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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges FIGURE G.1 The Savannah River Site occupies 310 square miles bordering the Savannah River in South Carolina. The site was established in the early 1950s when the U.S. government determined that there was a need for additional industrial-scale production of nuclear maerial in a location far away from the Hanford reservation SOURCE: Department of Energy.
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges Appendix G Savannah River Site INTRODUCTION The National Research Council Committee on Development and Implementation of a Cleanup Technology Roadmap held its fifth meeting in Augusta, Georgia on January 8-10, 2008. The purpose of the meeting was to obtain information relevant to the committee’s Statement of Task (SOT) through presentations and tours by Department of Energy (DOE) staff and their contractors.1 This appendix provides a factual summary of the information related to the four items in the committee’s SOT obtained during the meeting, the site visits, and documents provided to the committee. This appendix first describes the history and status of the DOE Savannah River Site (SRS), to provide perspective on the range of cleanup issues being managed by the DOE Office of Environmental Management (EM). The next sections summarize information presented to the committee, which guided the committee’s deliberations in addressing its SOT as described in the main text. This appendix thus provides support for the findings and recommendations developed by the committee. HISTORY In 1950 E.I. duPont de Nemours and Company was asked by the then Atomic Energy Commission to design, construct, and manage a plant for 1 The agenda for this meeting is shown in Appendix B.
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges producing nuclear weapons material on a 310-square-mile reservation bordering the Savannah River in South Carolina, see Figure G.1. DuPont had previously constructed the Hanford plant, and the U.S. government judged that a second production site, far away from Hanford, was necessary to ensure an adequate supply of weapons material as the United States entered the Cold War. The Savannah River Plant (SRP) began producing heavy water for site reactors in 1952. R-Reactor, the first production reactor onsite, began operating (“went critical”) in 1953. P-, L-, and K-reactors went critical in 1954, and the F-Canyon, a facility for reprocessing the reactor fuels, began radioactive operations. In 1955 C-Reactor and H-Canyon began operating, and the first plutonium shipment left the site. Construction of the basic plant was finished in 1956. The Savannah River Laboratory (SRL) provided research and development (R&D) capabilities to support the plant. With the end of the Cold War, most of SRP’s production activities were shut down between 1988 and 1992. In 1989 the Westinghouse Savannah River Company (which later became Washington Savannah River Company) became the site’s primary management and operations contractor, and the site was designated as the SRS. In May 2004, the Secretary of Energy designated the former SRL as the Savannah River National Laboratory (SRNL). DOE selected Savannah River Nuclear Solutions, LLC, as the management and operations contractor for SRS in January 2008. In December 2008, DOE selected Savannah River Remediations, LLC, as the liquid waste disposition contractor at SRS. In addition to EM’s site cleanup and environmental restoration work, SRS has a number of continuing missions, primarily dealing with plutonium and tritium processing.2 The President’s FY 2008 budget request for EM activities at SRS was about $1.4 billion (Allison 2008). CLEANUP PROGRAMS AND CHALLENGES This section describes ongoing cleanup programs and challenges as presented to the committee during its open meeting sessions at Augusta, Georgia, and its visits to SRS and to SRNL. The information is organized according to the program areas of the EM Science and Technology Roadmap (DOE 2008). Program Area: Waste Processing The SRS Waste Disposition Project addresses the site’s liquid and solid wastes. Its liquid waste mission includes stabilization and disposition of 2 See http://www.srs.gov/general/about/history1.htm.
