Nuclear waste

The Department of Energy's (DOE) Office of Environmental Management (EM) is responsible for one of the world's largest cleanup programs: treatment and disposal of radioactive and hazardous waste created as a by-product of nuclear weapons production and energy research at sites across the country, such as EM's Hanford Site in Washington State and the Savannah River Site (SRS) in South Carolina. Computer models, which represent physical and biogeochemical processes as mathematical formulas, are one tool EM uses in the cleanups. GAO was asked to (1) describe how EM uses computer models in cleanup decisions; (2) evaluate how EM ensures the quality of its computer models; and (3) assess EM's overall strategy for managing its computer models. GAO analyzed the use of selected models in decisions at Hanford and SRS, reviewed numerous quality assurance documents, and interviewed DOE officials as well as contractors and regulators.