Unique natural system modeling aspects of the H-Tank Farm at the Savannah river site - 15271

The U.S. Department of Energy (DOE) is in the process of closing radioactive waste storage tanks at the Savannah River Site (SRS). One of the key technical documents supporting closure and regulatory decision documents is the Performance Assessment (PA). PAs within the DOE complex are performance-based, risk-informed analyses of the fate and transport of residual contaminants, in this case any residual material remaining following cleaning and closure of the tank systems. There are two active radioactive waste storage facilities at SRS, F-Tank Farm (FTF) and H-Tank Farm (HTF), which consist of 51 carbon steel waste tanks. To date, six tanks have been emptied and closed in FTF. Activities are currently in progress to support closure of the first tanks in HTF. A PA has been developed for HTF and includes modeling that takes into account the unique aspects of the natural system associated with HTF. These unique aspects include the water table elevation in relation to the tanks and the complex flow patterns of the groundwater beneath HTF. (authors)