Characterization Plan for the Old Hydrofracture Facility

US Department of Energy (DOE) facilities are required to comply fully with all federal and state regulations. In response to this requirement, the Oak Ridge National Laboratory (ORNL) has established the remedial action program, to provide comprehensive management of areas where past research, development, and waste management activities have been conducted and have resulted in residual contamination of facilities or the environment. One of the objectives of this program is to define the extent of contamination at these sites. The intent is to document the known environmental characteristics of the sites and identify the additional actions, such as sampling, analytical measurements, and modeling, necessary to confirm contamination and the possible migration of contaminants from the sites. One of these sites is the Old Hydrofracture Facility (OHF). The OHF was used for the permanent disposal of liquid radioactive waste in impermeable shale formations at depths ranging from about 230 to 300 m (750 to 1000 ft), from 1964 to 1979. The liquid waste was blended into a pumpable grout by mixing it with cement and special clays used to immobilize radionuclides against groundwater transport. This report summarizes the results of several studies at ORNL that have measured the concentration of radionuclides and, to some extent, concentrations of hazardous chemicals in the sediment of the impoundment, as well as the concentrations in soils and groundwater near the facility. The report addresses only the contamination of and the potential releases to the environment that might result from the facility per se and makes not attempt to address potential releases that might result from permanent disposal of wastes (i.e., the grout sheets) during its operation. Outlined in the report are the additional actions needed to obtain the information required to confirm the extent of contamination within the facility. The major efforts include the measurement of radionuclides and potentially hazardous chemicals contained in the five underground waste storage tanks at the facility and determining of the lateral and vertical contamination due to seepage of waste from the impoundment