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges 36 million gallons of radioactive liquid waste currently stored in 49 underground storage tanks as a result of F- and H-Canyon operations, and closure of the emptied tanks.3 The project also includes stabilization and disposition of transuranic, hazardous, mixed, low-level, and sanitary wastes (Spears 2008). The 36 million gallons of tank waste at SRS contain nearly 400 million curies of radioactive materials, which is about half of the radioactivity in the DOE complex. The 27 tanks that have full secondary containment (i.e., they are double-walled tanks) are referred to as “compliant” tanks because they comply with the site’s Federal Facility Agreement (FFA). The remaining 22 tanks that have partial or no secondary containment are referred to as noncompliant. The FFA requires that all noncompliant tanks be closed by FY 2022. Additionally, waste must be removed from all tanks by FY 2028 in accordance with the Site Treatment Plan and Consent Order (Spears 2008). Tank closure requirements are laid out in Section 3116(a) of the Ronald W. Reagan National Defense Authorization Act for FY 2005 (NRC 2006). Most of the high-level tank waste originated from the reprocessing of nuclear fuels and irradiated targets for plutonium production via solvent extraction processes, which utilized nitric acid. The wastes were then made alkaline for compatibility with the site’s carbon steel waste tanks. Most of the actinides and fission products in the waste, along with nonradioactive elements such as iron, precipitated from the alkaline mixture to form an insoluble sludge in the tanks. The remaining water-soluble salt solution, which contained some radioactive materials, notably Cs-137, was evaporated to conserve tank space. This resulted in a salt cake and supernatant solution that are also in the tanks. Spears (2008) reported that the SRS tanks contain about 16.9 million gallons of supernate, 16.6 million gallons of salt cake, and 3.0 million gallons of sludge. Defense Waste Processing Facility (DWPF) SRS began operating the DWPF in 1996. Its objective is to vitrify high-level tank waste to yield a stable form ready for disposal in a federal repository. Borosilicate glass developed at SRL was selected to be the waste form matrix in the late 1970s. To vitrify the waste, a glass-forming “frit” material is mixed with waste slurry and the mixture pumped onto the top of an already molten frit/waste mixture in a ceramic-lined melter (“slurry feeding”). The vitrification process takes place at about 1,150°C in the melter. Heat is provided by passing electricity directly through the molten glass (Joule heating). The glassmaking is a continuous process. 3 SRS has closed 2 of its 51 high-level waste tanks.
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges Glass pours from the melter into a 10-foot tall, 2-foot diameter stainless steel canister. Filled canisters are allowed to cool, the top is welded shut, and the outside is decontaminated. The canisters are stored in a temporary onsite storage facility. At the time of the committee’s visit, the DWPF had filled over 2,430 canisters with vitrified tank sludge (Spears 2008). Continued efforts to optimize the frit composition now allow about 38 weight percent of waste to be incorporated into the borosilicate glass waste forms (Davis 2008). Salt Processing Concurrent with design of the DWPF, which began in 1977, SRS designed an in-tank process intended to use an organic complexing agent (tetraphenyl borate) that could simply be added to a waste tank to precipitate the Cs-137. Supernate and dissolved salt cake would be pumped into a compliant tank designated for the process, the complexant added, mixed, and the insoluble Cs-tetraphenyl borate separated by filtration. This small, but highly radioactive Cs-137 stream would be vitrified in the DWPF along with the sludge. The large-volume, slightly radioactive “decontaminated” salt stream would be grouted into a product referred to as saltstone and emplaced in concrete vaults for permanent onsite storage (NRC 2000, 2006). At about the same time that the DWPF began operating, the Defense Nuclear Safety Board and DOE determined that the in-tank precipitation process required further process chemistry assessment. During a test in Tank 48H, a substantial amount of flammable benzene from decomposition of the tetraphenyl borate was released into the tank (NRC 2000). Failure of the in-tank process left SRS without a means to disposition the bulk salts in its waste tanks and, hence, to empty the tanks. DWPF operations were essentially unaffected, since the tank sludge stream constitutes essentially all of the volume of waste that the DWPF was designed to vitrify. Unable to remove any significant amount of waste from its tanks for the past 10 years, SRS has a severe shortage of tank space. Spears (2008) reported only about 1.3 million gallons of usable space remains after accounting for that needed for tank farm operations and contingencies. Ongoing operations, including waste recovery and DWPF operations will continue to consume space. SRS has, however, begun some salt processing on an interim basis. Deliquification, Dissolution, and Adjustment (DDA) Tank waste salts at SRS are predominantly sodium nitrate (NaNO3), sodium nitrite (NaNO2), and sodium hydroxide (NaOH), which result from
