Appendix F
Overview of U.S. Geologic Repository Programs

The U.S. national commitment to achieve permanent isolation is the basis for the Nuclear Waste Policy Act (NWPA) of 1982 and its 1987 amendment, the Energy Policy Act of 1992, and regulations such as Public Health and Environmental Protection Standards for Yucca Mountain, Nevada (Title 40 of the Code of Federal Regulations Part 197) and Disposal of High-Level Radioactive Wastes in a Proposed Geologic Repository at Yucca Mountain (10 CFR 63). The NWPA has identified the Department of Energy (DOE) as the implementer of the repository program and the Nuclear Regulatory Commission (USNRC) as the regulator.1 The Congress also instituted the Nuclear Waste Technical Review Board (NWTRB) to “evaluate the technical and scientific validity of activities undertaken by the Secretary [DOE].” in the Yucca Mountain project. The NWTRB reports its findings, conclusions, and recommendations not fewer than two times per year to the Congress and to DOE and the Advisory Committee on Nuclear Waste, advises the USNRC on a wide range of waste-related matters, including Yucca Mountain.

DOE is also the implementer of another geologic repository for radioactive waste: the Waste Isolation Pilot Plant (WIPP). This geologic repository, located in southeastern New Mexico, is currently accepting transuranic2 waste and is regulated by the U.S. Environmental Protection Agency and the State of New Mexico (see Sidebar F.1).

F.1 The Yucca Mountain project

Congress established the regulatory framework for siting, characterizing, constructing, operating, and closing a permanent geologic repository. DOE planned its baseline roadmap and milestones for the high-level waste repository on the basis of the U.S. regulatory framework. This schedule is referred to as the “reference schedule” and is briefly described below. The schedule is further detailed in the Yucca Mountain’s Total System Description report (DOE-OCRWM, 2001b).

1  

The USNRC enforces the environmental standards for disposal of high-level waste in a geologic repository promulgated by the U.S. Environmental Protection Agency in 40 CFR 197. Based on these standards, the USNRC published its disposal regulations in 10 CFR 63.

2  

Transuranic waste consists primarily of clothing, tools, equipment, and debris contaminated with alpha-emitting nuclides with a half-life greater than 20 years and heavier than uranium. Transuranic waste was created from the manufacture of nuclear weapons and is still being generated during the cleanup of weapon production sites.



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Appendix F Overview of U.S. Geologic Repository Programs The U.S. national commitment to achieve permanent isolation is the basis for the Nuclear Waste Policy Act (NWPA) of 1982 and its 1987 amendment, the Energy Policy Act of 1992, and regulations such as Public Health and Environmental Protection Standards for Yucca Mountain, Nevada (Title 40 of the Code of Federal Regulations Part 197) and Disposal of High-Level Radioactive Wastes in a Proposed Geologic Repository at Yucca Mountain (10 CFR 63). The NWPA has identified the Department of Energy (DOE) as the implementer of the repository program and the Nuclear Regulatory Commission (USNRC) as the regulator.1 The Congress also instituted the Nuclear Waste Technical Review Board (NWTRB) to “evaluate the technical and scientific validity of activities undertaken by the Secretary [DOE].” in the Yucca Mountain project. The NWTRB reports its findings, conclusions, and recommendations not fewer than two times per year to the Congress and to DOE and the Advisory Committee on Nuclear Waste, advises the USNRC on a wide range of waste-related matters, including Yucca Mountain. DOE is also the implementer of another geologic repository for radioactive waste: the Waste Isolation Pilot Plant (WIPP). This geologic repository, located in southeastern New Mexico, is currently accepting transuranic2 waste and is regulated by the U.S. Environmental Protection Agency and the State of New Mexico (see Sidebar F.1). F.1 The Yucca Mountain project Congress established the regulatory framework for siting, characterizing, constructing, operating, and closing a permanent geologic repository. DOE planned its baseline roadmap and milestones for the high-level waste repository on the basis of the U.S. regulatory framework. This schedule is referred to as the “reference schedule” and is briefly described below. The schedule is further detailed in the Yucca Mountain’s Total System Description report (DOE-OCRWM, 2001b). 1   The USNRC enforces the environmental standards for disposal of high-level waste in a geologic repository promulgated by the U.S. Environmental Protection Agency in 40 CFR 197. Based on these standards, the USNRC published its disposal regulations in 10 CFR 63. 2   Transuranic waste consists primarily of clothing, tools, equipment, and debris contaminated with alpha-emitting nuclides with a half-life greater than 20 years and heavier than uranium. Transuranic waste was created from the manufacture of nuclear weapons and is still being generated during the cleanup of weapon production sites.

