Abstract

Within the framework of a monitoring programme, the RIVM measures the release of radioactivity into the waste water and atmosphere of NRG . Measurements are carried out eight times per year. This form of counterexpertise is aimed at verifying and supporting the reliability of the analyses carried out by the Borssele plant. The two different sets of measurements are generally in agreement, as was also the case in 2008. The few discrepancies that were observed in 2008 concern the gross-beta data in waste water; RIVM reports considerably lower gross-beta data than NRG does. This is partly explained by the presence of short-lived beta-emitters in waste water of NRG, and partly because of differences in the analytical methods applied by NRG and RIVM. In samples taken from ventilation air, RIVM determined in some cases an activity concentration below the detection limit of NRG. NRG measures the filters mainly for screening purposes and, therefore, applies a much shorter measuring time than RIVM. The RIVM analyzed eight waste water samples and eight samples of ventilation air taken by NRG at various time points dispersed throughout 2008. The analyses were carried out on behalf of the Department of Nuclear Safety, Security and Safeguards of the Dutch Ministry of Housing, Spatial Planning and the Environment (VROM).