Rocky Flats closure: The role of models in facilitating scientific communication with stakeholder groups

The Rocky Flats Environmental Technology Site (RFETS) was a U.S. Department of Energy (DOE) environmental cleanup site for a previous manufacturing plant that made components for the U.S. nuclear weapons arsenal. The facility was shut down in 1989 to address environmental and safety concerns, and left behind a legacy of contaminated facilities, soils, surface and ground water. In 1995, the Site contractor established the Actinide Migration Evaluation (AME) advisory group to provide advice and technical expertise on issues of actinide behavior and mobility in the air, surface water, groundwater, and soil. Through a combination of expert judgment supported by state-of-the-art scientific measurements, it was shown that under environmental conditions at Rocky Flats, plutonium and americium form insoluble oxides that adhere to small soil, organic, and mineral particles and colloids, or are colloidal materials themselves. A series of models ranging from conceptual, geostatistial, and large-scale wind and surface water erosion models were used to guide stakeholder interactions. The nature of these models, and their use in public communication is described.