Yucca Mountain Project The Office of Civilian Radioactive Waste Management (OCRWM) is a program of the U.S. Department of Energy (DOE) assigned to develop and manage a federal system for disposing of spent nuclear fuel from commercial nuclear reactors and high-level radioactive waste from national defense activities. The Yucca Mountain site is located in Nye County, Nevada, approximately 100 miles northwest of Las Vegas. For two decades, the OCRWM has conducted scientific and engineering investigations at Yucca Mountain to determine its suitability as a nuclear waste repository. In 2002, the Secretary of Energy, Spencer Abraham, recommended to President Bush that the Yucca Mountain site be developed as the nation’s first long-term geologic repository for high-level radioactive waste. The Yucca Mountain Project is using GoldSim to simulate the long-term performance of the proposed radioactive waste repository. The model computes the predicted environmental impact of the facility over the next 10,000 years. (The modeling effort was discussed in some detail in an article in Wired Magazine.) GoldSim played a key role in the recent recommendation to the President that the US move forward on developing Yucca Mountain as the sole high-level waste repository for commercial nuclear reactor waste. This is the largest GoldSim application that we know of, with over 25,000 elements. The Yucca Mountain performance assessment team is using the GoldSim Distributed Processing Module to run the model on 80 parallel processors and dramatically reduce the time to perform each Monte Carlo simulation.. GoldSim’s powerful presentation capabilities are critical for this project since the model structure and results must be effectively communicated to regulators, government officials, and the public. The Yucca Mountain. Project has designed a highly interactive GoldSim interface specifically for the public that provides an easy-to-understand summary of the entire project.