ML20078D787
| ML20078D787 | |
| Person / Time | |
|---|---|
| Issue date: | 09/30/1994 |
| From: | Michael Lee, Mcconnell K NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | |
| References | |
| NUREG-1494, NUDOCS 9411080076 | |
| Download: ML20078D787 (37) | |
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Staff Technical Position on Consideration of Fault Displacement Hazards in Geologic Repository Design e
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NUREG-1494 Staff Technical Position on Consideration of Fault Displacement Hazards in Geologic Repository Design l
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1 Manuscript Completed: March 1994 Date Published: September 1994 K. I. McConnell, M. P. Lee l
Division of Waste Management Omce of Nuclear Material Safety and Safeguards i
U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 i
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ABSTIMCT Nuclear Regulatory Commission regulations for the designing the geologic repository to take into account the disposal of spent nuclear fuel and high-level radioactive attendant effects (e.g., displacement) of faults of waste in a geologic repository recognize it t fault regulatory concern and expresses the staff's views on what displacement is a potentially adverse condition (10 CFR is needed from the U.S. Department of Energy if it 60.122(c)(11) and 60.122(c)(20)). However, they do not chooses to locate structures, systems, and components prohibit designing the t logic repository against the important to safety or important to waste isolation in effects of such a potentially adverse condition. This Staff areas that contain faults of regulatory concern.
Technical Position recognizes the acceptability of
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i iii NUREG-1494
t i
I CONTENTS ae v
ABSTRACT.......................................................................................
iii ACKN OWLEDG MENTS...........................................................................
vii.
t
- 1. INTR ODU CTION...............................................................................
1 1.1 Background.................................................................................
1 1.2 STPs as Tbchnical Guidance..................................................................
2 l
- 2. REG ULATORY FRAMEWORK.................................................................
3
- 3. STAFF TECHNICAL POSITIONS................................................................
4
.4.
DISCUSSION...................................................................................
5 5.REFE.o_cwcc................................................................................
7 APPENDICES AGLOSSARY.....................................................................................
A-1 B APPLICABLE 10 CFR PART 60 REGULATIONS.................................................. B-1 C DISPOSITION OF PUBLIC COMMENTS ON MARCH 18,1993, DRAFT STAFF TECHNICAL POSITION......................................................... C-1 y
D ACNW CO M MENTS............................................................................ D-1 4
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ACKNOWLEDGMENTS The authors gratefully acknowledge substantial have been-incorporated into the text of this Staff contributions from the staffs of the Division of Waste Tbchnical Position, as well as from Ellen Kraus, for.
i Management, the Office of the General Counsel, and the editorial guidance.
Center for Nuclear Waste Regulatory Analyses, which '
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vii NUREG-1494
1 INTRODUCTION The Nuclear Regulatory Commission Staff Technical Position (STP) on " Investigations to Identify Fault Displacement Hazards and Seismic Hazards at a Geologic Repositoty" (see NUREG-1451 (McConnell et al.,1992)) described an acceptable approach to identify and investigate faults (or fault zones) of possible regulatory concern to the geologic repositoty. In the approach described in that STP, those faults that are considered to be of possible regulatory concern to the geologic repository are ones that are subject to displacement (i.e., stratigraphic offset) and that may affect the design or performance of structures, systems, and components important to safety or important to waste isolation, and/or may provide significant input into models used in assessments of design or performance of structures, systems, and components important to safety or important to waste isolation.1 This STP addresses those situations in which faults of regulatory concern (designated as "'I}pe I" faults in NUR EG-14512) exist or are assumed to exist at the location of systems, structures, and components important to safety or important to waste isolation. Specifically, this STP recognizes the acceptability of designing the geologic repository to take into account the attendant effects (e.g., displacement) of faults of regulatory concern and expresses the staff's views on what is needed from DOE, if DOE chooses to locate structures, systems, and components important to safety or important to waste isolation in areas that contain "T}pe 1" faults (e.g., faults with Quaternary-age 3 displacement). For the purposes of this STP, "I}pe I" faults are adequately taken into account, accommodated, or compensated for when it can be demonstrated that their effects do not preclude meeting the pertinent 10 CFR Part 60 design criteria and the pre-and post-closure performance objectives. However, DOE should seek early resolution of fault-related design and performance issues, at the staff level, before submitting a license application to construct and operate a geologic repository.
1.1 Background
As with many potentially severe natural conditions, there is much uncertainty associated with the design and evaluation of nuclear facilities for seismic hazards (e.g., the effects of earthquake-related ground motion) and/or fault displacement hazards. Inadequate or inconclusive geologic evidence has made it difficult to establish accurate parameters for specific locations or the design basis for individual facilities-Despite recent advances in the treatment of fault displacement hazards (Coppersmith and Youngs,1992), large uncertainties still remain regarding their characterization. Because of these uncertainties,it has been difficult to place the contribution of geologic risk, specifically fault displacement, into proper perspective in the development of individual nuclear facility designs, thus typically leading to the assumption of conservative design bases (see NRC,1979). For example, for existing nuclear power plants licensed under Appendix A to 10 CFR Part 100 ("Scismic and Geologic Siting Criteria for Nuclear Power Plants" in Code offederalRegulations, Title 10, " Energy"), NRC requires " detailed" faulting investigations overan area of up to 4 times that containing the fault (orfault zone)in question 4to determine if the facility can be designed to withstand the effects of faulting. Because of the uncertainty associated with the assessment of the fault i
displacement hazard in the zone requiring detailed faulting investigation, the approach commonly used by past NRC license applicants has been to relocate nuclear facilities outside this zone, thereby obviating the need for such detailed
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investigations. Although not required by NRC's regulations, this practice has led to what could be referred to as a de facto
- setback" criterion.
1 10 CIR Part 60 is structured around the multiple-barrier concept and the Commission's principles of defense-insfepth, and primarily focuses on repository performance. 'Ihe applicant (the U.S. Department of Energy (DOE)) must demonstrate compliance with the performance ob-jectives of support E of 10 CFR Part 60, to have a potential geologic repisitory licensed. To ensure that such compliance can be demon-1 strated,10 CFR Part 60 sets out a number of specific siting and design entena. Performance issues are, therefore, closely linked with siting and design issues, ;and the staff position set out herein should be considered in that context.
2"Iype I" faults refer to those faults or fault zones that are subject to displacement and of sufficient length and located in such a manner that they may affect repository design and/or performance. As such, they should be investigated in detad. Only faults that are determined to be
" Type I are of regulatory concern. because it is those faults, both inside and outside the controlled area, that may require consideration in repository design, could have an effect on repository performance, Or could provide significant input into models used to assess repository per-formance (McConnell et al.,1992, p. 5)
Mhe staff has taken the position that, afor regulatory purposes," the age of the Quaternary Period is 2 million years (see NRC,1983b, p. 373).
4This is generally referred to as the " control width." See %ble 2, contained in Item (b)(1)," Determination of Zone Requiring Detailed Faulting Investigation," in Section V
- Seismic and Geologic Design bases," in Appendix A to 10 CIR Part 100. It should be noted, though, that NRC recently proposed amendments, to 10 CFR Part 100, to update the critena used in decisions regarding the siting of future nuclear power reactors including geologic, seismic, and earthquake engineering considerations (see NRC, 1992; 57 FR 47802-47814). Ihe proposed regulation would identify and establish basic requirements.
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1 NRC regulations for the disposal of spent nuclear fuel and high-level radioactive waste in a geologic repository,10 CFIt Part 60 (Code offederal Regulations, Title 10. " Energy"), recogni/c that fault displacement can be a potentially adverse condition (i.e 10 CFR 60.122(c)(20) or 60.122(c)(11)); however, they do not prohibit designing the geologic repository to q
accommodate the effects of such a potentially adverse condition. Given the differences in function and performance between geologic repositories and other nuclear facilities, the staff has developed this STP to express its views on an j
acceptable approach to the treatment of fault displacement in the design and operation of a geologic repository.
1 1.2 STPs as Technical Guidance STPs are issued to describe, and make available to the public, methods acceptable to the NRC staff, for implementing i
1 specific parts of the Commission's regulations, and to provide regulatory guidance to DOE. STPs are not substitutes for i
regulations, and compliance with them is not required. Methods and solutions differmg from those set out in the STPs will be acceptable if they provide a basis for the findings requisite to the issuance or continuance of a permit or license by the Commission.
4 Published STPs will be revised, as appropriate, to accommodate comments and to reflect new information and experience.
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i 2 REGULATORY FRAMEWORKS 10 CFR Part 60 is structured around the multiple-barrier concept and the Commission's principles of defense-in-depth, and primarily focuses on repository performance objectives.
The applicant (DOE) must demonstrate compliance with the performance objectives of Subpart E of 10 CFR Part 60, to receive a construction authorization.10 CFR Part 60 sets out a number of general siting (10 CFR 60.122(b-c)) and design criteria (10 CFR 60.131-135), to ensure that such compliance can be demonstrated. However, there are no specific site suitability or exclusionary technical criteria (NRC,1981; 46 FR 35284). lf potentially adverse conditions (10 CFR 60.122(c))
are identified as being present, they must be thoroughly analyzed (10 CFR 60.21(cXIXiiXA),60.21(cXIXiiXB), and 60.21(cXIXii)(F)), and it must be demonstrated that the conditions can be compensated for by the geologic repository design and/or by favorable conditions present in the geologic setting (10 CFR 60.122(a)). Although the multiple-barrier concept allows for advanced engineering design, the technical criteria in Subpart E of 10 CFR Part 60 are structured in a manner so as to favor the selection of a candidate site with certain natural waste isolation capabilities.
Thus, because of site-and design-specific considerations, the language in 10 CFR Part 60 is intentionally non-prescriptive; that is, it leaves to DOE the opportunity and responsibility to determine, in the first instance, how to site and design a potential geologic repository. As part of this process, DOE will conduct a program of site characterization (see DOE, 1988), during which it will gather sufficient information on the characteristics of a candidate site to permit an evaluation of its waste isolation capabilities and design in the context of the Subpart E performance objectives. Given this framework, DOE may propose engineering and/or design solutions to actual or potential geologic effects (such as fault displacement (60.122(cX20))at a candidate site, in concert with the occurrence of certain favorable conditions (10 CFR 60.122(b)); these solutions may be sufficient to enable DOE to demonstrate that the pertinent 10 CFR Part 60 performance objectives will be satisfied. Performance, therefore, is closely linked with siting and design, and the staff position described here must be understood in that context.
