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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges 3 Expertise and Infrastructure This chapter addresses the third and fourth items in the committee’s statement of task, which asked the committee to identify: Core capabilities at the national laboratories that will be needed to address the Office of Environmental Management’s (EM’s) long-term, high-risk cleanup challenges, especially at the four laboratories located at the large Department of Energy (DOE) sites (Idaho National Laboratory [INL], Oak Ridge National Laboratory [ORNL], Pacific Northwest National Laboratory [PNNL], and Savannah River National Laboratory [SRNL]). The infrastructure at these national laboratories and at EM sites that should be maintained to support research, development, and bench-and pilot-scale demonstrations of technologies for the EM cleanup program, especially in radiochemistry. To address its task statement the committee interpreted the term “core capabilities” in the first task item above to refer to the scientific and technical expertise of personnel at the national laboratories. The term “infrastructure” was taken to refer to physical facilities (i.e., buildings and equipment). Because scientific and technical personnel require appropriate facilities with which to conduct their work, and physical facilities are useless without appropriately skilled personnel to operate them, the committee chose to address both task items together in this chapter. The term “capabilities” will be used throughout this chapter to refer to both physical facilities and the personnel who have the needs and skills to
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges use them. When distinctions need to be made, the more specific terms—expertise or infrastructure—will be used. After reviewing the science and technology gaps identified in Chapter 2, the committee identified four kinds of capabilities (expertise and infrastructure) that will need to be maintained. Selecting these capabilities was a two-step process. First, a list of potential capabilities that would need to be maintained was developed from information gathered during the site visits and from committee members’ expertise and experience. Then this list was culled based on consideration of which capabilities were essentially unique to the DOE cleanup situation. The result was the following four: Handling radioactive materials, Conducting engineering and pilot-scale tests, Determining contaminant behavior in the environment, and Utilizing state-of-the-art science to develop advanced technologies. The remainder of this chapter describes each of these capabilities and their relevance to sustaining EM’s future research and development (R&D) programs. HANDLING RADIOACTIVE MATERIALS The capability to work with radioactive materials is fundamental to EM’s engineering and technology development. At least some stages of the R&D to address each of the gaps identified in Chapter 2, with the possible exceptions of DD-1 and DD-2, will require the use of radioactive tracers or actual radioactive waste. All of the national laboratories visited by the committee have the facilities and personnel for handling radioactive materials. All of their nuclear-related initiatives (e.g., energy, defense, medicine) require this capability. This capability, especially for highly radioactive materials and alpha-particle emitters, is essentially unique to the national laboratories—comparable capability does not exist in universities or the private sector in this country. If the capability for handling radioactive materials in the national laboratories were lost, it would effectively halt EM-relevant R&D. Radiochemical laboratories are typically restricted areas accessible only by qualified personnel. They have specially designed ventilation and waste handling systems. Laboratory air is constantly monitored for contamination. Personnel usually must wear protective clothing and be monitored when exiting to ensure they are free from contamination. Containment facilities in radiochemical laboratories typically include radiochemical hoods and glove boxes. Radiochemical hoods allow work-
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges ers to handle low levels of radioactive materials in essentially the same way that hazardous, nonradioactive chemicals are handled in commercial and university laboratories. Glove boxes are literally large metal boxes equipped with gloves and transparent windows. Workers insert their hands into the gloves to handle larger amounts of radioactive materials than can be handled safely in hoods (Figure 3.1). Radiochemical hoods and glove boxes are suitable for radioisotopes that do not emit penetrating radiation (e.g., Pu-239 and other primarily alpha-particle-emitting isotopes), but their limited shielding generally allows use of only tracer-level amounts of gamma-emitting isotopes. Shielded cells, often referred to as “hot cells,” allow safe handling of full levels of radionuclides that produce penetrating gamma or neutron radiation (e.g., actual tank waste, spent fuels). They feature thick concrete shielding walls, thick (typically 3 feet) multilayer leaded-glass windows, and remote manipulators (Figure 3.2). Other controls such as personnel access, monitoring, and ventilation are equal to or more rigorous than for radiochemical laboratories. The national laboratories visited by the committee have shielded cells, although there are differences in their design and potential uses. For example, the Irradiated Fuel Examination Lab (Building 3525) at ORNL can accept full-length light-water reactor fuels. It was used by EM for materials packaging from 1999 to 2003. FIGURE 3.1 Glove box in a radiochemical laboratory. Glove boxes provide safe containment for laboratory work with radioactive or chemically hazardous materials. Substantial amounts of radionuclides that do not emit penetrating radiation (e.g., Pu-239) can be handled in a glove box. Glove boxes offer good visibility and access, but the thick, often lead-lined gloves limit the manual dexterity of scientists and technicians. SOURCE: Department of Energy.
