Probabilistic Multiphase Flow Modeling Using the Limit‐State Method

This paper presents a study on the application of the limit‐state method for probabilistic multiphase flow modeling. The subsurface multiphase flow and heat transport simulator, TOUGH2 (Pruess, 1991), is combined with a computer shell for reliability analysis, CALREL (Liu et al., 1989). As applications of the combined code, the site at Yucca Mountain, Nevada for a potential high‐level radioactive waste repository is modeled under assumed conditions. The probability distributions of various performance functions (liquid saturation, travel time, and flux) are calculated for statistically described infiltration rate and matrix hydrogeologic parameters. Numerical experiments indicates that the limit‐state method compares fairly well with, and thus can be used as an alternative to, the Monte Carlo method for probabilistic multiphase flow simulations.