oversight

Nuclear Waste: Impediments to Completing the Yucca Mountain Repository Project

Published by the Government Accountability Office on 1997-01-17.

Below is a raw (and likely hideous) rendition of the original report. (PDF)

                 United States General Accounting Office

GAO              Report to Congressional Committees




January 1997
                 NUCLEAR WASTE
                 Impediments to
                 Completing the Yucca
                 Mountain Repository
                 Project




GAO/RCED-97-30
      United States
GAO   General Accounting Office
      Washington, D.C. 20548

      Resources, Community, and
      Economic Development Division

      B-275449

      January 17, 1997

      The Honorable Frank Murkowski
      Chairman
      The Honorable Dale Bumpers
      Ranking Minority Member
      Committee on Energy and Natural Resources
      United States Senate

      The Honorable Thomas J. Bliley, Jr.
      Chairman
      The Honorable John D. Dingell
      Ranking Minority Member
      Committee on Commerce
      House of Representatives

      The Congress is expressing growing concern about the pace, direction,
      and cost of the Department of Energy’s (DOE) program to permanently
      dispose of the highly radioactive waste produced by civilian nuclear power
      plants and DOE’s nuclear weapons activities. The centerpiece of the
      disposal program is the scientific investigation of Yucca Mountain,
      Nevada, as a candidate site for disposing of the waste in a geologic
      repository. The Nuclear Waste Policy Act of 1982, as amended, requires
      the Secretary of Energy to determine, on the basis of the investigation, if
      the site is suitable for a repository and, if this determination is positive,
      recommend to the President that the site be selected for that purpose. If
      the site is formally selected, DOE must apply to the Nuclear Regulatory
      Commission (NRC) for authorization (a license) to construct a repository
      there. DOE’s current objective is to begin disposing of waste in the
      repository in 2010, or 12 years later than had been originally expected.

      The perceived lack of progress on the repository project has led to
      renewed debate on the need for a federal facility to store waste until the
      repository has been constructed and a reduced allotment of
      appropriations for the project in fiscal year 1996. The administration had
      requested $472 million for the project, or almost $100 million more than
      the project’s previous appropriation allotment. However, the project was
      allocated $250 million of the appropriations for the entire disposal




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                       program, or 53 percent of the amount originally requested.1 Because of
                       congressional concern about DOE’s capability to maintain its schedule for
                       the repository with reduced appropriations, we identified the
                       (1) adjustments DOE made to the disposal program due to the reduced
                       appropriations and (2) potential impediments to achieving DOE’s objectives
                       and schedule for the repository project. We addressed these issues under
                       our responsibility, contained in the Nuclear Waste Policy Act of 1982, as
                       amended, to audit the disposal program and to report the results of such
                       audits to the Congress.


                       Because DOE did not receive the amount of appropriations requested for
Results in Brief       fiscal year 1996, it revised the scope and objectives of the repository
                       project with the goal of applying for a construction license in March 2002,
                       about 5 months later than had been planned. Specifically, DOE

                   •   curtailed most investigative activities at Yucca Mountain in favor of
                       analyzing the information already collected to focus the remaining
                       investigative activities on key uncertainties;
                   •   decided to revise its guidelines for determining if the Yucca Mountain site
                       is suitable for a repository by deleting those criteria that require
                       compliance with specific technical conditions, such as those concerning
                       the travel time for groundwater; and
                   •   will issue, in September 1998, an assessment of the expected design,
                       performance, and cost of a repository at Yucca Mountain. This report,
                       called a viability assessment, is intended to support decisions on
                       continuing the repository project and authorizing a waste storage facility
                       near Yucca Mountain that may be made before the Department has
                       determined if the site is suitable for a repository.

                       Several impediments must be resolved in DOE’s favor if the Department is
                       to achieve the project’s revised objectives and schedule. First, it is
                       uncertain when the Environmental Protection Agency (EPA) and NRC will
                       issue the health standards and licensing regulations, respectively, that DOE
                       needs to determine if Yucca Mountain is a suitable repository site. Also,
                       the absence of applicable standards and regulations creates uncertainty
                       about whether the scope of the Department’s site investigation is
                       adequate. Finally, limitations on (1) the information that DOE is collecting

                       1
                        The Energy and Water Development Appropriations Act of 1996 provided $400 million for the disposal
                       program. This included $152 million from the civilian Nuclear Waste Fund appropriation account and
                       $248 million from the defense nuclear waste disposal account. The act reserved $85 million of the
                       appropriation from the latter account for the development of a facility for the interim storage of waste
                       upon the enactment of statutory authority for such a facility. This effectively left DOE with
                       $315 million of available appropriations.



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             in key areas, such as hydrology and the effects of heat generated by waste
             on the performance of the repository, and (2) NRC’s preparations to review
             a license application add more uncertainty to the repository project.


             No country has yet developed a geologic repository for the permanent
Background   disposal of highly radioactive waste. Because this type of nuclear waste
             produces relatively intense levels of radiation for thousands of years,
             developing an acceptably safe repository is a complex task involving
             diverse scientific and technical challenges. For example, DOE must design
             a repository that is compatible with the site and will be safe to operate for
             several decades. In addition, the Department must demonstrate how the
             combination of geologic (natural) and engineered (man-made) barriers to
             the migration of waste from the repository will operate effectively.
             Inherent in this demonstration are numerous uncertainties related to
             understanding and predicting how a repository will perform over a very
             long period of time. Finally, safety standards for evaluating a proposed
             repository that recognize the inherent uncertainty in the repository’s
             performance must be established.

             In the Nuclear Waste Policy Act of 1982, the Congress found that federal
             efforts during the previous 30 years to devise a permanent solution to the
             problems of disposing of radioactive waste had not been adequate. The act
             established, among other things, federal policy and responsibility for the
             safe management and disposal of highly radioactive waste from civilian
             nuclear power plants.2 The act charged DOE with selecting and
             investigating candidate sites for two repositories, recommending the
             selection of two sites for development, and constructing and operating one
             repository. DOE was required to establish guidelines for selecting and
             recommending repository sites that made specified geologic
             considerations the primary criteria. To ensure the safe management and
             disposal of waste for current and future generations, the act also required
             EPA to set environmental standards for the disposal of waste in
             repositories and NRC to establish regulations containing technical
             requirements and criteria for approving or disapproving of DOE’s
             applications to construct and operate repositories.

             Amendments to the act in 1987 directed DOE to investigate only the Yucca
             Mountain site. And the Energy Policy Act of 1992 required EPA to adopt
             specific public health and safety standards for that site on the basis of, and

             2
              As permitted by the act, the President also decided in 1985 that highly radioactive waste from DOE’s
             nuclear weapons activities would also be disposed of in one or more civilian repositories.



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                     consistent with, a study of the scientific basis for such standards to be
                     issued by the National Academy of Sciences, at EPA’s request, by the end of
                     1993. The 1992 act also required that, within 1 year after EPA adopted its
                     standards for Yucca Mountain, NRC had to make its licensing regulations
                     consistent with the standards.

                     When the Congress passed the nuclear waste act, it expected that a
                     repository could be operable by 1998. Subsequently, however, DOE
                     extended the estimated date for a repository to 2003 and then to 2010. In
                     the meantime, nuclear waste is accumulating and being stored at civilian
                     nuclear power plants. The growing concern about the delay in beginning
                     to remove nuclear waste from nuclear plant sites is reflected by a recent
                     lawsuit and congressional consideration of legislation. In July 1996, the
                     U.S. Court of Appeals for the District of Columbia Circuit ruled that the
                     nuclear waste act creates an obligation for DOE to start disposing of
                     utilities’ waste no later than January 31, 1998, and remanded the case for
                     further proceedings.3 That same month, the Senate passed a bill (S.
                     1936) that, among other things, would have directed DOE to develop a
                     facility for the interim storage of utilities’ waste on DOE’s Nevada Test Site.4
                      (A portion of Yucca Mountain lies within the western boundary of the
                     Nevada Test Site.) Similar legislation was under consideration in the
                     House of Representatives when the 104th Congress adjourned.


                     Following the appropriation for fiscal year 1996, DOE (1) curtailed most
Fiscal Year 1996     investigative activities at Yucca Mountain, (2) decided to revise its
Adjustments to the   guidelines for determining if the site is suitable for a repository, and
Disposal Program     (3) announced that it would assess, in 1998, the “viability” of a repository
                     at Yucca Mountain. DOE anticipates that these changes could enable it to
                     submit a license application to NRC in March 2002 at an affordable cost.
                     (See fig. 1.)




                     3
                      Indiana Michigan Power Co. v. Department of Energy, 88 F.3d 1272 (D.C. Cir., 1996). The
                     administration has decided not to appeal the decision.
                     4
                     The site would be used for a storage facility unless the President, after determining that Yucca
                     Mountain is not a suitable site for a repository, designated another site for the facility.



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Figure 1: DOE’s Schedule Leading to License Application




      1997              1998                 1999                2000                  2001                   2002




        October
        Issue           September
                                         July                                                              March
        revised         Issue
                                         Determine if site is                         July                 Submit
        siting          viability
                                         suitable on the                              Recommend            license
        guidelines      assessment
                                         basis of the                                 selection of         application
                                         revised siting                               Yucca                to NRC
                                         guidelines                                   Mountain as
                                                                                      a repository
                                                                                      site


DOE Curtailed the                        During fiscal year 1996, DOE curtailed, for the second consecutive year, the
Investigation of Yucca                   scope of its investigation of Yucca Mountain. In January 1992, DOE had
Mountain                                 estimated that it would cost $6.3 billion through 2001 to investigate the site
                                         and prepare a license application. As we reported in 1993, however, the
                                         budget requests and allotments of appropriations for the repository
                                         project from fiscal years 1991 through 1993 were less than the estimated
                                         funding requirements.5 (See table 1.) Therefore, in December 1994, DOE
                                         announced a plan to reorganize the investigation around tests to
                                         determine if the site is suitable for a repository, tests to support a license
                                         application, and tests that could be deferred until after the application had
                                         been submitted to NRC.

Table 1: Estimated Funding Required,
Requested, and Appropriated for the      Dollars in millions
Repository Project                                                                                                                Funds
                                         Fiscal year                       Funds required       Funds requested             appropriated
                                         1991                                          $ 194                   $193                   $155
                                         1992                                            340                    172                    166
                                         1993                                            625                    248                    259
                                         Total                                        $1,159                   $613                   $580



                                         5
                                          Nuclear Waste: Yucca Mountain Project Behind Schedule and Facing Major Scientific Uncertainties
                                         (GAO/RCED-93-124, May 21, 1993).