Finally, as noted earlier, the staff has issued an STP, NUREG-1451 (see McConnell et al.,1992) to provide guidance on investigations to identify fault displacement hazards and seismic hazards at a geologic repository. DOE should consider the earlier referenced STP in conjunction with this HP.
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6Certain revisions to 10 CFR 60.21 and 60.122 have been proposed by the commission (see NRC 1993; $8 FR 36902). Should these revisions be adopted, the language of the citations quoted in Appendix B of this SP would need to be revised. They would not, however, require any change to the staff's technical positions set out here.
3 STAFF TECHNICAL POSITIONS In view of the aforementioned policy considerations and statements of regulatory consideration underpinning 10 CFR Part 60, the staff has adopted the following technical positions concerning hazards resulting from fault displacement (i.e.,
stratigraphic offset) at a geologic repository.
(1)
It is the NRC staff position that the presence of "I)pe 1" faults, as defined by NUREG-1451, inside the controlled area of a geologic repcitory, does not, by itself, disqualify a candidate site for a geologic repository.e (2)
In general, areas within the controlled area of a geologic repository that contain "I}pe I" faults should be avoided, where this can be reasonably achieved, when locating structures, systems, and components important to safety or important to waste isolation. However, if DOE chooses to locate structures, systems, and components important to safety or important to waste isolation in areas that contain "I)pe 1" faults, then:
(a)
DOE should recognize that reliance on engineering may be of limited value; and (b)
DOE must be able to demonstrate, with reasonable assurance, that any proposed geologic reposbory designed to accommodate the effects of faulting meets the 10 CFR Part 60 design criteria, and pre-and post-closure performance objectives.
'NUREG-1451 specifies that faults not conisdered to be "lype !" faults (i.e., "Iype II" and "Iype 111" faults) be peri <xlically reevaluated, based on the results of subsequent site characterization activities, at which time they may be reclassified as "I}pe 1" faults.
I 4 DISCUSSION Re following discussion parallels the list of technical positions given in Section 3.
(1)
In the statement of considerations for the proposed rule, the Commission noted that in proposing siting requirements, there are no specific site suitability or exclusionary technical criteria in 10 CFR Part 60. Rather, l
the Commission encouraged "... the selection of a site with favorabic geologic conditions.. [in order to]...
j greatly enhance the Commission's ability to make the prescribed findings.. " (NRC,1983a; 48 FR 28203)
However, the Commission identified certain site characteristics corsidered favorable for a geologic repository, as well as characteristics that, if present at the site, might compwmise site suitability and that would require careful analysis and measures as may be necessary, to compensate for them adequately. In the case of potentially adverse conditions, the Commission noted that there is not ".. the presumption of [ site]
unsuitability because of the presence of an unfavorable characteristic.." (NRC, 1981; 46 FR 35284) His axiom was later reinforced in the final rule, where the Commission noted that a site ".. was not disqualified as a result of the absence of a favorable condition or the presence of a potentially adverse condition.. "(NRC, 1983a: 48 FR 28201) His philosophy requires that if a potentially adverse condition, such as faulting, is prent, then DOE is required by the regulations to thoroughly characterize and analyze the condition, and in doing so must demonstrate that the condition can be compensated for by repository design and/or by other favorable conditions present nt this site.
'(2)(a) In promulgating 10 CFR Part 60, the Commission recognized that there would be considerable uncertainty in predicting the performance of a geologic repository for tens of thousands of years. Natural systems are difficult to characterize, and any understanding of a candidate site would have significant limitations and uncertainties. Tb overcome these limitations and uncertainties, the Commission adopted a multiple barrier, defense-in-depth approach consisting of engineered barriers (i.e., waste packages and the underground facility) and the natural barrier provided by the geologic setting.13y partitioning the geologic repository into two major barriers, the Commission sought to exploit the ability to design those engineered features as a means of reducing some of the uncertainties in predicting the performance of the natural system.
However, the Commission recognized that, at some point, the containment capabilities of the engineered system might prove ineffective, and "the geologic setting must provide for the isolation of wastes" (NRC,1981; 46 FR 35282). Moreover, the staff believes that the reliability of certain types of engineered measures are subject to limitations, and like the geologic setting, would represent an additional source of uncertainty in the evaluation of performance. Although (complex) engineering measures are not inherently unacceptable, their reliability must be carefully scrutinized in the licensing process (NRC,1983a; 48 FR 28213). In light of this consideration, the staff has attempted to identify and, when practicable, reduce sources of uncertainty in predicting geologic repository performance. Hus, the Commission adopted the provision, in the final rule, that rock or groundwater conditions that would require " complex" engineering measures could be viewed as "potentially adverse conditions" (10 CFR 60.122(c)(20))(Opt. cit).
Although 10 CFR Part 60.122(c)(20) does not specify what types or kinds of engineering measures are regarded as " complex," and thus the predicate of a potentially adverse condition, the staff believes that attempting to design the repository for the effects of fault displacement may pose several engineering challenges that, historically, have proven to be difficult to address.13ecause of these challenges, engineering solutions cannot always be demonstrated to compensate for the effects of ground displacement phenomena.7 Therefore, because of the uncertainties in the characterization of tectonic hazards, it may be difficult for DOE to demonstrate, with " reasonable assurance," that its engineering solutions to the actual or potential effects of fault displacement will compensate for the condition. Thus, the staff believes that when locating structures, systems, and components important to safety or important to waste isolation, it may be preferable, for the reasons noted previously, to avoid areas subject to fault displacement, rather than attempting to design for their effects.
(2)(b) The Commission also noted, in the statement of considerations for the rule, that in addition to a site with superior waste isolation capabilities, DOE would have to rely on certain engineering and/or design measures 71n the context of the geologic repository program, the issue of engineering design and faulting was recently raised by the Nuclear Waste 'Ibchnical Review Board (NWIRB). In this regard, the NWrRB critically noted that ".. although engmeering structures have been designed to accommo-date the effects of fault displacement, such design is not common practice among engineers (see NWIRB,1992, p.14).
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to provide " reasonable assurance" of meeting the relevant 10 CFR lbrt 60 standards and criteria. 'Ib enable the Commission to reach the requisite findings, with reasonable assurance,10 CFR Ibrt 60 requires a careful and exhaustive analysis of all features of the repository. For example, the regulatory criteria set forth in 10 CFR 60.21(cXIXii) require, from DOE, a description and assessment of the site at which the proposed geologic repository operations area (GROA) is to be located, with appropriate attention to those features (i.e.,
potentially adverse conditions, as defined in 10 CFR 60.122(c)) of the site that might affect GROA design and performance. The description and assessment called for in 10 CFR 60.21(cX1)(i-ii) must be in sufficient depth to support the assessment of the effectiveness of engineered and natural barriers called for in 10 CFR 60.21(cXIXiiXD), as well as the analysis of design and performance requirements for structures, systems, and components important to safety called for in 10 CFR 60.21(cX3).
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5 REFERENCES Code offederalRegulations, " Disposal of High-Level Radioactive Wastes in Geologic Repositories," Part 60, Chapter I, Title 10, " Energy."
Code of Federal Regulations, " Reactor Site Criteria," Part 100, Chapter I, Title 10, " Energy."
Coppersmith, K.J., and R.R. Youngs, "Modeling of Fault Rupture Hazz.rd for the Proposed Repository at Yucca Mountain, Nevada" Proceedmgs of the Third International Conference on High-Level Radioactive Waste Management, American Nuclear Society /American Society of Civil Engineers, Las Vegas, Nevada, April 12-16,1992, vol.1, pp.1142-1150.
McConnell, K.I., M.E. Blackford, and A.B. Ibrahim, " Staff Tbchnical Position on Investigations to Identify Fault Displacement Hazards and Seismic Hazards at a G eologic Repository," Nuclear Regulatory Commission, NUREG-1451, August 1992.
Nuclear Regulatory Commission, " Identification of Issues Pertaining to Seismic and Geologic Siting Regulation, Policy, and Practice for Nuclear Power Plants," SECY-79-300, April 27,1979.
Nuclear Regulatory Commission," Disposal of High-Level Radioactive Wastes in Geologic Repositories: Proposed Rule,"
Federal Register, Vol. 46, No.130, July 8,1981, pp. 35280-35296.
Nuclear Regulatory Commission, " Disposal of High-Level Radioactive Wastes in Geologic Repositories; Tbchnical Criteria [ Statement of Considerations in Final Rule]," FederalRegister, Vol. 48, No.120, June 21,1983a, pp. 28194-28229.
Nuclear Regulatory Commission," Staff Analysis of Public Comments on Proposed Rule 10 CFR Part 60, ' Disposal of High-Level Radioactive Wastes in Geologic Repositories,'" Office of Nuclear Regulatory Research, NUREG-0804, December 1983b.
Nucicar Regulatory Commission, " Reactor Site Criteria; Including Seismic and Earthquake Engineering Criteria for Nuclear Power Plants and Proposed Denial of Petition for Rulemaking from Free Environment, Inc., et al. [ Proposed rule and proposed denial of petition from Free Environment, Inc., et al.],"FederalRegister, Vol. 57, No. 203, October 20,1992, pp.47802-47814.
Nuclear Regulatory Commission, " Disposal of High-Level Radioactive Wastes in Geologic Repositories; Investigations and Evaluation of Potentially Adverse Conditions," Federal Register, vol. 58, no.130, July 9,1993, pp. 36902-36905.
Nuclear Waste Technical Review Board, Eifth Report to the U.S. Congress and the U.S. Secretary ofEnergy, U.S. Government Printing Office, June 1992.
U.S. Department of Energy, " Site Characterization Plan, Yucca Mountain Site, Nevada Research and Development Area, Nevada," Office of Civilian Radioactive Waste Management, Nevada Operations Office / Yucca Mountain Project Office, Nevada, DOE /RW-0199,9 Vols., December 1988.