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Sidebar F.1 The Waste Isolation Pilot Plant Located in southeastern New Mexico, the Waste Isolation Pilot Plant (WIPP) is a geologic repository for disposition of U.S. defense-generated transuranic waste. The waste emplacement area is excavated in a bedded salt formation 660 meters below the surface (NRC, 2001 a). WIPP is the world’s first licensed deep subsurface geologic repository for radioactive waste, and it is the result of almost four decades of scientific and technical work (NRC, 1996). The site was selected in 1975, and in 1992, through the Land Withdrawal Act, DOE became the owner of the land on which the WIPP facility was to be constructed. In 1996, DOE submitted a certification application to the U.S. EPA to open the repository. Certification was granted in 1998 (DOE-CAO, 1996). The State of New Mexico regulates the hazardous waste component of transuranic waste and monitors operations at the facility. New Mexico granted a hazardous-waste-handling permit to WIPP in 1999. WIPP has been in operation since March 1999. The WIPP Program Has Attributes of Both Adaptive Staging and Linear Staging The WIPP program has some elements of Linear Staging. The program’s schedule was rigid and did not take into account delays caused by public resistance or unexpected technical findings. The program adapted to different circumstances but often only as a last resort to external critiques. The program was not designed to take maximum advantage of systematic learning but responded after the fact to unanticipated results. For example, there was no in situ pilot stage with radioactive waste after the site was certified by the U.S. Environmental Protection Agency and permitted by the State of New Mexico. Learning occurred but only when triggered by external factors or by operational experience. Once waste was emplaced underground, only limited monitoring and tests were performed. The WIPP program also has some attributes of Adaptive Staging. Reversibility. An example of reversibility in the WIPP program was that DOE abandoned a potential site for the facility in New Mexico because of information gathered during site characterization in 1975. Transparency. The WIPP project has been subjected to independent external scientific and technical reviews throughout its history. Beginning in 1979, Congress provided funding to New Mexico’s Environmental Evaluation Group to oversee WIPP. The director of this group is appointed by the State of New Mexico. Since 1978, the National Academy of Sciences has continued to provide scientific and technical advice. These technical oversight groups have increased WIPP’s credibility and triggered many program adaptations. The compliance certification process was carried out transparently, according to rules agreed on, in advance, by all participants. Responsiveness. The program was responsive to concerns from parties external to the program. For instance, political resistance changed the scope of the facility: at one point early in WIPP’s history, DOE

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planned to use it as a research-and-development facility for demonstrating the safe disposal of transuranic waste and commercial spent nuclear fuel. In 1980, the Congress restricted WIPP’s scope to disposing of transuranic waste. Later this restriction was reinforced when the WIPP Land Withdrawal Act of 1992 banned the shipment of high-level waste or spent nuclear fuel to WIPP. The scientific program was responsive to the technical oversight groups and peer panels, frequently modifying and implementing new studies based on their suggestions and recommendations. The engineered barrier system was modified in response to technical concerns identified during the performance assessment studies (e.g., backfilling materials were introduced). In addition, a new type of backfill, magnesium oxide, was introduced to the program to provide an additional safety factor prior to the certification application. The emplacement of magnesium oxide was later modified in response to lessons learned from operational experience and improved chemical modeling. The repository horizon also changed in response to information acquired during excavation of the first panel of disposal rooms. Compared to the original baseline roadmap, the program experienced significant delays and cost overruns. Waste emplacement began 10 years later than the original schedule, when the Environmental Protection Agency was designated the regulator and additional compliance studies were initiated. In spite of these delays and costs overruns, WIPP is considered a successful geologic repository program because it is now in operation. The success of WIPP can be attributed to the following factors (University of New Mexico, 2001): There was (and continues to be) public support for WIPP in communities immediately near the repository and, albeit not as strong, in New Mexico. The public was relatively supportive of the WIPP for three reasons. First, WIPP provides jobs and economic development opportunities. DOE and the local community both benefited from working cooperatively. Second, there is a long history of involvement of New Mexico in national defense activities—Sandia National Laboratories and Los Alamos National Laboratory are two of New Mexico’s largest employers—and WIPP is viewed by many citizens as a legitimate national defense activity because it provides a solution to the defense transuranic waste problem. And a third related issue, the public did not perceive their state as being the “nation’s radioactive waste dump” because no commercial waste is to be sent to WIPP. WIPP is located in a sparsely populated, semiarid region with little potable groundwater, and the bedded salt is expected to provide an effective long-term barrier to the migration of transuranic radionuclides. Moreover, the U.S. Environmental Protection Agency requires a re-certification of WIPP every 5 years, and the state of New Mexico has authority to suspend or revoke WIPP’s hazardous waste facility permit. The public perceives transuranic waste as less risky than high-level waste. Defense transuranic waste has a relatively low radionuclide content and produces relatively little heat. Consequently, there is expected to be little thermal energy generated in the repository to promote processes

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that could complicate predictions of containment. Although some of these factors are site or waste specific, there are lessons from the WIPP program that can be applied to high-level waste repository programs—most notably, allowing sufficient time to undertake the scientific and technical investigations necessary to demonstrate site suitability; reversing course if there are questions about safety; obtaining external, independent scientific and technical reviews of these investigations; and seeking and demonstrating responsiveness to external input. Science and engineering details for the repository are published in the Yucca Mountain Science and Engineering Report (DOE-OCRWM, 2002a). The starting point for this committee’s work was the DOE’s 2001 schedule (DOE-OCRWM, 2001 b), but this has already undergone major changes (e.g., license application is now delayed from 2002 to December 2004). F.1.1 Selection of a geologic disposal option (1982) Building on early recommendations by the National Academy of Sciences (NRC, 1957), the NWPA designated geologic isolation as the choice for disposal of high-level waste and commercial spent nuclear fuel (NWPA, 1982). Although geologic disposal has often been questioned by groups that favor long-term, monitored surface storage, the original choice was openly documented (NRC, 2001 b). This choice caused little or no controversy or opposition before the contentious issue of actually siting a facility occurred. The NWPA requires the USNRC to limit DOE to disposal of no more than 70,000 metric tons of heavy metal (MTHM) of high-level waste (currently estimated to be composed of 63,000 MTHM of commercial spent fuel and 7,000 of defense-related waste) in the first geologic repository “until such time as a second repository is in operation” (NWPA, 1982; Section 114[d]). There are currently no plans for a second high-level waste repository. The NWPA Amendments of 1987 require DOE to report back to Congress between 2007 and 2010 on the need for a second repository (NWPA, 1982; section 161b). F.1.2 Site selection and characterization (1982–2002) The NWPA of 1982 directed DOE to select sites across the United States for characterization as candidate repositories for high-level waste. It also directed DOE to submit to the Congress a recommendation for a second site from any sites already characterized as a potential second repository. In the mid-1980s DOE conducted a program of site screening and selection, resulting in first nine, then five, and finally three sites selected for characterization. Seventeen states were initially screened for the second repository location. DOE ultimately recommended three locations as candidates for site characterization for the first repository: (1) Yucca Mountain, Nevada; (2) Hanford, Washington; and (3) Deaf Smith County, Texas. The siting process developed in stages, initially narrowing the number of candidate sites by multi-attribute utility analyses, which was reviewed by the National Research Council.