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges rendering the nitric acid reprocessing waste alkaline. Evaporating this liquid waste to the extent possible to conserve tank space resulted in a mixture of supernate and salt cake, as noted previously. The salt cake is relatively depleted in Cs-137 because the hydrated radius of Cs+ is larger than that of Na+, so the cesium tends to be excluded from the crystallized salt. Conversely, Cs-137 is concentrated in the supernatant solution. An expedient way to free tank space is to dissolve salt cake from selected tanks that contain relatively little Cs-137 and to send this material directly to the saltstone grout facility for permanent onsite disposal. At the time of the committee’s visit, SRS was intending to implement this process, referred to as “deliquification (draining away the supernate), dissolution, and adjustment” (DDA) to process Tank 41 waste (Spears 2008). Because of entrainment of supernate and Cs-137 in the salt, DDA is not very effective for partitioning Cs-137, and its use will be limited to only dissolved salt cake from Tank 41. Actinide Removal Process/Modular Caustic-Side Solvent Extraction Unit (ARP/MCU) After failure of the in-tank precipitation process, SRS sought other options for salt processing and, after a detailed evaluation, selected a solvent extraction process tailored for alkaline waste. The process is based on a calixarene crown ether extractant (referred to as BobCalixC6), which is highly selective for cesium in the presence of sodium. Development of the extractant began with basic research at Oak Ridge National Laboratory (ORNL) and was subsequently supported by EM through its Environmental Management Science Program. To initiate this efficient means of partitioning Cs-137 from the salt as soon as possible, SRS designed and constructed a “modular caustic-side solvent extraction unit” (MCU). This is essentially a pilot-scale unit intended to help recover tank space and to fully demonstrate the solvent extraction process (Spears 2008). SRS will also remove the traces of actinides (mainly plutonium) and Sr-90 that are in the salt waste using an ARP. In the ARP, a sorbent—monosodium titanate (MST)—is mixed with the salt solution, which is then filtered to remove the MST along with its adsorbed radionuclides. This filtered solution is sent to the MCU, and the MST is sent to the DWPF. Both the MCU and ARP were completing nonradioactive tests at the time of the committee’s visit. Start-up testing with actual waste began later in 2008 (Spears 2008).
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges Salt Waste Processing Facility (SWPF) SRS waste processing facilities operate under state-issued permits. The permitted limit for the total radioactivity to be disposed permanently onsite in the saltstone vaults is 1.4 million curies. Together the DDA and ARP/MCU processes might contribute 1.2 million curies (Spears 2008). SRS is therefore designing the SWPF. The SWPF is expected to process about 85 million gallons of supernate and dissolved salt cake at a rate of about 6 million gallons per year, while adding no more than about 0.2 million curies of radioactivity to the saltstone. The SWPF will use the same processes as the ARP/MCU at a larger and more efficient scale. For example, the centrifugal contactors (high-speed rotating devices that mix and then separate aqueous and organic phases in the solvent extraction process) will be larger and there will be more extraction stages than in the MCU. Davis (2008) stated that an SRNL-modified monosodium titanate (MMST) formulation that shortens Sr-90 and actinide removal times in the ARP will play an important role. Deploying MMST in lieu of MST will increase salt processing throughput such that the risk of not meeting the Site Treatment Plan requirement to vitrify all current and future high-level waste (HLW) by 2029 is reduced. Construction of the SWPF had begun at the time of the committee’s visit, and it is expected to be completed by the end of 2013 (Spears 2008). Tank 48 Recovery The in-tank precipitation test referred to previously left Tank 48H with about 240,000 gallons of highly radioactive liquid waste that also contains about 21,800 kilograms of organic compounds. Removing this waste will allow the 1.3-million-gallon compliant tank to be returned to tank farm service. SRS expects that Tank 48 will serve as a feed tank for the SWPF (Spears 2008). The Tank 48 treatment process had not been selected at the time of the committee’s visit. The process will be required to provide the capability to destroy the organics as well as to treat the salt waste. Options, which include fluidized bed steam reforming and wet air oxidation, are being developed by SRNL, Idaho National Laboratory (INL), and Pacific Northwest National Laboratory. Project completion is targeted for 1 year after SWPF startup to support maximum feed rates (Spears 2008). Technology Needs Spears (2008) named the following technology needs:
