RADIOCARBON IMPACT ON A NEARBY TREE OF A LIGHT-WATER VVER-TYPE NUCLEAR POWER PLANT, PAKS, HUNGARY

Tree-ring series were collected for radiocarbon analyses from the vicinity of Paks nuclear power plant (NPP) and a background area (Dunafoldvar) for a 10-yr period (2000-2009). Samples of holocellulose were prepared from the wood and converted to graphite for accelerator mass spectrometry (AMS) C-14 measurement using the MICADAS at ETH Zurich. The C-14 concentration data from these tree rings was compared to the background tree rings for each year. The global decreasing trend of atmospheric C-14 activity concentration was observed in the annual tree rings both in the background area and in the area of the NPP. As an average of the past 10 yr, the excess C-14 emitted by the pressurized-water reactor (PWR) NPP to the atmosphere shows only a slight systematic excess (similar to 6 parts per thousand) C-14 in the annual rings. The highest C-14 excess was 13 parts per thousand (in 2006); however, years with the same C-14 level as the background were quite frequent in the tree-ring series.