Print this pageRemedial Site Evaluation of Wells Associated with the New Hydrofracture Facility at Oak Ridge National Laboratory: A Case History
PAWLOWICZ, RICHARD M., ALBERT S. WILL III, and ROBERT K. DAVIS
Efforts began in the late 1950s to develop a means for permanent disposal of radioactive wastes temporarily stored on the Oak Ridge National Laboratory site. One such technology was subsurface hydrofracturing. The objective was to develop a grout that could be injected as a slurry into induced fractures in low-permeability shale to entomb the radioisotopes. This study evaluates monitoring wells near the plant, where approximately 750,000 curies of activity was injected in a grout carrier.
Rock cover wells were installed in strata underlying the injection horizon to monitor pressure and permeability; and observation wells monitored the position, depth, and location of the grout sheets within the injection horizon. After injection operations ceased, additional deep monitoring wells were installed to provide information on the geochemical and hydrologic conditions of the injection interval. Aqueous radiological contamination was discovered in the new wells, which are located along geologic strike from the injection well.
The primary goal of this investigation was to evaluate well conditions and recommend the best method of final disposition. To meet that goal, borehole geophysical logs were run and interpreted to determine well conditions and evaluate the extent of radiological contamination. The secondary goals were to determine the stratigraphic position of the wells and the subsurface stratigraphy at the site, and to identify possible artificially induced or natural pathways for the spread of radioactive contaminants.