14C Activity in the Atmosphere and Biological Samples in the Vicinity of the Krsko Nuclear Power Plant - 10 Years of Experience

Systematic and continuous monitoring 14C activity in atmospheric CO2 and biological samples (mostly apples, vegetable, cereals, corn) in the vicinity of the Nuclear Power Plant Krsko (NEK) in Slovenia has been performed since 2006. The aim of the monitoring is to determine 14C distribution in a close vicinity of the power plant and to estimate possible contribution of NEK to the effective dose of the local population through food chain. In this paper we describe some characteristics of the 14C distribution in the environment of NEK. The 14C activity of atmospheric CO2 at two locations inside the NEK area is on the average slightly higher than that in Zagreb. It depends on the 14C activity (A14C) released in air-born effluent. The influence of the 14C releases has been observed also in plants. Higher 14C activity in plants is most pronounced shortly after spring refuelling, when plants use atmospheric CO2 that contains 14C released from NEK. The influence of the released air-born 14C activity is measurable in both atmospheric CO2 and in plants; the higher the activity of gaseous effluent, the higher the atmospheric and plant 14C activity. However, the influence is temporally and spatially limited. Average 14C activity in plants at the control location Dobova does not differ from the average atmospheric 14C activity in Zagreb. It was shown earlier that the slightly increased 14C activity in plants does not contribute significantly to the effective dose of the local population due to ingestion of 14C. According to the experience of the whole monitoring, 14C is the only released radionuclide detected in the environment of NEK (Report IJS-DP-12059). (author).