APPENDIX A GLOSSARY As used in this guidance:
Controlled Area
- means a surface location, to be marked by suitable monuments, extending horizontally no more than 10 kilometers in any direction from the outer boundary of the underground facility, and the underlying subsurface, which area has been committed to use as a geologic repository and from which incompatible activities would be restricted following permanent closure.
Faults ofregulatory concern means those Type I faults that: (1) are subject to displacement; and (2) may affect the design or performance of structures, systems, and components important to safety, containment, or waste isolation; and/or (3) may provide significant input to models used in assessments of design or performance of structures, sycemc, and components important to safety, containment, or waste isolation (see McConnell et al.,
1002).
Geologic Setting
- rneans the geologic, hydrologic, and geochemical systems of the region in which a geologic repository operations area is or may be located.
Seismic ha:ard is a set of conditions, based on the potential for the occurrence of earthquakes, that might have a negative effect on facilities that protect the health and safety of the public.
Site
- means the location of the controlled area.
TypeIfaults refers to those faults or fault zones that are subject to displacement and of sufficient length and located in such a manner that they may affect repository design and/or performance. As such, they should be investigated in detail (McConnell et al.,1992, p. 5).
Type IIfaults refers to those faults or fault zones that are candidates for detailed investigation (McConnell et al.,1992, p. 5).
Type Illfaults refers to those faults or fault zones either (1) not subject to displacement or (2) subject to displacement, but of such length, or located in such a manner, that they will not affect repository design and/or performance. Consequently, they do not need to be investigated in detail (McConnell et al.,1992, p. 5).
For definitions of other relevant terms, see 10 CFR 60.2.
References Code ofFederalRegulations, " Disposal of High-Level Radioactive Wastes in Geologic Repositories," Part 60, Chapter I,'litle 10, " Energy."
McConnell, K.I., M.E. Blackford, and A.B. Ibrahim, " Staff Technical Position on Investigations to Identify Fault Displacement Hazards and Seismic Hazards at a Geologic Repository," Nuclear Regulatory Commission, NUREG-1451, August 1992.
- Code ofFederal Regulations, *litle 10, " Energy."
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1 APPENDIX B l
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APPLICABLE 10 CFR PART 60 REGULATIONS
@ 60.21 Content of application.
(c) ne Safety Analysis Report shall include: (1) A description and assessment of the site at which the proposed geologic repesitory operations area is to be located with appropriate attention to those features of the site that might affect geologic repository operations area design and performance. The description of the site shall identify the location of the geologic repository operations area with respect to the boundary of the accessible environment.
i (i) The description of the site shall also include the following information regarding subsurface conditions. This i
description shall, in all cases, include such information with respect to the controlled area. In addition, where subsurface conditions outside the controlled area may affect isolation within the controlled area, the description shall include such information with respect to subsurface conditions outside the controlled area to the extent such information is relevant and material. The detailed information referred to in this paragraph shall include:
(A) The orientation, distribution, aperture in-filling and origin of fractures. discontinuities, and heterogeneities; (B) The presence and characteristics of other potential pathways such as solution features, breccia pipes, or other potentially permeable features; (C) The geomechanical properties and conditions, including pore pressure and ambient stress conditions; (D) The hydrogeologic properties and conditions; (E)The geochemicalproperties; and (F) ne anticipated response of the geomechanical, hydrogeologic, and geochemical systems to the maximum design thermal loading, given the pattern of fractures and other discontinuities and the heat transfer properties of the rock mass and groundwater.
(ii) ne assessment shall contain: (A) An analysis of the geology, geophysics, hydrogeology, geochemistry, climatology, and meteorology of the site, (B) Analyses to determine the degree to which each of the favorable and potentially adverse conditions, if present, has been characterized, and the extent to which it contributes to or detracts from isolation. For the purpose of determining the presence of the potentially adverse conditions, investigations shall extend from the surface to a depth sufficient to determine critical pathways for radionuclide migration from the underground facility to the accessible emironment. Potentially adverse conditions shall be investigated outside of the controlled area if they affect isolation within the controlled area.
(C) An evaluation of the performance of the proposed geologic repository for the period after permanent closure, assuming anticipated processes and events, giving the rates and quantities of releases of radionuclides to the accessible environment as a function of time; and a similar evaluation which assumes the occurrence of unanticipated processes and events.
(D) The effectiveness of engineered and natural barriers, including barriers that may not be themselves a part of the geologic repository operations area, against the release of radioactive material to the environment. The analysis shall also include a comparative evaluation of alternatives to the major design features that are important to waste isolation, with particular attention to the alternatives that would provide longer radionuclide containment and isolation.
1Certain revisions to 10 CFR 60.21 and 60.122 have been proposed by the Comrnission (see NRC 1993; 58 FR 36902). Should these revisions be adopted, the language of the citations quoted in this appendix would need to be revised.
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(E) An analysis of the performance of the major design structures, systems, and components, both surface and subsurface, to identify those that are important to safety. For the purposes of this analysis, it shall be assumed that operations at the geologic repository operations area will be carried out at the maximum capacity and rate of receipt of radioactive waste stated in the application.
(F) An explanation of measures used to support the models used to perform the assessments required in paragraphs (A) through (D). Analyses and models that will be used to predict future conditions and changes in the geologic setting shall be supported by using an appropriate combination of such methods as field tests, in situ tests, laboratory tests which are representative of field conditions, monitoring data, and natural analog studies.
@ 60.122 Siting criteria.
(b) favorable conditions. (1) The nature and rates of tectonic, hydrogeologic, geochemical, and geomorphic processes (or any of such processes) operating within the geologic setting during the Quaternary Period, when projected, would not affect or would favorably affect the ability of the geologic repository to isolate the waste.
(2) For disposalin the saturated zone, hydrogeologic conditions that provide:(i) A host rock with low horizontal and vertical permeability; (ii) Downward or dominantly horizontal hydraulic gradient in the host rock and immediately surrounding hydrogeologic units; and (iii) Low vertical permeability and low hydraulic gradient between the host rock and the surrounding hydrogeologic units.
(3) Geochemical conditions that:(i) Promote precipitation or sorption of radionuclides; (ii) Inhibit the formation of particulates, colloids, and inorganic and organic compixes that increase the mobility of radionuclides; or (iii) Inhibit the transport of radionuclides by particulates, colloids, and complexes.
(4) Mineral assemblages that, when subjected to anticipated thermal loading, will remain unaltered or alter to mineral assemblages having equal or increased capacity to inhibit radionuclide migration.
(5) Conditions that permit the emplacement of waste at a minimum depth of 300 meters from the ground surface. (The ground surface shall be deemed to be the elevation of the lowest point on the surface above the disturbed zone.)
(6) A low population density within the geologic setting and a controlled area that is remote from population centers.
(7) Pre-waste-emplacement groundwater travel time along the fastest path of likely radionuclide travel from the disturbed zone to the accessible environment that substantially exceeds 1,000 years.
(8) For disposal in the unsaturated zone, hydrogeologic ccmditions that provide-(i) Low moisture flux in the host rock and in the overlying and underlying hydrogeologic units; (ii) A water table sufficiently below the underground facility such that fully saturated voids contiguous with the water table do not encounter the underground facility; (iii) A laterally extensive low-permeability hydrogeologic unit above the host rock that would inhibit the downward movement of water or divert downward moving water to a location beyond the limits of the underground facility; (iv) A host rock that provides for free drainage; or NUREG-1494 11-2
(v) A climatic regime in which the average annual historic precipitation is a small percentage of the average annual potential evapotranspiration.
(c) lbtentially adverse conditions. The following conditions are potentially adverse conditions if they are I
characteristic of the controlled area or may affect isolation within the controlled area.
1 (1) Potential for flooding of the underground facility, whether resulting from the occupancy and modification of floodplains or from the failure of existing or planned manmade surface water impoundments.
(2) Potential for foreseeable human activity to adversely affect the groundwater flow system, such as groundwater withdrawal, extensive irrigation, subsurface injection of fluids, underground pumped storage, military activity, or construction of large-scale surface water impoundments.
(3) Potential for natural phenomena such as landslides, subsidence, or volcanic activity of such a magnitude that large-scale surface water impoundments could be created that could change the regional groundwater flow system and thereby adversely affect the performance of the geologic repository.
(4) Structural deformation, such as uplift, subsidence, folding, or faulting that may adversely affect the regional groundwater flow system.
(5) Potential for changes in hydrologic conditions that would affect the migration of radionuclides to the accessible environment, such as changes in hydraulic gradient, average interstitial velocity, storage coefficient, hydraulic conductivity, natural recharge, potentiometric levels, and discharge points.
(6) Potential for changes in hydrologic conditions resulting from reasonably foreseeable climatic changes.
(7) Groundwater conditions in the host rock, including chemical composition, high ionic strength or ranges of Eh-pH, that could increase the solubility or chemical reactivity of the engineered barrier system.
t (8) Geochemical processes that would reduce sorption of radionuclides, result in degradation of the rock strength, or adversely affect the performance of the engineered barrier system.
(9) Groundwater conditions in the host rock that are not reducing.
(10) Evidence of dissolutioning such as breccia pipes, dissolution cavities, or brine pockets.
(11) Structural deformation such as uplift, subsidence, folding, and faulting during the Quaternary Period.
(12) Earthquakes which have occurred historically that if they were to be repeated could affect the site significantly.
(13) Indications, based on correlations of earthquakes with tectonic processes and features, that either the frequency of occurrence or magnitude of earthquakes may increase.
(14)More frequent occurrence of canhquakes or earthquakes of higher magnitude than is typical of the area in which the geologic setting is located.
(15) Evidence of igneous activity since the start of the Quaternary Period.
(16) Evidence of extreme crosion during the Quaternary Period.
(17)The presence of naturally occurring materials, whether identified or undiscovered, within the site, in such form that:
(i) Economic extraction is currently feasible or potentially feasible during the foreseeable future; or (ii) Such materials have greater gross value or net value than the average for other areas of similar size that are representative of and located within the geologic setting.
l (18) Evidence of subsurface mining for resources within the site.