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges FIGURE 3.2 Hot cell work with remote manipulators. Heavily shielded facilities, often called hot cells or caves, allow work with full levels of radioactive materials such as high-level waste and irradiated nuclear materials. Concrete walls and leaded-glass windows are typically 3 or more feet thick to provide shielding. The windows are often filled with oil to improve visibility, which is remarkably good, and to stop some types of radiation. Skilled operators can replicate most types of hands-on laboratory work with the manipulators, but this requires much training, experience, patience, and ingenuity. SOURCE: Department of Energy. Support services include radiochemical laboratories to provide sample analyses, standardized and quality-controlled radioactive sources, and equipment calibration. Monitoring, dosimetry, and other worker protection services—often referred to as radiation protection or health physics—are also required. Service organizations may simply support R&D work, but more often they also perform their own R&D, for example, to improve radiochemical analyses, radiation detection, and understanding of radiation health effects. All national laboratories visited provide such support services. SRNL highlighted special capabilities for high-sensitivity measurements of ultra-low levels of radioactivity.
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges Maintaining Capabilities for EM As applied to the gaps identified in Chapter 2, R&D in radiochemical laboratories and shielded cells may pertain to: Tank waste—its basic chemistry and rheological properties and how it can be processed; Radioactive contaminants in groundwater—their basic chemistry and their interactions with geologic media and microbes; and Radioactive contaminants remaining in facilities to be decontaminated—their basic chemistry and interactions with construction materials such as steel and concrete. Glove boxes and shielded cells will typically be used when basic R&D or process development requires use of actual waste. Transuranic-contaminated waste might be handled in glove boxes, whereas high-level tank waste must be handled in shielded cells. Some D&D work may require glove boxes or shielded cells. Radioanalytical laboratories house the same types of instruments used in well-equipped chemistry laboratories, such as inductively coupled plasma optical emission and mass spectroscopy, digital autoradiography, bulk and micro x-ray diffraction, scanning and transmission electron microscopy with wavelength dispersive spectroscopy, electron microprobe, liquid and ion chromatography, capillary electrophoresis, and multipoint surface area analysis. These instruments may themselves be contained in radiochemical hoods or glove boxes. Using these instruments to analyze radioactive samples usually requires that they be dedicated to this use (i.e., the instrument is considered to be contaminated with radioactive materials so it can be operated only in a radiologically controlled area). Obtaining and maintaining dedicated instruments is a substantial financial burden. Environmental samples, such as those from groundwater wells, may require analysis in low-background laboratories where low levels of radionuclides can be quantified. Scientists and engineers of all disciplines who are engaged in EM work are likely to do at least some of their work with radioactive materials. They become qualified to work with radioactive materials through onsite training and experience, although radiochemists, for example, may have done somewhat similar work at universities. Trained and experienced technicians and operators are essential for conducting work with radioactive materials. They understand and enforce strict procedures for handling these materials. Their skills are often unique, and like other crafts, they are learned from more experienced personnel. A year or more of experience may be necessary to become competent in