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In a 1987 amendment to the NWPA the Congress directed DOE to concentrate only on characterization of Yucca Mountain3 and to terminate activities at the other candidate sites for the first repository, and to “indefinitely postpone” siting activities associated with the second repository. DOE then built an in situ exploratory study facility within the potential repository horizon for site characterization at Yucca Mountain. The siting phase officially ended on July 9, 2002, when Congress determined that the suitability of Yucca Mountain allowed for further development and authorized DOE to submit a license application. As allowed by law, the governor of Nevada filed a “notice of disapproval,” that was subsequently overridden by votes in Congress. The next step in DOE’s repository program is to obtain a USNRC license for construction authorization. The application for construction authorization must contain a proposed design for the repository. The total design capacity is assumed to be approximately 70,000 MTHM of commercial spent nuclear fuel, including mixed-oxide (MOX) fuel; 2,500 MTHM of defense-related spent nuclear fuel, including naval waste; and approximately 22,000 canisters of vitrified high-level waste, including some canisters containing immobilized plutonium waste form contained in high-level waste glass (DOE-OCRWM, 2001a). In addition to high-level waste and spent nuclear fuel, Yucca Mountain is anticipated to receive other wastes as noted in Sidebar F.2. As part of site characterization and license application DOE is currently studying the natural system (e.g., geology, hydrology, and climatology) and the engineered barrier system (i.e., the engineered parts of the repository and the waste package) of the repository (DOE-OCRWM, 2002b). DOE is setting up a long-term science program (the Systems Performance Enhancement and Cost Reduction program) to operate in parallel with the science program for the license application. DOE is finalizing the repository design, the operating requirements, and the radiologic safety requirements to be included in the license application. The repository design continues to evolve with time. Major changes in design have included waste package characteristics (in particular the recent inclusion of a titanium drip shield4 and a change in container material to the C-22 alloy), an increase of the ventilation rate, and changes in the underground design to accommodate a range of thermal operating modes. The thermal operating mode will be finalized later in the operation phase, depending on the desired maximum post-closure temperatures of the waste package surfaces, the emplacement drift rock walls, the repository rock, and the humidity in the emplacement drifts (DOE-OCRWM, 2001a). The extent to which these changes result from a structured learning process, as advocated in Adaptive Staging, or result from unexpected findings or from external pressures is discussed below. 3   The Yucca Mountain site is located about 160 km (100 miles) northwest of Las Vegas, Nevada. The host rock proposed for the potential repository is an unsaturated welded tuff; a unit of the Topopah Spring Member (DOE-OCRWM, 2001a). 4   The engineered barrier system includes a titanium drip shield installed over the waste packages at the time of repository closure. DOE’s rationale for including a drip shields is to keep the waste packages dry for thousands of years, hence reducing the corrosion rate of the waste packages. The titanium drip shield would also protect the waste package from rock falls that could compromise the corrosion barrier of the waste package.

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Sidebar F.2 Other Wastes for Yucca Mountain Radioactive wastes are classified by their origin or radiotoxicity in order to ensure safe handling and disposal. High-level radioactive waste requires deep geologic disposal, while most low-level radioactive waste may be disposed of at or near the ground surface. The United States has an additional waste stream not so highly radioactive as high-level waste but that contains significant amounts of long-lived radioactive materials; transuranic waste from its defense program. This material may be isolated from the biosphere with the high-level waste or in similar disposal facilities. Currently, it is being disposed in a geologic disposal site, WIPP in New Mexico, under a different regulatory system than that which prevails for Yucca Mountain (see Sidebar F.1). The United States also has commercial nuclear low-level waste that is greater than Class-C (GTCC); it exceeds the limits of low-level waste set for disposal in near-surface licensed sites. These commercial GTCC wastes include transuranic wastes and highly irradiated metals from nuclear reactor core structures, other than the metal parts of the spent fuel assembly, which are considered to be high-level waste. The GTCC classification is not used for low-level waste generated in the DOE complex; all of the DOE low-level waste is the responsibility of DOE. Commercial GTCC wastes are the responsibility of DOE by Section 3(b)(D) of the Low-Level Radioactive Waste Policy Amendments Act of 1985. In revision of its low-level waste regulations the USNRC has ruled at 10 CFR Part 61.55 that “such waste [GTCC] must be disposed of in a geologic repository as defined in Part 60 or 63 of the chapter unless proposals for disposal of such waste in a disposal site licensed pursuant to this part are approved by the Commission.” Thus, quantities of these commercial GTCC wastes may be emplaced with the high-level waste at Yucca Mountain. F.1.3 Licensing The USNRC is the regulator for the high-level waste repository program in the United States. The USNRC’s role in any licensing action is to apply regulations and to review applications for proposed actions to determine compliance. The burden of proof is on DOE to show that the proposed action is safe, to demonstrate that regulations are met, and to ensure continued compliance with the regulations (USNRC, 2002a). The USNRC has set up a sequential licensing process consisting of the following specific licenses or amendments: license to construct the repository, license to receive and emplace waste, license to permanently close the repository, and termination of the repository license. The Supplementary Information to Title 10 CFR Part 63, reads:

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“Part 63 provides for a multi-staged licensing process that affords the Commission the flexibility to make decisions in a logical time sequence that accounts for DOE collecting and analyzing additional information over the construction and operational phases of the repository” (66 Federal Register 55738, November 2, 2001). The USNRC made a distinction in Part 63 about the level of safety assurance that is obtainable from the use of the performance assessment.5 This distinction has the effect of dividing the DOE application into two safety cases: one, for pre-closure safety, requires a finding of “reasonable assurance”; the other, for post-closure safety, requires a finding of “reasonable expectation.”6 The USNRC has a long history of licensing nuclear activities on the basis of a finding that may be stated as “reasonable assurance that the facility has been constructed and will be operated in conformity with the license, the provisions of this Act, and the Commission’s rules and regulations” (Atomic Energy Act of 1954, as amended, Section 185.b). The expression “reasonable assurance” has come to indicate the level of assurance a regulator can obtain from pervasive oversight of an activity from beginning to end. The USNRC in addressing comments on the promulgation of 10CFR Part 63 noted that the EPA commented that a connotation has developed around “reasonable assurance” that could lead to an extreme approach of selecting worst case values for important parameters. The EPA believes that “reasonable assurance” is appropriate for operating facilities that operate under active institutional controls during their lifetime. It is not appropriate, in EPA’s view, for the licensing of a repository where projections of performance have inherently large ranges of uncertainty. Where such pervasive oversight is not sustainable, as during long-term post-closure performance, a lesser level of assurance is all that can be attained. The USNRC adopted the EPA expression “reasonable expectation” as the level of assurance to be obtained for post-closure performance objectives. The USNRC noted that “confidence that DOE has, or has not, demonstrated compliance with EPA’s standards is the essence of NRC’s licensing process.” The USNRC went on to state its intent to review the full record before it to make the licensing determination (66 FR 55739–55740, November 2, 2001). In Part 63.31 the USNRC distinguishes the different levels of assurance when it requires that to authorize construction it must determine Safety, That there is reasonable assurance that the types and amounts of radioactive materials described in the application can be received and possessed in a geologic repository operations area of the design proposed without unreasonable risk to the health and safety of the public; and That there is reasonable expectation that the materials can be disposed of without unreasonable risk to the health and safety of the public. 5   For a definition of performance assessment see Sidebar 5.1 in Chapter 5. 6   Consistent with the U.S. Environmental Protection Agency’s high-level waste standards, the USNRC chose the term “reasonable expectation” rather than “reasonable assurance” in the regulatory context for Yucca Mountain.

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Paragraph (a)(1) applies to receipt and possession of the waste; (a)(2) applies to permanent disposal. DOE is currently planning to submit the application for construction authorization in 2004. The USNRC has three years (with a possible 12-month extension) to complete the review of the application and conduct a public hearing. Prior to receipt of a license application the USNRC conducts pre-licensing consultation with DOE. Although non-binding, this process provides for a public dialogue between the USNRC and DOE to discuss technical and safety issues and to identify paths to resolution. Additionally, the USNRC interprets and enforces the EPA’s safety requirements for the repository before the license application, principally through its regulation 10 CFR Part 63 (USNRC, 2001).7 The USNRC will review each license application submitted by DOE. If the USNRC review ultimately finds the application acceptable, the matter will be put before a USNRC Hearing Board to review contentions from involved parties. The license cannot be granted unless the Hearing Board issues a favorable judgment. Under the terms of the NWPA the USNRC has three years, with a possible one year extension that must come from the Congress, to complete the review and adjudication of the application for construction authorization (NWPA, Sec. 114[d]). A formal review and adjudication are required for each license or amendment. At each licensing phase the USNRC will ensure that DOE has specified the nature and extent of the performance confirmation program—a program that continues through to permanent closure with the objective of testing and challenging the technical basis for the safety analysis. After a license is granted the USNRC will provide oversight of DOE’s operation for construction, for receiving and emplacement of waste, and for closure and termination of the repository license. At the time of the first construction authorization and at each licensing step the USNRC will determine whether the license application is sufficient to demonstrate compliance with USNRC’s regulatory requirements. During the pre-licensing consultation period the USNRC identified 293 key technical issues (USNRC, 2002b) and reached agreement with DOE on its schedule for addressing these issues, some of which require work outside the repository area (e.g., corrosion testing of the C-22 alloy). F.1.3.1 The USNRC license hearing process The USNRC has traditionally used an Atomic Safety Licensing Board (ASLB) to hold formal litigation and judgment of the rightness of the licensing action for major actions. Informal hearings, typically with a single administrative law judge, are used for contested minor actions. The USNRC high-level waste regulations have long called for establishment of such an ASLB for all Yucca Mountain licensing actions and amendments. Experience with the potential for delay in licensing proceedings of this type apparently prompted the Congress to impose the schedule requirements in Section 114(d) of the NWPA “that the Commission shall issue a final decision approving or disapproving the issuance of a construction authorization not later than the expiration of 3 years after the date of submission of such application.…” These litigations have a formality and process that are different from the processes of a continuing program. 7   The role of the U.S. Environmental Protection Agency in the Yucca Mountain Project ended in 2001 with the promulgation of the Yucca Mountain standard for radioactive release limits.