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                                     According to DOE, the plan identified an aggressive field program,
                                     including drilling about 25 to 30 deep boreholes, and tests to be conducted
                                     from the surface of the site, in laboratories, and in the underground
                                     exploratory studies facility. This facility, which DOE expects to complete in
                                     1997, is a U-shaped, 5-mile underground tunnel through Yucca Mountain.
                                     (See fig. 2.) DOE estimated that the reorganized investigation would cost
                                     about $2.9 billion for the 6 fiscal years from 1995 through 2000.


Figure 2: Artist’s Conception of a
Repository at Yucca Mountain


                                                    Yucca
                                                    Mountain                       th
                                                    Ridge                       Nor p
                                                                                 R m
                                                                                  a


                                                                           Lower                  uth
                                                                                                So amp
                                                                           Emplacement           R
                                                                           Block




                                                                Upper                                    ble
                                                                Emplacement                       ter Ta
                                                                                               Wa
                                                                Block




                                                                                                               N

                                                Exploratory Studies Facility


                                     Source: DOE.




                                     Shortly after DOE received its appropriations for fiscal year 1996, it further
                                     reduced the scope of the investigation and eliminated about 875 positions




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                            for contract employees in the repository project. In addition, DOE reduced
                            funding for waste storage, transportation, and program management
                            activities by $82 million and eliminated more than 200 related positions for
                            contract employees. The revised investigation is now focused on
                            completing the viability assessment and, according to DOE, was developed
                            using the following priorities, in descending order of importance:
                            (1) synthesis and modeling of available information to focus testing
                            programs on key uncertainties, (2) testing in the exploratory studies
                            facility, and (3) surface testing, such as using existing and new wells from
                            holes drilled into the groundwater underneath the site to test the
                            characteristics of the groundwater. DOE estimated the cost of the revised
                            investigation at about $2.1 billion for the 7 fiscal years from 1996 through
                            2002.


DOE Decided to Revise Its   Fundamental to the success of DOE’s revised approach for the repository
Suitability Guidelines      project is its decision to revise its guidelines for determining if Yucca
                            Mountain is a suitable site for a repository.6 DOE’s existing siting guidelines
                            address the operation of a repository before it is permanently closed
                            (preclosure guidelines) and the long-term behavior of the repository after
                            it is closed (postclosure guidelines). For both areas, the guidelines are
                            divided into “system” and “technical” guidelines. For example, the
                            postclosure system guideline requires a demonstration that a proposed
                            repository site and design would likely comply with EPA’s disposal
                            standards and NRC’s licensing regulations. The technical guidelines
                            establish specific conditions that are important to meeting the system
                            guidelines. For example, the postclosure technical guidelines contain nine
                            conditions that must be present at a site (qualifying conditions) and six
                            conditions that must be absent from a site (disqualifying conditions) for
                            DOE to find that the site is suitable for permanent waste disposal.


                            Instead of comparing the Yucca Mountain site’s features to the technical
                            conditions in DOE’s existing guidelines, the Department now plans to
                            compare how a repository at Yucca Mountain would be expected to
                            perform to EPA’s disposal standards and NRC’s licensing regulations. This
                            approach, DOE says, will lead to a more efficient process for determining
                            the site’s suitability by enabling the Department to focus investigative
                            activities on issues that are most important to the performance of a
                            repository at the site. The Department’s proposed changes to the
                            guidelines were published for public comment on December 16, 1996 (61
                            Federal Register 66157).

                            6
                             The nuclear waste act gave the Secretary of Energy the authority to amend the siting guidelines.



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DOE Will Assess the            The principal objective of DOE’s new approach for the repository project is
Viability of a Repository at   to issue a “viability assessment” in September 1998. The assessment will
Yucca Mountain                 be a statement of the (1) tentative design and expected performance of the
                               repository system, (2) necessary investigation activities and associated
                               costs to submit a license application, and (3) estimated cost to construct
                               and operate the repository. The assessment, in DOE’s view, will represent
                               an improved appraisal of the prospects for disposing of nuclear waste at
                               Yucca Mountain.

                               According to the director of the disposal program, the assessment is
                               intended to guide the completion of the work required for a site
                               recommendation and to provide policymakers with a better estimate of the
                               “viability” of a repository in the time frame required for decision-making.

                               If the repository appears to be “viable,” then DOE intends to complete the
                               work necessary to determine the suitability of the site, recommend that
                               the site be selected for a repository, and, if the site is formally selected,
                               apply for a construction license. The Department has not defined what
                               constitutes a “viable” repository project; however, the assessment is not
                               intended to demonstrate either that the Yucca Mountain site is suitable for
                               or can be licensed as a repository.

                               DOE  also intends that the assessment be used to “inform” a possible
                               decision in 1999 by the administration and the Congress to develop a
                               facility near Yucca Mountain for storing nuclear waste until a repository is
                               operational. An affirmative decision would trigger the beginning of the
                               construction and operation of the storage facility and the transport of
                               waste from nuclear power plants to the facility. As shown in figure 1,
                               however, DOE does not expect to make a determination of the site’s
                               suitability until July 1999 or to recommend a site until July 2001.
                               Therefore, an earlier decision to develop a storage facility near Yucca
                               Mountain could be viewed as a firm commitment to disposing of waste at
                               Yucca Mountain.

                               For example, the administration opposed S. 1936 because the bill would
                               have designated a location on DOE’s Nevada Test Site as a site for a storage
                               facility before DOE had completed the viability assessment. Such a
                               designation, in the administration’s view, would have destroyed the
                               credibility of the disposal program by prejudicing a future decision on a
                               permanent repository at Yucca Mountain. According to the disposal
                               program’s director, making a decision to develop a storage facility near
                               Yucca Mountain after the viability assessment, although before DOE



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                           determines if the Yucca Mountain site is suitable for a repository, would
                           provide for a more informed decision.


                           Several uncertainties must be resolved in DOE’s favor if the Department is
Potential                  to achieve the project’s revised objectives and schedule. First, it is
Impediments to             uncertain when EPA and NRC will issue the health standards and licensing
Achieving the              regulations, respectively, that DOE will use to determine if Yucca Mountain
                           is a suitable repository site. Also, the lack of applicable standards and
Objectives and             regulations creates uncertainty about whether the scope of the
Schedule for DOE’s         Department’s site investigation has been adequate. Finally, limitations on
                           the information that DOE is collecting in key areas and on NRC’s
Repository Project         preparations to review a license application add more uncertainty to the
                           repository project.


Timing of Standards and    The time it will take for EPA to issue its new disposal standards for Yucca
Regulations Could Affect   Mountain and for NRC to conform its licensing regulations to those
DOE’s Objectives and       standards could affect DOE’s ability to make a decision on the site’s
                           suitability and a recommendation on its current schedule. When EPA and
Schedule                   NRC will issue their respective standards and licensing regulations is
                           uncertain, but it could take 2 years or longer.

                           Because NRC is required to conform its licensing regulations to EPA’s
                           disposal standards, the standards must be issued first. In February 1993,
                           EPA contracted with the National Academy of Sciences for the study,
                           mandated by the Energy Policy Act of 1992, of the scientific basis for
                           standards applicable to the Yucca Mountain site. In August 1995, the
                           Academy issued its report. As of January 15, 1997, however, EPA had not
                           issued proposed standards for public comment. EPA anticipates that it may
                           be able to issue final standards within 1 year of proposing the standards
                           for comment. According to officials of NRC’s waste management division,
                           NRC expects to begin the process of revising its licensing regulations after
                           EPA proposes its standards. For example, when NRC’s staff provides the
                           Commission with comments on EPA’s proposed standards for the
                           Commission’s consideration, the staff also plans to provide the
                           Commission with a strategy for revising NRC’s licensing regulations.

                           The two regulatory agencies’ previous experiences with earlier standards
                           and licensing regulations have shown that it could take 2 years or longer to
                           issue the new standards and revised licensing regulations. For example,
                           EPA took almost 3 years from December 1982, when it proposed its original




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standards for nuclear waste repositories, to issue the final standards.7
After the standards were successfully challenged in court in 1987, EPA
issued revised standards for public comment in February 1993 and final
standards in December 1993. In June 1981, NRC proposed technical
regulations for repositories. Subsequently, it took about 2 years for NRC to
adopt the final technical regulations.

Thus, it is unlikely that EPA’s standards and NRC’s revised licensing
regulations will be in place by September 1998, when DOE expects to issue
its viability assessment of the Yucca Mountain project. According to DOE,
however, it is not important to have the standards and licensing
regulations in place for the viability assessment because the Department
does not intend to compare, in the assessment, the expected performance
of the repository to the standards and regulations.8

The timing of EPA’s standards and NRC’s revised licensing regulations could,
however, affect DOE’s schedule for completing a report that would provide
the technical basis for determining if the Yucca Mountain site complies
with the Department’s siting guidelines and for making the site selection
recommendation. As discussed earlier, the Department intends to make
compliance with the standards and licensing regulations its criteria for
determining if Yucca Mountain is a suitable site for a repository.
According to DOE, it needs to have the standards and licensing regulations
in place at least 1 year before it makes the determination. In July 1999, DOE
plans to complete an “interim evaluation” of the site’s suitability (see fig.
1) by issuing a technical report addressing the site’s compliance with the
siting guidelines. To adhere to the Department’s schedule for completing
the report, DOE needs to have the standards and licensing regulations in
place by July 1998.

Moreover, a recommendation by the Secretary to the President that the
Yucca Mountain site be selected for a repository must, according to the
nuclear waste act, be based on a comprehensive statement of the basis for
the recommendation. Among other things, the comprehensive statement
must contain NRC’s preliminary comments on the sufficiency of DOE’s
investigation of Yucca Mountain for inclusion in a license application and

7
 At that time, these standards would have applied at the Yucca Mountain site; however, the Energy
Policy Act of 1992 required EPA to develop specific standards for a repository at that site.
8
 The Department’s fiscal year 1997 appropriations act directed DOE to issue the viability assessment to
the President and the Congress. The act also instructed DOE to include in the assessment a
comparison of the probable behavior of the repository to the “overall system performance standards.”
This language is essentially identical to language in S.1936, which would have established an overall
system performance standard of 100 millirems of radiation exposure to the affected population per
year.



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                          the proposed form of the waste. In April 1999, DOE plans to issue a report
                          to NRC documenting the investigation’s results. This report, DOE says, will
                          provide information describing and modeling the site’s characteristics, the
                          designs of the repository and waste packages, and the expected
                          performance of the overall repository system. DOE intends to use this
                          integrated discussion of its case for a safe repository at Yucca Mountain as
                          the basis for NRC to provide its preliminary comments to DOE by
                          January 2000. The Department will not be able to issue a meaningful
                          report and NRC will not be in a position to provide the Department with its
                          formal comments on the sufficiency of DOE’s site investigation until the
                          standards and regulations have been issued.