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(19) Evidence of drilling for any purpose within the site.
(20) Rock or groundwater conditions that would require complex engineering measures in the design and construction of the underground facility or in the sealing of boreholes and shafts.
(21)Geomechanical properties that do not permit design of underground opening that will remain stable through permanent closure.
(22) Potential for the water table to rise sufficiently so as to cause saturation of an underground facility located irr the unsaturated zone.
(23) Potential for existing or future perched water bodies that may saturate portions of the underground facility or provide a faster flow path from an underground facility located in the unsaturated zone to the accessible environment.
(24) Potential for the movement of radionuclides in a gaseous state through air-filled pore spaces of an unsaturated geologic medium to the accessible environment.
@ 60.131 General design criteria for the geologic repository operations area.
(a) Radiologicalprotection. The geologic repository operations area shall be designed to maintain radiation doses, levels, and concentrations of radioactive material in air in restricted areas within the limits specified in Part 20 of this chapter. Design shall include: designing equipment for ease of repair and replacement and providing adequate space for case of operation; (1) Means to limit concentrations of radioactive materials in air; (2) Means to limit the time required to perform work in the vicinity of radioactive materials, including, as appropriate, designing equipment for case of repair and replacement and providing adequate space for case of operation:
(3) Suitable shielding; (4) Means to monitor and control the dispersal of radioactive contamination; (5) Means to control access to high radiation areas or airborne radioactivity areas; and (6) A radiation alarm system to warn of significant increases in radiation levels, concentrations of radioactive matenal in air, and of increased radioactivity released in effluents. De alarm system shall be designed with provisions for cahbration and for testing its operability.
(b) Structures, systems, and components important to safety-(1) Protection against naturalphenomena and erwironmental conditions. He structures, systems, and components important to safety shall be designed so that natural phenomena and environmental conditions anticipated at the geologic repository operations area will not interfere with necessary safety functions.
(2) Protection against dynamic effects of equipmentfailure and similar events. %e structures, systems, and components important to safety shall be designed to withstand dynamic effects such as missile impacts, that could result from equipment failure, and similar events and conditions that could lead to loss of their safety functions.
(3) Protection againstfires and e.xplosions. (i) Re structures, systems, and componcnts importtnt to cafety shall be designed to perform their safety functions during and after credible fires or explosions in the geclogit repository operations area.
(ii) To the extent practicable, the geologic repository operations area shall be designed to incorporate the use of noncombustible and heat-resistant materials.
(iii) ne geologic repository operations area shall be designed to include explosion and fire detection alarm systems and appropriate suppression systems with sufficient capacity and capability to reduce the adverse effects of fires and explosions on structures, systems, and components important to safety.
NUREG-1494 B-4
1 (iv) ne geologic repository operations area shall be designed to include means to protect systems, structures, and components important to safety against the adverse effects of either the operation or failure of the fire suppression systems.
(4) Emergency capability. (i)The structures, systems, and components important to safety shall be designed to maintain control of radioactive waste and radioactive effluents, and permit prompt termination of operations and evacuation of personnel during an emergency.
(ii) The geologic repository operations area shall be designed to include onsite facilities and services that ensure I
a safe and timely response to emergency conditions and that facilitate the use of available offsite services (such as fire, police, medical and ambulance service) that may aid in recovery from emergencies.
(5) Utility services. (i) Each utility service system that is important to safety shall be designed so that essential safety functions can be performed under both normal and accident conditions.
(ii) The utility services important to safety shall include redundant systems to the extent necessary to maintain, with adequate capacity, the ability to perform their safety functions.
(iii) Provisions shall be made so that, if there is a loss of the primary electric power source or circuit, reliable and timely emergency power can be provided to instruments, utility service systems, and operating systems, including alarm systems, important to safety.
(6) Inspection, resting, and maintenance. He structures, systems, and components important.o safety shall be designed to permit periodic inspection, testing, and maintenance, as necessary, to ensure their continued functioning and readiness.
(7) Cnticality control. All systems for processing, transporting, handling, storage, retrieval, emplacement, and isolation of radioactive waste shall be designed to ensure that a nuclear criticality accident is not possible unless at least two unlikely, independent, and concurrent or sequential changes have occurred in the conditions essential to nuclear criticality safety. Each system shall be designed for criticality safety under normal and accident conditions.
The calculated effective multiplication factor (kerr) must be sufficiently below unity to show at least a 5% margin, after allowance for the bias in the method of calculation and the uncertainty in the experiments used to validate the method of calculation.
(8) Instrumentation and control systems. The design shall include provisions for instrumentation and control systems to monitor and control the behavior of systems important to safety over anticipated ranges for normal operation and for accident conditions.
(9) Compliance with mining regulations. Tb the extent that DOE is not subject to the Federal Mine Safety and Health Act of 1977, as to the construction and operation of the geologic repository operations area, the design of the geologic repository operations area shall nevertheless include such provisions for worker protection as may be necessary to provide reasonable assurance that all structures, systems, and components important to safety can perform their intended functions. Any deviation from relevant design requirements in 30 CFR, Chapter I, Subchapters D, E, and N will give rise to a rebuttable presumption that this requirement has not been met.
(10) Shaft conveyances used in radioactive waste handling. (i) Hoists important to safety shall be designed to preclude cage free fall.
(ii) Hoists important to safety shall be designed with a reliable cage location system. (iii) 1.oading and unloading systems for hoists important to safety shall be designed with a reliable system of interlocks that will fail safely upon malfunction.
(iv) Hoists important to safety shall be de ' red to include two independent indicators to indicate when waste packages are in placund ready for transfer.
@ 60.132 Additional design criteria for surface facilities in the repository operations area.
(a) Facilitiesfor receipt and retrievalof waste. Surface facilities in the geologic repository operations area shall be designed to allow safe handling and storage of wastes at the geologic repository operations area, whether these wastes are on the surf ce before emplacement or as a result of retrieval from the underground facility.
B-5 NUREG-1494
(b) Surfacefacility ventilation. Surface facility ventilation systems supporting waste transfer, inspection, decontamination, processing, or packaging shall be designed to provide protection against radiation exposures and offsite releases as provided in 9 60.111(a).
(c) Radiation control and monitoring-(1) Effuent control. 'Ihe surface facilities shall be designed to control the release of radioactive materials in effluents during normal operations so as to meet the performance objections of 9 60.111(a).
(2) Effuent monitoring. The effluent monitoring systems shall be designed to measure the amount and concentration of radionuclides in any effluent with sufficient precision to determine whether releases conform to the design requirement for effluent control. The monitoring systems shall be designed to include alarms that can be periodically tested.
j (d) Waste treatment. Radioactive waste treatment facilities shal! be designed to process any radioactive wastes generated at the geologic repository operations area into a form suitable to permit safe disposal at the geologic repository operations area or to permit safe transportation and conversion to a form suitable for disposal at an Pternative site in accordance with any regulations that are applicable.
(e) Consideration of decommissioning. The surface facility shall be designed to facilitate decontamination or dismant'ement to the same extent as would be required, under other parts of this chapter, with respect to equivalent activities licensed thereunder.
@ 60.133 Additional design criteria for the underground facility.
(a) General criteriafor the undergroundfacility. (1)The orientation, geometry, layout, and depth of the underground facility, and the design of any engineered barriers that are part of the underground facility shall contribute to the containment and isolation of radionuclides.
(2) The underground facility shall be designed so that the effects of credible dis.ruptive events during the period of operations, such as flooding, fires and explosions, will not spread through the facility.
(b) Fleibility of design. The underground facility shall be designed with sufficient flexibility to allow adjustments where necessary to accommodate specific site conditions identified through in situ monitoring, testing, or excavation.
(c) Retrieval of waste. The underground facility shall be designed to permit retrieval of waste in accordance with the performance objectives of 60.111.
(d) Control of water and gas. The design of the underground facility shall provide for control of water or gas intrusion.
l (e) Underground openings. (1) Openings in the underground facility shall be designed so that operations can be carried out safely and the retrievability option maintained.
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(2) Openings in the underground facility shall be designed to reduce the potential for deleterious rock l
movement or fracturing of overlying or surrounding rock.
(f) Rock excavation. The design of the underground facility shall incorporate excavation methods that will limit the potential for creating a preferential pathway for groundwater to contact the waste prktpd w radionuclide l
migration to the accessible environment.
(g) Undergroundfacility ventilation. The ventilation system shall be designed to:
(1) Control the inmsport of radioactive particulates and gases within and releases from the underground facility in accordance with the performance objectives of 9 60.111(a);
(2) Assure continued function during normal operations ard under accident conditions; and (3) Separate the ventilation of excavation and waste emplacement areas.
l NUREG-1494 B-6 i
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1 9
!r (h) Engineered barriers. Engineered barriers shall be designed to aesist the geologic setting in meeting the performance objectives for the period following permanent closure.
(i) Thermalloads.The underground facility shall be designed so that the performance objectives will be met I
taking into account the predicted thermal and thermomechanical response of the host rock, and surrounding strata, groundwater system.
@ 60.134 Design of seals for shafts and boreholes.
(a) General design criterion. Seals for shafts and boreholes shall be designed so that following permanent closure they do not become pathways that compromise the geologic repository's ability to meet the performance objectives for the period following permanent closure.
(b) Selection ofmaterials andplacement methods. Materials and placement methods for seals shall be selected to reduce, to the extent practicable:
(1) The potential for creating a preferential pathway for groundwater to contact the waste packages or (2) For radionuclide migration through existing pathways.
S 60.135 Criteria for the waste package and its components.
(a) High-level-wastepackage design in general. (1) Packages for HLW shall be designed so that the in situ chemical, physical, and nuclear properties of the waste package and its interactions with the emplacement environment do not compromise the function of the waste packages or the performance of the underground facility or the geologic setting.
(2) The design shallinclude but not be limited to consideration of the following factors: solubility, oxidation / reduction reactions, corrosion, hydriding, gas generation, thermal effects, mechanical strength, mechanical stress, radiolysis, radiation damage, radionuclide retardation, leaching, fire and explosion hazards, thermal loads, and synergistic interactions.
