Environmental radiological surveillance around nuclear power plants in Argentina

During the last five years of operation of Atucha I nuclear power plant (CNA I) and Embalse nuclear power plant (CNE), a field team from the Environmental Radioactivity Division of Nuclear Regulatory Authority (ARN) of Argentina has carried out surveillance programs in the surroundings of these facilities, in order to estimate the radiological impact. The Argentine nuclear power plants use natural uranium as fuel and heavy water as refrigerant and moderator. During normal operation, radionuclides are released to the environment through liquid and gaseous discharges; mainly tritium which is generated from the neutron activation of heavy water deuterium. One of the environmental radioprotection requirements for a nuclear facility licensing is the compliance of the dose limit (1 mSv/year) to the most exposure members of the public (critic group). The authorised annual dose limits established for ARN, to control the release of radioactive effluents are 50 and 100 μSv/year for CNA I and CNE respectively. The surveillance programs carried out around the mentioned nuclear facilities included the radionuclide analysis of H-3, Cs-137, Co-60. I-131 and Sr-90. The matrixes analysed were milk, grass, diet, fish and groundwater, surface and tap water. The results, including the dose assessment, are presented. The measured results of the radionuclides mentioned above were, in general, below the detection limit (except for tritium). The doses estimated for both, liquid and gaseous discharges, varied from 4 to 5 μSv/year for each nuclear power plant, since 1998 to 2002. This implies that the population living in the vicinity of these areas receives no significant exposure. (author)