Contra-expertise on the determination of radioactivity of waste water and ventilation air of the Borssele nuclear power plant : Period 2015

RIVM controleert acht keer per jaar de metingen die de kerncentrale Borssele (KCB) verricht in lozingen van radioactiviteit in afvalwater en ventilatielucht. Deze 'contra-expertise' dient als controle op de betrouwbaarheid van de analyses die de kerncentrale zelf uitvoert. De te analyseren monsters worden verspreid over het jaar door Borssele genomen. Doorgaans komen de analyses overeen met de resultaten van Borssele, zo ook in 2015. Enkele verschillen waren zichtbaar bij radionucliden in afvalwater. De vergelijking in de 3H data was iets verbeterd vergeleken met de voorgaande rapportage. In ventilatielucht hebben zowel RIVM als KCB geen enkele gamma- activiteit boven de detectiegrens aangetroffen. De analyses in 3H en 14C ventilatielucht, bemonsterd met een zeolietpatroon, in het eerste en tweede kwartaal van 2015 kwamen goed overeen. Dit is vergelijkbaar met de verbetering die in 2014 is ingezet. Het RIVM heeft de contra-expertises in 2015 uitgevoerd in opdracht van van de Autoriteit Nucleaire Veiligheid en Stralingsbescherming (ANVS).Within the framework of a monitoring programme, the RIVM measures the release of radioactivity into the waste water and atmosphere of the nuclear power plant at Borssele. Measurements are carried out eight times per year. This form of counter-expertise 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 is also the case in 2015. The agreement in the activity concentrations of gamma emitters in waste water was good with a few exceptions. Some differences concern radionuclides in waste water with a tendency to attach to solid particles. These differences originate from an inhomogeneous distribution in the water sample and can hardly be improved. RIVM analyzed eight waste water samples and eight samples of ventilation air taken by KCB at various time points dispersed throughout the year. For 3H in waste water the agreement was slightly improved compared to the last report. In ventilation air no gamma activity was observed. The analyses in the data for 3H and 14C, which were collected by a zeolite cartridge, show good agreement in the first and second quarter. This is comparable to the improvement which was observed in the year 2014. RIVM carried out this counter-expertise on behalf of the Authority for Nuclear Safety and Radiation Protection (ANVS).Autoriteit Nucleaire Veiligheid en Stralingsbescherming (ANVS