(b) Specipe criteria for HLWpackage design-(1) Explosive, pyrophoric, and chemically reactive materials. The waste package shall not contain explosive or pyrophoric materials or chemically reactive materials in an amount that could compromise the ability of the underground facility to contribute to waste isolation or the ability of the geologic repository to satisfy the performance objectives.
(2) Free liquids. The waste package shall not contain free liquids in an amount that could compromise the ability of the waste packages to achieve the performance objectives relating to containment of HLW (because of chemical interactions or formation of pressurized vapor) or result in spillage and spread of contamination in the event of waste package perforation during the period through permanent closure.
(3) Handling. Waste packages shall be designed to maintain waste containment during transportation, emplacement, and retrieval.
(4) Unique identifcation. A label or other means of identification shall be provided for each waste package. The identification shall not impair the integrity of the waste package and shall be applied in such a way that the information shall be legible at least to the end of the period of retrievability. Each waste package identification shal!
be consistent with the waste package's permanent written records.
(c) Waste form criteria for HLW. High-level radioactive waste that is emplaced in the underground facility shall be designed to meet the following criteria:
(1) Solidification. All such radioactive wastes shall be in solid form and placed in scaled containers.
l (2) Consolidatien. Particulate waste forms shall be consolidated (for example, by incorporation into an encapsulating matrix) to limit the availability and generation of particulates.
(3) Combustibles. All combustible radioactive wastes shall be reduced to a noncombustible form unless it can be demonstrated that a fire involving the waste packages containing combustibles will not compromise the integrity of B7 NUREG-1494
other waste packages, adversely affect any structures, systems, or components important to safety, or compromise the ability of the underground facility to contribute to waste isolation.
(d) Design criteriafor other radioactive wastes. Design criteria for waste types other than HLW will be addressed on an individual basis if and when they are proposed for disposal in a geologic repository.
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NUREG-1494 g,g
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t APPENDIX C DISPOSITION OF PUBLIC COMMENTS ON MARCH 18,1993, DRAFT STAFF TECIINICAL POSITION Note: A" hough Nuclear Regulatory Commission Staff 1bchnical Positions (STPs) are usually generic in nature, some of the public comments and the attendant staff responses contained in this appendix are in the context of the candidate site at Yucca Mountain, Nevada. Also, the draft STP referenced here is dated March 18,1993 (NRC,1993; 58 FR 14594).
Association Of Engineering Geologist (AEG) General Commentsi The AEG supports the Staff Technical Position on " Consideration of Fault Displacement Hazards in Geologic Repository Design." The document recognizes several technical aspects pertinent to the design ci a critical facility located near a fault or fault zone. The document recognizes that numerous natural seismic and geologic conditions exist and that the characterization should be left to the technical investigator. This is consistent with performance-based regulations which the AEG supports; the professional should be allowed to investigate the fault as deemed appropriate in the field. Another observation is that several portions of the document appear to be left purposefully ambiguous. The AEG concurs that if the document attempted to specifically address every anticipated condition, the document would be extremely long and could in no way address every condition that exists in nature.
Site investigations for critical facilities sometimes discover unexpected and undesirable conditions that could render the site unacceptable. For example, at the North Anna project or the Shearon Harris Nuclear power i
plant, a fault was discovered close to the site foundation. Subsequent investigations determined that the faults were, " geologically inactive." However, if in the case of a geologic repository such faults were determined to be "I)pe I" faults, the STP recognizes that the site is not necessarily disqualified, only that the fault must be better understood and the engineering design factor in the appropriate seismic component. The AEG supports the concept of a thorough investigation rather than an immediate " knee jerk" reaction.
I A significant factor in the STP is the recognition that detailed fault investigation has merit. This is directly referred to in the " Discussion" and also in the Appendix B (" Applicable 10 CFR Part 60 Regulations"). One recent and disturbing trend in neotectonic studies is the move towaid studies which minimize the collection of new data and attempt to rely on reworking of older data. The AEG is steadfastly opposed to any methodology that limits field observation, the collection of new data, both of which form the basis of a thorough investigation.
New information in the field of neotectonics, in just the last two years, has greatly changed our thinking regarding intraplate scismicity. For example, note the field discovery last year of a major prehistoric earthquake in the Illinois / Indiana Wabash River Valley.
A fault investigation to determine the seismic history and predict future fault activity is basically a scientific investigation. The appropriate application of engineering principles and sound engineering parameters can occur only after thorough scientific work has been performed. The most basic aspect of the scientific method is the formation and testing of a hypothesis. The only way to test these hypotheses is to collect data unique to this particular fault. There are no shortcuts to good scientific investigations.
Response
The staff agrees with this comment. No modification of the STP is requested and thus no changes are necessaty.
Specific Comments 1.
- 1. INTRODUCTION (paragraph 4 "This Staff Tbchnical Position recognized :he acceptability of designing the geologic repository to take into account the attendant effects (e.g., displacement) of faults.."). The concept
'The comments presented below constitute the official position of the AEG, and have been prepared jointly by AEG's Engineering Geology Standards Committee and the Seismic Safety Committee. In addition, the comments have been endorsed by AEG President Keaton.
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that the presence of an active fault does not by itself automatically force site abandonment is supported by the AEG.
Response
j He staff agrees with this comment. No modification of the STP is requested and thus no changes are necessary.
2.
- 1. INTRODUCTION (Footnote No. 3 " Quaternary-age... The staff has taken the position that, 'for regulatory purposes,' the age of the Quaternary Period is 2 million years.") The age of the Quaternary period has been defined to range from 1.6 to 2.0 million years before present (BP). For example, the Geological Society of America (GSA) defines the Tbrtiary/ Quaternary boundary at 1.6 million years BP. The 400,000 year difference between the GSA and NRC definitions is an extremely long time and has great significance when attempting to determine fault activity. However, from an engineering application, use of the 2 million year BP date is the most conservative approach and the AEG can support this definition.
Response
Re staff notes this comment and wishes to point out that the definition of the Quaternary Period used in the STP is the same definition adopted by the staff, and commented on by the public, in the promulgation of the final rule (see NRC,1983, p. 373).
j 3.
- 1. INTRODUCTION (paragraph 2 "Therefore, DOE should seek early resolution of fault-related design and performance issues, at the staff level, before submitting a license application to construct and operate a geologic repositorv.") The concept of dealing with fault issues early in the design stage, rather than waiting and attempting to " force-fit" a design to an adverse condition is strongly endorsed by the AEG.
Response
The staff agrees with this comment. No modification of the STP is requested and thus no changes are necessary.
4.
1.1 Background (paragraph 2 "Despite recent advances in the treatment of seismic hazards (Bernreuter et al.,
1985 and 1989).") The concept of " averaging" diverging experts' opinions is highly questioned and the AEG cannot support this methodology.
Response
l The staff wishes to note that the reference to the Bernreuter et al. (1985 and 1989) and EPRI (1986) in the draft version of the STP was for illustrative purposes only and was not intended to suggest an endorsement of these two i
approaches. However, the staff recognizes the need to revise this sentence in order to better clarify its intent and thus has no objection to modifying the sentence in question, as follows:
"Despite recent advances in the treatment of fault displacement hazards (Coppersmith and Youngs,1992), large uncertainties still remain regarding their characterization and in the characterization of fault displacement hazards."
l 5.
1.1 Background (paragraph 3 "NRC regulations for the disposal of spent nuclear fuel and high-level radioactive waste in a geologic repository,10 CFR Part 60 (Code offederal Regrdations, Title 10, " Energy")
recognize that the fault displacement can be a potentially adverse condition (10 CFR 60.122(c)(20)); however, they do not prohibit designing the geologic repository to accommodate the effects of such a potentially adverse condition.") The concept that the existence of a fault displacement condition should not automatically rule out a site is endorsed by the AEG.
Response
ne staff agrees with this comment. No modification of the STP is requested and thus no changes are necessary.
6.
1.2 STPs as Technical Guidance (paragraph 4 " Methods and solutions differing from those set out in the STPs will be acceptable if they provide a basis for the findings requisite to the issuance or continuance of a permit or license by the Commission.") As in the spirit of a performance-based regulation, the burden of proof is on the C-2 NUREG-1494
investigator. AEG strongly believes that professional judgment should never be taken away from the field.
investigator.
Response
The staff agrees with this comment. No modification of the FTP is requested and thus no changes are necessary.
7.
- 3. STAFF TECHNICAL POSITIONS: (1)It is the NRC staff position that the presence of "I)pe I" faults, as defined by NUREG-1451, inside the controlled area of a geologic repository, does not, by itself, represent a
" disqualifying" feature of the candidate site for a geologic repository." As stated above, the concept that the existence of a fault displacement condition should not automatically rule out a site is endorsed by the AEG.
Response
The staff agrees with this comment. No modification of the STP is requested and thus no changes are necessary.
8.
- 4. DISCUSSION... (1)... This philosophy requires that if a potentially adverse condition, such as faulting is present, then DOE is required by the regulations to thoroughly characterize and analyze the condition, and in doing so must demonstrate that the condition can be compensated for by repository design, certain limited engineering measures, and/or by other favorable conditions present at this site." As similarly stated above, AEG strongly supports site-specific thorough characterizations and analysis, rather than a re-analysis of old data or a less site-specific probabilistic study.
Response
The staff agrees with this comment. No modification of the STP is requested and thus no changes are necessary.
DOE Comments The STP accurately documents past DOE /NRC interactions which have reached a common understanding of i
the NRC position. DOE concurs with the general nature of the STP and believes that: (1)it provides sufficient guidance to DOE with one exception at this time; and (2) the on-going scientific investigations will provide the information needed to determine specific solutions that meet this guidance.
DOE agrees with the NRC staff position that the presence of a "Iype I" fault does not, by itself, represent a disqualifying feature for a candidate repository site. This does not prohibit designing the geologic repository against the effects of such a potentially adverse condition.
DOE is planning a topical report that will discuss both deterministic and probabilistic approaches to determining fault displacen ent hazards in geologic repository design.
Response
The staff agrees vith this comment. No modification of the STP is requested and thus no changes are necessary.
