The end use recommendations for the former K-25 Site at the East Tennessee Technology Park were approved on June 11, 1998. The signed recommendations and an end use map are presented on page 50, page 51, and page 52 . The minority opinion is present on page 53.

Physical Description

Of the 4,600 acres that lie within the administrative watershed of the East Tennessee Technology Park (see Figure 4.5), only about 1,000 acres have been impacted by operations at the former K-25 Site. Natural topography of the site has been radically altered since operations began in 1941.

Figure 4.5 Aerial View of the Former K-25 Site Looking West

Over time, many operations were conducted at the former K-25 Site, formally also known as the Oak Ridge Gaseous Diffusion Plant. Enrichment by the S-50 thermal diffusion process took place from 1944-1945 in a part of the site near the Powerhouse area; this process proved ineffective and was discontinued. From 1945-1964, the K-25 Site was a gaseous diffusion enrichment facility for weapons-grade uranium. From 1965-1985, the site produced commercial grade uranium. Uranium hexafluoride was used as feed for this enrichment process. A centrifuge enrichment process occurred in the K-1200 Buildings from the 1960s until 1985. The Atomic Vapor Laser Isotope Separation process was operated in 1985.

The East Tennessee Technology Park (ETTP) also contains many support buildings, including laboratories, maintenance shops, garages, holding ponds/cooling towers, warehouses, disposal areas, power and utilities, waste treatment plants, and decontamination facilities.

The site is partially bordered by the Clinch River and its tributary Poplar Creek. Groundwater flows into Mitchell Branch, Poplar Creek, and the Clinch River. The Tennessee Valley Authority (TVA) controls water levels in the river, and this impacts groundwater flow. During the winter, when the river is dropped, the highest contaminated groundwater flux is seen. Storm drains also affect groundwater movement. Several of these storm drains lie below the water table, so they serve as pathways for groundwater flow to surface water. In addition, karst features, including sinkholes and subsurface cavities, are found at ETTP. Building sumps affect groundwater flow by creating drawdown conditions that restrict contaminated groundwater plumes. If the sumps were not in place, the groundwater table would rise and the distribution of contaminants would change. The site also has an intricate network of water supply lines that sometimes leak. As these lines are repaired, groundwater flow! paths will change.

Characterization of the ETTP watershed is still at an early stage in the CERCLA process. The nature and extent of contamination is not fully known. However, data exists from past surveillance and maintenance activities, environmental investigations, operational history, and employee interviews. Through the CERCLA process, DOE will examine those areas that are known or suspected to be contaminated. The Remedial Investigation is not due to regulators until January of 1999. Several areas on the site have already undergone preliminary remedial actions.

The gaseous diffusion process operations area has more than 500 buildings with more than 15 million square feet of floor area. The K-25 and K-27 buildings contain high-enrichment process facilities, and the K-29, K-31, and K-33 buildings contain low-enrichment process equipment. Contaminants in the process buildings are radiological (enriched uranium with trace amounts of highly soluble technetium-99 and transuranic elements) and non-radiological (asbestos, PCBs, and RCRA materials).

More than 270 auxiliary facilities contain more than 2.5 million square feet of floor area. Auxiliary buildings housed support operations including feed/withdrawal, product, tails, testing, maintenance, plating, decontamination, and storage. Site contamination is not universal but is related to specific operations and facilities and is both radiological and non-radiological in nature.

There are about 290 other buildings and trailers on the site that house offices, labs, storage areas, containerized waste management, change-houses, and infrastructure. Very few of these buildings are contaminated.

Principal contaminants in groundwater are volatile organic compounds and some radionuclides, and metals. The most ubiquitous contaminants are TCE and technetium-99. These groundwater contaminants are associated with support facilities and not with process buildings. Many groundwater plumes are now captured and treated at the Central Neutralization Facility. Groundwater contaminated with technetium-99 is limited to two areas, the K-1070-A Burial Ground and Mitchell Branch. The source for the primary contamination problem in Mitchell Branch is probably the 1407-B Pond. Outfall 760 into Mitchell Branch shows elevated levels of radionuclides, and Outfall 780 shows elevated levels of metals. For the most part, contamination levels are below benchmark values in surface water and ecological improvements are occurring in Mitchell Branch.

