The Tricastin's riddle

In July 2008, a leak at the Socatri plant set on the largest nuclear site in Europe (the Tricastin site) led to a contamination of surface and underground water beyond the limit value of 15 μg/l of uranium. The Socatri is specialized into the processing of nuclear effluents. A storing tank overflowed into a retention basin presenting a crack. 20 m3 of effluents leaked on the ground of the plant and in the neighbouring river. A quantity of 74 Kg of uranium is assessed to have leaked. Because of no contamination of staff or people the event has been graded on the first level of the INES scale. Measures limiting the use of water were taken by local authorities. A campaign of measurements has shown the existence of an ancient contamination whose origin is not clear, the site homing various nuclear activities and particularly an ancient enrichment plant whose wastes are still stored on the site. (A.C.)