Substance of Standards    Until the substantive requirements of EPA’s disposal standards and NRC’s
and Regulations Could     revised licensing regulations are known, DOE will not know if its scientific
Affect DOE’s Objectives   investigation of Yucca Mountain has adequately addressed all of the
                          technical issues that are important to a credible determination of the site’s
and Schedule              suitability and an acceptable license application.

                          Although EPA has not yet proposed its standards, the National Academy of
                          Sciences’ report to EPA on the technical basis for Yucca Mountain
                          standards and DOE’s comments on that report show that there are
                          significant differences of opinion about what the substantive requirements
                          of the standards should be. The Academy recommended, among other
                          things, standards that (1) limit the health risk, rather than the radiation
                          dose, to individuals from the radioactive materials released from the
                          repository; (2) require the measurement of compliance out to the time of
                          peak risk, which is expected to occur tens or hundreds of thousands of
                          years after the repository has been closed; and (3) define a critical group
                          that would be at risk.

                          Subsequently, DOE expressed three key concerns with the Academy’s
                          recommendations and made recommendations to EPA on how the
                          standards should be written. First, DOE recommended limiting compliance
                          calculations to a 10,000-year period on the basis that the uncertainties in
                          calculations over a longer period of time would limit the usefulness and
                          validity of the calculations in a licensing proceeding. Second, DOE
                          recommended using a less conservative level of risk than the Academy had
                          recommended as a starting point for rulemaking. Third, DOE recommended
                          a less complex and conservative approach to calculating risk to the critical
                          group than the two options discussed in the Academy’s report. (See app. I
                          for a more detailed discussion of the Academy’s report, DOE’s comments,



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and other issues related to the development of EPA’s standards and NRC’s
licensing regulations.)

The extent to which NRC revises its licensing regulations in making the
regulations consistent with EPA’s standards could also affect the adequacy
of DOE’s scientific investigation. Currently, NRC’s regulations require DOE to
demonstrate compliance with EPA’s “generally applicable environmental
standards.” However, these standards have been revised to pertain to
repositories at sites other than Yucca Mountain. In addition, to provide
sufficient confidence that a repository would perform as predicted, NRC’s
regulations require DOE to demonstrate that the repository would comply
with three more specific requirements. These requirements, called
subsystem performance requirements, establish a minimum lifetime for
packages containing waste, limits on the rate at which radioactive
materials can be released from engineered (man-made) barriers within the
repository, and the minimum time that water might take to travel from the
repository to the accessible environment. NRC included these additional
requirements because of the inherent uncertainty in an assessment of the
performance of a repository over a long period of time.

In its August 1995 report, the Academy concluded that NRC’s subsystem
performance requirements could adversely affect the performance of a
repository at Yucca Mountain by limiting DOE’s design flexibility. DOE
agreed and recommended that NRC reconsider the use of these
requirements. There are, however, arguments favoring these requirements.
As recognized by NRC in the early 1980s, the subsystem performance
requirements provide “defense in depth” by increasing confidence in
assessments of compliance with EPA’s standards. Also, NRC pointed out that
its regulations provide considerable design flexibility by permitting NRC to
change the subsystem performance requirements, if warranted, during a
licensing proceeding.

According to the deputy director of NRC’s Division of Waste Management,
NRC’s staff is considering whether or not the regulatory agency should
retain these subsystem performance requirements in its licensing
regulations and will address this issue when it provides the Commission
with a proposed strategy for revising the agency’s licensing regulations.
The outcome of this issue, as well as other issues that may arise as NRC
revises its licensing regulations, could affect the scope and depth of the
scientific investigation that DOE must perform to determine if Yucca
Mountain is a suitable site for a repository.




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DOE May Not Have          Regardless of the timing and substance of the final repository regulations,
Adequately Investigated   limitations on the information that DOE is collecting and on NRC’s
Key Areas                 preparations to review a license application increase uncertainty about the
                          sufficiency of the Department’s investigation of Yucca Mountain.

                          According to DOE, among the most important attributes of a repository at
                          Yucca Mountain are the rate at which water seeps into the repository, the
                          period of time that the packages containing waste will prevent the release
                          of radioactive materials from them, and the manner in which radioactive
                          materials that eventually reach the water table beneath the repository will
                          be diluted by groundwater. Also, heat generated by the waste in the
                          repository will affect the movement of water through the repository and
                          the durability of the waste packages. There are indications of
                          shortcomings in DOE’s investigation of all of these areas.

                          For example, DOE may not have done enough to investigate the
                          groundwater beneath and beyond Yucca Mountain, including where and
                          how fast water moves and the rate at which water contaminated with
                          waste materials would be diluted and dispersed as it enters the
                          groundwater. According to the U.S. Geological Survey, which performs
                          groundwater research for DOE, new questions about the importance of
                          groundwater to the scientific investigation are beginning to arise; in the
                          last decade, however, no new boreholes to address these uncertainties
                          have been drilled, and only limited testing of the groundwater has
                          occurred. One such issue is the unexplained cause of the large drop in the
                          elevation of the water table at the northern end of Yucca Mountain.
                          Geological Survey scientists say that this feature, which was discovered in
                          1981, is the most striking hydrologic feature in the area. According to the
                          scientists, until they can explain the cause of the drop in the water table,
                          they would find it difficult to claim that they understand the hydrology of
                          the site.

                          DOE agrees that the drop in the water table has not been fully evaluated.
                          According to the Department, however, preliminary observations of a
                          recently completed pumping test in an existing well indicate that this
                          feature of the site has no effect on the flow of groundwater in the aquifer
                          beneath Yucca Mountain.

                          According to a 1996 report by DOE on the quality of the Geological Survey’s
                          hydrologic investigations, major uncertainties, such as the unexplained
                          drop in the groundwater level, at this stage of the scientific investigation
                          limit understanding of how radioactive materials would move in



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groundwater. In the opinion of the report’s authors, the Geological
Survey’s research has been severely handicapped by, among other things,
the elimination of most borehole drilling from the investigation. (App. II
discusses this limitation and others on DOE’s investigations of the
hydrology at Yucca Mountain, as well as limitations on its investigations of
the effects of heat on the repository’s performance and the testing of
candidate materials for waste packages.)

Under the existing legislative framework, NRC, not DOE, will ultimately
decide if the Department’s investigation of Yucca Mountain has been
adequate. Over the years, NRC has reviewed DOE’s repository project to
identify and resolve technical issues, to prepare to review a license
application, and to develop criteria for an acceptable license application.
The criteria would provide guidance to DOE on NRC’s expectations for a
license application that would adequately address the requirements of
NRC’s licensing regulations.


In 1995, NRC modified its approach to reviewing DOE’s repository project.
Instead of trying to review all aspects of the project, NRC decided to
identify and emphasize the 10 most important technical issues. According
to NRC, however, in fiscal years 1996 and 1997 it eliminated its contractor
support for independently evaluating 3 of these 10 issues because its
nuclear waste appropriations for each year were only half of its
$22 million appropriation for 1995. In the absence of funding, NRC will not
conduct any more independent studies of the three issues. Instead, NRC’s
staff will monitor DOE’s related activities and will bound related regulatory
issues using conservative assumptions. Moreover, NRC said, if the recent
budget trend continues, the agency would have to discontinue its
contractor’s work on two more key technical issues and would not be able
to complete its review of a DOE license application in the 3-year period
required by the nuclear waste act.

Thus, an additional uncertainty confronting DOE’s repository project is
NRC’s  position on the contents of an acceptable license application. NRC’s
review of and comments on DOE’s 1998 viability assessment will provide
the first insights into NRC’s formal position. (DOE does not intend to request
comments on its viability assessment; however, NRC believes that its
evaluation of the assessment would provide vital input to future decisions
on the repository project.) For those key technical issues that NRC has
reviewed, it intends to identify potential licensing weaknesses and major
concerns with DOE’s designs or testing plans that could affect DOE’s
estimate of the cost of the repository. For technical issues for which NRC



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               has eliminated technical work by its contractor, the agency’s reviews of
               DOE’s designs and technical basis for performance assessments and cost
               estimates in the viability assessment will be limited and based on
               conservative assumptions and available knowledge.

               The viability assessment, however, is not a step required by the nuclear
               waste act. The first formal opportunity that the act provides NRC to
               comment on the sufficiency for a license application of DOE’s investigation
               of Yucca Mountain will occur when DOE seeks NRC’s preliminary comments
               on the sufficiency of the investigation. DOE expects to seek NRC’s
               comments in April 1999 and to receive the comments in January 2000.
               NRC’s next formal opportunity will be its initial review of DOE’s license
               application in 2002 to determine if the application is acceptable to begin
               the licensing proceeding. To the extent that NRC is unable to review
               important issues to gain confidence in DOE’s investigation and develop
               acceptance criteria, the agency intends to adopt conservative regulatory
               positions. Conservative positions could have the consequence of either
               requiring DOE to obtain and provide NRC with more information or,
               alternatively, to make modifications to the design of the repository system
               that could increase the system’s cost.


               DOE’s  viability assessment may provide important insights into the
Observations   expected design, performance, and cost of a repository at the Yucca
               Mountain site. However, the assessment’s utility as the basis for a decision
               in 1999 to develop a waste storage facility near the site is limited because
               the assessment will not demonstrate compliance with applicable siting
               guidelines, standards, and licensing regulations. Therefore, making such a
               decision on the basis of the viability assessment could be perceived as a
               firm commitment to eventually disposing of nuclear waste at the site. For
               essentially this reason, the administration opposed the provisions of S.
               1936 that would have designated a site near Yucca Mountain for a storage
               facility before DOE had completed its viability assessment. The
               administration argued that such a designation would have destroyed the
               credibility of the disposal program by prejudicing a future decision on a
               permanent repository at Yucca Mountain. In our view, the logic of the
               administration’s position would also apply to such a designation made
               after the assessment has been completed but in advance of the decision on
               the site’s suitability, a recommendation that the site be selected for a
               repository, and the decision on licensing that must be made on the basis of
               compliance with the guidelines, standards, and regulations.




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                     We provided a draft of our report to DOE, EPA, and NRC for their review and
Agency Comments      comment. DOE and NRC provided written comments on this report, which
and Our Evaluation   appear in appendixes III and IV, respectively. EPA declined to comment on
                     the report.

                     DOE said that our report recommends that decisions involving the
                     construction of a repository be suspended until the Secretary has
                     recommended to the President that Yucca Mountain be selected for a
                     repository. We did not propose such a recommendation. We merely
                     observed that deciding to develop a waste storage facility near Yucca
                     Mountain before the Department has determined that the proposed
                     repository site complies with applicable siting guidelines, standards, and
                     licensing regulations could be perceived as a firm commitment to
                     eventually disposing of nuclear waste at the site. We revised our
                     observation section to make clear that we were not proposing any
                     recommendation.

                     DOE also said that we appear to be misinformed about its plans to continue
                     addressing the uncertainties related to hydrology, the effects of heat from
                     waste on the performance of the repository, and waste package materials.
                     The Department intends to make every reasonable effort to reduce
                     uncertainties and, in a license application, will identify and discuss any
                     remaining major uncertainties and the steps planned to reduce them. It is
                     important to note, DOE added, that it is not required to demonstrate the
                     performance of the repository system or components of this system until it
                     submits a license application. We disagree that we are misinformed about
                     DOE’s plans for addressing key technical issues. Our report states that, on
                     the basis of the limited information that DOE has collected and concerns
                     raised by technical experts, resolving existing uncertainties about these
                     issues could affect the Department’s ability to achieve its objectives and
                     schedule for the repository project. Whether or not DOE’s current plans to
                     address key uncertainties are adequate can be definitively answered only
                     after the Department has submitted an application to construct a
                     repository.

                     DOE provided other specific clarifying comments that we incorporated as
                     appropriate.

                     NRC pointed out that its previous and ongoing reviews of DOE’s site
                     investigation project and interactions with the Department have
                     documented feedback to DOE on what is needed for licensing. Therefore,
                     NRC’s comments on the viability assessment’s discussion of DOE’s plans for




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the license application will reflect whatever significant differences remain
between NRC’s staff and the Department. Moreover, NRC said, interactions
between the two agencies focused on resolving licensing issues will
continue, and should differences of opinion persist, they will be
documented in the Commission’s preliminary sufficiency comments to be
included in DOE’s site recommendation report. NRC provided other specific
clarifying comments that we incorporated as appropriate.


We performed our review at DOE’s headquarters in Washington, D.C., and
at DOE’s Yucca Mountain Site Characterization Project Office in Las Vegas,
Nevada. We also performed our review at the headquarters of NRC in
Rockville, Maryland, and EPA in Washington, D.C. We visited the Yucca
Mountain site in southern Nevada and met with representatives of the
state of Nevada and Clark County, Nevada. We conducted our review from
February 1996 through January 1997 in accordance with generally
accepted government auditing standards. (See app. V for details of our
scope and methodology.) A list of related GAO products appears at the end
of this report.

We are sending copies of this report to the Secretary of Energy; the
Chairman, NRC; the Administrator of EPA; and the Director, Office of
Management and Budget. We will also make copies available to others on
request.

Please call me at (202) 512-3841 if you or your staff have any questions.
Major contributors to this report are listed in appendix VI.




Victor S. Rezendes
Director, Energy, Resources, and
  Science Issues




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Contents



Letter                                                                                                 1


Appendix I                                                                                            20
                        Background                                                                    20
Uncertainties About     EPA’s Standards Could Affect DOE’s Repository Project                         22
Regulatory              NRC’s Revised Licensing Regulations Could Affect DOE’s                        25
                          Repository Project
Requirements Could      DOE’s Siting Guidelines Are to Be Based on EPA’s Standards and                27
Affect the Objectives     NRC’s Licensing Regulations
and Schedule for
DOE’s Repository
Project
Appendix II                                                                                           30
                        Waste Containment and Isolation Strategy                                      30
Limitations of DOE’s    Limitations in DOE’s Hydrology Program                                        32
Activities Could        Limited Information Will Be Available on the Effects of Heat                  36
                          From Waste
Affect the Objectives   Limitations on Waste Package Research                                         39
and Schedule for
DOE’s Repository
Project
Appendix III                                                                                          41

Comments From the
Department of Energy
Appendix IV                                                                                           48

Comments From the
Nuclear Regulatory
Commission
Appendix V                                                                                            53

Scope and
Methodology



                        Page 18               GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
                        Contents




Appendix VI                                                                                          54

Major Contributors to
This Report
Related GAO Products                                                                                 55


Table                   Table 1: Estimated Funding Required, Requested, and                           5
                          Appropriated for the Repository Project

Figures                 Figure 1: DOE’s Schedule Leading to License Application                       5
                        Figure 2: Artist’s Conception of a Repository at Yucca Mountain               6




                        Abbreviations

                        DOE        Department of Energy
                        EPA        Environmental Protection Agency
                        NRC        Nuclear Regulatory Commission


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Uncertainties About Regulatory
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and Schedule for DOE’s Repository Project
               The Department of Energy’s (DOE) efforts to determine if a safe repository
               can be developed at Yucca Mountain are made more difficult because the
               site investigation is proceeding in parallel with fundamental changes to the
               regulations governing the project. If the site is eventually selected for a
               repository, DOE must demonstrate, in a licensing proceeding conducted by
               the Nuclear Regulatory Commission (NRC), that the proposed repository
               would comply with health standards issued by the Environmental
               Protection Agency (EPA) and NRC’s licensing regulations. However, EPA is
               just beginning the process of issuing health standards for the Yucca
               Mountain site that must be consistent with the findings and
               recommendations of a study by the National Academy of Sciences. And
               after EPA issues its standards, NRC must, if necessary, revise its licensing
               regulations to make the regulations consistent with the standards.

               The Academy has recommended that EPA take a different approach to
               setting standards for Yucca Mountain than the agency took a decade ago
               in setting its original standards for all nuclear waste repositories, including
               Yucca Mountain. DOE, however, has disagreed with several of the
               Academy’s findings and recommendations because, in part, of the
               perceived difficulty in implementing the recommended standards in a
               licensing proceeding on a repository at Yucca Mountain.

               Moreover, whether DOE’s scientific investigation of Yucca Mountain will be
               adequate to support a determination of the site’s suitability, a
               recommendation to select the site, and an acceptable license application
               on the Department’s current schedule will, to some extent, depend on
               when the final standards and licensing regulations are issued and their
               substantive requirements. Finally, DOE is in the process of basing its
               guidelines for determining the suitability of Yucca Mountain for a
               repository on EPA’s standards and NRC’s licensing regulations. Thus, the
               timing and content of the standards, licensing regulations, and siting
               guidelines that will be used for determining if the site is suitable for a
               repository, recommending that the site be selected for a repository, and
               applying for a license are currently unknown.


               The Nuclear Waste Policy Act of 1982 charged EPA with setting generally
Background     applicable environmental standards for the disposal of nuclear waste in
               repositories and NRC with setting criteria and technical requirements for
               licensing and regulating repositories. In December 1982, EPA proposed, and
               in September 1985 issued, its original disposal standards (40 C.F.R. part
               191). The primary standard was based on containing waste materials



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    and Schedule for DOE’s Repository Project




    within a repository.9 Specifically, the standard limited the cumulative
    releases of radioactive materials from the boundary of the repository to
    the accessible environment (the biosphere) for 10,000 years after closing a
    repository. In issuing this standard, EPA expected that the assessments of
    the long-term performance of a repository would be based on
    mathematical predictions of the anticipated behavior of both the natural
    and engineered (man-made) barriers making up the repository system and
    the likelihood of unanticipated events and processes, such as earthquakes
    and human intrusion, that could disrupt the repository.10

    Subsequently, the Energy Policy Act of 1992 directed EPA to set specific
    disposal standards for the Yucca Mountain site that would prescribe the
    maximum annual effective dose to individual members of the public from
    the release of radioactive materials (disposed of in the repository) to the
    accessible environment. The act also required EPA to (1) arrange for an
    analysis by the National Academy of Sciences of the scientific basis for a
    standard to be applied at Yucca Mountain and (2) adopt health and safety
    standards on the basis of, and consistent with, the Academy’s findings and
    recommendations. Finally, the act required NRC to make its licensing
    regulations for a repository at Yucca Mountain consistent with EPA’s
    standards.

    In February 1993, EPA contracted with the Academy to study the technical
    basis for disposal standards for a repository at Yucca Mountain. The
    Academy issued its report to EPA in August 1995.11 Among other things, the
    Academy recommended that EPA

•   limit the risk to individuals of adverse health effects from releases of
    radioactive materials from the repository rather than limiting the radiation
    dose to individuals or the cumulative releases of radioactive materials
    from the repository;12



    9
     EPA also established standards for protecting (1) individuals in areas surrounding a repository from
    receiving harmful radiation doses and (2) groundwater from radioactive contamination for 1,000 years.
    The standards also contained qualitative assurance requirements to increase confidence that the
    long-term containment requirements would be met.
    10
     The exception to the release standards includes expected or accidental events that, while
    conceivable, are expected to have less than 1 chance in 10,000 of occurring over 10,000 years.
    11
       Technical Bases for Yucca Mountain Standards, National Research Council, National Academy of
    Sciences, Aug. 1995.
    12
      The Academy recognized that the dose-based and risk-based standards are closely related. The
    risk-based standard would be based on a statistical distribution of health effects (i.e., premature fatal
    cancers), which are derived from a distribution of dose and the expected consequences (i.e., health
    effects) per unit dose.


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                         Uncertainties About Regulatory
                         Requirements Could Affect the Objectives
                         and Schedule for DOE’s Repository Project




                     •   measure compliance with the standard out to the point of peak risk to
                         individuals, which is expected to occur tens or hundreds of thousands of
                         years in the future, rather than the 10,000-year period in EPA’s original
                         standards;
                     •   define the “critical group” that would be at risk, rather than basing
                         compliance on exposures of collective or worldwide populations to
                         radiation;13 and
                     •   separately evaluate the risk and consequences of intrusion into the
                         repository by future humans and focus this evaluation on the repository’s
                         capability to withstand such intrusion.

                         As of January 15, 1997, EPA had not proposed standards for a repository at
                         Yucca Mountain; however, according to the agency’s director of the
                         Radiation Protection Division, Office of Radiation and Indoor Air, the
                         agency may be able to issue final standards within 1 year of proposing the
                         standards.


                         EPA’sdisposal standards for Yucca Mountain must be based on and
EPA’s Standards          consistent with the Academy’s findings and recommendations. DOE,
Could Affect DOE’s       however, expressed several concerns about the Academy’s
Repository Project       recommendations. Depending on the substantive requirements of the
                         standards that EPA eventually adopts, DOE may have to modify its scientific
                         investigation of Yucca Mountain.

                         In a November 2, 1995, letter to EPA, DOE expressed three key concerns
                         about the Academy’s recommendations for a Yucca Mountain standard.
                         First, the Department is concerned that uncertainties in the results of
                         quantitative calculations made for a period that is greater than 10,000
                         years would limit the usefulness and validity of the calculations in a
                         licensing proceeding. Therefore, DOE recommended that compliance
                         calculations be limited to a period of 10,000 years. In DOE’s view,
                         reasonably reliable calculations of a repository’s expected performance
                         can be made for the shorter period of time.

                         Second, DOE is concerned that the level of permissible risk to the
                         designated critical population group that the Academy recommended as a
                         starting point for developing the standards is unnecessarily conservative.
                         The recommended level of risk would limit annual fatal cancers from the

                         13
                           The critical group has been defined by the International Commission on Radiological Protection as a
                         relatively homogeneous group of people whose location and habits are such that they are
                         representative of those individuals expected to receive the highest doses as a result of the discharges
                         of radioactive materials.



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and Schedule for DOE’s Repository Project




operation and closure of the repository to an increase of from 1 in
1 million to 1 in 100,000 in the affected population. According to DOE, none
of the other federal and international regulations the Academy examined
in its study require such a stringent limit over a period of hundreds of
thousands of years. Moreover, DOE said, because of the overwhelming
conservatism in the Academy’s study related to the calculations of risk
levels, EPA should relax the starting point by a factor of 10; that is, the
permissible level of risk should be a range of 1 in 100,000 to 1 in 10,000
increased fatal cancers per year.14

Third, DOE is concerned that the two options the Academy presented for
calculating risk to the critical group and establishing a future reference
biosphere are either too complex or too conservative. The majority of the
Academy’s panel had recommended that EPA use theoretical statistical and
analytical techniques to identify the observed characteristics of people
currently living in the vicinity of the repository and to calculate the risk to
this group. One panel member had recommended that EPA derive the
average risk calculation from the radiation dose likely to be received by a
“subsistence farmer.” This farmer was defined as the person likely to
become the most contaminated because of his use of water extracted from
a well near the repository to drink and to grow all of his food. DOE
commented that the first of these two options is unprecedented and,
among other things, would be very complicated to implement. The second
option, according to DOE, appears to be simpler and easier to implement
but would result in a very conservative level of risk. DOE suggested that a
better option for calculating risk would be to base the calculations on the
characteristics of a current population group perceived to be most at risk
to radiation exposure from drinking contaminated groundwater and using
it to irrigate the crops they would consume. In this option, DOE said,
specific factors, such as the diversity of occupations and lifestyles and the
relative consumption of local and imported foods, would be considered.

The eventual content of EPA’s standard for Yucca Mountain is likely to
influence the extent of the work that DOE must complete to determine if
Yucca Mountain is a suitable site for a repository, recommend that the site
be selected for that purpose, and submit an acceptable license application
to NRC. For example, the substantive requirements of the standards could
affect the scope of the investigation of groundwater around Yucca
Mountain that is necessary to demonstrate compliance with the standards.
According to DOE’s current strategy for containing and isolating waste in a

14
 One example DOE mentioned was the Academy’s assumption that future humans can and will use
groundwater contaminated as a result of a repository losing its integrity over time and that they will
not test and treat their water supply.



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Uncertainties About Regulatory
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and Schedule for DOE’s Repository Project




repository at Yucca Mountain, the use of a dose-based or risk-based
standard—instead of the release-based standard in EPA’s original standards
for all repositories—would place additional emphasis on how radioactive
materials would move through the rock layers in the saturated zone (the
area containing groundwater) beneath and around Yucca Mountain. A goal
of DOE’s containment strategy is to prove that the radioactive materials
escaping into the saturated zone will be dispersed and diluted before they
reach the accessible environment and therefore will result in acceptably
low doses to humans over thousands of years.

Hydrologists at the U.S. Geological Survey, who are investigating the
hydrology of Yucca Mountain for DOE, told us that they are measuring the
movement of injected tracer materials among three wells developed in
close proximity to one another to model the flow of groundwater. In
conjunction, DOE’s Los Alamos National Laboratory is modeling how the
groundwater would transport radioactive materials. A limitation of the
tests, however, is that they measure the transport of radioactive materials
at only one point in time and space. For this reason, the tests are not likely
to answer questions about the total flow of the groundwater system. A
Geological Survey official stated that the project’s study plans provide for
drilling another series of holes at a different location in 1998 and 1999, but
the specifics of the study plans are uncertain. Thus, DOE may need to
undertake additional work to help explain the flow of groundwater in the
saturated zone and transport characteristics to verify theories that
dispersion and dilution of radioactive materials will keep radiation doses
low for thousands of years.

Similarly, the period of regulatory compliance that EPA adopts in the final
standard could affect the relative importance of hydrologic studies to a
compliance determination. Geological Survey scientists told us that a
period of compliance that is much longer than 10,000 years would place
more emphasis on the behavior of the saturated zone. Currently, these
scientists believe that very little water would move from Yucca Mountain
down into the saturated zone in 10,000 years. Over a much longer time
period, however, more water may reach the saturated zone. This
possibility raises questions about how radioactive materials escaping the
repository over the longer time period would be diluted in the
groundwater to limit potential human exposure. As discussed above and in
appendix II, however, groundwater flow and transport properties in the
saturated zone are not well understood.




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                        Uncertainties About Regulatory
                        Requirements Could Affect the Objectives
                        and Schedule for DOE’s Repository Project




                        The revisions that NRC may make to its licensing regulations could affect
NRC’s Revised           DOE’s ability to meet the objectives and schedule for its repository project.
Licensing Regulations   As required by the 1992 energy act, NRC is to make its licensing regulations
Could Affect DOE’s      consistent with EPA’s disposal standards for Yucca Mountain. Because EPA
                        has not yet issued its standards, there are outstanding questions about
Repository Project      how DOE will implement both the standards and NRC’s revised licensing
                        regulations. One key unanswered question, for example, is whether NRC
                        will retain certain requirements for repository performance that are
                        contained in its existing licensing regulations.

                        NRC’s existing licensing regulations require DOE to demonstrate compliance
                        with EPA’s disposal standards. However, when NRC developed its
                        regulations in the early 1980s, it recognized that the assessment of the
                        performance of a repository over a long period of time entails
                        considerable uncertainty. Therefore, to provide sufficient confidence that
                        a proposed repository would perform as predicted, NRC’s regulations also
                        require DOE to demonstrate that a repository would comply with three
                        more specific requirements. These requirements, called subsystem
                        performance requirements, establish (1) a minimum lifetime for packages
                        containing waste, (2) limits on the rate at which radioactive materials may
                        be released from engineered barriers within the repository, and (3) a
                        minimum period of time that groundwater may take to travel from the
                        repository to the accessible environment.

                        In its report to EPA, the National Academy of Sciences concluded that the
                        retention of the subsystem performance requirements in NRC’s licensing
                        regulations could result in a less than optimal design and level of
                        performance for the repository. For example, according to the Academy,
                        DOE might find it necessary to move the repository site within Yucca
                        Mountain to meet the subsystem performance requirement for
                        groundwater travel time. In doing so, the Academy suggested, DOE might
                        also increase the risk of human exposure to radioactive gases moving from
                        the repository to the surface. Accordingly, the panel recommended
                        precluding the subsystem performance requirements from foreclosing
                        design options that ensure the best long-term performance of the
                        repository. DOE, in commenting on the Academy’s report, agreed and
                        recommended that NRC reconsider the use of subsystem performance
                        requirements. In a previous report on seven foreign countries’ programs
                        for disposing of nuclear waste, we noted that regulators in most of these
                        countries are concerned only that proposed repositories meet overall




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and Schedule for DOE’s Repository Project




safety goals (standards). These regulators said they expect to leave the
design details to the repository developers.15

On the other hand, there are arguments in favor of retaining subsystem
performance requirements. For example, in response to public comments
on NRC’s proposed technical regulations for repositories, issued in
June 1981, NRC stated that there is significant uncertainty in making
assessments of the overall performance of a repository for a period
covering thousands of years. NRC added that subsystem performance
requirements provide “defense-in-depth” by increasing confidence in the
assessments of compliance with EPA’s standards. NRC also pointed out that
the subsystem performance requirements are not absolute—the final
regulations, issued in June 1983, permit NRC to change them, if warranted,
during a repository licensing proceeding. Thus, in NRC’s view at that time,
its licensing regulations provided DOE with considerable flexibility to
design an optimal repository system at a specific site. Furthermore, NRC
noted, the subsystem performance requirements may be necessary to
ensure that a repository will meet the numerical criteria in EPA’s (original)
containment standard for unanticipated processes and events (such as
earthquakes, flooding, or disruption of the repository by humans). Finally,
NRC noted that its task is not only one of mathematically modeling a
system and assigning values for particular barriers represented in the
model to arrive at a “bottom line” for overall system performance. NRC is
also concerned, it said, that its final judgments be made with a high degree
of confidence. Accordingly, NRC stated, it can and will expect the
performance of barriers to be enhanced so as to provide greater
confidence in its licensing judgments, wherever practicable to do so.

According to the deputy director of NRC’s Division of Waste Management,
NRC’s staff expects to review its technical requirements for repositories
and its licensing criteria and will re-evaluate, as part of this review, the
need for subsystem performance requirements. However, NRC is waiting
for EPA to issue its proposed standards for Yucca Mountain before
proposing any changes to its licensing regulations.




15
 Nuclear Waste: Foreign Countries’ Approaches to High-Level Waste Storage and Disposal
(GAO/RCED-94-172, Aug. 4, 1994).



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                        Appendix I
                        Uncertainties About Regulatory
                        Requirements Could Affect the Objectives
                        and Schedule for DOE’s Repository Project




                        Fundamental to the success of DOE’s revised approach to completing the
DOE’s Siting            repository project is its decision to revise its criteria for determining if
Guidelines Are to Be    Yucca Mountain is a suitable site for a repository. The Nuclear Waste
Based on EPA’s          Policy Act required DOE to establish general guidelines for the
                        recommendation of sites for nuclear waste repositories. These siting
Standards and NRC’s     guidelines must specify detailed geologic considerations that shall be the
Licensing Regulations   primary criteria for the selection of sites in various geologic media. After
                        obtaining public comment, including NRC’s concurrence with the
                        guidelines, DOE issued them as a regulation in December 1984. The siting
                        guidelines require that DOE evaluate individual sites and compare them on
                        the basis of criteria that address (1) the operation of a repository before it
                        is permanently closed (preclosure guidelines) and (2) the long-term
                        behavior of the repository after it is closed (postclosure guidelines).

                        Both the preclosure and postclosure guidelines are divided into system
                        and technical guidelines. Three preclosure system guidelines establish
                        performance objectives that must be taken into account during a
                        repository’s operations in the areas of radiation safety; environment,
                        socioeconomics and transportation; and ease and cost of siting,
                        construction, operation, and closure. The postclosure system guideline
                        establishes broad performance objectives for protecting public health and
                        safety that are based on compliance with EPA’s disposal standards and
                        NRC’s licensing regulations. These requirements must be met by the
                        repository system, which must contain both natural and engineered
                        barriers. The engineered barriers are to be designed to complement the
                        natural barriers, which are to provide the primary means for waste
                        isolation.

                        The preclosure and postclosure guidelines also contain technical
                        guidelines which establish specific conditions that are important to
                        meeting the system guidelines.16 For example, the postclosure technical
                        guidelines contain nine conditions that must be present at (qualifying
                        conditions) and six conditions that must be absent from (disqualifying
                        conditions) a site for DOE to find that the site is suitable for permanent
                        waste disposal. For each such technical guideline, DOE is to make an
                        evaluation of qualification or disqualification.




                        16
                         For the postclosure guidelines, the conditions address site characteristics, processes, and events that
                        may influence the performance of a repository system after closure of the repository. They include
                        hydrological and chemical characteristics of the site; changes in climate, erosion, rock quality,
                        movement of tectonic plates comprising the earth’s crust; and human interference with the repository
                        system.



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Until recently, DOE had intended to use these siting guidelines as the basis
for determining if Yucca Mountain is a suitable site for a repository. To
this end, DOE had planned to complete, at an estimated cost of
$634 million, sufficient scientific investigations and related technical
reports to make preliminary technical findings in 1998 on whether Yucca
Mountain meets the criteria contained in the guidelines. DOE has now
decided, however, to amend the siting guidelines by adding new guidelines
that would pertain only to the Yucca Mountain site.

The proposed guidelines, which were published for public comment on
December 16, 1996, would base the determination of the suitability of
Yucca Mountain as a site for a repository on a comparison of the overall
performance of a repository system at that site to EPA’s new disposal
standards and NRC’s revised licensing regulations. DOE does not, as
required by the original guidelines, intend to determine the presence or
absence of each qualifying and disqualifying condition contained in the
technical guidelines. An overall system performance approach, DOE says,
will lead to a more efficient process for evaluating the suitability of the
Yucca Mountain site.

DOE  believes that the overall approach to a repository system’s
performance is the appropriate method to consider all relevant site
features because the approach identifies, in an integrated manner, those
attributes of the site and engineered components that are most important
to the protection of health and safety. According to DOE, the information
gained from the site investigations and the preliminary assessments of
how a repository would perform at the site show that the significance of
selected site characteristics should not be judged in isolation from one
another or from a specific design concept for the repository.17 For
example, a geological structural feature may seem to be a detriment
because it provides a fast pathway for groundwater flow through the
mountain when considered alone, but in consideration with a specific
repository design, the feature may act beneficially by channeling
groundwater flow away from the waste, thereby reducing the chances that
the groundwater will contact the waste packages and cause them to fail.

According to DOE, its amendments to the siting guidelines will be
developed concurrently with the development of a site-specific
radiological protection standard for Yucca Mountain by EPA and
conformance of the licensing regulations to this new standard by NRC.

17
 Consistent with the provisions in the original EPA standards, DOE is using an analytical method
known as “performance assessment,” which uses computer models to simulate and predict the
behavior of the Yucca Mountain site and repository over thousands of years.



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Moreover, as DOE agreed when it issued the original guidelines, the
Department intends to obtain NRC’s concurrence with the amended
guidelines.

After the completion of a public comment period, DOE expects to issue the
revised guidelines in 1997. A key uncertainty, however, is the timing of the
issuance of EPA’s standards and NRC’s revised licensing regulations.
According to DOE’s manager for site suitability and licensing, DOE needs
NRC to complete revisions to its licensing regulations 1 year before DOE
makes its determination of site suitability (now scheduled for
July 1999) and 2 years beforehand if NRC makes major changes to the
regulations. He added that DOE’s determination of the suitability of Yucca
Mountain will be based on comparing an up-to-date assessment of the
repository’s performance to EPA’s standard and NRC’s licensing regulations.




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                         To preserve the repository project at Yucca Mountain following the
                         unexpectedly low appropriations for fiscal year 1996, DOE redirected the
                         project to address the major unresolved technical issues so that, in 1998,
                         the Department can assess the viability of a repository at the site. DOE is
                         developing a strategy for containing and isolating waste in the repository
                         to guide the preparation of this assessment. The draft strategy specifies
                         the natural and engineered (man-made) barriers that DOE will rely on to
                         isolate waste from the accessible environment and provide the technical
                         basis for setting priorities for designing the repository and completing the
                         scientific investigation of Yucca Mountain. Following the viability
                         assessment, DOE would complete the work it believes is necessary to
                         (1) determine if Yucca Mountain is a suitable site for a repository,
                         (2) recommend selection of the site for that purpose, and (3) submit a
                         license application to NRC.

                         However, the limited information that DOE will have in several areas that
                         are important to its strategy for containing and isolating waste could affect
                         its ability to achieve its objectives for the repository project on its current
                         schedule. These key areas include the hydrology of Yucca Mountain and
                         the surrounding area, the effects of heat on the repository’s performance,
                         and the testing of candidate materials for waste packages.


                         In 1994, the Nuclear Waste Technical Review Board concluded that DOE
Waste Containment        had not established exploration and testing priorities for determining if
and Isolation Strategy   Yucca Mountain is a suitable site for a repository.18 To that end, the Board
                         recommended that DOE articulate a clear waste isolation strategy that
                         provides an understandable technical rationale for assigning priorities to
                         studies of the site. DOE agreed and began developing the elements of such
                         a strategy.

                         In July 1996, DOE published a draft of its evolving strategy for containing
                         and isolating waste in a repository at Yucca Mountain. The strategy, which
                         represents DOE’s approach to addressing and resolving issues related to the
                         long-term performance of the repository, is based on the observation that
                         there is very little water in the rocks in and around the repository area to
                         dissolve and transport radioactive materials to the environment. The goals
                         of the strategy are to contain nearly all radioactive materials within waste
                         packages for several thousands of years and ensure that doses to the
                         public living near the site will be acceptably low.

                         18
                           The Nuclear Waste Policy Amendments Act of 1987 created the Nuclear Waste Technical Review
                         Board as a source of independent review of the scientific and technical activities undertaken by DOE
                         in managing highly radioactive wastes.



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    The strategy relies primarily on emplacing waste packages in an area in
    Yucca Mountain above the water table to delay and minimize releases of
    radioactive materials to the environment when the waste packages finally
    begin to fail. Secondary lines of defense to enhance containment and
    isolation lie in potential engineered (man-made) barriers adjacent to the
    waste packages and in the natural system that are expected to delay the
    movement of radioactive materials released from waste packages.19 The
    strategy defines the following key attributes for predicting the
    performance of engineered and natural barriers:

•   The rate at which water seeps into the repository. Assessments of the
    repository’s performance have shown that water seeping into the
    emplacement areas is the most important attribute of the ability of the site
    to contain and isolate waste. This process affects all aspects of
    performance, from the life of the waste packages to the movement of
    radioactive materials.
•   The integrity of waste packages (containment). As long as waste packages
    remain intact, the waste will be completely contained and prevented from
    any contact with the surrounding rock or the groundwater. According to
    DOE, containment times exceeding 1,000 years are feasible.
•   The rate of release of radioactive materials from failed waste packages.
    Performance assessments have shown that the release rate is one of the
    key factors in determining the peak doses of radiation that the affected
    public would be exposed to each year.
•   The transport of radioactive materials through barriers. The potential
    radiation dose depends directly on the concentration of radioactive
    materials in water. These concentrations change as the materials move in
    water through engineered and natural barriers to points where people can
    use the water.
•   The dilution in the groundwater. Dilution is an important factor that can
    reduce concentrations of radioactive materials and limit doses of radiation
    to humans. If the amount of water seeping into the repository and
    contacting the waste is small, the concentration of radioactive materials
    will be reduced when the contaminated water is added to the
    groundwater.

    The strategy also hypothesizes that some cross-cutting issues, such as the
    effects on the repository’s performance of the heat generated by the waste,
    can be dealt with successfully as the repository is designed and that other
    issues, such as the potential effects of climate changes, human

    19
     DOE is evaluating whether a backfill of crushed rock around the waste packages will be used to limit
    water contact with the packages to delay corrosion and, following corrosion, to limit the dissolution
    and transport of radioactive materials.



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                       interference, and volcanoes, will not significantly reduce the repository’s
                       performance. The strategy outlines tests and analyses to be pursued to try
                       to substantiate the five key attributes and to address cross-cutting issues.

                       According to DOE, the waste containment and isolation strategy will guide
                       its plans for a viability assessment in 1998. DOE would use the strategy to
                       guide the scientific and engineering studies necessary to confirm or revise
                       the models that are used to predict the performance of the repository and
                       to provide the technical basis for a license application.

                       In a report on its activities for 1995, the Nuclear Waste Technical Review
                       Board concluded that DOE was making considerable progress in
                       developing its waste strategy and made several recommendations for
                       improving it. First, the Board said the strategy relies heavily on the
                       presumed dryness of the Yucca Mountain site and recommended that the
                       strategy identify ways to compensate for an unexpectedly high movement
                       of water between the repository and the water table. Second, the Board
                       criticized the qualitative descriptions of the waste attributes and
                       recommended that DOE designate a numeric limit for radiation doses to
                       individuals and specify conditions under which exposures to releases of
                       radioactive materials would be assumed to occur.

                       Also, the Board said, DOE’s strategy does not contain criteria for validating
                       or rejecting the five attributes; therefore, a clearer understanding is
                       needed of the degree of proof that is being sought for each attribute.
                       Finally, after pointing out that all five attributes address favorable
                       conditions, the Board said the strategy would be strengthened if DOE
                       placed more emphasis on identifying potential mechanisms for the
                       repository system to fail and on formulating testable hypotheses about the
                       importance of these mechanisms.


                       Knowing how water moves through and under Yucca Mountain is critical
Limitations in DOE’s   to the repository project. DOE is studying the hydrology of both the
Hydrology Program      groundwater beneath the site and the area above the water table because
                       the movement of water through the mountain to the groundwater is
                       considered the primary means by which radioactive materials could move
                       from the repository to the environment. Recently, the U.S. Geological
                       Survey identified a number of issues concerning studies of the saturated
                       (groundwater) and unsaturated (above the water table) zones at Yucca
                       Mountain.




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In April 1996, Geological Survey scientists wrote a memorandum that
updated their understanding of the key inputs for the models of the flow of
water in the saturated zone. They noted that as new issues about the
importance of uncertainties about the saturated zone have been raised, the
level of understanding of many issues has not increased. They attributed
this situation to the lack of new boreholes drilled to the saturated zone
since the mid-1980s and the limited testing of the saturated zone since
then. One key issue the scientists raised is the resolution of a large drop in
the elevation of the groundwater (hydraulic gradient) at the northern end
of Yucca Mountain that was discovered in 1981.20 Estimates of the
direction and rate that water moves beneath the site and how radioactive
materials would be diluted in the groundwater may differ considerably,
depending on different explanations of the cause of the gradient. The
gradient remains a concern because the scientists cannot account for its
origin. It would be difficult, they said, to claim that they understood the
hydrology of the site if they could not explain the cause of the most
striking feature in the area. Earlier, in 1992, the technical project officer
for the Geological Survey wrote that the large hydraulic gradient must be
understood to understand the hydrology of the saturated zone and that it
would be “folly” to determine the suitability of the site without a
reasonable understanding of this feature and its durability.

In commenting on a draft of our report, DOE pointed out that one existing
well is being used to test hypotheses about the origin of the large hydraulic
gradient and that the Geological Survey is currently interpreting the test
information. The test information, DOE said, may either tell it what it needs
to know or indicate how to approach the problem by, for example, drilling
another hole or identifying another type of necessary test. Also, NRC
commented that studies to date have not shown a significant negative
effect on performance as the result of the gradient.

The Geological Survey also identified what it considers important21
hydrological issues concerning the (1) scarcity of transport data and
(2) flow of water directly from the Amargosa Desert near Yucca Mountain
to Death Valley to the west. The first issue reflects a severe lack of
information to support transport models, which in turn support
performance assessment models. According to the Geological Survey


20
 A key issue is one that is central to having sufficient understanding of the saturated zone’s flow
system to make a meaningful evaluation of the contributions that the saturated zone can make in
meeting regulatory requirements.
21
 An important issue is one that warrants careful consideration but may not be resolvable or may be so
difficult or costly to resolve that the Yucca Mountain Project may choose not to resolve it.



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scientists, transport data are scarce because measurements are being
made at only one site and may be made at only one additional site in the
future. The second issue reflects a potential change in the conceptual
model of the flow of groundwater in the region. Little information is
available to choose among competing models, and what information is
available is subject to different interpretations. Acquiring additional,
unambiguous information, however, would be very expensive and may not
be warranted.

In June 1996, DOE issued a report on the Geological Survey’s program to
ensure the quality of its research on the repository project. Although the
report’s authors concluded that the quality assurance program was
adequate, they also expressed concern about persistent, major,
unquantified uncertainties at this stage in the project. The report’s authors
also concluded that the project was severely handicapped by the absence
of high-quality hydrochemical data from the site and the elimination of
most borehole drilling from DOE’s site investigation plans. Specifically, they
noted that (1) boreholes to resolve the cause of the large hydraulic
gradient north of the site and to test an aquifer at a second location have
not been drilled, (2) existing boreholes in the Amargosa Desert have not
been sampled or instrumented and drilling in the Southern Funeral
Mountains (southwest of Yucca Mountain, in the direction of Death Valley)
has not occurred, and (3) instrumentation to measure water levels in
numerous boreholes has been removed and mothballed. These actions are
inconsistent, they continued, with what is expected of a useful model for
the flow of water in the saturated zone, particularly insofar as such a
model would be used to support evaluations of the transport of radioactive
materials. The issues appear to have been caused by unrealistic
expectations for “bounding” system performance in the absence of data
that would allow uncertainties to be quantified.

According to the Geological Survey scientists, an important aspect of
understanding how water would flow through the unsaturated zone at
Yucca Mountain is to study the rate at which water infiltrates the mountain
from the surface. Using a network of shallow boreholes across the site,
scientists are monitoring changes in moisture content in the upper 50 feet
of ground where these changes occur each year. This monitoring program
is necessary to develop an adequate record of moisture changes in what is
one of the driest areas of the country. The Geological Survey has
developed a model of soil moisture and produced a preliminary map of the
rates at which water infiltrates the unsaturated zone across the mountain.
According to the scientists, the model is fairly rigorous, but certain



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assumptions must be made while using it. However, the infiltration
program has ended sooner than had been planned and no new work is
planned to study uncertainties in the model. The scientists are concerned
about whether there is a sufficient level of confidence in the supporting
assumptions used in its model of soil moisture and whether the data and
assumptions supporting the model can withstand external scrutiny. They
stated that drilling and instrumenting more boreholes would provide more
information, but project officials are considering an alternative approach
of compensating for uncertainty in this area by backfilling the repository
with a material that would keep water away from waste longer.

Geological Survey scientists are also concerned about the adequacy of the
studies of water moving through the repository horizon (i.e., percolation).
According to these scientists, such studies have been reduced
substantially from original plans. The project had planned to drill 17
boreholes to the water table at various locations around the site.
Monitoring of pneumatic pressure, temperature, and water potential was
to be performed in each borehole for a minimum of 3 to 5 years. According
to the Geological Survey, however, while 15 boreholes have been drilled, 4
of them were drilled in different locations than planned. Of the 15
boreholes, 8 do not reach the repository horizon, and no borehole has
been drilled deep enough to characterize the Ghost Dance Fault in the
Calico Hills Formation. In addition, only seven of the boreholes have been
instrumented to monitor pneumatic pressure, temperature, and water
potential. Finally, other tests have been reduced or deleted from the
testing program altogether.

In commenting on a draft of our report, DOE recognized that more
information on the saturated zone is needed and stated that its long-range
site investigation plan includes additional tests in the saturated zone. DOE
added, however, that its primary focus remains on the unsaturated zone
because of the importance of this area to its strategy for containing and
isolating waste. After DOE has acquired a better understanding of the
overall performance of the proposed repository system, the Department
said, it may decide that it can get better performance from the repository
system by changing waste package materials rather than by more precisely
defining some aspect of water flow. Finally, DOE stated that the concept of
backfilling waste storage rooms in the repository with a selected material
is one option for improving the repository’s performance but that this
concept is unrelated to the potential need to reduce hydrological
uncertainties.




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                       One other issue has recently emerged that affects DOE’s understanding of
                       the hydrology of the unsaturated zone at Yucca Mountain. DOE has
                       detected the presence of the isotope chlorine-36, produced from
                       atmospheric tests of nuclear weapons about 50 years ago, at the level of
                       the proposed repository. DOE has been testing for the presence of this and
                       other elements to provide information on the age of the water at various
                       locations in the mountain and on the travel time of water through
                       preferential paths, such as faults and fractures, in the rock. DOE found
                       elevated levels of chlorine-36 in samples from five locations within the
                       exploratory studies facility. According to the disposal program’s director,
                       the findings need not be, but could be, a critical problem. In DOE’s current
                       view, the findings appear to indicate rapid flow of water along preferential
                       pathways. DOE is collecting and analyzing additional samples to confirm
                       results and to provide new information on new areas of the exploratory
                       tunnel. In addition, DOE will perform more modeling studies to evaluate the
                       chlorine-36 data as they relate to the understanding of the hydrologic
                       processes of Yucca Mountain and DOE’s conclusions about the repository’s
                       performance.


                       According to DOE, a key issue that it must address in its investigation of
Limited Information    Yucca Mountain is the uncertainty about the interaction of the heat
Will Be Available on   generated by waste in the repository with the surrounding rock, the water
the Effects of Heat    contained in Yucca Mountain, and the packages containing waste. To
                       provide information on this issue, DOE planned a series of experiments in
From Waste             the exploratory studies facility and at the surface near Yucca Mountain
                       that began in 1996 and will continue until about 2000. DOE’s general testing
                       strategy is to perform simpler, smaller-scale tests first and then move to a
                       more complex, larger test. However, a peer review team, the Nuclear
                       Waste Technical Review Board, and DOE’s Lawrence Livermore National
                       Laboratory have raised concerns about the testing program. In general,
                       these concerns are that DOE is not doing large enough tests for long enough
                       periods of time.

                       Because of the decay of radioactive materials in nuclear waste, it will
                       continue to produce heat for thousands of years after its disposal in a
                       repository. The Nuclear Waste Technical Review Board described this
                       issue—called thermal loading—as one that would largely determine the
                       level of uncertainty about the repository’s long-term performance. As early
                       as 1990, the Board stated that the strategy selected to control the
                       temperatures in a repository is a fundamental decision because the
                       selected strategy will affect most components of the waste management



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system, including methods for storing and transporting waste, the design
of waste packages, and the design, size, performance, and cost of the
repository.

The thermal load of the repository has the potential to significantly
redistribute moisture within Yucca Mountain, resulting in extended
periods of dryness in the repository or channeling of moisture toward
waste packages. Therefore, it is necessary to understand the effects of the
thermal load on the temperature of the surrounding rock as well as the
movement of water and gases in the vicinity of the repository to have
confidence in predictions of containment and long-term waste isolation.
The distribution of temperature, liquid saturation, and humidity within the
repository will influence the corrosion of metals, alteration of minerals,
and geochemistry. These factors are important in predicting the
containment time within the waste package and transport times through
both the engineered and natural barrier systems.

DOE’s  thermal test strategy described several sequential tests, in general
order of scale and complexity, in the exploratory studies facility. Early
tests would be relatively small in scale and limited in complexity.
Information gained from these early tests would help in understanding and
interpreting results from larger, more complex tests of longer duration. In
the first underground test, a long heating rod would be inserted in a
horizontal hole to heat the surrounding rock. The next test that DOE
intends to perform is intended to heat a larger volume of rock with rows of
heating rods emplaced in the walls of an excavated room and in heaters,
shaped like waste containers, placed on the floor of the room. DOE
considers this test, called a drift-scale test, to be a smaller, less complex,
and less costly surrogate to a large-scale, long-duration test that would
address information needs that could only be answered by tests that
approach the scale of several waste storage rooms (drifts) in the
repository.

In addition to its planned underground thermal tests, DOE initiated a test on
the surface near Yucca Mountain in a large isolated block of rock. This test
was intended to develop and evaluate techniques and data for monitoring
the changes in thermal and hydrological properties in a heated rock mass
with controlled boundary conditions and provide data to understand the
larger and more complex tests in Yucca Mountain. DOE stopped this
large-block test in fiscal year 1996 due to budget reductions but restarted it
in fiscal year 1997.




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In 1995, DOE established a team of six experts to conduct an external peer
review of its thermal testing program. The objective of the review was to
evaluate the program’s approach to understanding the thermohydrologic
conditions at Yucca Mountain that would be generated by the heating of
the repository. In its review of the thermal testing program, the review
team’s primary recommendation was that a large-scale, long-duration test
and the large-block test be carried out. The review team concluded that
the smaller, less complex tests with single and multiple heating rods are
not needed because these tests would be insufficient in scope to fully
develop relevant processes. Only the large-scale, long-duration test, the
review team said, would give results over a cross-sectional area large
enough to be meaningful. The review team noted that DOE is in a major
undertaking involving the thermohydrologic behavior of a fractured rock
mass for which there is no precedent. By setting up a long-term
experiment, DOE could acquire a substantial database, and analysis of the
data could begin almost immediately after the experiment has begun. In
addition, the review team said, critical design decisions cannot be made
using smaller tests because the volume of rock being affected is too small
to develop the effects that reveal the “global” picture. The team cautioned
that the cost and time to perform the large-scale, long-duration test would
be substantial but also stated that scientific defensibility must overrule
mandated scheduling and cost constraints. If DOE is forced to choose from
among all the tests, the review team said, the large-scale, long-duration
test should be done.

DOE  disagreed with the review team’s recommendation on the large-scale,
long-duration test. According to DOE, its planned approach to conducting
the large-block test, the test with a single heating rod, and the drift-scale
test is consistent with DOE’s strategy of progressing from simple to
complex and small to large thermal tests and will likely provide the
necessary data to defend a thermal loading strategy for the site.
Consequently, DOE’s current plans do not include performing the
large-scale, long-duration test; however, the Department will consider
implementing the large-scale, long-duration test if it determines that the
planned tests of smaller scale and duration do not provide sufficient data
and confidence in related models.

In 1995, the Nuclear Waste Technical Review Board wrote that there is
considerable uncertainty associated with the thermohydrologic processes
at Yucca Mountain. According to the Board, there is agreement that some
heater tests have to be done, but there is no clear enunciation of what
types of data are to be collected, how they will be obtained, or the ultimate



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                       use to which the data will be put. Furthermore, the relatively limited
                       experience of the scientific community in modeling complex
                       thermohydrologic problems in areas like the unsaturated zone at Yucca
                       Mountain will make it especially difficult for DOE to establish the validity of
                       predictions through short-term thermal testing. The Board supported the
                       initiation of a long-term, tunnel-scale thermal test, recommended that DOE
                       give more thought to how more information can be obtained from all
                       heater tests, and concluded that little data will be available for use in DOE’s
                       1998 viability assessment.

                       Finally, as early as 1992, DOE’s Lawrence Livermore National Laboratory
                       had raised concerns about the length of heater tests at Yucca Mountain.
                       DOE had established a task force to consider this issue.22 A draft report by
                       the task force recommended that in order to meet the schedule for
                       submitting a license application in 2001, a heater test to be performed by
                       the laboratory should be completed in 6 years. At that time, scientists at
                       the laboratory argued that a 6-year test period would barely be long
                       enough for geochemical reactions to take place that could be sampled.
                       Therefore, the scientists said, the 6-year test duration was the minimum
                       time that they could support from a technical standpoint. As currently
                       planned, the drift-scale test would run for 4 years with options for a longer
                       test period if evaluation of the test data warrants the longer duration.

                       In commenting on a draft of our report, NRC stated that its principal
                       concern is that the thermal testing be representative of the range of
                       repository conditions, rather than the scale or duration of the tests. It
                       added that the testing information that will be available at DOE’s current
                       planned date of license application will be limited and will need to be
                       confirmed by additional data collected during performance confirmation
                       or, if the additional data differ significantly from the original design bases
                       and assumptions in the license application, the design may be modified
                       through the license amendment process.


                       NRC has questioned whether DOE is allowing enough time to test potential
Limitations on Waste   materials for waste packages before it submits a license application to NRC.
Package Research       The waste package refers to the waste form and any containers, shielding,
                       packing, and other absorbent materials surrounding an individual waste
                       container. According to DOE, waste packages will consist of multiple metal

                       22
                         The Yucca Mountain Project Office established the Heater Test Duration Task Force to consider
                       required test durations for the project. The task force consisted of representatives of the organizations
                       responsible for testing on the Yucca Mountain Project as well as management and operating
                       contractor representatives.



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barriers designed to contain the wastes by resisting corrosion for
thousands of years. In July 1995, NRC’s representatives observed DOE’s
audit of the effectiveness of the waste package design processes used by
the Department’s primary contractor for the repository project. Following
the audit, NRC’s representatives reported to their managers at NRC’s
headquarters that DOE is following a strategy of continuing development
and analytical work on a selected set of candidate waste package
materials. According to this report, the final choice of materials for waste
packages will not be made until a prototype waste package is made or by
the time DOE submits its license application to NRC. Also, DOE’s primary
contractor for the repository project indicated that none of the currently
available data on the performance of materials, such as corrosion, will be
used for licensing. NRC’s report stated that the contractor plans to obtain
test data over only 5 years to analyze long-term failures of waste packages
in the license application. Validating waste package performance is
expected to continue during the operation of the repository. In their
report, NRC’s representatives concluded that predicting the long-term
performance of waste packages will be difficult using only the relatively
short-term test results that will be available when the license application is
submitted in 2002.

DOE   does not agree with the comments in NRC’s report. The Department
expects that available data on mechanical and corrosion performance of
materials will be used to support a license application. Also, DOE said it is
not clear that NRC’s conclusion about predicting long-term performance of
waste packages from short-term test results is accurate. NRC said it may
still be possible to show, with reasonable assurance, that the overall
system performance standard is met at the time of license application. NRC
added that its licensing regulations anticipate that additional research may
be required to determine the adequacy of the design and provide that a
license to construct a repository may have conditions related to the
satisfactory resolution of safety questions for which research is being
conducted.




Page 40                    GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
Appendix III

Comments From the Department of Energy




               Page 41   GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
Appendix III
Comments From the Department of Energy




Page 42                 GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
Appendix III
Comments From the Department of Energy




Page 43                 GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
                  Appendix III
                  Comments From the Department of Energy




Now on p. 2.




Now on p. 5.


Now on pp. 6,7.




Now on p. 8.




                  Page 44                 GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
                Appendix III
                Comments From the Department of Energy




Now on p. 11.




Now on p. 13.




Now on p. 14.




Now on p. 24.


Now on p. 33.




                Page 45                 GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
                    Appendix III
                    Comments From the Department of Energy




Now on pp. 33,34.




Now on p. 34.




Now on p. 37.




Now on p. 39.




                    Page 46                 GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
Appendix III
Comments From the Department of Energy




Page 47                 GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
Appendix IV

Comments From the Nuclear Regulatory
Commission




              Page 48   GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
                Appendix IV
                Comments From the Nuclear Regulatory
                Commission




Now on p. 14.




Now on p. 14.




Now on p. 14.




Now on p. 14.




                Page 49                 GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
                    Appendix IV
                    Comments From the Nuclear Regulatory
                    Commission




Now on p. 39.




Now on p. 10.




Now on pp. 10,15.




Now on p. 10.




                    Page 50                 GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
                Appendix IV
                Comments From the Nuclear Regulatory
                Commission




Now on p. 9.




Now on p. 29.




Now on p. 9.




Now on p. 26.


Now on p. 12.




                Page 51                 GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
Appendix IV
Comments From the Nuclear Regulatory
Commission




Page 52                 GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
Appendix V

Scope and Methodology


             To identify the adjustments the Department of Energy made to its disposal
             program and the potential impediments to achieving the Department’s
             current objectives and schedule for the repository project, we performed
             our work primarily at DOE’s headquarters in Washington, D.C., and its
             Yucca Mountain Site Characterization Project Office in Las Vegas, Nevada.
             At these locations, we obtained and reviewed information from officials of
             DOE’s Office of Civilian Radioactive Waste Management, including officials
             assigned to the site investigation project; officials of DOE’s management
             and operating contractor for the project; and officials of the U.S.
             Geological Survey, which is a participant on the project. We also visited
             the candidate repository site at Yucca Mountain, Nevada, including
             observing activities under way in the exploratory studies facility tunnel in
             the mountain.

             We also obtained and reviewed information from officials of the
             (1) Division of Waste Management, Nuclear Regulatory Commission;
             (2) Office of Radiation and Indoor Air, Environmental Protection Agency,
             Washington, D.C.; (3) Agency for Nuclear Projects, state of Nevada,
             Carson City, Nevada; (4) comprehensive planning office of Clark County,
             Nevada; and (5) Nuclear Waste Technical Review Board, Arlington,
             Virginia.




             Page 53               GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
Appendix VI

Major Contributors to This Report


                        Dwayne E. Weigel, Assistant Director
Resources,              John J. Bagnulo, Senior Evaluator
Community, and          Victor J. Sgobba, Senior Evaluator
Economic                Cassandra Joseph, Reports Analyst
                        Susan W. Irwin, Senior Attorney
Development
Division, Washington,
D.C.




                        Page 54              GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
Related GAO Products


              Department of Energy: Unethical Conduct at DOE’s Yucca Mountain
              Project (GAO/OSI-96-2, Sept. 30, 1996).

              Nuclear Waste: DOE’s Management and Organization of the Nevada
              Repository Project (GAO/RCED-95-27, Dec. 23, 1994).

              Nuclear Waste: Comprehensive Review of the Disposal Program Is Needed
              (GAO/RCED-94-299, Sept. 27, 1994).

              Nuclear Waste: Foreign Countries’ Approaches to High-Level Waste
              Storage and Disposal (GAO/RCED-94-172, Aug. 4, 1994).

              Independent Evaluation (GAO/RCED-94-258R, July 27, 1994).

              Nuclear Waste: Yucca Mountain Project Management and Funding Issues
              (GAO/T-RCED-93-58, July 1, 1993).

              Nuclear Waste: Yucca Mountain Project Behind Schedule and Facing
              Major Scientific Uncertainties (GAO/RCED-93-124, May 21, 1993).

              Energy Issues: Transition Series (GAO/OGC-093-13TR, Dec. 1992).

              Nuclear Waste: Status of Actions to Improve DOE User-Fee Assessments
              (GAO/RCED-92-165, June 10, 1992).

              Nuclear Waste: DOE’s Repository Site Investigations, a Long and Difficult
              Task (GAO/RCED-92-73, May 27, 1992).

              Nuclear Waste: Development of Casks for Transporting Spent Fuel Needs
              Modification (GAO/RCED-92-56, Mar. 13, 1992).

              Nuclear Waste: Operation of Monitored Retrievable Storage Facility Is
              Unlikely by 1998 (GAO/RCED-91-194, Sept. 24, 1991).

              Nuclear Waste: Changes Needed in DOE User-Fee Assessments
              (GAO/T-RCED-91-52, May 8, 1991).

              Nuclear Waste: DOE Expenditures on the Yucca Mountain Project
              (GAO/T-RCED-91-37, Apr. 18, 1991).

              Nuclear Waste: Changes Needed in DOE User-Fee Assessments to Avoid
              Funding Shortfall (GAO/RCED-90-65, June 7, 1990).



              Page 55               GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
           Related GAO Products




           Nuclear Waste: Quarterly Report as of March 31, 1989 (GAO/RCED-89-178,
           Aug. 14, 1989).




(302186)   Page 56                GAO/RCED-97-30 Impediments to the Yucca Mountain Repository
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