Integrated Methodologies for Tracer Use in Radioactive Waste Management

Tracer techniques are commonly used in the hydrogeological field and in the radioactive waste management. In hydrogeology, they are used to obtain indirect information about the water cycle. In radioactive waste management, tracer techniques could be applied to study the evolution of the system “site-nuclear facility”, for example to estimate potential radionuclide migration in groundwater and subsoil. Tracer techniques can be associated with modeling applications, to determine where and when radionuclides can be found in the environment and to predict the transport and potential targets under different environmental conditions. In this work, an integrated methodology was applied to investigate the unsaturated zone of the Italian nuclear site in Saluggia (VC). Results obtained by means of a tracer test and of data provided from natural isotopes were compared and integrated with simulations of mass transport in soil. Main hydrogeological and transport information on the unsaturated zone of the area were extrapolated, to compare qualitative and quantitative results. This integrated analysis provides information about predictivity of the model for what concern the migration paths of potentially released pollutants in the unsaturated zone. Once the model is calibrated, it may be used for the development of simulations, with the aim to define hypothetical scenarios of the radionuclide leakage (accidental or incidental conditions) from nuclear facilities.