However, it sho 21d be noted that the staff has yet to take a position on acceptable approaches to the analysis of fault displacement bzards. As noted in a staff response to an earlier DOE comment on this topic (see McConnell et al.,
1992, pp. D D-2), guidance in the analysis of data related to fault displacement hazards (and seismic hazards) will be addressed in a subsequent STP under development at this time.
Specific Comments:
1.
Section 1.1-the wording of the first sentence implies that fault displacement is separate and distinct from seismic hazards. Suggest revising the wording to "...there is uncertainty associated with the design and evaluation of nuclear facilities for seismic hazards, and specifically for fault displacement hazards."
Response
'D1is comment is noted. However, the staff believes that it is important to distinguish between the two types of hazards, and that this distinction is also expressed in 10 CFR Part 60 (i.e.,10 CFR 60.122(c)(11) vs.10 CFR C-3 NUREG-1494
l 60.122(c)(12); 60.122(c)(13); and 60.122(c)(14)). As noted in McConnell et al. (1992, p.1), the terms " fault displacement hazards" and seismic hazards" are considered by the staff to be limited to the hazards resulting from fault displacement (i.e., stratigraphic offset) and vibratory ground motion that can affect the design and performance of a geologic repository.
2.
Section 1.1-He wording of the second sentence is confusing. It is not clear what parameters are being referred to, and the use of " accurate" and " accurately" is redundant. If it is appropriate to your intent, DOE suggests rewording to say, " Inadequate or inconclusive geologic evidence has made it difficult to accurately establish parameters for specific locations or the design basis for individual facilities." In addition, the parameters should be specified.
Response
As regards the first portion of this comment, the staff has no objection to making the proposed modification requested.
However, as regards the request to specify design parameters, this issue is beyond the scope of this STP. As noted in a staff response to an earlier DOE comment on this topic (see McConnell et al.,1992, pp. D D-2), the staff is developing guidance on an approach to identify those parameters necessary for the development of design bases in a subsequent STP under consideration at this time.
Nuclear Energy Institute Comments:2 1.
Pages 1,2,5, and 6-The draft STP addresses those situations in which faults of regulatory concern (designated by the NRC staff as " Type I" faults) exist or are assumed to exist at the location of structures, systems, and components important to safety or waste isolation. In particular, the draft STP recognizes the acceptability of l
DOE's designing the geologic repository to "take into account," or " accommodate," or " compensate for," the attendant effects (e.g., displacement of " Type I" faults) Although it is possible to glean their meaning from context, nowhere are the terms "take into account," " accommodate," or " compensate for" specifically defined.
lb reduce uncertainty and avoid misunderstanding, the final STP should clearly state that "lype 1" faults are adequately taken into account, accommodated, or compensated for when their effects do no; result in exceeding the pre-and post-closure performance requirements of 10 CFR Part 60.
Response
The staff notes the concern raised by this comment and has no objection to the requested addition, with modification. Accordingly, the staff has added the following sentence to paragraph 2 in Section 1 of the final STP:
"For the purposes of this STP, " Type 1" faults are adequately taken into account, accommodated, or l
compensated for when it can be demonstrated that their effects do not preclude meeting the pertinent 10 CFR Part 60 design criteria and the pre-and post-closure performance objectives."
2.
Section 4, Items (1) and (2a)-Pages six and seven contain a discussion of using engineered measures in geologic repository design. Within that discussion, there is a statement that "[I]f a potentially adverse condition, such as faulting, is present, then DOE is required by the regulations to thoroughly characterize and analyze the condition, and in doing so must demonstrate that the condition can be compensated for by repository design, certain limited engineering measures, and/or by other favorable conditions present at this site." (emphasis added) He referenced limitations to engineering measures, however, are not identified and without basis.
Accordingly, the words "certain limited" thould be eliminated.
Response
The words "certain limited" were used by the staff to express its understanding that there are practical limitations to l
what engineering or design solutions can ultimately achieve, relative to the compensating for the effects of fault displacement (and other certain natural hazards). However, to avoid further ccmfusion on this subject, the staff has deleted the phrase "certain limited engineering measures" from the sentence in Item (2a) of Section 4. The staff believes that this modification does not change the intent of this sentence because the concept in question is implicitly being addressed as part of the on-going design process for the geologic repository.
2Formerly the 1% son Electric Institute /tJtility Nuclear hte and Transportation Program.
C-4 NUREG-1494
State Of Nevada Comments:
The subject STP was apparently prepared as a logical extension of a previous STP titled " Investigations to Identify Fault Displacement liazards and Seismic Hazards at a Geologic Repository," NUREG-1451 (McConnell et al.,1992). As stated in the introduction, the subject STP was prepared specifically for the purpose of addressing "those situations in which faults of regulatory concern ("1}pe I" faults) exist or are assumed to l
exist at the location of systems, structures, and components important to safety or important to waste isolation,"
That purpose for the most part is accomplished. The NRC staff's position, in summary is: (1) that the presence of "T}pe I" faults inside the controlled area does not by itself represent a " disqualifying" feature; (2) that "T)pe 1" faults should be avoided where possible; and (3)if "l}pe I" faults cannot be avoided, then the DOE should l
be prepared to show how site waste isolation performance will not be compromised.
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The message conveyed by this STP regarding the acceptability to the NRC of ' Type I" faults inside the controlled area versus the potential applicant's determination regarding site suitability is clear. However, it is
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the State of Nevada's view that it is extremely unlikely an applicant wi'i ever be able to develop sufficient data i
to provide " reasonable assurance" that a repository can be safely sited, engineered, constructed and operated where there are demonstrated "T}pe I" faults within the controlled area. While recognizing that this difference in viewpoints between the State of Nevada and the NRC staff likely will continue, we are providing the following comments for staff's consideration in revising the dmft STP.
General Comments In its present form, the STP seems to primarily focus on the structural engineering issue of designing the repository and its systems to withstand the direct physical effects of discrete displacement on any "l}pe I" fault within the controlled area. We arrived at that conclusion based on the references used in this STP; 10 CFR Part 100, Appendix A; Draft Regulatory Guide DR-1015; NUREG-1451; SECY-79-300 (NRC,1979); EPRI NP-4616; and Bernreuter et al. (1985 and 1989). All of these documents and their references deal with the basic fault descriptors of length, width, sense of displacement, orientation, recurrence intervals, etc., as related primarily to vibratory ground motion. Although the issue of designing and licensing a nuclear facility for fault displacement and near-field vibratory ground motion will not be a trivial exercise, by any means, the issues are potentially tractable.
However, we are concerned that the STP does not strongly point out, with greater specificity, a potentially more serious issue of I}pe I" faults. These faults may serve as direct, permeable pathways to the accessible environment, if the fault intersects the repository or becomes a preferential pathway for groundwater to ccmtact the waste package in the event of fault activity. Furthermore, if the thermal design of the repository is for rock temperatures above 100*C, significant, highly uncertain effects can be expected due to hydrologic conditions along the " Type I" faults.
Because the State of Nevada will participate as a party in any license review (10 CFR 63(a)), if the proposed Yucca Mountain Project reaches that point, we believe that Sections 2 and 4 of the STP should be expanded to provide additional regulatary guidance on the additional issues we have noted above. We suggest that the additions be structured around the following two 10 CFR Part 60 regulatory requirements:
First, the requirements of 10 CFR 60.21(c)(1)(ii)(B). "for the purpose of determining the presence of the potentially adverse conditions, investigations shall extend to a sufficient depth to determine critical pathways for radionuclide migration from the underground facility to the accessible environment." It is our position that for a "T}pe I" fault, the investigation would, at a minimum, need to include the entire area of the fault surface between the ground surface and the saturated groundwater system if the fault intersects any part of the underground opening and the attendant disturbed zone.
Second, the requirement of 10 CFR 60.21(c)(14). "for structures systems and components important to safety and for the engineered and natural barriers important to waste isolation, DOE shall provide a detailed description of the programs designed to resolve safety questions, including a schedule of when these questions would be resolved." It is our position that the key waste isolation issue of "T}pe I" faults being potential radionuclide critical pathways should be planned for full investigation and evaluation now rather than enjoined at the time of license application. This STP should make it clear that the NRC expectation is the same.
C-5 NUREG-1494
I i
he program plans that will be required under 10 CFR 60.21(cX14) should include, at a minimum, a description
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of how DOE will determine; 1
(1) the extent to which any "Iype I" fault within the site, in its present state, constitutes a critical pathway l
for potential radionuclide migration to the accessible environment (10 CFR 60.21(cX1)(iiXB));
(2) the extent to which any "Iype I" fault within the site, if displaced in the future, will create new critical l
pathways for potential radionuclide migration to the accessible environment (10 CFR 60.122(cX5));
(3) relative to a " hot" repository thermal design, the extent to which any "Iype I" fault in its present or possible future state would allow for instantaneous groundwater flow into or through the
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underground facility in the event of a large near-field earthquake (10 CFR 60.122(cX22) and 60.122(cX23));
(4) the extent to which any "lype I" fault in its present state or possible future state is part of the disturbed zone for the purpose of calculating pre-waste-emplacement groundwater travel time (10 l
l' CFR 60.122(cX24)) or post-waste emplacement radionuclide travel time (e.g.,"C) to the accessible environment (10 CFR 60.113(aX2)); and '
s (5) the extent to which any " Type I" fault within the site in its present state, will need to be treated in terms of sealing requirements (10 CFR 60.134).
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Response
l The intent of this STP is to express the staff's view that the presence of a "Ippe I" fault (or fault zone) inside the controlled area, as it relates to fault displacement hazards, does not, by itself, represent a " disqualifying" feature of a i
candidate site and expresses the staff's views on what is needed from DOE if it chooses to locate structures, systems, i
and components important to safety or important to waste isolation in areas that contain faults of regulatory concern.
Hus, the staff agrees with the State of Nevada's overall comment that the scope of this STP considers only those I
hazards related to differential fault displacement along "Ippe I" faults or fault zones at or near a geologic repository.