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges Sludge heel removal, including improved chemical cleaning and mechanical cleaning; Sludge mass reduction, which essentially involves removing nonradioactive constituents from the sludge so that the amount of waste that must be vitrified is reduced; Waste processing, primarily increasing the production rate and loading of DWPF glass; and Ensuring the availability of methods to recover Tank 48. Davis (2008) listed similar DWPF-related technology needs: Increase the waste loading in glass, Increase DWPF throughput, and Improve sludge preparation and qualification in the tank farm. Davis (2008) noted that the cost of operating the HLW system is about $500 million per year. Salt processing and sludge vitrification are the rate-limiting steps; thus technologies that increase the rate of salt or sludge processing can reduce the life-cycle cost. Some options for increasing the melt rate include improving the glass-forming frit, improving the ability to mix the contents of the melter, and using a higher temperature alternative melter design. He also said that improving the sludge feed preparation steps in the tank farm can also increase DWPF throughput. These steps include removing aluminum from the sludge and washing the sludge to remove sodium salts—both sodium and aluminum increase the amount of glass required to vitrify a given amount of sludge. The rate of sludge settling after it is washed is the limiting step in these operations, and Davis (2008) suggested that the rotary microfilter is a new technology that could support continuous, rather than batch, sludge washing. Davis (2008) stated that completion of salt processing is now expected to be about 2 to 5 years after sludge vitrification is completed. This is largely due to the salt processing difficulties described earlier in this appendix. One way to accelerate salt processing is to augment the SWPF with a process called small-column ion exchange. The process would include relatively small ion exchange columns mounted in risers (access ports) on the top of a compliant tank. The ion exchange media could be either an elutable, resorcinol formaldehyde organic resin or a nonelutable crystalline silico-titanate (CST) resin. The CST process would be simpler to operate but would produce more waste to be vitrified in the DWPF. Either resin would be fed from a rotary microfilter also mounted in a tank riser. Davis (2008) judged that the ion exchange technologies are maturing and could be deployed in about 3 years. He suggested that small-column ion exchange
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges could avoid $2.5 billion in cost by reducing the DWPF life-cycle schedule by 5 years. Lastly as a technical challenge, Davis (2008) stated that SRS tank waste processing must operate as an integrated system. All of its components, including the tank farms, SWPF, DWPF, and saltstone, must be kept operating simultaneously. Tank Waste Retrieval and Tank Closure Of the 24 noncompliant tanks, two have been closed and four more were expected to be ready for closure by the end of FY 2010 (Spears 2008). Tank closure requires removing waste from a tank until only an acceptable amount of residual waste remains. Once the tank is deemed “clean enough” it is filled with engineered grout. In the first two tanks to be closed, there are three grout layers: a chemically reducing grout at the bottom to maintain the radionuclides and toxic heavy metals in their most stable forms, a controlled low-strength material to fill most of the space, and then a stronger “cap” at the top to discourage intruders. Future closures may use chemically reducing grout to fill the entire tank (NRC 2006). The use of carbon steel as the material for underground tanks necessitated neutralizing the tank contents rather than leaving them in their original acidic form. As a result, metal oxides and hydroxides precipitated, forming a sludge at the bottom of the tank that contains a high proportion of the radioactivity and is very difficult to remove. Oxalic acid is effective for chemical cleaning, but it causes degradation of the carbon steel (NRC 2006). The two tanks that have been closed so far were selected from among the easier ones to clean, since they had no cooling coils; greater difficulties are anticipated with future cleaning campaigns (NRC 2006). Forty-three of the remaining compliant and noncompliant tanks have extensive cooling coil systems—some 20,000 to 25,000 feet of 2-inch-diameter carbon steel pipe per tank (Davis 2008). These coils present obstacles to the cleaning of the tanks by blocking water spray in their “shadows” and making it difficult for mechanical waste removal equipment to navigate around them. In addition the vertical pipes could represent “fast flowpaths” from the near-surface tank tops to residual waste on the tank bottom. These flowpaths must be eliminated, either by filling the pipes with stable material or cutting the pipes, before the tanks can be closed (Davis 2008). The tank farm also has an extensive intertank waste transfer system. This includes 3-inch-diameter stainless steel pipes within carbon steel jackets or concrete encasements. Requirements for closing these transfer lines have not been finalized; however, Davis (2008) noted that approaches used at the INL site might be useful for SRS as well.