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges operating an apparatus while wearing thick gloves in a glove box or in handling glassware with remote manipulators. Much of the infrastructure to handle radioactive material at DOE sites (e.g., the Radiochemical Processing Laboratory at PNNL, the Radiochemical Engineering Development Center at ORNL) is decades old. These facilities degrade over time without adequate maintenance and programs to utilize them. In some cases some key facilities (e.g., the Radiochemical Processing Laboratory) have been threatened with shutdown. In recent years support for such facilities has improved. However, despite EM’s need for them, agencies other than EM, such as DOE’s Office of Science (SC) and National Nuclear Security Administration and the Department of Homeland Security, are providing most of their support (PNNL 2007). CONDUCTING ENGINEERING AND PILOT-SCALE TESTS EM’s engineering and technology development includes testing to provide basic parameters (e.g., heat and mass transfer, mixing, corrosion) to design new processes and equipment and to demonstrate them at the pilot scale or larger.1 Capabilities for engineering and pilot-scale testing are needed to support R&D to address all of the gaps identified in Chapter 2, especially WP-1 through WP-5, GS-2, GS-4, DD-1, and DD-3. Engineering test facilities, sometimes referred to as semiworks, are used throughout the private sector, and all the national laboratories the committee visited have them. EM contractors and universities often use their own facilities for EM projects. As one example, Clemson University tested prototype glass melters for the Savannah River Sight (SRS) Defense Waste Processing Facility (DWPF). Engineering facilities generally do not allow the use of radioactive materials, although two important exceptions are described in this section. Tank mock-up facilities are onsite capabilities that EM will need for many years to support waste tank cleaning. Retrieval of tank waste is a major challenge at Hanford and SRS. Both sites have full-diameter tank mock-ups used by contractors and national laboratory personnel to test retrieval technologies (e.g., pumps, high-pressure water lances, robotic devices). The mock-ups allow the simulation of limited equipment access to the tank interior, as is the case for the actual tanks, and for SRS, the ability to reproduce the complicated internal cooling coil geometries that make tank cleaning especially challenging for that site (Chapter 2, Figure 2.3). INL used a mocked-up tank floor for testing grout flow and emplacement methods to encapsulate sludge heels. 1 Pilot scale typically refers to testing with kilogram quantities of materials or more, up to perhaps half of the production of the full-scale process.
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges High-bay buildings, large buildings with sections that provide several stories of overhead space, are necessary for onsite equipment fabrication and testing. Much of the equipment used in EM cleanup work is physically large, especially waste processing equipment. PNNL is testing pulse jet mixers, special devices for mixing liquids and sludges in Hanford’s Waste Treatment Plant, in its high-bay building 336 (Figure 3.3). SRNL highlighted its engineering development laboratory during the committee’s site visit. SRS also operates a mock-up facility where every component to be installed in the DWPF is pretested. Engineering laboratories are necessary for testing materials and equipment components to ensure process safety, operability, and reliability. Examples of materials and component tests include fatigue or fracture under high-temperature, -pressure, -stress, or corrosive conditions. Small-scale versions of new equipment or processes are often set up and tested in engineering laboratories. Tests for quality control and quality assurance are also included. Such capability is common in the private sector. Onsite capability FIGURE 3.3 High-bay building for engineering tests. High-bay buildings provide two or more stories of vertical space for testing or demonstration of large equipment, which is typically required for waste processing. In this photo, pulse jet mixers are being tested for use in Hanford’s Waste Treatment Plant. Thorough testing of such newly designed equipment is necessary because it must operate reliably as designed, and with little or no opportunity for maintenance, once placed into radioactive service. SOURCE: Department of Energy.
