The Oak Ridge National Laboratory (ORNL) is one of three major facilities established at the Oak Ridge Reservation (ORR) to support atomic weapons development and production during World War II. Oak Ridge National Laboratory is research-oriented, with the Y-12 Plant and Gaseous Diffusion Plant focusing on production. Approximately 200,000 people reside within a 25-mile radius, with 180,000 living in the City of Knoxville.
ORNL is located in the Clinch River drainage basin and is bounded on three sides by the river. The Tennessee Department of Public Health classifies the Clinch River for a wide range of uses, including drinking water, wildlife, recreation, irrigation and fish and aquatic life (Remedial Investigation Plan for ORNL, Waste Area Grouping 5 - March, 1988 - ORNL/RAP/Sub-87/99053/8&V1;). Two distinct but interconnected "flow systems" (aquifers) have been identified below ORNL. The water table fluctuates with the seasons and with topography (near surface in valleys) from a few feet to approximately 60 feet below ground.
In the 40+ years of operations at ORNL, a variety of radioactive and hazardous wastes have been generated and disposed of on-site. For eight years beginning in 1955, the Atomic Energy Commission (AEC) designated ORNL as the Southern Regional Burial Ground. Approximately 37,000 cubic yards of "poorly characterized" radioactive waste was received from 50 agencies and disposed in ORNL burial grounds. Burial procedures involved use of unlined trenches and auger holes. Liquid Low Level Waste (LLLW) has been disposed using direct discharge to White Oak Creek watershed, evaporation, disposal in trenches and pits, and deep-well injection.
An area of leading environmental concern at ORNL is Solid Waste Storage Area (SWSA) 5. There are approximately 230 trenches within SWSA 5, many within 2 feet of perched groundwater. Existing records (others were lost to fire) indicate that 3 million cubic feet of waste containing an estimated 200,000 curies of radioactivity have been buried in SWSA 5 South. An unknown quantity of transuranic (TRU) waste was also buried in this area. In addition to the trenches, a roughly circular "dump area" (roughly 400 feet in diameter) excavated to within 2 feet of the groundwater table was used for disposal of radiologically contaminated soil and equipment. Certain auger holes were also used within SWSA 5 for disposal of high-level radioactive waste and fissible material. The content, quantity and location of these auger holes is largely unknown due to loss of records by fire. Other contaminated process and disposal facilities include underground tanks (many filled to near-capacity), waste sludge basins, transfer lines (ILLW and LLW) and a surface impoundment.
Water samples collected from seeps (artesian springs) in the SWSA 5 area indicate that strontium-90 and tritium are principal contaminants. Water samples collected one mile downstream from SWSA 5 provide evidence that several thousand curies of tritium have passed that point each year since the mid-1960s. Most of this material is believed to have been discharged to surface water (Melton Branch) through groundwater contaminated from SWSA 5 disposal practices (Webster, 1976). Further studies in 1984 (Spalding and Munro) found elevated levels of strontium-90 in two areas bordering SWSA 5. A significant portion of strontium discharge to White Oak Creek drainage also comes from SWASA 5. Although some corrective measures have occurred to rectify continued contamination, ". . . the measures have provided only a partial and probably temporary fix" (ORNL/RAP/Sub-87/99053/8&V1;).
A liquid waste storage pond known as the Old Hydrofracture (OHF) Impoundment has also been identified as releasing radiological and chemical contaminants into the groundwater. The OHF impoundment was used as an emergency storage facility during deep-well injection of radioactive liquid waste. An 8" line originating in a waste pit also enters the impoundment. Although construction drawings specified an asphalt and plastic liner, no such protective material has been observed during recent sampling (Stansfield and Francis - 1986). Studies have documented that "significant" levels of tritium, strontium-90, cesium-137, and PCBs in monitoring wells downgradient of the OHF impoundment. Upgradient wells have shown higher levels of tritium than downgradient wells, indicating a "recharge" (downward movement) of water from the impoundment into the earth. Six wells and a seep were sampled in 1985, all showing strontium-90 and cesium-137 contamination. An estimated 1,950 cubic feet of radioactive sediment remain in the impoundment and represent a continued source of potential groundwater contaminants.
RKK, Ltd. can immediately install its CRYOCELL containment methodology to completely isolate the entire SWSA 5 site, or individual waste trenches, burial pits, tanks, or surface impoundments within its perimeter. All mixed and high level waste present at this site can be stopped form leaching any further into surrounding uncontaminated soils and aquifers. CRYOCELL is the only containment system available today that provides diffusion free, monitorable, full containment and isolation, that is removable and repairable in-situ. No other technology available today can compare to or provide these design standards for mixed or high level waste containment. A CRYOCELL barrier provides groundwater control and excavation support should either be removed or treated in-situ. CRYOCELL engineering is site specific. RKK's Thermodynamic Model-ing/Monitoring Program incorporates all site characteristics into a three dimensional model which RKK uses to design and estimate costs of CRYOCELL, and to develop a real-time computer image of barrier status throughout its life-cycle. RKK's modeling/monitoring program provides the ability to detect irregularities and quickly return the barrier to acceptable performance limits.
A conservative total site cost for a CRYOCELL barrier fully containing the Old Hydrofracture impoundment for 30 years is approximately $2,250,000. This barrier can be installed and fully functional within 6 months of a request to proceed. Cost per square foot for a CRYOCELL barrier isolating the entire SWSA 5 area is approxamately $14.41. This is cost comparable to Slurry Wall "containment", however, CRYOCELL provides the advantage of diffusion free containment with on-line/real-time barrier monitoring throughout the installation's life cycle. Removal costs for Slurry Walls can exceed initial installation costs. Removal costs of CRYOCELL run approxamately 10% to 15% of installation costs or $2.05/sf.