The Yucca Mountain Performance Confirmation program consists of tests, monitoring activities, experiments, and analyses to evaluate the adequacy of assumptions, data, and analyses that form the basis of the conceptual and numerical models of flow and transport associated with a proposed radioactive waste repository at Yucca Mountain, Nevada. The Performance Confirmation program uses an eight-stage risk-informed, performance-based approach. Selection of the Performance Confirmation activities for inclusion in the Performance Confirmation program was done using a risk-informed performance-based decision analysis. The result of this analysis was a Performance Confirmation base portfolio that consists of 20 activities. The 20 Performance Confirmation activities include geologic, hydrologie, and construction/engineering testing. Some of the activities began during site characterization, and others will begin during construction, or post emplacement, and continue until repository closure.