Site characterization summary report for Waste Area Grouping 10 Wells at the Old Hydrofracture Facility, Oak Ridge National Laboratory, Oak Ridge, Tennessee

The Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, is operated for the Department of Energy (DOE) by Martin Marietta Energy Systems (Energy Systems). As part of its DOE mission, ORNL has pioneered waste disposal technologies throughout the years of site operations since World War II. In the late 1950s, efforts were made to develop a permanent disposal alternative to the surface impoundments at ORNL at the request of the National Academy of Sciences. One such technology, the hydrofracture process, involved forming fractures in an underlying geologic host formation (a low-permeability shale) at depths of up to 1000 ft and subsequently injecting a grout slurry containing low-level liquid waste, cement, and other additives at an injection pressure of about 2000 psi. The objective of the effort was to develop a grout slurry that could be injected as a liquid but would solidify after injection, thereby immobilizing the radioisotopes contained in the low-level liquid waste. The scope of this site characterization was the access, sampling, logging, and evaluation of observation wells near the Old Hydrofracture Facility (OHF) in preparation for plugging, recompletion, or other final disposition of the wells