[Federal Register Volume 64, Number 229 (Tuesday, November 30, 1999)]
[Proposed Rules]
[Pages 67054-67089]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-30668]



[[Page 67053]]

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Part IV





Department of Energy





_______________________________________________________________________



10 CFR Parts 960 and 963



Office of Civilian Radioactive Waste Management; Nuclear Waste 
Repositories; Yucca Mountain Site Suitability Guidelines; Proposed 
Rulemaking

  Federal Register / Vol. 64, No. 229 / Tuesday, November 30, 1999 / 
Proposed Rules  

[[Page 67054]]



DEPARTMENT OF ENERGY

10 CFR Parts 960 and 963

[Docket No. RW-RM-99-963]
RIN No. 1901-AA72


Office of Civilian Radioactive Waste Management; General 
Guidelines for the Recommendation of Sites for Nuclear Waste 
Repositories; Yucca Mountain Site Suitability Guidelines

AGENCY: Office of Civilian Radioactive Waste Management, Department of 
Energy (DOE).

ACTION: Supplemental Notice of Proposed Rulemaking.

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SUMMARY: DOE invites public comment on a revised proposal to amend the 
policies under the Nuclear Waste Policy Act of 1982 for evaluating the 
suitability of Yucca Mountain, Nevada, as a site for development of a 
nuclear waste repository. Today's revised proposal focuses on the 
criteria and methodology to be used for evaluating relevant geological 
and other related aspects of the Yucca Mountain site. Consistent with 
longstanding policy to conform DOE regulations regarding its nuclear 
waste repository program to comparable regulations of the Nuclear 
Regulatory Commission, DOE's proposed criteria and methodology are 
based on the Nuclear Regulatory Commission's recently proposed 
regulations for licensing a nuclear waste repository at Yucca Mountain.

DATES: Written comments must be received by February 14, 2000. DOE 
requests one copy of the written comments. DOE will hold two public 
hearings on this supplemental notice of proposed rulemaking. A 
subsequent Federal Register document, that will announce hearing dates, 
locations, and times, will be issued during the comment period.

ADDRESSES: Written comments should be addressed to Dr. William J. 
Boyle, U.S. Department of Energy, Yucca Mountain Site Characterization 
Office, P.O. Box 98608, Las Vegas, Nevada 89193-8608, or provided by 
electronic mail to 10CFR[email protected].
    Copies of the transcripts of the hearings, written comments, and 
documents referenced in this notice may be inspected and photocopied in 
the Yucca Mountain Science Center, 4101B Meadows Lane, Las Vegas, 
Nevada, (702) 295-1312, and the DOE Freedom of Information Reading 
Room, Room 1E-190, Forrestal Building, 1000 Independence Avenue, SW, 
Washington, DC (202) 586-3142, between the hours of 8:30 a.m. and 4 
p.m., Monday through Friday, except for Federal holidays. For more 
information concerning public participation in this rulemaking, please 
refer to the Opportunity for Public Comment section of this notice.

FOR FURTHER INFORMATION CONTACT: Dr. William J. Boyle, U.S. Department 
of Energy, Office of Civilian Radioactive Waste Management, Yucca 
Mountain Site Characterization Office, P.O. Box 98608, Las Vegas, 
Nevada 89193-8608, (800) 967-3477.

SUPPLEMENTARY INFORMATION:

I. Introduction
II. Background
    A. Enactment of the Nuclear Waste Policy Act
    1. Development of the Nuclear Waste Policy Act
    2. Overview of the Nuclear Waste Policy Act
    B. DOE Promulgation of the General Guidelines at 10 CFR part 960
    1. Overview of the General Guidelines
    2. Structure of the General Guidelines
    3. Bases for Structure of the General Guidelines
    4. Consistency with NRC Technical and Procedural Conditions
    C. DOE Application of the Guidelines
    D. 1987 Amendments to NWPA
    E. Yucca Mountain Site Characterization Plan
    1. Statutory Requirements
    2. Structure of the Site Characterization Plan
    F. Energy Policy Act of 1992
    G. Evolution of the Site Characterization Program
    H. The 1993-1995 Public Dialogue on the Guidelines
    I. The 1996 Notice of Proposed Rulemaking
    J. Proposed NRC Regulation, 10 CFR part 63
    1. Background
    2. Structure of Proposed part 63
    K. Proposed EPA Regulation, 40 CFR part 197
    1. Background
    2. Structure of Proposed part 197
III. Basis for Proposal
    A. Legal Authority and Necessity to Amend the Guidelines and 
Criteria
    1. Overview
    2. Section 112
    3. Section 113
    B. Events Necessitating Amendment of the Guidelines and Criteria
    1. Congressional Redirection of the Program
    2. Consistency Between DOE and NRC Regulations
    3. Improvements in Analytical Methods
IV. Response to Public Comments on the 1996 Proposal
    A. Legal Authority
    B. C-K
V. Description of Proposal--10 CFR part 960
    A. Subpart A--General Provisions
    B. Subpart B--Implementation Guidelines
    C. Appendix III
VI. Description of Proposal--10 CFR part 963
    A. Subpart A--General Provisions
    B. Subpart B--Yucca Mountain Site Characterization Suitability 
Determination, Methods and Criteria
VII. Opportunity for Public Comment
    A. Participation in Rulemaking
    B. Written Comment Procedures
    C. Hearing Procedures
VIII. Regulatory Review
    A. Review for Compliance with the National Environmental Policy 
Act (NEPA)
    B. Review under the Regulatory Flexibility Act
    C. Review under the Paperwork Reduction Act
    D. Review under the Unfunded Mandates Reform Act
    E. Review under Executive Order 12612
    F. Review under Executive Order 12866
    G. Review under Executive Order 12875
    H. Review under Executive Order 12988
    I. Review under Executive Order 13084
    J. Review under the Treasury and General Government 
Appropriations Act, 1999

I. Introduction

    DOE today publishes this supplementary notice of proposed 
rulemaking in order to revise its December 16, 1996, proposal (61 FR 
66158) to amend the ``General Guidelines for the Recommendation of 
Sites for Nuclear Waste Repositories'') (Guidelines) (10 CFR part 960) 
that DOE promulgated under the Nuclear Waste Policy Act (NWPA) in 1984 
(42 U.S.C. 10101, et seq.). The General Guidelines describe the DOE 
policies applicable to three sequential stages of the NWPA siting 
process, which are: (1) Preliminary site screening; (2) nomination of 
sites for site characterization (geological investigation of selected 
sites); and (3) selection of a site for recommendation to the 
President. The Guidelines are consistent with the licensing regulations 
of the Nuclear Regulatory Commission (NRC) in 10 CFR part 60.
    In its December 16, 1996, proposal, DOE published proposed 
regulatory amendments to the Guidelines to reflect the prevailing 
scientific view on how to evaluate the suitability of the Yucca 
Mountain site for the development of a nuclear waste repository. 
Because the preliminary site screening stage was complete and Congress 
has required DOE to focus on Yucca Mountain, Nevada, DOE's proposed 
regulatory amendments dealt with provisions of the Guidelines 
applicable to the site recommendation stage. Today DOE is revising the 
terms of its proposal for three reasons.
    First, during the comment period on the December 16, 1996, 
proposal, DOE received comments from members of the public, State and 
local officials of Nevada, the U.S. Environmental

[[Page 67055]]