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In a licensing hearing the ASLB is expected to hear DOE testimony to support its application and safety case as well as testimony to support the USNRC staff evaluation report. Contentions filed by the intervening parties with standing would be argued before the ASLB, with all parties able to cross examine the witnesses. The state is automatically given standing in the proceeding. During the litigation the repository design is “frozen.” After the hearings are concluded and with due consideration the ASLB makes its findings to the USNRC. Depending on the outcome the proposed action may be approved, modified, or denied. If dispute remains, the ASLB ruling can be appealed to the USNRC itself for adjudication. The process can take years to complete but must remain within the three-year constraint imposed by Section 114(d) of the NWPA, unless the USNRC seeks a one-year extension from the Congress under that same section. F.1.4 Construction This phase will begin once DOE obtains the USNRC license to construct the repository, and is scheduled to last 4 years. The initial plan was to construct the entire repository continuously while applying for the license to receive and emplace waste after a substantial portion was constructed. The current plan is to adopt a modular design in which the surface and subsurface facilities are built as discrete segments or panels. This modular repository design consists of completing about 10 percent of the emplacement drifts during the initial construction phase (before initiation of waste emplacement), with the remainder of the emplacement drifts being completed during the operation phases.8 The proposed repository at Yucca Mountain consists of surface and subsurface facilities to prepare the waste for emplacement, handle low-level waste produced on site and underground facilities to dispose of the waste (for details see DOE-OCRWM, 2002a). The repository design changed considerably during the history of the Yucca Mountain project. There still are different design options for the surface and underground facilities as of late 2002. For instance, the thermal operating mode of the repository (i.e., above or below boiling temperature of water), waste package design and protection (drip shields), backfill, and the operational strategy of the repository have yet to be finalized. F.1.5 Operation Before the beginning of this phase DOE must receive USNRC authorization to take title of defense high-level waste and commercial spent nuclear fuel at generator sites, transport it, and emplace it in the repository. The purpose of performance confirmation is to confirm (or invalidate) the predicted performance of the engineered and natural barrier systems relative to waste containment and isolation. Throughout its implementation, performance confirmation will include measures to ensure and maintain the repository system’s ability to retrieve any of the emplaced waste at any time before closure. This assurance will be accomplished through the use of subsurface facilities to monitor the natural and 8   For further information on the modular design see DOE-OCRWM (2002c,d).

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engineered barriers, the emplacement drift and main drift environments, the rock temperature and moisture regimes, the water inflow into emplacement drifts, waste package integrity, and any seismic activity of the site. The types of performance confirmation facilities will include post-closure test drifts, observation drifts, alcoves, niches, and boreholes. One or a combination of these facilities may be used depending on the requirements for access to the monitored geologic media and on the objectives of the monitoring. The performance confirmation activities will provide data to verify that subsurface conditions and changes resulting from construction and waste emplacement are within predicted limits. The performance confirmation also verifies that the natural and engineered systems and components are functioning as anticipated and intended. After all waste is emplaced, the repository environment adjusts to its selected thermal operating mode. The current repository design is intended to have the capability to operate over a range of thermal conditions. The thermal operating mode can be varied by changing the spacing of waste packages and by controlling ventilation rates and duration. For the high-temperature configuration the design will allow the repository to be closed as early as 30 years after the last waste package is emplaced. For the full range of thermal operating conditions needed to implement the flexible design approach, the design will allow the repository to remain open, with appropriate monitoring and maintenance, for up to 300 years after final waste emplacement. Preserving the capability of the repository design to remain open for up to 300 years provides the flexibility needed to adopt such thermal management approaches as extended drift ventilation that could prove successful in reducing uncertainties in repository performance. However, this also requires maintaining institutional continuity and oversight. The repository will be monitored and maintained from the start of waste emplacement and for at least 50 years after the end of waste emplacement until the time the repository is permanently closed. Monitoring includes collecting and analyzing data to confirm predicted repository performance, as well as maintenance of the subsurface facility. The monitoring will be done using sensors that will collect data from waste packages, drifts, and the surrounding rock. Remotely controlled inspection gantries will be used to investigate conditions in the emplacement drifts. When waste emplacement activities are completed and it has been confirmed that the repository will perform as expected, an amendment to the repository license will be sought to close the facility. The baseline plan does not include an intermediate regulatory decision between license to receive and possess and license to close the repository. DOE will report to the USNRC every 24 months any significant deviations from expected conditions and recommend action. License amendments will be needed for substantial design changes, such as changes in the repository design or in the waste emplacement rate. F.1.6 Closure and post-closure The closure process is designed to configure the repository in such a manner that little or no human support will be required to continue to isolate the waste for tens of thousands of years. Before closure a monitoring period is maintained after all the waste has been emplaced. Monitoring includes collecting and analyzing data to confirm predicted repository performance as well as maintenance of the subsur-

