18.8.1 US experience

For over five decades, the United States generated a large quantity and variety of nuclear wastes. Significant progress has been made in the treat­ment and disposal of these wastes and the cleanup and closure of nuclear sites. Much has been accomplished, but work remains to be done before the cleanup mission is complete.

The DOE has over 20 years of experience in site cleanup. DOE EM manages the DOE cleanup program, which has:

• stabilized millions of liters/gallons of radioactive tank waste

• completed 11 waste tank closures, including two in 2012 at the SRS in South Carolina

• operated the DWPF at the SRS since 1996 making 5,850 metric tons of borosilicate glass, which stabilized 1.5 x 106 Tera-Becquerels of radioactivity

• operated and completed waste processing at the West Valley Demon­stration Project (WVDP) in New York from 1996 to 2002 making -500 metric tons of borosilicate glass which stabilized 9 x 105 Tera-Becquerels of radioactivity

• begun construction of three major tank waste processing facilities.

The tank waste processing facilities include the WTP in Washington (2003), SWPF in South Carolina (2005), and the Sodium Bearing Waste Treatment Facility in Idaho (2003). The IWTU at the Idaho facility is expected to begin operations in 2013. See Section 18.7.6 for more detail about these three construction projects.

In addition, the world’s first geological repository — WIPP — began opera­tions in 1999, and had received over 11,000 shipments as of February 2013. The first CH TRU waste shipment arrived at WIPP from Los Alamos in 1999, and the first RH waste shipment arrived at WIPP from Idaho in 2007.

The DOE has also treated 240 km2 of contaminated groundwater and stabilized more than 180 contaminated groundwater plumes. It has exten­sive experience in deactivation and decommissioning (D&D), including D&D of about 1,500 facilities. For example, it is in the process of decom­missioning and demolishing the K-25 facility in Tennessee, a building nearly one mile long used to enrich uranium from 1945 to 1964. It contained nearly 5 million ft2 of floor space. Demolition of the west wing, which comprises just under half of the entire facility, began in 2008 and finished in 2010.

Another example of a completed D&D activity is the P Reactor in South Carolina (which was entombed in place using concrete grout to fill the rooms below ground level), disassembly basin, and reactor vessel. Cleanup of the Experimental Breeder Reactor-II in Idaho, which operated for about 30 years from the mid-1960s to the mid-1990s, is currently in progress. The systems and structures above the reactor building will be demolished and most of the remaining systems and structures will be grouted in place.

Other D&D projects include the K-Basins project and N Reactor closure in Washington. The K-Basins stored spent fuel; they were demolished in 2009, and remediation of the nearby soil was completed in 2010. N-Reactor operated from 1963 to 1987; its support facilities have been demolished, and it is being placed into safe interim storage.

The DOE has experience in LLW disposal. At the Hanford site, the Environmental Restoration Disposal Facility began operation in 1996 to dispose of contaminated soils, D&D waste, asbestos, and hazardous waste from onsite cleanup. Waste is disposed in cells approximately 150 x 150 m in area and about 20 m deep. Another LLW disposal facility at the Oak Ridge Reservation in Tennessee, the Environmental Management Waste Management Facility, has been operating since 2002.

The DOE has closed two former nuclear sites: the Rocky Flats Plant in 2005 and the Fernald Site in 2006. The Rocky Flats Plant was established in 1951 as part of the US nuclear weapons complex to manufacture nuclear weapons components. The site covers about 6,500 acres near the Rocky Mountains northwest of Denver. Most of the land served as a security buffer around an approximately 400-acre industrial area near the center of the site. When production of weapons components ended at Rocky Flats in 1994, its mission changed to cleanup and closure.

Because of operational problems and practices during the plant’s history, facilities contained substantial amounts of hazardous materials and con­tamination. Liquids remained in process piping and in tanks in unknown quantities and chemical configuration, which resulted in a significant envi­ronmental cleanup and closure challenge for the DOE.

In October 2005, the DOE and its contractor completed an accelerated ten-year, $6.7 billion cleanup of chemical and radiological contamination left from nearly 50 years of production. The cleanup required the decom­missioning, decontamination, demolition, and removal of more than 800 structures, including six processing and fabrication building complexes; removal of more than 500,000 m3 of LLW; and remediation of more than 360 potentially contaminated environmental sites. The majority of the prop­erty at the site was transferred to the US Department of Interior for man­agement by the US Fish and Wildlife Service as the Rocky Flats National Wildlife Refuge in July 2007 (DOE, 2011a).

The Fernald site, formally known as Feed Materials Production Center, was a uranium processing facility that produced high-purity uranium metal products as the first step in the US nuclear weapons production cycle. The site ’s production mission began in 1951 and continued until 1989, when production operations ceased and Fernald’ s mission changed to environ­mental remediation. The comprehensive environmental remediation and ecological restoration of the site was completed in 2006, at a total cost of $4.4 billion.

The 1,050-acre site, now known as the Fernald Preserve, is open to the public as a nature preserve. The ecological restoration has made the Fernald Preserve attractive to a large number of nesting and migrating birds, including locally rare species. Restoration activities at the site have created one of the largest man-made wetlands, including open water, forests, 360 acres of grassland, and seven miles of trails that provide access to varied habitats (DOE, 2011b).

Significant challenges remain in the DOE cleanup program. The DOE must safely store, retrieve, and treat approximately 340 million L (about 90 million gallons) of liquid radioactive waste stored in 230 underground tanks, remediate approximately 6.5 trillion L of contaminated groundwater, reme­diate approximately 40 million m3 of contaminated soil, and D&D over 2,500 facilities.

In addition, the DOE has decommissioned and cleaned up uranium mines and mill tailings. For conventional US uranium mills, waste is primarily the onsite disposal of tailings (residual ore after the uranium was leached). UMTRCA classified the tailings as either residual radioactive material or 11e.(2) byproduct material depending on the status of the facility at the time UMTRCA was passed in 1978. Since passage of UMTRCA, activities at Title I sites have focused largely on decommission­ing and cleanup of residual radioactive material by US governmental entities.

UMTRCA Title I required the DOE to complete surface remediation and groundwater cleanup at the listed inactive uranium milling sites at which uranium was processed solely for sale to the US government. Resid­ual radioactive material, including any wind-blown dust, may have been consolidated into a single cell or perhaps relocated to a cell constructed on another site. These cells are now under long-term surveillance by the DOE (or possibly by the state or tribal governments in which the cell is located) and licensed by the NRC. Annual site inspections are performed as part of the long-term surveillance program at 22 Title I disposal sites.