Carbon-14 in Tree Rings in the Vicinity of Ignalina Nuclear Power Plant, Lithuania

The results of 14C measurements in the annual tree rings from the Ignalina Nuclear Power Plant (INPP) vicinity, Lithuania, for the period of its operation from 1984 to 2002 are presented. The terrestrial samples, mainly moss and related topsoil, are studied in places as well. The tree rings have shown the slightly enhanced 14C activity due to operation of the nuclear power plant. The maximal calculated normalized 14C release of 11 TBq/GWe/year and the maximal effective dose of 2.0x10-3 mSv/year resulting from the 14C were estimated for 1999. The excess of 14C specific activity measured in the moss and soil samples from moss-covered sites near the nuclear power plant (up to 0.5 km) showed highly elevated 14C contents (up to 813 pMC), probably indicating releases of the particulate material.