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face facility (see Appendix E). During the closure period the implementer emplaces the titanium drip shield, over the waste. Finally, the implementer backfills shafts, ramps, mains, and extension drifts, permanently seals the repository, dismantles surface facilities, and constructs physical barriers such as fences, walls, and other systems preventing access to the site, a well as warning signs, markers, and monuments. Detailed records and information on the repository will be distributed to local, state, and federal agencies for their use in controlling access to the site, thus creating institutional barriers. The actual repository closure and decommissioning activities are currently scheduled to last nine years. After closure, monitoring of the site from the surface can continue for as long as desired. The stated extended service life of 300 years allows future generations to decide whether it is appropriate to continue to maintain the repository in an open, monitored condition or to close it based on development of their criteria and level of certainty regarding ultimate repository performance. The emplaced waste will be retrieved if performance confirmation activities indicate that the repository is unsuitable for long-term isolation of the waste or if recovery of the waste as a valuable resource is warranted. Retrieval concepts are currently being evaluated. F.2 How much Adaptive Staging is currently incorporated in the U.S. program? In reaction to the committee’s interim report released in 2002 (NRC, 2002), DOE and the USNRC both expressed the view that the U.S. program is consistent with Adaptive Staging. In the committee’s judgment DOE has recognized potential advantages of staging its Yucca Mountain Project repository development program and has, since this study commenced, taken further actions to encourage aspects of Adaptive Staging. The following is a summary (in italics) of the information provided by DOE and the USNRC (Williams, 2002; Federline, 2002) to describe staging aspects of the program, together with the committee’s comments. The committee’s overall assessment is reported in Chapter 5, Section 5.2. Both DOE and the USNRC reported to the committee that the U.S. program’s decision-making process is characterized by decisions at stable, well-defined points having logical links to the safety case. This is an approach with a primary objective of increasing safety and reducing uncertainties. DOE updated twice its safety analysis for the Viability Assessment and Site Recommendation. The precedent at the Waste Isolation Pilot Plant (seeSidebar F.1) suggests periodic performance assessment updates during operation. Moreover, the USNRC regulations require: a safety assessment for license application for construction, an updated safety assessment based on information obtained during construction to support license to receive and possess, and an updated safety assessment based on performance confirmation data for the application for a license amendment to close the repository. The committee perceives the U.S. program’s roadmap as being largely characterized by a single predetermined path to a defined end point in which stages are defined principally as milestones driven by cost and schedule. These milestones correspond to the minimum stages required by the statute and the regulations for

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USNRC licensing. For instance, it appears that there are no intermediate decisions between license to receive and emplace waste and repository closure. The committee is concerned as to whether there will be any re-evaluation of the safety case during the operational phase.9 The roadmap is re-evaluated only if compelling new evidence requires it (i.e., if parties external to the program or the regulator raise concerns). While it is true that the roadmap has adapted with time, the adaptations were mostly triggered by external events, as detailed at the end of this section. DOE and the USNRC believe that the U.S. program matches the attributes of Adaptive Staging: Commitment to systematic learning. The performance confirmation program defines a systematic learning path with a primary objective toward challenging the safety case with the goal of increasing confidence. The committee believes that the learning aspect has been underemphasized. DOE tends to give the message prematurely that everything is known in sufficient detail. The positive results of being able to introduce changes into the program are not built into the basic approach; in other words, DOE relies on Linear Staging. Accordingly, each time DOE changes the baseline roadmap or the repository design it is strongly criticized by some stakeholders. DOE has not set appropriate expectations with stakeholders about the need for systematic learning, that can lead to changes. Flexibility. The U.S. repository program allows opportunities for safety enhancements or cost benefit changes consistent with safety. The USNRC process of license amendments and license conditions10 provides flexibility for changes for the enhancement of safety that are available for public review. A requirement in Part 63.44(c)(2) instructs DOE to report to the USNRC every two years on changes, tests, and experiments that were made or conducted without amendment. The committee agrees that opportunities for flexibility are available. More specific details on the interactions between DOE and USNRC that would allow this flexibility to be used in the licensing phases are discussed in Section 5.4.2. 9   The committee acknowledges that the USNRC requires DOE to submit reports every 24 months with new information; however, this information does not necessarily trigger a revision of the safety case. 10   A license condition is not a partial license. The English usage of “condition” in the licensing context is the same as use of the word for conditions of a contract (i.e., terms that must be satisfied to satisfy the contract). The USNRC does not define the term in its regulations, but it does state in 10 CFR 72.44(a): “(a) Each license under this part shall include license conditions. The license conditions may be derived from the analyses and evaluations included in the Safety Analysis Report and amendments thereto submitted pursuant to 72.24. License conditions pertain to the design, construction and operation. The Commission may also include additional license conditions as it finds appropriate.”

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Reversibility. The USNRC requires DOE to preserve the option to retrieve the waste for 50 years after initiation of waste emplacement The committee’s understanding of reversibility goes far beyond this regulatory requirement. Retrievability is only one aspect of reversibility; it is, however, important to maintain and demonstrate its feasibility until the repository is closed. Equally important is that reversibility, either totally or at least to a lesser degree such as design change, must be considered as an option at each stage (see Fig. 2.1a). We hope the probability of reversal decreases with time. DOE provides another prominent example of reversibility: With Congress, reversibility of policy is always an option. Examples of congressional control are: Development of controlling legislation (NWPA, NWPAA, National Energy Policy Act of 1992). State veto override process. Annual appropriations (which often contain program direction), such as: FY 1994—blocked funding of grants for feasibility studies for potential volunteer sites for a federal storage facility. FY 1996—report language directed DOE to focus on scientific issues related to suitability and to delay work on license application. FY 1997—directed submission of Viability Assessment. The committee recognizes these as opportunities for the Congress to reverse the program. However, the spirit of Adaptive Staging is that all parties acknowledge throughout the program that reversibility is always a possibility to consider before moving to the following stage. Moreover, reversibility should be driven by knowledge not by politics or cost. Transparency, auditability, and integrity. DOE points out that transparency, auditability, and integrity are ensured in the U.S. program through the regulatory process, federal control, Congressional policy, and technical oversight, as well as through public involvement. This is illustrated by the following examples: The USNRC formal review process provides an auditable and transparent record of the safety case and the regulatory decisions on contested issues. The independence of the regulator is the foundation for the integrity of the process. The U.S. program, as a federal program, is subject to transparency and auditability requirements, the purpose of which is to ensure the integrity of the program. Examples of transparency and auditability requirements are the Freedom of Information Act, Federal Advisory Committee Act, and the Administrative Procedures Act. Many program documents and available directly on the Internet. The NWTRB, the statutory oversight board, has access to all draft and final documents by law. The Office of Management and Budget and the Congress provide policy oversight and control the program through funding allocations. Budget and justification are made public in the President’s budget.

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Opportunities for public involvement are included at each stage of the program in several ways: The USNRC provides opportunities to the public to participate in dialogue and to provide comments on all pre-licensing issues. There will also be formal opportunities for public involvement in the licensing hearing process. The public was involved in development of the NWPA through the following channels: Interagency Review Group was composed of 14 agencies and held multiple hearings; 15,000 copies of draft were circulated and 3,300 comments were received. This review group considered strategies ranging from proceeding with repository in salt to delaying until alternatives to geologic disposal were developed. Generic Environmental Impact Statement process. Alternative disposal technologies were considered. The EPA workshops on repository regulation. Extensive interest group participation occurred in NWPA hearings from 1978 through passage in 1982, including inputs from several groups. The public was involved in the development of DOE, USNRC, and EPA regulations under the Administrative Procedures Act. The State of Nevada and affected units of government receive funds for program oversight; in particular, the Nye County science program is providing input to the program. Nevada has the right to a negotiated “consultation and cooperation” agreement with DOE; Nevada can provide inputs at identified key events, milestones, and decisions. The agreement allows binding arbitration for dispute resolution. DOE observes that the State of Nevada has not availed itself of the opportunity. Extensive hearings and opportunities to review and comment on program documents were offered during the Environmental Impact Statement and site recommendation process. The public has direct influence through congressional representatives, for instance, through the state veto override process and through the annual appropriations process. NWTRB meetings offer opportunities for public comment. The committee shares the opinion that the U.S. program is one of the most open waste management programs worldwide. The volume of information available to the public is impressive, and efforts are made to communicate the information. However, the improvements that might be made to the program go beyond simply providing data to the stakeholders. Resulting data for all programs would be made available. Important also is that the justification for choosing the specific investigation areas is made accessible for review and comment. Not all decisions have been transparent. For example, adoption of the titanium drip shield was a development that took place suddenly and without much external discussion. Other decisions in the program that do not correspond to the principles of Adaptive Staging have sometimes been taken out of the hands of DOE. In the 1987 amendment to the NWPA the Congress narrowed the process, directing DOE to terminate activities on or about other sites and concentrate only on characterization of Yucca Mountain. This pragmatic narrowing to one site lost one of the desir-

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able aspects of Adaptive Staging: maintaining alternative choices; the decision made by the Congress placed alternative site choices in sequential order rather than parallel. The committee listened to public views expressing the opinion that the communication from DOE continued to be too one-sided. There was a perception that DOE was not acting on what was heard. In addition, there was no mechanism for stakeholder and public input into decision-making. Much of the controversy surrounding the Yucca Mountain project has revolved around the lack of cooperation between DOE and the State of Nevada. The committee recommends in Chapter 6 that the state participate in the creation of a technical oversight group and a stakeholder advisory board. DOE has expressed willingness to support this and the state has so far refused to participate. Responsiveness. The USNRC process requires responsiveness to new information at key decisions and timely consideration of any information with significant safety implications. This information is also provided to the stakeholders in a timely manner. As an example of responsiveness, the program is now addressing the 293 key technical issues raised by the USNRC. Other examples of responsiveness are the following major changes in the program in response to recommendations by the NWTRB: adoption of robust, long-lived engineered barriers, use of tunnel-boring machine instead of drill and blast, excavation of the cross drift in the Exploratory Studies Facility, evolution to flexible design to preserve low-temperature option suggested by NWTRB, and implementation of an independent review of age of fluid inclusions. The committee recognizes that DOE has often responded to external input by amending its program. For example, Evolution to a modular repository design was triggered by budgetary concerns and accelerated by the committee’s progress report. According to DOE the initial incentives for implementing a modular repository design were to reduce initial investment and to waste emplacement. Development of a flexible thermal operating mode was triggered by concerns repeatedly expressed by the NWTRB (2002). The viability assessment was introduced as a useful intermediate stage on the way to site-suitability determination. Again, the reason was external: primarily that DOE faced reduced funding for fiscal year 1996 and was instructed by the conference report accompanying the appropriations act to concentrate the repository effort on the major unresolved technical questions posed by the USNRC. The Site Characterization Plan was submitted to USNRC in late- 1988; the USNRC provided extensive comments and two significant objections in mid-1989. The two objections argued that (1) DOE did not have adequate quality assurance for gathering and retaining site- characterization data and (2) DOE did not have an adequate repository design control process. The viability assessment was completed and reported in 1998. The viability assessment represented a new stage that was not contemplated in the initial roadmap. The external input appears not to have been gathered through a systematic learning and decision-making process but rather was perceived as a potential “showstopper” that had to be addressed. Addressing the 293 key technical issues is

