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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/ROD/R10-95/120
ROD Date:  08/18/1995
Operable Unit(s):  01
Media:  Groundwater
Contaminant:  Trichloroethene, tetrachoroethene, 1,2-dichloroethene, tritium, str uranium
Abstract:  Please note that the text in this document summarizes the Record of Decision for the purposes of facilitating searching and retrieving key text on the ROD. It is not the officially approved abstract drafted by the EPA Regional offices. Once EPA Headquarters receives the official abstract, this text will be replaced.

The Idaho National Laboratory (INEL) is an 890 square-mile Federal facility operated by the US Department of Energy (DOE). The facility is located on the northern edge of the Eastern Snake River Plain. INEL employs approximately 11,700 people. The land at the INEL currently is used for nuclear research and development and waste management. The developed area within the INEL is surrounded by a buffer zone used for cattle and sheep grazing. The Test Area North (TAN) complex is located approximately 50 miles northwest of Idaho falls in the northern portion of the INEL and extends over an area of approximately 12 square miles. The Technical Support Facility (TSF) is centrally located within TAN and consists of several experimental and support facilities used for conducting research and development activities on reactor performance. Operations at TAN were initiated in the early 1950s to support the US Air Force aircraft nuclear propulsion (ANP) project. The objectives of the ANP project were to develop and test various designs for nuclear-powered engines and fuels for use on aircraft. Four facilities were built at TAN including the TSF, Initial Engine Test (IET), Low Power Test Facility/ Experimental Beryllium Oxide Reactor, and Loss-of-Fluid Test (LOFT).

The remedy for OU 1-07B is intended to reduce the potential risk to human health by reducing groundwater contamination and preventing the ingestion of contaminated groundwater by future residents at this site. The principal source of groundwater contamination at TAN is the TSF-05 Injection Well located in the southeast corner of TSF. The TSF-05 Injection Well was used from 1953 to 1972 to dispose of TAN liquid wastes into the fractured basalt of the Snake River Plain Aquifer. These wastes included organic, inorganic, and low-level radioactive wastewaters added to industrial and sanitary wastewater. Activities generating these wastes included efforts to develop a nuclear-powered aircraft and tests simulating accidents involving the loss of coolant from nuclear reactors. Releases to TAN groundwater were first identified in 1987 when low levels of the organic compounds trichloroethene (TCE) and tetrachloroethene (PCE) were detected in the production wells that supply drinking water to TSF.

The INEL was listed on the National Priorities List (NPL) on November 21, 1989. As a result of this listing, the U.S. Department of Energy (DOE), the U.S. Environmental Protection Agency (EPA), and the Idaho Department of Health and Welfare (IDHW) entered into a Federal Facility Agreement and Consent Order in December 1991. This established a procedural framework for agency coordination and a schedule for all cleanup activities conducted at the INEL.
Remedy:  The remedy for OU 1-07B addresses the groundwater beneath TAN that has, or is expected to have, concentrations of TCE above safe levels. The remedy is groundwater plume extraction and treatment of a heavily TCE-contaminated plume and hydraulic containment of the TSF-05 Injection Well hotspot with above ground treatment. Cleanup will occur in three phases followed by institutional controls and groundwater monitoring.
Text:  View full-text ROD [ 172K ]
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