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges Program Area: Soil and Groundwater SRS identified a total of 515 waste units—areas where there is contaminated soil, groundwater, and/or surface water—for remediation. The SRS Area Completion Project (ACP) is responsible for remediating these waste units, if warranted, as well as for facility deactivation and decommissioning. Whitaker (2008) reported that since 1993 the project has met all 1,990 of its scheduled FFA milestones and Resource Conservation and Recovery Act permit commitments, and 352 of the 515 waste units have been dispositioned. He added that the ACP’s current approach addresses large groupings of waste units and facilities in a geographic area, rather than dealing with individual units. SRS has 14 groundwater contamination areas. For remediation, each plume is considered to be in three parts: The source area or “hot spot,” The primary groundwater plume, and The dilute plume, which leads the primary plume in the direction of the groundwater flow. Hot spot remediation involves thorough characterization of the source and highly aggressive technologies, such as excavation, heating to drive off volatile compounds, in situ chemical oxidation, and active soil vapor extraction. For the primary plume, characterization and groundwater extraction are optimized to reduce the treatment volume. Technologies may include air stripping, recirculation wells, hydraulic barriers, phyto-irrigation, and base injection. For the dilute plume ahead of the primary, characterization is needed to predict mass transfer and flux. Remediation involves low-energy technologies such as passive soil vapor extraction, and natural attenuation. Currently 14 active groundwater remediation systems are operating to address the groundwater contamination areas (Whitaker 2008). Whitaker (2008) described some of the more significant soil and groundwater program activities. One is a steam injection and contaminant removal system that is remediating a 3-acre area regarded as the primary source of subsurface contamination in A- and M-Areas. This dynamic underground stripping system is expected to complete the remediation in 5 years versus an estimated 200+ years using conventional technologies. The system had removed 380,000 pounds of solvents at the time of the committee’s visit. Electrical resistance heating removed 710 pounds of solvents at C-Reactor in 2006. The system achieved 99 percent efficiency according to soil samples, and completed the cleanup 2 years faster than soil vapor extraction. In 2007, the aboveground equipment was relocated to an area where
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges chemicals, metals, and pesticides were disposed in a pit (referred to as the CMP Pit) (Whitaker 2008). SRS consolidated the waste from three seepage basins into the area where low-level solid wastes were originally disposed, referred to at the “Old Radioactive Waste Burial Ground.” A geosynthetic cover was then constructed over the 76-acre burial ground to close that facility. Phytore-mediation is controlling tritiated groundwater, which originates in the area of the old burial ground and discharges to a stream. The control system includes a sheet pile dam to create a 2-acre pond, and using the pond water to irrigate 22 acres of pine forest that evapotranspires the tritiated water. This has reduced tritium entering the stream by 70 percent (Whitaker 2008). Technology Challenges and Needs Whitaker (2008) presented a prioritized list of technology challenges for the ACP, and he noted that the continued development and deployment of new technologies are critical to project success. The challenges he listed are the following: Mass transfer limitations that affect removing contaminants from “tight zones,” Remediating abandoned