This editorial was contributed by Susan Wood, director of the Savannah River Technology Center.
This editorial was contributed by Susan Wood, director of the Savannah River Technology Center.
Throughout its long history, the Savannah River Site (SRS) has benefited from close relationships with the national laboratories, not the least of which is a special relationship with Los Alamos, based on our complementary capabilities in tritium and plutonium. These partnerships are essential in enabling this key Department of Energy (DOE) site to fulfill its current and future missions. The SRS is a DOE industrial complex dedicated to stewardship of the environment, the enduring nuclear weapons stockpile, and strategic nuclear materials. The SRS processes and stores nuclear materials in support of national defense and U.S. nuclear nonproliferation efforts.
With its applied research and development (R&D) lab, the Savannah River Technology Center (SRTC), the site also develops and deploys technologies to improve the environment and treat nuclear and hazardous wastes left from the Cold War.
The siteÑwith its five nuclear reactors (now shut down) and two chemical separations plants, plus numerous other production and waste-management facilitiesÑwas built in the 1950s to produce materials used in nuclear weapons, primarily tritium and plutonium-239. The SRS complex covers about 310 square miles encompassing parts of three South Carolina counties along the Savannah River, on the South CarolinaÐGeorgia border.
PAR Pond is a man-made lake, constructed in 1958 as a cooling pond for the Savannah River Site's P and R reactors, hence the name. "RAP Lake" was also considered as a name, but the site's location near Augusta, Ga. (home of the Masters golf tournament), prompted site officials to choose the acronym PAR instea "living laboratory" for studying alligators, several species of fish, and migratory birds.
Science and technology (S&T) have always been important at SRS because they support plant operations, enhance environmental cleanup, reduce cost, enhance safety, and enable new missions.
The S&T for SRS needs may come to the site from SRTC, one of the national laboratories, or elsewhere. Whatever the origin, it typically is transmitted through SRTC, which then assumes responsibility forongoing support; hence our slogan, "We Put Science to Work." It is essential that we work closely with the national laboratories to leverage and integrate our respective capabilities as well as to provide a seamless transition from a "lead lab" to a production site.
Each mission area necessitates different partnerships and relationships tailored to its specific needs and the S&T strengths of respective laboratories. Optimizing such integration requires mutual respect of each other's capabilities and a willingness to share and team.
An operator works on the Defense Waste Processing Facility's (DWPF) equipment through a shielded window with the aid of video monitors. Remote operations, coupled with five-foot-thick walls, are necessary to keep workers from being exposed to high levels of radiation produced by the waste going through the facility. DWPF is the largest radioactive waste glassification plant in the world. It is where high-level liquid nuclear waste currently stored at the Savannah River Site is converted into a solid glass form suitable for long-term storage and disposal. Since radioactive operations began in March 1996 at DWPF, more than 1,300 canisters of glassified waste have been poured. It is expected to take seventeen to twenty-five years to turn the entire site inventory of high-level waste into glass.
Tritium, with a half-life of 12.5 years, must be replenished, and SRS is the nation's only facility for recycling and reloading tritium from nuclear weapons reservoirs returned from service. All tritium unloading, mixing, and loading is performed in a facility that went into operation in 1994, replacing older facilities that processed the nationÕs tritium for thirty-five years. A new facility is being built to extract tritium created in the Tennessee Valley Authority's light-water reactors.
SRS and Los Alamos have a fully integrated S&T roadmap, which supports both short- and long-term production mission objectives. Together, we represent the nation's core tritium capability. In addition, the Accelerator Production of Tritium (APT) team leveraged the joint core competencies in R&D and technology application to mutual benefit and success. This was an ideal role model for future work, which not only enabled rapid technology deployment, but broadened career opportunities as well. Pacific Northwest National Laboratory (PNNL) also played a key role by performing experimental and modeling work to demonstrate tritium extraction from Tritium Producing Burnable Absorber RodsÑor TPBARs.
For more than three decades, the Receiving Basin for Offsite Fuels (RBOF) has been safely receiving and storing on-site fuels and fuels from domestic and foreign research reactor programs. Until 1988, it was routine for foreign researchers to return U.S.-origin spent fuel to this country. At the urging of the U.S. Department of State and the International Atomic Energy Agency, the Department of Energy renewed that policy in 1996. Plans are under way to deinventory RBOF, transferring spent fuel to Savannah River Site's L Area Disassembly Basin, a much larger facility. That basin was modified and received its first shipment of foreign spent fuel in January 1997.
Spent fuel currently stored at SRS is from the site's production reactors and from domestic and foreign research reactor programs. All of this fuel is stored in water-filled concrete storage basins, which were intended originally for interim storage while spent fuel awaited processing in a chemical separations facility. In addition, studies are under way to find alternative technologies, such as dry cask storage, for the spent fuel.
SRS is the DOE's Center of Excellence for the dispositioning of aluminum clad fuel, an effort supported by Los Alamos.
Savannah River Site's two primary separations facilities, called canyons, are located in F and H areas. F Canyon and H Canyon-together with the FB Line and HB Line, which are located atop the canyons-are where nuclear materials historically have been chemically recovered and purified.
Savannah River Site (SRS) has two primary separations facilities where nuclear materials historically have been chemically recovered and purified. Called F and H "canyons" for their long, narrow shapes, these large, remotely operated, heavily shielded facilities were constructed in the early 1950s to provide materials, initially plutonium-239, for the U.S. nuclear arsenal. As the chemical separations processes developed and matured, these canyons showed a versatility well beyond their original scope, processing a variety of materials, including uranium-235 and neptunium-237 (which, when irradiated, produced plutonium-238, which is used in power systems for the U.S. deep space exploration programs).
