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Record of Decision System (RODS)



City & State:  IDAHO FALLS  ID  83401
EPA ID:  ID4890008952
EPA Region:  10
NPL Status:  Currently on the Final NPL
ROD Type:  Record of Decision
ROD ID:  EPA/541/R-00/036
ROD Date:  07/14/2000
Operable Unit(s):  10
Abstract:  The Idaho National Engineering and Environmental Laboratory (INEEL) is a U.S. Department of Energy (DOE) facility located in southeastern Idaho, 51.5 km (32 mi.) west of Idaho Falls. The laboratory encompasses approximately 2,305 km2 (890 mi2) of the northeastern portion of the Eastern Snake River Plain and extends across portions of five Idaho counties: Butte, Jefferson, Bonneville, Clark, and Bingham.

The Idaho National Engineering and Environmental Laboratory (INEEL) was established in 1949 as the National Reactor Testing Station by the U.S. Atomic Energy Commission (AEC) for nuclear energy research and related activities. It was re-designated the Idaho National Engineering Laboratory in 1974 and the INEEL in 1997 to reflect the expansion of its mission to include a broader range of engineering and environmental management activities. The INEEL was placed on the National Priorities List in November 1989.

Current land use at the INEEL is primarily for nuclear research, development, and waste management. The perimeter area of the INEEL is leased for cattle and sheep grazing under the management of the U.S. Bureau of Land Management. The perimeter area functions as a controlled safety-and-security buffer between INEEL activities and the general public. No grazing takes place within 0.8 km (0.5 mi.) of any facility boundaries. Controlled hunting is permitted on INEEL land, but is restricted to the 0.8 km (0.5 mi.) strip just inside the site boundary.

State Highways 22, 28, and 33 cross the northeastern portion of the INEEL and U.S. Highways 20 and 26 cross the southern portion. Except for public travel on the highways, access to the INEEL is controlled by fences and security personnel.

The Snake River Plain Aquifer (SRPA), the largest potable aquifer in Idaho, underlies the Eastern Snake River Plain. The aquifer covers an area of approximately 24,853 km2 (9,600 mi2). Approximately 9% of the aquifer's area is below the INEEL. The depth of the aquifer varies from approximately 61 m (200 ft.) below Test Area North (TAN) to approximately 274 m (900 ft.) on the southwest edge of the INEEL.

More than 400 plant species, 190 bird species, and 40 mammal species have been identified on the INEEL. Several bird species at the INEEL warrant attention because of sensitivity to disturbance or their threatened status, including the ferruginous hawk (Buteo regalis), bald eagle (Haliaeetus leucocephalus), long-billed curlew (Numenius americanus), and the loggerhead shrike (Lanius Ludovicianus). In addition, the Townsend's big-eared bat (Plecotus Towndendii) and pygmy rabbit (Brachylagus Idahoensis) are listed by the U.S. Fish and Wildlife Service as candidates for consideration as threatened or endangered species. The ringneck snake (Diadophis punctatus), whose occurrence is considered to be INEEL-wide, is listed by the Idaho Department of Fish and Game as a Category C sensitive species.

The INEEL lies within the lands traditionally occupied by the Shoshone-Bannock Tribes. The tribes used the land and waters within and surrounding the INEEL for fishing, hunting, and plant gathering, in addition to medicinal, religious, ceremonial, and other cultural uses. Under the cooperative Agreement-in-Principle between the Shoshone-Bannock Tribes and the U.S. Department of Energy (DOE 1998) some tribal activities continue today within the INEEL boundaries.
Remedy:  Alt 3a, Alt 3b, Alt 4
The selected remedy for Central Facilities Area (CFA) 04 is alternative 3a, excavation, treatment by stabilization, and on-site disposal. No Institutional Controls (IC's) would be required for the CFA-04 Pond after completing the remediation, providing soil exceeding the final remediation goal (FRG) is removed. This alternative includes:

- Characterizing the site and excavating soil and sediments from the pond exceeding FRG. Soil contaminated at concentrations above the FRG will be excavated to a maximum depth of 3 m (10 ft.) bgs or to basalt. No basalt will be excavated.
- Transporting excavated soil exceeding the FRG to the Idaho National Engineering and Environmental Laboratory (INEEL) Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Disposal Facility (ICDF).
- Stabilizing soil exceeding the Resource Conservation and Recovery Act (RCRA) characteristics hazardous waste levels for mercury with cement.
- Disposing treated and nontreated soil at the ICDF.
- Performing verification sampling to ensure that there is no identified contamination remaining at the site exceeding the FRG.
- Backfilling the pond and any adjacent excavations with uncontaminated soil to grade.
- All excavations will be contoured to match the surrounding terrain and revegetated.

Alternative 4, containment, is the selected remedy for the CFA-08 Drainfield. Under this alternative, the contaminated site will be covered with an engineering protective cover. This cover will be an engineered barrier, constructed of layers of rock and soil with a vegetative cover. This cover will isolate the waste and minimize water infiltration. The cover will be designed to isolate the low-level radioactive contaminants from human and biotic intrusion and to provide radiation shielding for a period of 189 years. The following remedial actions will be performed at the site:

1. Constructing an engineered cover. Clean native soil will be used for fill material as needed.
2. Contouring and grading the surrounding terrain to direct the surface water runoff away from the cover.

The continued effectiveness of this remedy will be evaluated through soil cover integrity monitoring and above-ground radiological surveys. Because contamination is to be left in place, ICs are necessary to restrict access until the land can be released for unrestricted use. ICs to be implemented include:

- Restricting access through the use of signs and permanent markers
Text:  View full-text ROD [ 645K ]
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