sewer lines, Demonstrating monitored natural attenuation (MNA) and enhanced attenuation (EA) for chlorinated solvents, Technologies that can support long-term institutional control, and MNA and EA for metals and radionuclides. Contaminants in tight zones include organics, metals, and radionuclides across the entire SRS due to its variably layered geology. Possible technologies to overcome mass transfer limitations in these zones include fracturing the clay to create openings, vadose heating to increase mass transfer rates, and long-term development of sustainable passive barriers (Whitaker 2008). Abandoned sewer lines are responsible for diffuse, non-point source contamination. Innovative or improved tools are needed for characterization and remediation of up to 10 miles of underground lines associated with each industrial area at SRS. Possible technologies could include geophysics, gas tracers, robotics, in situ removal, and/or stabilization systems (Whitaker 2008). For transitioning the site to long-term stewardship, monitoring tools will be necessary to demonstrate that natural attenuation is occurring as expected or to implement EA to ensure that continued active remediation
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges is not required. Demonstrations of EA, for example, barometric pumping, long-lived electron-donor (e.g., vegetable oil) injection, and post-thermal treatments, are also needed. MNA/EA demonstrations will be needed for chlorinated solvents, metals, and radionuclides (Whitaker 2008). Technologies to support long-term stewardship and institutional control include improved tools and strategies (do we look at individual plumes or collectively at an entire watershed?), alternatives to current practice that require frequent measurements in large numbers of monitoring wells, and innovative systems for monitoring remediations that depend on caps or waste isolation (Whitaker 2008). Program Area: Deactivation and Decommissioning (D&D) The SRS ACP integrates facility D&D with soil and groundwater remediation. Whitaker (2008) reported that SRS had 985 total excess facilities and that 246 had been decommissioned at the time of the committee’s visit. He described the T-Area completion as an example of a completed, integrated project. T-Area, formerly referred to as TNX, was an engineering semiworks area that used non-enriched uranium, but no other radioactive materials. Eight waste units were remediated, D&D was completed for 28 facilities, and a 10-acre geosynthetic cover installed. Groundwater remediation is under way (Whitaker 2008). The reactor in P-Area is the first SRS reactor that will undergo D&D. Initial D&D work at P-Reactor has included removing the heavy-water moderator, friable asbestos, and historical artifacts; mold abatement; installing temporary power and lighting; and restarting building exhaust fans on temporary power (Allison 2008). Overall the P-Area project encompasses 100 acres and includes five waste units. Early characterization of tritium, solvents, and cesium contamination is complete. A Record of Decision for P-Area is scheduled for FY 2010 (Whitaker 2008). Program Area: Spent Nuclear Fuels (SNF) and Nuclear Materials Complexwide, DOE identified about 21 metric tons (MT) of surplus weapons-usable highly enriched uranium (HEU) and about 2 MT of surplus non-pit plutonium. This includes HEU in 19,500 SNF assemblies and 7.5 MT of HEU materials. In August 2006 the Deputy Secretary of Energy approved the continued operation of the H-Canyon at SRS as the preferred alternative for dispositioning these materials. H-Canyon is expected to remain in operation for this purpose until 2019 (Allison 2008). The SRS nuclear materials program includes surplus enriched uranium, SNF, and surplus non-pit plutonium (McGuire 2008).