Other possible design or performance issues (e.g., transport pathways) are beyond the scope of this STP. The staff also agrees with the State of Nevada position that if any "I)pe I" fault is found to connect the GROA underground facility with the accessible environment, that DOE should undertake some form of investigation and analysis so as to L
understand the possible effects of the fault, if any, on the flow and transport of radionuclides as part of the site
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characterization program. However, the staff disagrees with the first proposed recommendation to cite 10 CFR j
60.21(cXIXiiXB) because issues concerning the investigation and analysis of faults (or fault zones) are beyond the scope of this STP.
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Similarly, the staff disagrees with the second recommendation to cite 10 CFR 60.21(cX14), because the proposed addition concerns activities related to the design of geologic repository operations area facilities which also are beyond the scope of this STP. However, the staff does agree with the State of Nevada observation that DOE will not i
only need to demonstrate an understanding of how "Iype I" faults might affect the design and performance, but I
should also "... seek early resolution of fault-related design and performance issues, at the staff level, before l
submitting a license application to construct and operate a geologic repository."
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Specific Comments (1) Page 1; Section 1; 2nd paragraph; 2nd sentence-This sentence implies that the primary concern is for the direct effects of fault displacement on operating systems during the pre-closure phase. Without question, the direct i
effects of fault displacement on operating systems poses a serious safety issue that, in itself, would probably disqualify the site for use as any other type of nuclear facility, including low-level waste disposal and independent spent fuel storage installation (ISFSI). Although the phrase "or important to waste isolation" t
appears to have been added in order to address the post-closure performance issue, the implication still seems to be that fault displacement would be a brief transitory structural effect that would easily be accommodated r
because the facility is underground. We feel that the STP, in general, and this statement in particular, fails to adequately address our concern for the even more serious problem of " Type 1" faults as permeable pathways that are directly connected to the accessible environment (e.g., the atmosphere above the repository and the c
saturated groundwater system below the repository). This problem could be somewhat alleviated by providing the full text of the definition of a " Type I" fault from McConnell et al. (1992, p. 5) as part of footnote No. 2.
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Response
ne staff has no objection to making the proposed modification requested by this comment. Footnote No. 2 has been modified to read as follows:
"Iype I" faults refer to those faults or fault zones that are subject to displacement and of sufficient length and j
located in such a manner that they may affect repository design and/or performance. As such, they should be investigated in detail. Only faults that are determined to be "'Iype 1" are of regulatory concern, because it is those faults, both inside and outside the controlled area, that may require consideration in repository design, could have an effect on repository performance, or could provide significant input into models used to assess repository performance (McConnell et al.,1992, p. 5).
2.
Page 1; Section 1.1; 1st paragraph; 1st sentence-The wording of this sentence implies that the fault displacement hazard is one aspect of the overall seismic hazard problem and does not also constitute a separate and distinct hazard relative to waste isolation and overall systems performance.'It is the position of the State of l
Nevada that fault displacement of any amount within the proposed repository site at Yucca Mountain, whether primary or secondary, will constitute a condition that would provide a direct connection to the accessible environment. Because of the obvious detrimental effect this condition could have on waste isolation, particularly if the " Type I" fault is within the controlled zone, the State would probably find the condition unacceptable. We suggest that the sentence be modified to read, "and/or fault displacement hazard."
Response
The staff recognizes the need to clarify this sentence to make more understandable its intent and thus has no objection to using the proposed modification requested by this comment. However, the staff does not agree with the position that the State of Nevada takes in this comment that ".. that fault displacement of any amount within the proposed repository site at Yucca Mountain, whether primary or secondary, will constitute a condition that would provide a direct connection to the accessible environment."
3.
Page 2; Section 1.1; 2nd paragraph; 1st sentence-the reference to Bernreuter et al. (1985 and 1989) and EPRI (1986) are inappropriate for the problem of dealing with fault displacement at Yucca Mountain. These references all deal solely with the issue of seismic risk in the eastern United States and provide no insight at all into dealing with the issue of fault displacement hazards. A statement along the lines of Section 1.2 of NUREG-1451 (in McConnell et al.,1992, p.1), might be more appropriate. If a reference is needed, we suggest that DOE be pointed in the direction of the licensing proceedings for Bodega Bay, CA, and Humboldt, CA, nuclear power stations.
Response
See staff response to AEG specific comment no. 4.
4.
Page 2; Section 1.1; 2nd paragraph; 3rd sentence-In regards to the fault investigation requirements called for in 10 CFR Part 100, Appendix A, it should also be recognized that the type of data obtained is primarily used to establish design parameters for vibratory ground motion and do not even begin to address the more serious problem of determining fracture permeability distribution along active ("7ype I") faults and the impact on system performance.
Response
The staff notes this comment. If any "7)pe 1" fault is found to connect the GROA underground facility with the accessible environment, the staff would expect that DOE will undertake some form of fracture pathway analysis and/or flow and transport permeability analysis, in the context of 10 CFR 60.122(c)(4) and 60.112. However, the analysis of those two issues is beyond the scope of this STP.
5.
Page 2; Section 1.1; 3rd paragraph; 1st sentence-We request a reference be added to potentially adverse condition 10 CFR 60.122(c)(II)in order to be more consistent with NUREG-1451 (see Section 4.1.2, p.14).
Providing a duplicate of the 1st paragraph in Section 4.1.2 of NUREG-1451 (p.14), with the addition of a reference to 60.122(c)(20), is an alternative.
C-7 NUREG-1494 i
Response
The staff has no objection to making the proposed modification requested by this comment.
6.
Page 2; Section 1.1; 3rd paragraph; 1st sentence-Although the language of Id CFR Part 60 does not specifically prohibit designing a geologic repository to accommodate fault displacement, it is implicit in Sections 60.133(aX1),60.133(eX2),60.133(h), and 60.134(b)(1-2) that the design will require some kind of setback unless the applicant can somehow demonstrate that the presence of a fractured permeable pathway " assists the geologic setting" in meeting the performance objectives (60.21(cXIXn)(F) and 60.21(cX3Xii)).
Response
The staff does not agree with the State of Nevada's interpretation of the type of design measures that might be needed to comply with the 10 CFR Part 60 design criteria set forth in 60.133 - 60.135.'fb ensure that compliance with the performance objectives of Subpart E of 10 CFR Part 60 can be demonstrated,10 CFR Part 60 sets out a number of specific siting and design criteria; these siting and design criteria do not implicitly or explicitly require a setback from "'Ippe I" faults. Performance issues are closely linked with siting and design issues, and the staff position set out herein must be understood in that context.
However, as noted in Section 1.1 (" Background") of the STP, the staff does recognize that it has been difficult to place the contribution of geologic risk, specifically fault displacement, into proper perspective in the development of i
individual nuclear facility designs. In light of this concern, the staff has thus defined the technical position (No. 2) set forth in Section 3 of this STP that "... areas within the controlled area of a geologic repository that contain "I)pe l' faults should be avoided, where this can be reasonably achieved, when locating structures, systems, and components important to safety or important to waste isolation."
7.
Page 4; Section 2.0; 2nd paragraph; 3rd sentence-We request that a reference to 10 CFR 60.21(cXIXiiXF) be added after the phrase "They must be thoroughly analyzed" and a reference to 10 CFR 60.21(cX3Xu) after the phrase "must be demonstrated" in order to better clarify the State's interpretation of intent.
Response
The staff notes the need to clarify the sentence in question, which concerns the treatment of both favorable conditions (10 CFR 60.122(b)) and potentially adverse conditions (10 CFR 60.122(c)), es suggested by this comment.
The staff has expanded the recommended reference to 10 CFR 60.21(cXIXii)(F)in Secten 2 to also Mclude 10 CFR 60.21(cXIXiiXA) and 60.21(c)(1XH)(B) which reflects the staff's position on how these requamn's are to be implemented by DOE in the context of evaluating favorable conditions and potentially adverse conditions. However, the reference to 10 CFR 60.21(cX3)(ii)is an erroneous application of this panicular regulatory requirement. Section 60.21(c)(3Xii), in the staff's opinion, is applied to the evaluation of DOE's geologic repository designs and would be used out of context in this particular case.
8.
Page 4; Section 2; 3rd paragraph; 2nd sentence-We request that a reference to 10 CFR 60.21(cXIXn)(F),
l 60.21(CX3)(ii),60.133(aX1),60.133(eX2),60.133(h), and 60.134(bX1-2) be added to this sentence in order to clarify the State's interpretation of intent.
Response
(
The intent of this STP (as well as the sentence in question)is not to describe which 10 CFR Part 60 regulatory requirements relate to the engineeri"g design of the geologic repository operations area (GROA) facilities. Nor is it the intent of this STP to outline the attributes of an acceptable approach, from a regulatory standpoint, on how to demonstrate that DOE's GROA design complies with the pertinent 10 CFR Part 60 design criteria. Rather, the intent of this STP has a much narrower focus which, as stated earlier, is to express the staff's view that recognizes the acceptability of designing the geologic repository to take into account the attendant effects (e.g., displacement) of faults of regulatory concern and expresses the staff's views on what is needed from DOE if it chooses to locate structures, systems, and components importam to safety or important to waste isolation in areas that contain faults of regulatory concern.
It should be noted, though, that the NRC staff has provided guidance to DOE on which specific 10 CFR Part 60 regulatory requirements it should consider in the siting and design of the geologic repository in both draft Regulatory l
C-8 NUREG-1494
t Guide DG-3003 (NRC,1990) and NUREG-1323 (NRC,1994). Draft Regulatory Guide DG-3003 identifies the scope of information to be provided by DOE in a potential license application to construct and operate a geologic repository. For its part, the NRC staff has begun to describe, in NUREG-1323, information on what is to be reviewed in a potential DOE license application, the (regulatory) basis for conducting the review, how the review is to be accomplished, and the conclusions that are sought regarding the applicable regulatory requirements.
9.
Page 4; Section 2: 4th paragraph; 1st sentence-We request that either NUREG-1451 be modified / appended or alternatively the subject S1T' be expanded to better assure DOE recognizes the minimal information requirements the State feels will be necessary in order to deal with 10 CFR 60.133(aXiiXB)(2); 60.122(a)(2Xi-ii);
and 60.122(c)(22-24). It is the State's position that the requirements of 10 CFR 60.21(c)(1)(ii)(A-F) and 60.140 t
will have to be met for each "'I}pe I" fault (system) that in any way connects the underground facility with the accessible environment.
