Hydrogeological studies for radiological monitoring of shallow groundwater in the Eurex plant of Saluggia (Vercelli, Italy).

In 2004, contaminated water was found inside the safety interspace around the spent fuel pool; therefore, an ample monitoring programme of the structure, soils and shallow groundwater was started in order to detect any radioactive leakage into the environment. A first group of piezometers was installed. In the one nearest to the pool, an anomalous activity of 90Sr (∼10−2 Bq l−1) was found, calling for the following actions: gradual enlarging of the monitoring network, implementation of in situ permeability tests and groundwater tracer test and study of groundwater mobility of the main radionuclides contained in the pool water: 90Sr, 137Cs, 241Am and 239/240Pu. Because 90Sr is the only artificial radionuclide detected in groundwater, this study mainly focused on this one. All the investigations demonstrated that 90Sr coming from the pool is not detectable any longer just some tens of metres from the building and allow the correlation of 90Sr concentration to flow and water-table fluctuations. Moreover, such a wide mass of hydrogeological and radiological data allows the estimation of an environmental value for environmental radiological significance. [ABSTRACT FROM PUBLISHER]