Monitoring of surface deformation and microseismicity applied to radioactive waste disposal through hydraulic fracturing at Oak Ridge National Laboratory
Low-level liquid nuclear wastes are disposed of at Oak Ridge National Laboratory by the hydrofracture process. Wastes are mixed with cement and other additives to form a slurry that is injected into shale of low permeability at 300 m depth. The slurry spreads radially along bedding plane fractures before setting as a grout. Different methods for monitoring the location and behavior of the fractures have been investigated. Radioactive grout sheets can be located by gamma-ray logging of cased observation wells. Two other methods are based on the fact that the ground surface is deformed by the injection. The first entails surface leveling of a series of benchmarks; uplift up to 2.5 cm occurs. The second method involves use of tiltmeters that are sensitive and measure ground deformation in real time during an injection. Both methods show subsidence during the weeks following an injection. Interpretive models for the tiltmeter data are based on the elastic response of isotropic and anisotropic media to the inflation of a fluid-filled fracture. A fourth monitoring method is based on microseismicity. Geophone arrays were used to characterize the fracture process and to provide initial assessment of the feasibility of using seismic measurements to map the fractures as they form. An evaluation of each method is presented. 8 refs., 6 figs.
- Research Organization:
- Oak Ridge National Lab., TN (USA); Applied Geomechanics, Inc., Santa Cruz, CA (USA); Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5630988
- Report Number(s):
- CONF-850314-69; ON: DE85012777
- Country of Publication:
- United States
- Language:
- English
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Subsurface disposal of liquid low-level radioactive wastes at Oak Ridge, Tennessee
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Related Subjects
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
COMMINUTION
FAILURES
FRACTURES
FRACTURING
HYDRAULIC FRACTURING
LIQUID WASTES
LOW-LEVEL RADIOACTIVE WASTES
MANAGEMENT
MATERIALS
MONITORING
NATIONAL ORGANIZATIONS
ORNL
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTES
UNDERGROUND DISPOSAL
US AEC
US DOE
US ERDA
US ORGANIZATIONS
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES