The polluted sites are all former production facilities used during the Cold War to supply enriched uranium for nuclear warheads and commercial nuclear reactors. Located in Tennessee, Kentucky, and Ohio, the plants encompass more than 30 million square feet of floor space, miles of interconnecting pipes, and thousands of acres of land that are contaminated with radioactive and hazardous materials. Enriched uranium was a key component of the weapons, but the material did not exist naturally in the quantities needed.
The PGDP consists of over facilities, with 19 miles of roadway and 5 miles of fence. PGDP was constructed in the early s as a uranium enrichment facility to support the fabrication of fuel assemblies for commercial and military nuclear reactors and military weapons.
Four large cascade process buildings that enriched uranium by the gaseous diffusion process served as the hub of the PGDP until the commercial uranium enrichment process was terminated in July Past PGDP operations generated hazardous substances, some of which were released into the environment.
Spills, leaks, and other releases allowed large quantities of contamination to reach the regional groundwater aquifer. Inenvironmental monitoring and investigation began at PGDP and identified contaminant plumes that extended off site.
Primary contaminants are TCE and the radionuclide technetium 99 99Tcan element with a half-life of overyears. PGDP demonstrates several complexities including extensive plumes, multiple long-lived contaminants and contaminant sources, heterogeneous geologic conditions, and off-site contaminant migration.
The main technical complexities include DNAPLs, multiple contaminants VOCs and 99Tcchallenging geological heterogeneity lower permeability fine-grained sediments in the vadose zone and shallow groundwaterand an important aquifer Figure Site geology significantly limits the performance of remedial technologies and is representative of many contaminated sites.
A significant amount of contamination is also retained in the silts and clays of the UCRS. Thus, the overlying UCRS vadose zone and the underlying RGA-McNairy interface act as a contaminant reservoir that slowly discharges like a capacitor or a battery over a long time into the flowing groundwater aquifer.
The team is supported by technical resources from universities, national laboratories, and contractors. This team currently works together to address PGDP groundwater contamination. Facility operations began in and released TCE into the subsurface. The area that includes the C Cleaning Building and nearby facilities such as the former cylinder drop test area and burial grounds coincides with the highest TCE concentrations and comprises the centroid of the groundwater plumes at PGDP Figure The subsurface near the C Cleaning Building Figure 43 has three relevant hydrogeologic zones: Consistent with the site-specific conditions, the groundwater project team recognized that a combination of technologies was needed to effectively and efficiently address the varying conditions within the plumes.
Technologies are used for the following tasks: Progress toward site objectives for PGDP groundwater has been achieved through a combination of standard and innovative technologies.
Under the FFA, an outline was established to achieve remediation targets and work toward achieving site objectives. DOE placed areas with contaminated drinking water wells on an alternate water supply. These systems were constructed and placed into operation in andrespectively.
Several innovative approaches were tested to determine whether they could effectively remove contaminants from the lower permeability UCRS, the most contaminated areas of the RGA, and the underlying McNairy Formation.
Two promising removal technologies, electro-thermal and thermally enhanced steam injection, were tested as pilot projects and deployed at production scale to reduce the source term. In the s, Monsanto, General Electric GEand DuPont developed an electro-thermal remediation process Lasagna that applies electrical energy to the subsurface to accelerate contaminant removal and destruction.
Lasagna creates an electric field underground via the installation of layered anode and cathode electrodes. This electric current creates osmotic gradients that induce the movement of water through defined treatment zones containing a treatment material such as zero-valent iron. The electric current also heats the soil through resistive heatingwhich mobilizes contaminants for treatment or collection.
The pilot studies also identified several advantages of the method: The system was installed using a sheet pile technique that generated minimal wastes. Lasagna was selected as a full-scale remedy for source area TCE at SWMU 91 and operated for two years following deployment from to Electrical resistive heating ERH was identified to remediate the primary and secondary source contamination associated with Building C This technology heats the subsurface by applying an electric current between electrodes networked in the target volume.
Heat is generated from the resistance to current flow, which increases the vapor pressure and volatility of solvents such as TCE. Reduce the time that TCE concentration in groundwater remains above the MCL, and meet the statutory preference for attaining permanent solutions through treatment.
Satisfy the requirements set forth in 40 CFR f 1 ii for interim measures that will become part of the total remedial action that will attain ARARs.
As an interim measure, it is not expected to meet MCLs. Be cost-effective, based upon the estimates available at the time of the ROD.paducah gaseous diffusion plant hearing before the subcommittee on energy of the committee on energy and natural resources united states senate one hundred eighth congress first session on the paducah gaseous diffusion plant december 6, paducah, ky (printed for the use of the.
Attorney General Jack Conway today met with the deputy secretary of the U.S. Department of Energy (DOE) to discuss the future of the Paducah Gaseous Diffusion Plant, efforts to clean up the nuclear material from the site, and how to preserve the jobs at the plant that come from enriching uranium.
facilities: three gaseous diffusion plants in Kentucky, Ohio, and Tennessee, and the Worker Health Protection Program Expands Lung Cancer Screening Component exposures at the Paducah Gaseous Diffusion Plant got off the ground. The project. The Paducah Gaseous Diffusion Plant in Paducah, Kentucky, was the last U.S.-owned uranium enrichment facility in the United States.
Owned by the U.S. Department of Energy, it was leased and operated by Centrus Energy Corp.’s predecessor until October Class action suit involved former employees of the Paducah Plant who claimed that they had been exposed to excess levels of uranium, plutonium, and other transuranics during their employment.
The Paducah Gaseous Diffusion Plant is a facility located in McCracken County, Kentucky, near Paducah, Kentucky that produced enriched uranium – The plant is now operated by United States Enrichment Corporation, a subsidiary of USEC Incorporated, a .