Characterization of subjective uncertainty in the 1996 performance assessment for the Waste Isolation Pilot Plant

The 1996 performance assessment (PA) for the Waste Isolation Pilot Plant (W IPP) maintains a separation between stochastic (i.e. aleatory) and subjecti ve (i.e. epistemic) uncertainty, with stochastic uncertainty arising from t he possible disruptions that could occur at the WIPP over the 10,000 yr reg ulatory period specified by the US Environmental Protection Agency (40 CFR 191, 40 CFR 194) and subjective uncertainty arising from an inability to un iquely characterize many of the inputs required in the 1996 WIPP PA. The ch aracterization of subjective uncertainty is discussed, including assignment of distributions, uncertain variables selected for inclusion in analysis, correlation control, sample size, statistical confidence on mean complement ary cumulative distribution functions, generation of Latin hypercube sample s, sensitivity analysis techniques, and scenarios involving stochastic and subjective uncertainty. Published by Elsevier Science Ltd.