The potential impacts to groundwater and surface water from radiological releases from spent fuel in proposed geological repository Yucca Mountain over the next 1 million years are small, says a report from the Nuclear Regulatory Commission. NRC deems the projected impacts from the facility in Nevada to be small rather than moderate or large. “The environmental effects are not detectable or are so minor that they will neither destabilize nor noticeably alter any important attribute,” it says. The agency’s finding is part of an assessment of future human activity that considers differences in groundwater usage and changing climate conditions. The report supplements environmental impact statements prepared in 2002 and 2008 by the Department of Energy with analysis of potential contaminant release, accumulation, and behavior over time in the surrounding environment and aquifer. NRC estimates that the peak annual individual radiological dose near Yucca Mountain over 1 million years after closure of the repository is 1.3 millirem, which is a fraction of the natural background radiation dose of 300 millirem/yr that the average American receives currently. Political opposition from Nevada officials has stalled completion of the repository for years.