obelić, Bogomil ; Krajcar Bronić, Ines ; Barešić, Jadranka ; Sironić, Andreja ; Breznik, Borut

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
Regional and Global Aspects of Radiation Protection: Final Programme and Abstracts / - Bukurešt : International Radiation Protection Association (IRPA), 2007, 215, T9-P14

ISBN
10 973-87778-3-6

Skup
IRPA Regional Congress for Central and Eastern Europe: Regional and Global Aspects of Radiation Protection

Mjesto i datum
Brašov, Rumunjska, 24.09.2007. - 28.09.2007

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
14C; nuclear power plant; biological samples; monitoring; atmospheric CO2; Krško

Sažetak
Radioactive isotope 14C is naturally produced in the atmosphere and then distributed in the atmosphere and biosphere. The equilibrium 14C atmospheric specific activity equals 226 Bq/kg of carbon. In the second half of the 20th century the natural 14C distribution was disturbed by atmospheric bomb tests. After the ban of atmospheric bomb tests the present-day atmospheric 14C activity approaches the natural (non-disturbed) values. 14C is produced also in nuclear power plants. The emitted CO2 enters the natural carbon cycle, and through food chain it may contribute to the dose of the local population. Specific 14C activity of biological samples (apples, corn, cereals, borecole, grass) was measured in immediate and wider vicinity of the Nuclear Power Plant Krško (NPPK) in Slovenia, close to the border with Croatia. Sampling campaigns were performed in July and in October 2006 at sampling sites that were chosen in the immediate vicinity of the NPP stack (250 – 700 m difference), in a wider environment (1000 – 1500 m), and at a control site 10 km away. The aim of this study was to determine possible contribution of NPPK to the effective dose of local population through food chain. Biological samples were dried, carbonized at 400°C, and combusted in a stream of oxygen. The obtained CO2 was absorbed in a mixture of Carbosorb E and Permafluor E. 14C activity was measured by a liquid scintillation counter Quantulus 1220. Mean a14C at the control site was in July 233 ± 3 Bq/kg C. Most of the locations in the vicinity of NPPK showed slightly higher 14C activities. The largest difference was 66 Bq/kg C. The results are similar for the October campaign: at the control site we measured 235 ± 3 Bq/kg, and highest activities (difference up to 53 Bq/kg C) were measured again at the same locations as in July. Spatial distribution of 14C activities around NPPK showed the activity dependence on the distance and on the direction. Increased (especially the highest) 14C activities in both sampling campaigns were in the SW-NE direction, and this direction coincided with the most pronounced wind directions. A conservative estimate of the effective dose (ingestion of food of the highest 14C activity throughout the year) gives the difference of about 3 µ Sv above dose from natural 14C. A more realistic estimate, however, results in the contribution of NPPK through the ingestion of food grown in its vicinity of less than 1 µ Sv.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

Napomena
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