Response
The 10 CFR Part 60 regulatory requirements cited in this comment relate to descriptive information to be submitted as part of any potential license application submittal, design criteria for the GROA underground facility, potentially adverse condition siting conditions, and general requirements for the performance confirmation program. These issues are beyond the scope of this STP. (Also see the staff response to the State of Nevada specific comment nos. 4 and 8.)
- 10. Page 5: Section 3; Item (1)-In regards to the use of the term " disqualifying feature;" we are under the impression that there are no "disqualifiers" in NRC regulations with the possible exception of 10 CFR 60.113(aXiiX2) related to groundwater travel time. We suggest that this sentence be rephrased to something like "does not, by itself, represent a singular adverse condition that would disqualify a candidate site for a geologic repository."
Response
The Commission view on the effect of particular conditions (with respect to " disqualification")is addressed in Section 4 of the STP. In light of that discussion (see Item (1)in " Discussion"), the staff has no objection to modifying the sentence in question to address the substance of the recommendation, as follows:
"(1) It is the NRC staff position that the presence of Iype 1" faults, as defined by NUREG-1451, inside the controlled area of a geologic repository, does not, by itself, disqualify a candidate site for a geologic repository."
It is the staff's view that this modification does not change the intent of the technical position.
- 11. Page 6; Section 4(2)(a); 1st paragraph 3rd sentence-The State feels that there is an appearance of incompatibility between the Commission's " multiple barrier, defense-in-depth" approach that consists of engineered barriers (i.e., waste packages and the underground facility) and the natural barriers provided by the geologic setting when there are " Type I" faults present and the staff technical position as presently stated in Section 3, p. 5, of this STP. It is the State's position that DOE will have to demonstrate why any fault within the controlled zone should not be considered a "'I}pe I" fault (see paragraph 4.1.2 in NUREG-1451; p.14) using the criteria required by 10 CFR 60.21(c)(1)(iiXB). If the results of these investigations on any fault are inconclusive then that fault must be treated as a "1}pe I" fault for the purpose of satisfying the requirements of 10 CFR 60.133 and 60.134. It is irrational to consider that a '"I}pe I" fault, which by definition is subject to displacement and an implicit decrease in waste isolation capability, could at the same time somehow be engineered to " assist the geologic setting in meeting the performance objectives" of waste isolation. A design that allows for the location of any system or component that contains radioactive waste to be in contact with a "'lype I" fault is unacceptable to the State of Nevada.
Response
As regards the both the first and second portions of the State of Nevada's comment, "... that DOE will have to demonstrate why any fault within the controlled zone should not be considered a " Type I" fault..." and that "... if the results of these [10 CFR 60.21(cXIXii)(B)] investigations on any fault are inconclusive then that fault must be treated as a ' Type I" fault. ", the staff agrees with the State's positions. These positions are consistent with the intent of the staff's technical positions set forth in NUREG-1451.
C-9 NUREG-1494
However, as regards the final portion of the State of Nevada's comment, the staff disagrees with the State's observation that ". a ~I}pe 1" fault, which by definition is subject to displacement, [would] implicit [ly] decrease [the]
waste isolation capability [of the site]." It is not clear from any assessments performed to date, either by NRC or DOE, what impact " Type I" faults (or fault zones) might have on the waste isolation capability of the site.
- 12. Page 7, Section 4(2)(a); 1st paragraph; Last sentence-We suggest that a reference to 60.122(c)(11) be added in order to provide compatibility with NUREG-1451,4.1.2, p.14.
Response
The concern raised by this comment is noted and the staff has no objection to making the proposed modification in order to ensure consistency with NUREG-1451. However, the staff believes that the requested modification should be made to Section 1.1 (" background"), paragraph 3 rather than to Section 4(2)(a)(" Discussion"), paragraph 1, as proposed, because the focus of the discussion in this section of the STP is on 10 CFR 60.122(c)(20), not 10 CFR (a122(c)(11).
- 13. Page 7; Section 4(2)(a); 3rd paragraph-We request that a discussion of the pre-closure requirements 60.133(a)(1); 60.133(e)(2); 60.133(f) and the post-closure requiremenis 60.133(h): 60.134(b)(1-2) be added between the first and second sentences.
Response
The 10 CFR Part 60 regulatory requirements cited in this comment relate to the design criteria for the GROA underground facility. As noted previously, this issue is beyond the scope of this STP. However, as noted in the staff's response to DOE specific comment no. 8, the NRC staff has previously provided guidance to DOE on which specific 10 CFR Part 60 regulatory requirements it should consider in the design of the GROA in both Regulatory Guide DG-3003 and NUREG-1323.
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C-10 NUREG-1494 N
REFERENCES Bernreuter, D.L, J.B. Savy, R.W. Mensing, J.C. Chen, and B.C. Davis, " Seismic Hazard Characterization of the Eastern United States, Lawrence Livermore National Laboratory, Livermore, California, UC/LLNL UCID-2041,2 vols.,1985.
Bernreuter, D.L., J.B. Savy, R.W Mensing, J.C. Chen, and B.C. Davis, " Seismic Hazard Characterization of 69 Nuclear Power Plant Sites East of the Rocky Mountains," Nuclear Regulatory Commission / Lawrence Livermore l
National Laboratory, NUREG/CR-5250, 8 vols., January 1989.
Coppersmith, KJ., and R.R. Youngs, "Modeling of Fault Rupture Hazard for the Proposed Repository at Yucca l
Mountain, Nevada" Proceedings of the Third International Conference on High-Lewt Radioactive Waste Management, l
American Nt, clear Society /American Society of Civil Engineers, Las Vegas, Nevada, April 12-16,1992, vol.1, pp.
1142 - 1150.
l Electric Power Research Institute, " Seismic Hazard Methodology for the Central and Eastern United States," Palo Alto, California, EPRI NP-4626, 3 vols., July 1986. [ Prepared by Risk Engineering, Inc., Woodward-Clyde i
Consultants, Geomatrix Consultants, Inc., and the CYGNA Corporation for EPRI.]
McConnell, K.I., M.E. Blackford, and A.B. Ibrahun, " Staff Tbchnical Position on Investigations to Identify Fault Displacement Hazards and Seismic Hazards at a Geologic Repository," Nuclear Regulatory Commission, l
NUREG-1451, August 1992.
Nuclear Regulatory Commission, " Disposal of High-Level Radioactive Wastes in Geologic Repositories; Technical Criteria [ Statement of Considerations in Final Rule]," Federal Register, Vol. 48, No.120, June 21,1983, pp.
l 28194-28229.
Nuclear Regulatory Commission, " Format and Content for the License A" plication for the High-Level Waste Repository," Office of Nuclear Regulatory Research, Regulatory Guide DR. : J3, November 1990.
Nuclear Regulatory Commission, " Availability of Draft Staff Tbchnical Position on Consideration of Fault l
Displacement Hazards in Geologic Repository Design," Federal Register, Vol. 58, No. 51, March 18,1993, p.14594.
Nuclear Regulatory Commission, "Ijcense Application Review Plan for a Geologic Repository for Spent Nuclear Fuel and High-Level Waste," Office of Nuclear Material Safety and Safeguards, NUREG-1323, August 1994.
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C-11 NUREG-1494
APPENDIX D ACNW COMMENTS Following the end of the public comment period, the NRC staff briefed the Advisory Committee on Nuclear Waste (ACNW) on the stafT's disposition of public comments received on the March 1993 draft Staff Tbchnical Ibsition (STP) and any proposed revisions to the STP based on the public comments. As a result of that briefing, dated March 24,1994, the ACNW recommended, without additional comment, that the staff publish the STP in final form.
D-1 NUREG-1494
I l
NRC FORM 335 U.S. NUCLEAR REGULATORY COMICSSION
- 1. REPORT EMBER (2-89)
(Assigned by NRC, Add Vol.,
NRCM 1102, Supp., Rev., and Addendurn Num-32o1,32c2 BIBLIOGRAPHIC DATA SHEET b"'* -
8' ""Y 1 (See instructions on th. revers.)
- 2. TITLE AND SUBTITLE
- 3. DATE REPORT PUBUSHED Staff 7bchnical Ibsition on Consideration of Fault Displacement Hazards l
uONTH YEAR in Geologic Repository Design September 1994
- 5. AUTHORLS)
- 6. TYPE OF REPORT K. I. McConnell, M. P. Lee
- 7. PERIOD COVERED (inclusive Dates) i
- 8. F2RFORMING ORGANIZATION - NAME AND ADDRESS (if NRC, provios Division, Office or Region, U.S. Nuclear Regulatory Commission, and mDiling address; it contractor, prov6de name and malling address.)
Division of Waste Management Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
- 8. SPONSORING ORGANIZATION - NAME AND ADDRESS (tf NRC, type 'Same as above"; it contractor, provide NRC Division, Offee or Region, U.S. Nuclear Regulatory Commission, and malling address.)
Same as 8, above.
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- 10. SUPPLEMENTARY NOTES l
- 11. ABSTRACT (200 wcros or less) l l
Nuclear Regulatory Commission regulations for the disposal of spent nuclear fuel and high-level radioactive waste in a geologic repository recognize that fault displacement is a potentially adverse condition (10 CFR 60.122(c)(11) and 60.122(c)(20)). However, they do not prohibit designing the geologic repository against the effects of such a potential-ly adverse condition. This Staff Technical Position recognizes the acceptability of designing the geologic repository to I
take into account the attendant effects (e.g., displacement) of faults of regulatory concern and expresses the staff's views on what is needed from the U.S. Department of Energy ifit chooses to locate structures, systems, and compo-nents important to safety or important to waste isolation in areas that contain faults of regulatory concern.
- 12. KEY WORDS/DESCAPTORS (List words or phrases that will assist researchers in locating the report.)
- 13. AVAILA81UTY STATEMENT Unlimited
- 14. SECURITY CLASSIFICATION (This Page)
Geologic Repository Unclassified Rcpository Design (Th "*P')
Fault Displacement Hazards Unclassified
- 16. NUMBER OF PAGES
- 16. PRICE NRC FORM 335 (2-69)
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