The 890-square mile Idaho National Engineering Laboratory (INEL), located 32 miles west of Idaho Falls, Idaho, is operated by the U.S. Department of Energy. Land use in the area is predominantly industrial and mixed use. The site overlies a sole source Class I aquifer, known as the Snake River Plain Aquifer. Within INEL, an area known as the Power Burst Facility (PBF) operated from 1972 to 1985 and supported the testing of pressurized-water fuel rods under hypothetical reactor accidents. The selected interim remedial action for this site includes removing and solidifying/stabilizing the 100 cubic yards of contaminated sediment from the evaporation pond by grouting, followed by onsite disposal in the Radioactive Waste Management Complex (RWMC) at INEL along with existing low-level waste containers; removing sludge and sediment from the waste sump; treating the sludge by grouting, if feasible, based on the results of treatability studies, and disposing of the treated sludge onsite in RWMC; decontaminating the discharge pipe; and sampling the remaining sediment to verify residual contaminant concentrations. The estimated total cost for the remedial action is $480,000. No O & M were provided for the remedial action.