Characterization of soil contamination has examined only certain types of contaminants, but sitewide radiological walkovers and sampling have been performed. This soil characterization information will be reviewed in preparation for the Remedial Investigation. Overall, there is a difference in the types of contaminants found in shallow soils and deeper soils. Contaminants in shallow soils include radionuclides, metals, and organics. Sources of this contamination include spills, overflows, building runoff, atmospheric releases, and process line leaks. Contaminants in deeper soils include volatile organic compounds, fuel products, and some radionuclides. The sources are waste line leaks, tank leaks, and burial grounds.

The site was divided into three areas for end use: The K-901/Duct Island/ Powerhouse Area; K-27/29/31/33 and the Administration Area; and the Main Plant.

The K-901/Duct Island/Powerhouse Area has limited industrial development and considerable ecological habitat. Sites of potential concern in this area are the
K-1070-A Burial Ground, the K-895 Cylinder Destruct Facility, the K-770 scrapyard, the K-901 disposal areas, and the Powerhouse Area. A Record of Decision is expected to be signed for the K-1070-A Burial Ground, calling for excavation. Contaminants at the K-895 Cylinder Destruct Facility include cesium, thorium, uranium, and technetium. The K-770 scrapyard consists of 30 acres with about 40,000 tons of scrap metal. Contaminants in the scrapyard include uranium, asbestos, PCBs, and metals. The K-901 disposal areas were used for construction debris and is not expected to be highly contaminated. Early actions at the K-901-A Holding Pond have included removal of cylinders and PCB-contaminated fish. Most of the Powerhouse facilities have been demolished but the remaining soil contamination must be addressed.

The K-27/29/31/33 and the Administration Area has considerable industrial development, limited hot spots of shallow and deep soil contamination, limited access, and few ecological habitats. One potential hot spot is a laundry pit with uranium contamination, and another is cesium-contaminated soil in the southwest corner of K-1004-J. The K-1007-P Pond has PCB-contaminated fish and may also contain debris.

The Main Plant Area is an area with heavy industrial activity, active waste management units, very limited ecological habitat, and limited access. Sites with potential contamination are K-1401 Acid Line; K-1420 Process Lines; K-1414 Diesel Tank; K-1064 Drum Storage/Burn Areas; K-1407-B/C Ponds; the K-25 building;
K-1410 neutralization pit; and the K-1070-B and K-1070-C/D Classified Burial Grounds. K-1410 is to be demolished. Both the K-1407-B/C Ponds and K-1070-C/D G-Pit have Records of Decision. The K-1070-C/D Burial Ground received classified materials, low-level radioactive and non-hazardous materials. Contaminants are mostly uranium isotopes, technetium-99, and organics. Several early groundwater actions have occurred in the Main Plant Area.

The EUWG decided that contamination in the Powerhouse Area could be reasonably excavated and disposed. Although they did not want to see the area used for residential purposes, an uncontrolled industrial use that focused on natural resource conservation was satisfactory to most members. Members felt that
K-27/29/31/33 and the Administrative area could be cleaned to an uncontrolled industrial use, but that the Main Plant Area would require a controlled industrial use except for the K-1070-B and K-1070-C/D Burial Grounds, which would require a restricted waste disposal end use.

Because the EUWG focused on end uses following remediation, the current reindustrialization process and the TSCA Incinerator were not considered to be within the EUWG scope.

• concerns about the lack of complete characterization of the site, which impacts end use recommendations;
• concerns about the presence of uranium hexaflouride cylinders at the site;
• concerns about the impacts of contamination on workers’ health;
• concerns about the current reindustrialization approach;
• concerns about beryllium levels at the site; and
• the lack of monitoring wells in certain areas at the site.