Protection Agency (EPA), and the U.S. Nuclear Waste Technical Review 
Board, that in substance criticized the omission from the proposed 
regulatory amendments of the essential details of the criteria and 
methodology for evaluating the suitability of the Yucca Mountain site 
for the location of a nuclear waste repository. Some of the comments 
made pointed recommendations for guidelines at a more definitive level 
of specificity than the proposed regulatory text provided. Also, there 
were comments critical of the legal basis for DOE's proposal and its 
consistency with what those commenters viewed as DOE's past position on 
the meaning of sections 112(a) and 113(b) of the Act. As explained in 
detail later in this notice, DOE concluded that there was enough merit 
in these comments to warrant revision of the proposed regulatory 
amendments and expansion of the explanation of the factual and legal 
bases for them.
    Second, in December, 1998, DOE issued, pursuant to Congressional 
direction, the Viability Assessment of a Repository at Yucca Mountain 
(Viability Assessment) (DOE/RW-0508). This document, which is available 
through the Internet on the web site (www.ymp.gov) or in hard copy upon 
request (see above, Further Information) sets forth the bases for the 
site suitability criteria DOE is proposing to use and the methodology 
for applying the criteria to a design for a proposed repository at the 
Yucca Mountain site. DOE can now assist commenters in responding to 
DOE's proposal with appropriate descriptions of, and references to, key 
portions of the Viability Assessment in the Supplementary Information.
    Third, after the close of the comment period, the U.S. Nuclear 
Regulatory Commission (NRC), consistent with Congressional direction to 
the EPA to develop a site-specific radiation protection standard for 
the Yucca Mountain site, proposed to issue site-specific licensing 
requirements for that site in a new 10 CFR part 63 and to eliminate the 
site from coverage under 10 CFR part 60. Thereafter, EPA issued the 
Congressionally-mandated proposal for site-specific public health and 
safety standards for a repository at Yucca Mountain, to be codified at 
40 CFR part 197. Section 113(c) of the NWPA provides that a 
determination of site suitability for development as a repository is 
largely an estimate that an application to the NRC for a construction 
authorization would be successful. 42 U.S.C. 10133(c). Thus, the 
details of the NRC proposal, which were not available when DOE 
formulated its December 16, 1996, proposal, affect the continuing 
usefulness of existing 10 CFR part 960, the text of DOE's proposed 
regulatory amendments, and the bases for those amendments in performing 
the analysis required by section 113. For reasons explained in detail 
below, DOE is of the view that the proposed part 63, if finalized 
without significant change, would make it illogical to apply the 
existing provisions of 10 CFR part 960, which are explicitly linked to 
provisions of the NRC's part 60. Moreover, the details of the NRC's 
proposal suggest the need for making conforming changes to the December 
16, 1996, proposal to set forth the requirements for carrying out a 
total system performance assessment as the method for applying the site 
suitability criteria to the data developed during site characterization 
of the Yucca Mountain site.
    Consistent with EPA's proposal for site-specific public health 
standards and NRC's proposal to limit part 60 and to establish a new 
part 63 for the Yucca Mountain site, DOE today is proposing regulations 
to: (1) Limit 10 CFR part 960 to preliminary site screening for 
repositories located elsewhere than Yucca Mountain; and (2) establish a 
new part 963 to contain the site suitability criteria and the methods 
for considering the potential of the Yucca Mountain site for a nuclear 
waste repository under those criteria. The proposed suitability 
criteria and methods provide a link between the geologic considerations 
identified in section 112(a) of the NWPA as primary criteria for siting 
a repository, and the current scientific understanding of site 
characteristics and related processes that are important to assessing 
the performance and safety of a potential geologic repository at the 
Yucca Mountain site. Although closely linked to the NRC's proposed part 
63 licensing criteria and requirements, as is necessary and 
appropriate, DOE's proposed regulations in part 963 are not the 
equivalent of a determination that the site necessarily will meet all 
requirements to obtain a license from the NRC, or to be recommended by 
the Secretary for development as a geologic repository. Rather, DOE is 
proposing this new rule to better define its policies and criteria for 
determining the suitability of the Yucca Mountain site only in terms 
of, and based on, the information and data developed through the 
program of site characterization activities DOE has conducted over the 
years at Yucca Mountain under section 113(b) of the NWPA.
    In issuing this notice, DOE is seeking to improve its policies for 
determining site suitability by enhancing their transparency, validity, 
and verifiability. In terms of transparency, DOE is aiming at 
regulations that are easier to read and understand. In terms of 
validity, DOE is aiming at an explanation of the legal and scientific 
basis for the regulations that shows how DOE's policies logically 
follow from scientifically supportable and legally sound premises. In 
terms of verifiability, DOE is aiming to show that the scientific 
conclusions underlying its policies are based on documented empirical 
results of experiments, and computer analyses of relevant data 
sufficient to warrant the conclusions DOE may eventually draw from 
known facts in a supporting statement for site recommendation to the 
President.
    DOE hereby invites interested members of the public, State and 
local officials, and other Executive Branch agencies to review today's 
revised proposal and to provide comments on how well this rulemaking 
achieves these objectives. In addition, DOE intends to follow the 
consultation procedures set forth in section 112(a) of the NWPA for 
promulgation of the Guidelines in seeking review and comment on this 
revised proposal.

