A STOCHASTIC-ANALYTICAL FRAMEWORK FOR SAFETY ASSESSMENT OF WASTE REPOSITORIES .1. THEORY

A model framework for safety assessment of waste repositories is deriv ed on the basis of stochastic-analytical solution techniques. The appr oach is computationally simple but maintains a relatively detailed des cription of processes and uncertainty. The framework consists of separ ate subunits for the engineered system, the geosphere, and impact eval uation in the biosphere. The impact in the biosphere is probabilistica lly assessed using the derived first two statistical moments of the ma ss flux or cumulative mass flux out from the geosphere. Various regula tory criteria related to the mass fluxes or contaminant travel times m ay be used for the impact assessment. The subunits of the framework ar e presented in the context of a repository for high-level nuclear wast e.