We have over twenty years experience assessing the performance of the proposed Yucca Mountain nuclear waste repository. For this project we have analyzed the effects on future populations of ground water infiltrating the repository, earthquakes, volcanoes, and human intrusion. We have considerable experience in managing a diverse range of experts and in consolidating their analyses to quantify the risk of ingestion and resulting health effects from radionuclides proposed to be buried at the site. We can combine multiple interpretations of failure scenarios to find the consolidated risk for a complex system. Performance assessment for waste facilities can be studied using alternate models and parameters that project what may occur over thousands or even millions of years.