Geosphere performance indices: Comparative measures for site selection and safety assessment of deep waste repositories

The concept of Geosphere Performance Indices (GPIs) is proposed. The 'performance' refers to the geosphere's capacity to retain/contain radionuclides in the event of their accidental release at some point in time. The GPIs are based on the Lagrangian stochastic-analytical framework for transport in the subsurface and are believed to render useful tools in performance assessment studies in general and in the site selection process in particular. A few advantages of the GPIs are: their transparency, low computational and the fact that additional data in a site selection programme can be incorporated in an iterative manner. Illustration examples indicate that the probability of the GPIs depends strongly on the dimensionless system parameters eB, aB and (dB)0.5/T. It is proposed that the derived framework is further elaborated and applied for realistic geosphere cases