Evaluation of D and D alternatives for a DOE nuclear material processing facility - 15265

Ten scenarios for SRS Building 235-F were evaluated relative to groundwater protection through use of a 235-F GoldSim^TM fate and transport model. The scenarios included two extreme scenarios, a no action scenario, four D and D grouting scenarios, and three D and D inventory removal scenarios. The fate and transport model simulated contaminant release from four 235-F process areas and the 294-2F Sand Filter and fate and transport through the vadose zone, the Upper Three Runs (UTR) aquifer, and the UTR creek. The model was a stochastic model for which 1,000 realizations were run over 100,000 years for each scenario. In association with the seven D and D alternatives only three groundwater standards out of 25 were exceeded, with the combined radium standard showing the greatest exceedance. The standards were only exceeded at the edge of the building after 10,000 years. It was estimated that there was a 90% likelihood that the combined radium standard would be exceeded for all four D and D grouting scenarios and that a 95% inventory removal from process cells 1-5 would result in an essentially zero percent likelihood that any standards would be exceeded. (authors)