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges for EM work is needed as a practical matter, and all national laboratories visited have engineering laboratories. Radioactive semiworks for pilot-scale testing of large-scale processes are highly desirable but usually infeasible due to construction time and cost. Notable exceptions are the actinide removal process (ARP) and the modular caustic-side solvent extraction unit (MCU) that are being operated at SRS until its Salt Waste Processing Facility (SWPF) is completed in about 2013. Processing the salt portion of SRS tank waste has been delayed for a variety of reasons. The ARP and MCU were built primarily to process some of the salt because the site’s waste tanks are almost full (Appendix G; NRC 2006b). These facilities can provide data and operating experience to help ensure that the SWPF meets its performance objectives—a major risk reduction opportunity for EM noted in gap WP-2. Maintaining Capabilities for EM R&D Engineers of essentially all disciplines, along with technicians and operators, typically use and maintain engineering-test and pilot-scale facilities for their experimental work and process demonstrations. Mock-ups may test equipment or processes at pilot scale or full scale. Since high-bay buildings already exist on sites and at national laboratories, keeping them, rather than demolishing and rebuilding as programs change, is probably cost-effective. Assembling equipment for engineering tests and operating it successfully require a good deal of experience and technical savvy among technicians and operators. The capabilities to accurately machine special alloys, weld them, and operate high-pressure devices are examples. Accumulating this knowledge may take years of hands-on experience and mentoring from more experienced personnel. Further, if the technicians and operators have experience with the site problems that their project is addressing, they often contribute innovative, practical ideas toward their solutions. DETERMINING CONTAMINANT BEHAVIOR IN THE ENVIRONMENT Each of the DOE sites has a unique history in the disposal or release of contamination and unique geohydrological characteristics, which largely control the movement of these contaminants. Contamination has reached the groundwater at all four sites visited. Groundwater and soil remediation are in progress and will continue for the duration of the EM cleanup. Capabilities for determining contaminant behavior in the environment are needed to support R&D to address the groundwater and soil (GS) gaps identified in Chapter 2.
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges These capabilities are widely available in the private sector and universities. EM contractors and national laboratory and university researchers are often partners in projects aimed at understanding contaminant behavior at the DOE sites and in conducting remediation projects. Sampling, monitoring, and implementing remedial actions must, of course, be done on the site itself. Field test facilities that provide actual data on contaminant behavior in the environment, often referred to as “contaminant fate and transport,” are an essential and unique capability for the sites and national laboratories. The needs are specific to each site due to the individual site histories and discharges of contaminants, types of contaminants, site characteristics, and possibilities of future releases from storage or disposal facilities (e.g., waste tanks, capped trenches). Field test facilities can include physical structures in designated areas of the site, or they may simply be monitoring wells or stream sampling points located on- and off-site. All national laboratories visited have field test facilities and are actively conducting field tests to determine contaminant fate and transport at their associated sites. ORNL highlighted its Field Research Center during the committee’s site visit (Figure 3.4). SRNL described site monitoring and FIGURE 3.4 Oak Ridge Field Research Center. Site-specific data are required for characterizing geohydrology and measuring contaminant transport and effects of remedial actions. A specific location on a site, including dedicated boreholes, water wells, and equipment, may be developed for this purpose. Monitoring wells located around the site and surface water sampling also provide field data. Geohydrological parameters usually change slowly, so maintaining these facilities for years or decades is necessary. SOURCE: Department of Energy.