II. Background

    This section provides an overview of the developments which have 
led DOE to propose to revise certain sections of the existing General 
Guidelines for the Recommendation of Sites for Nuclear Waste 
Repositories and to adopt a new rule governing the site suitability 
criteria for the Yucca Mountain site.

A. Enactment of the Nuclear Waste Policy Act of 1982

1. Development of the Nuclear Waste Policy Act
    The Nuclear Waste Policy Act of 1982 (NWPA) was enacted to provide 
for the siting, construction, and operation of repositories for which 
there is a reasonable assurance that the public and the environment 
will be adequately protected from the hazards posed by spent nuclear 
fuel and high-level radioactive waste (hereinafter referred to as 
``spent fuel'' or ``high-level waste'' or both). The NWPA established 
the Federal responsibility and defined Federal policy for the disposal 
of spent fuel and high-level waste. Because this waste remains 
radioactive for many thousands of years, Congress recognized that 
disposal involved many complex and novel technical and societal issues. 
To develop an appropriate framework for the resolution of these issues, 
several

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years of intense legislative effort were required before a political 
consensus emerged to support enactment of the NWPA.
    To meet the well-recognized reluctance of communities to host such 
facilities, the NWPA included a national site selection process that 
was designed to ensure fairness and objectivity in the identification 
of potential candidate sites for a repository. To ensure that the DOE 
would consider only candidate sites that had good potential for being 
licensed by the NRC, the NWPA required the DOE to obtain NRC 
concurrence on the DOE's general siting guidelines. And to ensure that 
the regulatory requirements for a repository would be set independently 
of any responsibility assigned to the DOE to develop that repository, 
the EPA was authorized to promulgate generally applicable standards for 
the protection of the environment. The NRC was authorized to establish 
repository licensing requirements and criteria, although these 
requirements and criteria could not be inconsistent with any comparable 
standards promulgated by the EPA.
2. Overview of the Nuclear Waste Policy Act
    As originally enacted in 1982, the NWPA set forth requirements for 
selecting sites for the disposal of spent fuel and high-level wastes in 
a geological repository. 42 U.S.C. 10101, et seq. Several stages were 
established for the evaluation of potential sites, and these stages 
were defined in section 112, Recommendation of Candidate Sites for Site 
Characterization; section 113, Site Characterization; and section 114, 
Site Approval and Construction Authorization.
    Section 112 of the NWPA addresses the initial stage of the site 
selection process, and includes four distinct steps: (1) DOE 
preliminary site screening (42 U.S.C. 10132(a)); (2) DOE nomination of 
at least five sites as suitable for characterization (42 U.S.C. 
10132(b)(1)(A)); (3) DOE recommendation to the President of three of 
the five nominated sites as candidates for characterization (42 U.S.C. 
10132(b)(1)(B)); and (4) Presidential approval of nominated sites for 
characterization (42 U.S.C. 10132(c)). Specifically, section 112(a) 
directs the DOE to issue general guidelines for the recommendation of 
candidate sites for site characterization. Section 112 directed DOE to 
consult with several federal agencies and obtain NRC concurrence on 
these guidelines.
    Under section 112(a), DOE was required to specify in the 
guidelines: (1) detailed geologic considerations that were to be the 
primary criteria for the selection of sites for characterization in 
various geologic media; (2) certain factors (e.g., hydrology, 
geophysics, seismic activity) that would either qualify or disqualify a 
site from characterization; and (3) population density and distribution 
factors that would disqualify any site for characterization. 42 U.S.C. 
10132(a). Section 112(a) also required DOE to include certain factors 
related to the comparative advantages among candidate sites. The DOE 
was directed to use the guidelines to consider candidate sites for 
recommendation as candidates for characterization. Section 112(a) 