In recent years, the canyons have been used to stabilize and manage legacy materials at SRS, including plutonium-bearing materials and highly enriched uranium. F Canyon completed its scheduled production mission in March 2002; H Canyon continues to operate.
In addition to defense materials, HB Line has produced plutonium-238 for Los Alamos, which NASA used for the 1997 Cassini mission.
F Canyon completed its PUREX processing mission in March 2002. PUREX is an extraction process in which fuel elements are dissolved in nitric acid and the uranium and plutonium are chemically separated out with solvents. H Canyon continues to stabilize and manage most of the remaining inventory of plutonium-bearing materials at SRS. In addition, DOE has determined that H Canyon should be used to convert a large quantity of weapons-usable highly enriched uranium (HEU) to low-enriched material suitable as fuel in commercial power reactors.
Additionally, the H Canyon role in plutonium stabilization will be expanded to include materials from dismantled weapons and surpluses from other DOE sites. SRS is also the announced location for the DOEÕs plutonium pit disassembly and conversion (PDCF) and mixed-oxide (MOX) fuel fabrication facilities. Technology development for the plutonium immobilization facility, which has been suspended, involved a strong partnership with Lawrence Livermore National Laboratory, which had the technology lead.
Both the past and the future of SRS plutonium missions involve close interaction between Los Alamos and SRS. Traditionally, we have synergistically shared and used actinide chemistry and process knowledge. The plutonium-238 mission was a joint program, which was transferred to Los Alamos in 1995. Furthermore, Los Alamos is the lead lab for the PDCF, but we have not achieved the level of integration in plutonium that has been accomplished with the tritium mission. SRS has a vital role in plutonium management for DOE. In its support of SRS missions, SRTC has a vital role in plutonium research, development, and technology (RD&T), as does Los Alamos. I believe that improved teaming and integration of RD&T would provide benefits for the customer and the technical staff at both locations. Certainly, it would facilitate technology transfer and ongoing support to the production site.
A technician works inside a glovebox on the HB Line, located on top of
H Canyon. HB Line was built in the early 1980s to support the production of plutonium-238, a power source for the nation's deep space exploration program. Decisions announced between December 1995 and October 1997 concluded that HB Line should be used to stabilize solutions stored in H Canyon. HB Line consists of three process lines. The Scrap Recovery Line is used to recycle legacy plutonium scrap (sometimes mixed with other radioactive materials) for purification and concentration to a solid form. The Neptunium-237/Plutonium-239 Oxide Line can produce solid oxide material from neptunium-237 or plutonium-239 nitrate solutions. (This line started operations for the first time in November 2001. The plutonium material is shipped to FB Line for storage and eventual disposition. The neptunium material will be shipped offsite for further processing.) The Plutonium-238 Oxide Line can produce plutonium-238 oxide from nitrate solutions; there is not a current mission for this line.
Weapons material production created unusable byproducts, such as radioactive waste. About 38 million gallons of high-level radioactive liquid waste are stored in tanks at SRS. The Defense Waste Processing Facility (DWPF), which began operations in 1996, is processing the highly radioactive waste by bonding radioactive elements in borosilicate glass. Much of the volume in the tanks ultimately will be separated as relatively low-level radioactive salt solution, which is mixed with cement, ash, and furnace slag, and poured into permanent concrete monoliths for disposal at a facility called Saltstone.
Construction began on the first high-level waste tanks at the Savannah River Site (SRS) in 1951, while the last waste tank was constructed in 1981. The waste tanks vary in size, from 750,000 gallons to 1.3 million gallons. There were fifty-one tanks originally constructed at SRS. However, in 1997 SRS closed the first two high-level waste tanks in the nation by filling them with a special grout mixture and concrete, bringing the number of waste tanks available to forty-nine. There are about 37 million gallons of waste stored in these tanks awaiting processing. The highly radioactive portion of the waste stored in the tanks will be sent to the Defense Waste Processing Facility, where it will be immobilized by converting the liquid waste into glass. The low-level portion of the waste material will be treated and stored on site in a special grout-cement mixture until its radioactive constituents decay to harmless levels.
Savannah River Site's working relationships with national laboratories in support of the high-level waste mission are many and varied. They include strong teaming with PNNL on vitrification and waste pretreatment, together with Oak Ridge National, Argonne National, and Idaho National Engineering and Environmental Laboratories. The key has been to identify the best capabilities and integrate them to support mission needs, assisted by the Tanks Focus Area (part of the Environmental Management R&D Program). The integrated technology roadmap is, however, more near-term than the tritium model described earlier. Thus, while resources are best used and networking relationships are strengthened by this approach, it does not promote long-term partnerships.
Similar relationships are in place to support the mission to remediate the site's 515 inactive waste and groundwater units. Waste sites range in size from a few square feet to tens of acres and include basins, pits, piles, burial grounds, landfills, tanks, and associated groundwater contamination. While there are many common factors across SRS contamination sites that also extend to other parts of the DOE complex, there are also many site-specific factors that impact chosen remedies. Thus, rapid knowledge-sharing and technology reapplication skills are key to successful technology reuse at multiple sites. In all of these activities, teaming with the national laboratories is part of everyday life at Savannah River. A continued strengthening of the special relationship between SRS and Los Alamos will be beneficial to all of us, as we jointly pursue our enduring missions.
NMT |
LANL |
DOE
Phone Book |
Search |
Help/Info
L O S A L A M O S
N A T I O N A L
L A B O R A T O R Y
Operated by the University of California for the US Department of
Energy
Questions? -
Copyright © UC
1998-2000
-
For conditions of use, see Disclaimer