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges field tests of various remediation technologies, including bioremediation (Appendix G). INL described enhanced bioremediation tests, which involve injecting microbes and nutrients into a carbon tetrachloride plume source (“hot spot”) and monitoring the groundwater (Appendix E). PNNL is operating the Hanford 300 Area Integrated Field Research Center, which is funded by SC and is intended to provide a fundamental understanding of coupled geochemical, hydrologic, and microbiologic processes in the contaminated aquifer that will enable development of an effective, long-term remedial strategy for uranium at the site.2 PNNL is also testing an engineered barrier (“Hanford cap”) to provide long-term control of contaminant migration from buried waste (Appendix D). Information archives that maintain the long-term accumulated knowledge relevant to understanding contaminant fate and transport at the cleanup sites are unique capabilities of the national laboratories. Each site has an essentially permanent relationship with a colocated national laboratory, dating back to the establishment of the site. Data on waste disposals, contaminant releases, and environmental monitoring have accumulated over the years and will continue to do so. Along with this is the growing understanding of the site characteristics that govern fate and transport. Such information comes from site contractors and university research as well as from the national laboratories. However, only the national laboratories have the long-term capabilities to maintain and synthesize all of this information into sufficiently detailed conceptual understanding and site models to guide EM’s remediation work and DOE’s long-term stewardship planning. Geoscience and geotechnical laboratories that support site cleanup are often equipped for handling low levels of radionuclides as well as for engineering tests, for example, tests to determine sorption of contaminants onto soils and rocks and their permeabilities. Geotechnical laboratories typically are part of the national laboratory infrastructure for handling radioactive materials and conducting engineering tests described in the previous two sections. INL highlighted its geocentrifuge, which allows accelerated tests of flow through geologic media. Maintaining Capabilities for EM Site and national laboratory facilities for environmental studies typically are shared freely among national laboratory, university, and other researchers engaged in this work. Environmental scientists, geoscientists, chemists, and engineers are typically involved in contaminant fate and transport studies. 2 See http://ifchanford.pnl.gov/.
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges Field test facilities at the sites are unique in the sense that they cannot be replicated elsewhere to measure the same phenomena. Field tests, for example, of the engineered barriers described in GS-3, must usually be run for years before they provide useful information. The Nuclear Regulatory Commission suggested exhuming an SRS saltstone lysimeter, which operated over 20 years ago, to help resolve some questions about saltstone performance; see gap GS-4. Professional researchers and technicians require years to become fully acquainted with the geohydrological characteristics of a site and how they have affected the fate and transport of contaminants released to the site. Information archives would include not just physical databases, but also experienced personnel to interpret and build on accumulated knowledge. For a 30-year program with many experienced personnel now retiring, accumulated site knowledge will have to be passed on through perhaps two generations of new scientists. UTILIZING STATE-OF-THE-ART SCIENCE TO DEVELOP ADVANCED TECHNOLOGIES The national laboratories maintain extensive and diverse world-class scientific capabilities that are supported primarily by the DOE SC. Presentations by the national laboratories during the committee’s site visits and by SC during the committee’s April 2008 meeting (Appendix B) provided an overview of these capabilities. Clearly SC capabilities are necessary for EM’s engineering and technology development. In addition, it is clear that the state of the art will advance over the next 30 years of the EM cleanup in ways that cannot be imagined today. While EM would not be expected to be a primary user or financial supporter of advanced scientific facilities, EM’s and SC’s continued close cooperation and coordination can ensure that EM is able to utilize state-of-the-art science (Chapter 4). As a DOE office, SC shares with EM the responsibility for protecting citizens and the environment from deleterious effects of DOE’s legacy of nuclear materials production. A particularly important SC-funded resource for EM-related studies has been the capability for x-ray and infrared spectroscopies, microspectroscopies, and tomography available at the nation’s synchrotron light sources (including the Advanced Photon Source, the National Synchrotron Light Source, the Advanced Light Source, and other sources located at DOE laboratories).3 Through studies led by researchers from universities 3 EM researchers have made significant use of DOE SC synchrotron facilities and the Environmental Molecular Science Laboratory (EMSL) to determine the spatial locations, mineral associations, and chemical nature of DOE contaminants in subsurface sediments from vadose zone and groundwater plumes. The resulting scientific information has been im
