UNCERTAINTY AND SENSITIVITY ANALYSIS TECHNIQUES FOR USE IN PERFORMANCE ASSESSMENT FOR RADIOACTIVE-WASTE DISPOSAL

Uncertainty and sensitivity analysis techniques for use in performance assessments for radioactive waste disposal are reviewed. Summaries ar e given for the following techniques: differential analysis, Monte Car lo analysis, response surface methodology, and Fourier amplitude sensi tivity test. Of these techniques, Monte Carlo analysis is felt to be t he most widely applicable for use in performance assessment. Monte Car lo analysis involves five steps: (1) selection of a range and distribu tion for each input variable; (2) generation of a sample from the inpu t variables; (3) propagation of the sample through the model under con sideration; (4) performance of uncertainty analysis; and (5) performan ce of sensitivity analysis. These steps are discussed and illustrated with an analysis performed as part of a preliminary performance assess ment for the Waste Isolation Pilot Plant (WIPP).