Uncertainty and sensitivity analysis for two-phase flow in the vicinity ofthe repository in the 1996 performance assessment for the Waste Isolation Pilot Plant: disturbed conditions

Uncertainty and sensitivity analysis results obtained in the 1996 performan ce assessment (PA) for the Waste Isolation Pilot Plant (WIPP) are presented fur two-phase flow in the vicinity of the repository under disturbed condi tions resulting from drilling intrusions. Techniques based on Latin hypercu be sampling, examination of scatterplots, stepwise regression analysis, par tial correlation analysis and rank trans formations are used to investigate brine inflow, gas generation, repository pressure, brine saturation, and b rine and gas outflow. Of the variables under study, repository pressure and brine flow from the repository to the Culebra Dolomite are potentially the most important in PA for the WIPP. Subsequent to a drilling intrusion, rep ository pressure was dominated by borehole permeability and generally below the level (i.e, 8 MPa) that could potentially produce spallings and direct brine releases. Brine flow from the repository to the Culebra Dolomite ten ded to be small or nonexistent, with its occurrence and size also dominated by borehole permeability. Published by Elsevier Science Ltd.