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. In June 2008, the DOE submitted a formal license application to the Nuclear Regulatory Commission (NRC). (In March 2010 the DOE filed a motion with the NRC to withdraw its license application. Multiple lawsuits to stop this action have been filed by states, counties, and individuals across the country.)
A waste repository would consist of a sub-surface facility (underground tunnels) for storing the waste, and a surface facility for receiving and packaging the waste into containers that are to be place in the tunnels. Golder Associates was a member of the Management and Technical Support Services contractor team that supported the OCRWM. Golder used GoldSim to model the surface and sub-surface facility designs for the proposed Yucca Mountain Repository. The objectives of these models were: 1) to provide OCRWM a tool to help verify that their high-level design requirements were complete, integrated, and robust, 2) to provide real-time decision analysis support for DOE to identify the robustness of the design to meet throughput requirements and to evaluate various design concepts, 3) to provide a tool for evaluating interfaces with the other systems OCRWM managed (e.g., transportation, and 4) to provide a tool for evaluating alternative scenarios and operating strategies.
The flexibility of GoldSim allowed for the development of a fairly complex discrete event simulation model of how the design would perform. The model tracked several key metrics including how rapidly nuclear waste transport casks could be processed through the facility, the rate that waste could be made ready for emplacement in the proposed repository, and estimates of required capacity for staging nuclear waste inside the facility. The model aided in the identification of operational constraints. Project engineers used this information to refine the design to make it more efficient.