RECORD OF DECISION FOR THE MELTON VALLEY WATERSHED, OAK RIDGE NATIONAL LABORATORY, OAK RIDGE TENNESSEE FROM DECISION DOCUMENT APPROVAL TO PLANNING FOR IMPLEMENTATION

摘要

Much planning was required and undertaken by Bechtel Jacobs Company LLC (BJC) teamed with the Department of Energy (DOE) to prepare for the implementation of a Comprehensive Environmental Response, Compensation, and Liability Act remedial decision encompassing in excess of 200 contaminated sites in the Melton Valley near Oak Ridge, Tennessee. Remedial actions to be implemented include the installation of approximately 150 acres of caps, acres of contaminated soil excavation, decontamination or demolition of numerous contaminated structures, in-situ grouting, in-situ vitrification, water treatment facilities; in all, this remediation effort is estimated to cost in excess of $250 million. The Melton Valley watershed is identified as an area of more than 1062 acres throughout which numerous contaminated sites, ranging in size from 10’s of square feet to more than 40 acres, are located. Included within these waste units are three major radioactive and mixed waste burial grounds, numerous auger holes that were used for the disposal of radioactive waste, seven seepage pits and trenches, nine impoundments, and two deep hydrofracture liquid radioactive waste injection wells. Interspersed throughout the valley are more than 1000 monitoring wells requiring remediation and numerous low-levelliquid waste pipelines and areas of surface contamination. Primary contaminants in Melton Valley include radionuclides (short- and long-lived), metals, and organic compounds (e.g., volatile organic compounds and polychlorinated biphenyls) in waste, soil, groundwater, surface water, sediment, and biota. Migration from shallow groundwater to surface water is the principal exit pathway from contaminant source areas in Melton Valley. The Decision Document Remedial Action Objective was designed with 'source control' as a primary objective. The remedial decision covers over 200 individual primary waste sites; however, some elements are not within the scope of this decision (i.e., long-term stewardship, White Oak Creek and White Oak Lake). Due to the size and complexity of the decisions being made, approval of the Record of Decision for Interim Actions for the Melton Valley Watershed at the Oak Ridge National Laboratory, Oak Ridge, Tennessee comprised an extensive five-year team effort involving DOE, the U.S. Environmental Protection Agency, Tennessee Department of Environment and Conservation, the public, and BJC representatives inclusive. A massive effort was undertaken to plan for the implementation of this sizeable and complex remedial action. Prioritization of remedial actions was primarily based upon risk. Additionally, grouping of like projects was instrumental in realizing implementation efficiencies. Successful completion of this baselining/sequencing effort is credited to the combined efforts of the staff of the ORNL Project Team, including DOE representatives. This effective planning is expected to result in the efficient, cost-effective, and timely implementation of remedial actions in Melton Valley.