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges Surplus Enriched Uranium SRS is currently storing aluminum-, stainless steel-, and zirconium-clad fuels in L-Area. The site continues to receive fuel from both foreign and domestic research reactors. As part of the HEU disposition project, SRS will receive, in addition to its current inventory, aluminum-clad fuel from Idaho; in turn SRS will ship its stainless steel- and zirconium-clad fuels to Idaho for disposal. The aluminum-clad fuels will be dissolved and processed in H-Canyon to recover the HEU, which will then will be mixed with low-enriched uranium (“downblended”) to provide uranium that is suitable for power generation but not usable for weapons (McGuire 2008). As noted earlier in this appendix, H-Canyon was designed and used for HEU processing to support the site’s former weapons material production mission (NRC 1998). Surplus Non-Pit Plutonium SRS is storing significant quantities of plutonium materials that were produced at SRS and returned from the former Rocky Flats Site. DOE has also begun to consolidate surplus non-pit plutonium from Hanford, Los Alamos National Laboratory, and Livermore National Laboratory at SRS. Most of these materials have been stabilized and packaged in accordance with DOE Standard 3013 (NRC 2003). SRS will either disposition this material or repackage it for long-term storage (McGuire 2008). McGuire (2008) noted that dispositioning the material could involve H-Canyon, a new mixed-oxide (uranium and plutonium) fuel fabrication facility (MFFF), which is being built at SRS, and a proposed plutonium facility to prepare this material for processing at the MFFF. Technology Needs McGuire (2008) noted that there may be alternatives to the current plutonium disposition strategy, and that DOE seeks advice on technology needs to assist in evaluating potential alternatives. He also described technology needs associated with surveillance and storage of the DOE Standard 3013 containers. These include: Design and demonstration of furnace technology to oxidize and stabilize plutonium metal, Dustless material transfer technology (which would be an integral part of the furnace technology), Design of a modular sand filter that allows adding filtering capacity as needed (rather than building and operating a full-size sand filter from the
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges disposition project’s outset—sand filters are a final step to ensure air that passes through a facility is safe to release to the environment), and A device to make welds on the outside of a 3013 can that comply with the standard. CAPABILITIES AND INFRASTRUCTURE AT SRNL The SRL was established in 1951 to provide R&D support for nuclear materials production at the SRP, now the SRS. In May 2004, the Secretary of Energy designated the laboratory as the Savannah River National Laboratory (SRNL). In early 2006, SRNL was further designated as EM’s corporate laboratory. SRNL’s total funding for FY 2007 was $154 million. DOE provided $139 million of this total, including $67 million from EM, $50 million from the National Nuclear Security Administration, $7 million from the Office of Science, and $15 million from other DOE offices (Marra 2008). As the EM corporate laboratory, SRNL supports all EM closure activities at SRS and, in addition, assists and helps coordinate EM technology development and application at other sites. To explain the concept of a corporate laboratory, Gilbertson (2008) stated that EM is responsible for SRNL from an institutional perspective, and the laboratory serves as a resource for EM. Marra (2008) referred to SRNL as an “embedded” national laboratory. Marra (2008) noted that EM activities (e.g., waste management, environmental restoration) have been a major SRS mission for 40 years. Marra (2008) listed SRNL’s core capabilities as: Process development, pilot testing, design, and construction; Regulatory document and start-up support; and Production support and process optimization. To provide these capabilities in EM areas, SRNL staff have expertise in: Radioactive chemical processing; Glass waste forms and vitrification process development; Application of environmental remediation technologies; Development and qualification of nuclear material packaging and nuclear fuel storage and handling; and Ultra-low-level, high-sensitivity nuclear measurements (SRNL 2007). SRNL has a variety of both unique and traditional laboratory facilities for research and prototype development, including:
