Oak Ridge National Laboratory Gunite and Associated Tanks Stabilization Project-Low-Tech Approach with High-Tech Results
Environmental restoration of the Gunite and Associated Tanks (GAAT) at the Oak Ridge National Laboratory (ORNL) was a priority to the U. S. Department of Energy (DOE) because of their age and deteriorating structure. These eight tanks ranging up to 170,000 gallons in capacity were constructed in 1943 of a Gunite or ''sprayed concrete material'' as part of the Manhattan Project. The tanks initially received highly radioactive waste from the Graphite Reactor and associated chemical processing facilities. The waste was temporarily stored in these tanks to allow for radioactive decay prior to dilution and release into surface waters. Over time, additional wastes from ongoing ORNL operations (e.g., isotope separation and materials research) were discharged to the tanks for storage and treatment. These tanks were taken out of service in the 1970s. Based on the structure integrity of GAAT evaluated in 1995, the worst-case scenario for the tanks, even assuming they are in good condition, is to remain empty. A recently completed interim action conducted from April 1997 through September 2000 removed the tank liquids and residual solids to the extent practical. Interior video surveys of the tanks indicated signs of degradation of the Gunite material. The tanks continued to receive inleakage, which generated a relatively high volume waste stream that required periodic removal, treatment, and disposal. For these reasons, DOE chose in-place stabilization of Tanks W-3 through W-10 as a non-timecritical removal action under Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). Tank stabilization activities involved removal of liquid from inleakage and placement of a grout mixture or ''flowable fill'' into the tanks to within 3-ft of the ground surface. Bechtel Jacobs Company, LLC (BJC) awarded Safety and Ecology Corporation (SEC) a subcontract in March 2001 to complete the documentation and fieldwork necessary to achieve tank stabilization in accordance with the Action Memorandum. Tank stabilization activities began on April 23, 2001, and were completed one month ahead of schedule on August 31, 2001. Over 7400 cubic yards of grout were placed in these tanks stabilizing over 4,000 Ci of radioactive material in place. This schedule acceleration was the result of good pre-planning during pre-mobilization by working with BJC, grout vendor, and pumping company, and other subcontractors. This planning allowed refinement of the pump and hose system used to convey the grout and the formulation of the grout mixture. Because of expediting the work, additional activities could be accomplished at the GAAT site that resulted in complete site restoration to a paved area for future parking, which was completed by September 30, 2001. This paper will focus on the following items associated with this successful environmental restoration project: regulatory process; integrated safety management systems used to achieve zero accident performance while expediting the schedule; tank stabilization design and implementation; and implementation strategies involving partnering of multiple subcontractors, DOE, and regulators.
- Research Organization:
- Safety and Ecology Corporation 2008 Solway Road, Knoxville, TN (US); Bechtel Jacobs Company, LLC P. O. Box 4699, Building 7078A, Mail Stop 6402, Oak Ridge, TN (US)
- Sponsoring Organization:
- US Department of Energy (US)
- OSTI ID:
- 829618
- Resource Relation:
- Conference: Waste Management 2002 Symposium, Tucson, AZ (US), 02/24/2002--02/28/2002; Other Information: PBD: 26 Feb 2002
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
54 ENVIRONMENTAL SCIENCES
ISOTOPE SEPARATION
MANAGEMENT
MANHATTAN PROJECT
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
STABILIZATION
SURFACE WATERS
TANKS
US SUPERFUND
WASTE MANAGEMENT
WASTES