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges as well as from federal laboratories, these capabilities and infrastructure have identified the chemical environment of contaminants on soil minerals using spatially resolved x-ray fluorescence (XRF) and x-ray absorption (XAS) spectroscopies; identified the speciation of Pu, U, and other heavy metals in soils and sediments, in association with plants and microbes, and on engineered surfaces requiring decontamination; and aided in the evaluation of chemical remediation strategies through providing data to better model the mobility and fate of contaminants. For example, Los Alamos researchers were able to use x-ray absorption near edge spectroscopy to identify the speciation of plutonium in contaminated soil and concrete samples from the Rocky Flats site, data that were very valuable in informing cleanup efforts (LANL 2002). Another recent study cited the use of XAS at the Advanced Photon Source at Argonne National Laboratory to identify the chemical and mineral state (critical to understanding mobility) of uranium beneath high-level waste tanks at the Hanford site (Catalano et al. 2006). Microprobe XRF measurements have been conducted at the National Synchrotron Light Source at Brookhaven National Laboratory on treated sediment samples from the Savannah River and the Hanford sites to study the effect of phosphate and microbes on removal of uranium to develop improved technologies for remediation (Knox et al. 2008). Development of waste separations technology has also benefited from synchrotron analysis: XAS studies at the Stanford Synchrotron Radiation Laboratory have been used to characterize the composition of Np- and Pu-containing waste-sludge alkaline-wash solutions, identifying highly soluble species and leading to design of enhanced chemical separations processes (Neu et al. 1999). Overall, by allowing university and national laboratory researchers to both thoroughly investigate samples taken from DOE sites and create controlled experiments with model matrices, surfaces, and sets of conditions analogous to in situ environments, synchrotron and complementary surface and molecular spectroscopies are extremely valuable resources for the DOE’s EM mission. Advanced computing is an overarching capability to support all facets of EM engineering and technology development. Such capability includes modeling waste inventories and interactions, treatment processes and process design, site geohydrology, and contaminant fate and transport. Advanced computing is a basic capability required for conducting state-of-the-art science, and all national laboratories visited have powerful computers for basic and applied research. Those at ORNL and PNNL were portant in the definition of the geochemical state of sorbed contaminants and is the first step in devising a remedial strategy. Use of these state-of-the-art facilities for EM’s radioactively contaminated samples, however, required the facilities to implement expensive safety and health procedures.
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Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges highlighted during the committee’s site visits. Computing capabilities are essential to address all of the gaps described in Chapter 2, especially WP-2, WP-3, GS-1, GS-2, and DD-3. Surface analyses are another example of state-of-the-art capabilities that can help EM address its engineering and technology gaps. Surface analyses are important for understanding the chemical and physical interactions of contaminants with the primary materials of interest for D&D projects (concrete, stainless steel, paints, strippable coatings), waste form development (glasses, ceramics), and environmental studies (soils, biofilms) to gain a better understanding of how contaminants bind to and penetrate these materials. Some concrete and steel surfaces in DOE structures have been in contact with radioactive materials for 60 years. Surface analytical capabilities include those at the EMSL at PNNL such as time-of-flight secondary ion mass spectroscopy, infrared spectroscopies, and high-sensitivity surface probe microspectroscopies. SRNL reported surface analytical capabilities, including glove-box-contained electron microscopies and vibrational and electron spectroscopies. ORNL highlighted its spallation neutron source and high flux isotope reactor for materials studies. In many cases, custom-designed systems with high sensitivities and intensities not normally available in commercial instruments have been developed through significant expenditures of effort on the part of DOE-supported researchers. Surface analysis and spectroscopic capabilities are particularly important to waste form development, WP-5; understanding long-term behavior of cementitious materials, GS-4; and removing contamination from surfaces, DD-3. CONCLUSIONS The capabilities (personnel expertise and physical infrastructure) described in this chapter are those that the committee judged to be necessary to support R&D to address the science and technology gaps identified in Chapter 2. The committee intentionally highlighted those capabilities that are essentially unique to the DOE sites and national laboratories. Most are important resources for other DOE programs as well as those of EM, and many are in fact being utilized by other DOE offices such as the Office of Nuclear Energy. Partnering with these other programs to leverage EM’s engineering and technology initiatives is described in Chapter 4.
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