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges Shielded cells—special containment facilities that provide the shielding and confinement necessary for examination, analysis, and testing of highly radioactive materials; Glove-box facilities—sealed, protectively lined compartments with attached gloves that allow workers to handle hazardous materials safely; Radiochemistry and analytical laboratories with contained instruments; Remote systems laboratory for the design, development, fabrication, and testing of equipment for use in radioactive, hazardous, or inaccessible environments; Engineering development laboratory for performing tests and demonstrations of equipment and existing or proposed designs; High-pressure test facility with steel-walled cells for high-pressure hydrogen exposure and testing, fatigue testing, and fracture toughness testing of metal specimens; Atmospheric Technologies Center with extensive capabilities for worldwide meteorological forecasts and real-time atmospheric transport modeling and assessment; Ultra low-level underground counting facility located 50 feet below ground that allows high-sensitivity measurements of ultra-low amounts of radioactivity; Advanced fracture mechanics laboratory with extensive capability for fracture testing in harsh environments and modeling to support system or component life extension; Primary standards laboratory providing calibration services compliant to the requirements of the American National Standard; Rapid fabrication facility, which produces low-cost prototypes, parts, and complete working models; Gamma irradiation facility for testing materials’ abilities to withstand radiation exposure; Materials processing and fabrication laboratory to conduct materials processing, including powder metallurgy and solidification processing of nuclear materials; and Digital radiography facility that provides a highly sensitive alternative to traditional film x-rays for looking at the contents inside a container, verifying the quality of welds, and detecting deformations (SRNL 2007). Shedrow (2008) noted that SRNL has developed a variety of technologies that have been applied to environmental remediation at SRS and other locations. These include: Optimized groundwater remediation systems, Field screening and technology deployments,
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges Special sensors, Barrier monitoring and containment, Waste disposal forms, Wetlands remediation, Environmental biotechnology, Fate and transport modeling, and Environmental dosimetry. Shedrow (2008) added that SRNL is the national lead laboratory for the monitored natural attenuation/enhanced attenuation project for chlorinated solvents. She also stated that SRNL has developed and applied innovative solutions for dense nonaqueous phase liquid characterization and remediation. REFERENCES Allison, J. 2008. Savannah River cleanup. Presented to the Committee on Development and Implementation of a Cleanup Technology Roadmap, Savannah River Site, Augusta, GA, January 8. Davis, N. 2008. LWO technology development. Presented to the Committee on Development and Implementation of a Cleanup Technology Roadmap, Savannah River Site, Augusta, GA, January 10. DOE (Department of Energy). 2008. Engineering and Technology Roadmap: Reducing the Uncertainty in the EM Program. Washington, DC: DOE. Gilbertson, M. 2008. Comments to the committee. Presented to the Committee on Development and Implementation of a Cleanup Technology Roadmap, Savannah River Site, Augusta, GA, January 10. Marra, J. 2008. An overview of the Savannah River National Laboratory. Presented to the Committee on Development and Implementation of a Cleanup Technology Roadmap, Savannah River Site, Augusta, GA, January 9. McGuire, P.W. 2008. Nuclear Material Stabilization Project overview and technology needs. Presented to the Committee on Development and Implementation of a Cleanup Technology Roadmap, Savannah River Site, Augusta, GA, January 8. NRC (National Research Council). 1998. Research Reactor Aluminum Spent Fuel: Treatment Options for Disposal. Washington, DC: The National Academies Press. NRC. 2000. Alternatives for High-Level Waste Salt-Processing at the Savannah River Site. Washington, DC: The National Academies Press. NRC. 2003. Improving the Scientific Basis for Managing DOE’s Excess Nuclear Materials and Spent Nuclear Fuel. Washington, DC: The National Academies Press. NRC. 2006. Tank Waste Retrieval, Processing, and On-Site Disposal at Three Department of Energy Sites: Final Report. Washington, DC: The National Academies Press. Shedrow, D.M. 2008. Environmental science and biotechnology overview. Presented to the Committee on Development and Implementation of a Cleanup Technology Roadmap, Savannah River Site, Augusta, GA, January 9. Spears, T.J. 2008. Savannah River Site Waste Disposition Project. Presented to the Committee on Development and Implementation of a Cleanup Technology Roadmap, Savannah River Site, Augusta, GA, January 8.
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges SRNL (Savannah River National Laboratory). 2007. Savannah River Laboratory Overview. Factsheet available from SRNL public affairs, Savannah River Site, Aiken, SC, May. Whitaker, W. 2008. Area Completion Project: Soil and groundwater remediation and facilities deactivation and decommissioning. Presented to the Committee on Development and Implementation of a Cleanup Technology Roadmap, Savannah River Site, Augusta, GA, January 8.