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not an example of Adaptive Staging’s responsiveness, because it is imposed on DOE by the USNRC to obtain a license. DOE plans to address (not resolve) all key technical issues by 2004, the date of the submission of the license application. Adaptive Staging would not presume, without good justification, that the key technical issues could be addressed by a fixed date. An example of the more difficult key technical issue concerns the corrosion rate of C-22 alloy. Adaptive Staging may alter resolution of a key technical issue and alter the repository design itself. The committee acknowledges that DOE is under pressure to address these key technical issues within a specific time frame in order to file a complete application. However, the committee believes that with Adaptive Staging, DOE would be better positioned to formalize the learning process and to address broader technical and societal issues while building stronger public trust. References DOE-CAO (Department of Energy, Carlsbad Area Office). 1996. Compliance Certification Application for the Waste Isolation Pilot Plant, DOE/CAO-1996– 2184. Carlsbad, N.Mex. DOE-OCRWM (Department of Energy, Office of Civilian Radioactive Waste Management). 2001 a. Analysis of the Total System Life Cycle Cost of the Civilian Radioactive Waste Management Program. DOE/RW-0533. Washington, D.C.: U.S. Department of Energy. Available at: http://www.rw.doe.gov/tslccr1.pdf. DOE-OCRWM. 2001b. Civilian Radioactive Waste Management System Total System Description Revision 02 (TDR-CRW-SE-000002). DOE/RW-0500. U.S. Department of Energy. Available at: http://www.rw.doe.gov/tsdkrb/tsdkrb.htm. DOE-OCRWM. 2002a. Yucca Mountain Science and Engineering Report. Technical Information Supporting Site Recommendation Consideration. Revision 1. February 2002. DOE/RW-0539–1. Available at: http//www.ymp.gov/documents/ser_b/front.pdf. DOE-OCRWM. 2002b. The Yucca Mountain Project. Project Operations. Available at: http://www.ymp.gov/toc/functional/func.htm. DOE-OCRWM. 2002c. Final Environmental Impact Statement for a Geologic Repository for the Disposal of Spent Nuclear Fuel and High-level Radioactive Waste at Yucca Mountain, Nye County, Nevada. DOE/EIS-0250. February 2002. Available at: http://www.ymp.gov/documents/feis_a/index.htm. DOE-OCRWM. 2002d. Modular Construction System Evaluation. Pre-Decisional Study. TDR-CRW-SE-000023 REV 00. August 2002. Prepared by Bechtel SAIC Company LLC. Washington, DC: Department of Energy. Federline. M. 2002. USNRC’s Feedback on Committee’s Interim Report. Presentation before the committee. June 10. Washington, D.C. NRC (National Research Council). 1957. The Disposal of Radioactive Waste on Land. Washington, D.C.: National Academy Press. NRC. 1996. The Waste Isolation Pilot Plant: A Potential Solution for the Disposal of Transuranic Waste. Washington, D.C.: National Academy Press.

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NRC. 2001a. Improving Operations and Long-Term Safety of the Waste Isolation Pilot Plant. National Academy Press. Washington, D.C.: National Academy Press. NRC. 2001b. Disposition of High-level Waste and Spent Nuclear Fuel. The Continuing Societal and Technical Challenges. Washington, D.C.: National Academy Press. NRC. 2002. Principles and Operational Strategies for Staged Repository Systems: Progress Report. Washington, D.C.: National Academy Press. NWPA (Nuclear Waste Policy Act). 1982. Available at: http://www.rw.doe.gov/progdocs/nwpa/nwpa.htm. NWTRB (Nuclear Waste Technical Review Board). 2002. Letter report to Congress and the Department of Energy. January 24. Washington, D.C. University of New Mexico. 2001. Institute for Public Policy, Public Opinion Profile of New Mexico Citizens. Focus on WIPP. Report for Fall 2000/Spring 2001. Public Opinion Profile of New Mexico Citizens 13(1). Available at: www.unm.edu/instpp. USNRC (U.S. Nuclear Regulatory Commission). 2002a. Yucca Mountain Review Plan. NUREG-1804. Rev. 2. USNRC March. USNRC. 2002b. List and Status of Key Technical Issues for High-Level Waste. Available at: http://www.nrc.gov/waste/hlw-disposal/reg-initiatives/list-status-kti.html. Williams, J. 2002. DOE’s Vision of Staging. Presentation before the committee. June 10. Washington, D.C.