Drilling intrusion probabilities for use in performance assessment for radioactive waste disposal

Abstract

Product integral techniques are used to derive computational procedures to determine probabilities for scenarios resulting from drilling intrusions at geologic disposal facilities for radioactive waste. For these derivations, the occurence of individual drilling intrusions is assumed to be random in time and space, although the drilling rate is not assumed to be constant or even continuous through time. The use of product integral techniques allows the probability model for drilling intrusions to be initially cast in a very general form involving interval functions and then specialized to nonhomogeneous Poisson processes and ultimately to homogeneous Poisson processes. The resultant computational procedures are illustrated with results for the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico using the maximum drilling rate specified by the US Environmental Protection Agency (EPA) in its standard for the geologic disposal of radioactive waste (40 CFR 191).