explicitly authorized DOE to modify the guidelines consistent with the 
provisions of section 112(a).
    Furthermore, section 112(a) directed DOE to develop certain 
qualifying or disqualifying factors for the preliminary site screening 
stage of the site selection process. Except for population density, the 
specific content of the qualifying or disqualifying factors was left to 
DOE's informed discretion. Because these factors are part of the 
Guidelines, their specific content could be modified in accordance with 
the authority in section 112(a).
    Section 112(b) of the NWPA addressed DOE's recommendation to the 
President of sites for site characterization, that is, for intensive 
investigation of geologically related characteristics through surface 
and subsurface testing, among other investigative techniques. DOE was 
to nominate at least five sites as suitable for characterization. Each 
nominated site was to be accompanied by an environmental assessment. Of 
the five sites, DOE was to recommend three to the President for 
characterization. Section 112(c) of the NWPA addresses the President's 
review and approval of candidate sites for characterization.
    Section 113 of the NWPA addresses site characterization, which 
involves activities that could proceed only after the section 112 
actions had been completed. Section 113(a) authorizes DOE to conduct 
site characterization activities at the sites that had been approved by 
the President for characterization. Section 113(b) establishes the 
scope of DOE's site characterization activities, and directs the 
publication of a general plan for these activities. 42 U.S.C. 
10133(b)(1)(A). DOE is to report semiannually on its ongoing and 
planned site characterization activities and the information derived 
therefrom. 42 U.S.C. 10133(b)(3). Section 113(b) also directs that the 
DOE include in the site characterization plan, criteria to be used to 
determine the suitability of a site for the location of a repository, 
developed pursuant to section 112(a). 42 U.S.C. 10133(b)(1)(A)(iv). 
Section 113(c) establishes limits on DOE's site characterization 
activities, and provides direction on how DOE is to proceed if at any 
time it determines that a site would be unsuitable for development as a 
repository.
    Section 114 addresses site approval and construction authorization, 
and can only proceed as the section 113 site characterization 
activities near completion. Four distinct steps are defined in this 
section: (1) DOE recommendation of a site to the President for approval 
to develop as a repository [42 U.S.C. 10134(a)]; (2) recommendation of 
a site by the President to Congress [42 U.S.C. 10134(a)(2)]; (3) 
Congressional designation of the site [42 U.S.C. 10134(b)]; and (4) 
conduct of a licensing proceeding by the NRC [42 U.S.C. 10134(c)]. 
Further, under section 115, after the President recommends a site to 
Congress, the Governor and the legislature of the host State may submit 
a notice of disapproval. If the State disapproves, Congress must enact 
a resolution of siting approval in order to designate the site. 42 
U.S.C. 10135(b). If the Congressional designation takes effect, DOE 
must submit an application to the NRC for a construction authorization. 
42 U.S.C. 10134(b).
    Section 114(a) provides for DOE activities necessary to prepare a 
recommendation to the President for Presidential approval of a site for 
development as a repository. These activities include public hearings 
in the vicinity of the site to inform residents of the area and receive 
their comments, and the completion of site characterization. Upon 
completion of these hearings and site characterization, the Secretary 
may decide to recommend the site to the President. A comprehensive 
statement of the basis for this recommendation is to accompany the 
recommendation, and be made available to the public. 42 U.S.C. 
10134(a)(1). Section 114(b) then authorizes DOE to apply to the NRC for 
construction authorization, if the President recommends a site to the 
Congress and that recommendation is permitted to take effect. Sections 
114(c)-(e) direct the NRC and DOE on certain aspects of the 
construction authorization process. Section 114(f) requires that a 
final Environmental Impact Statement (EIS) accompany the Secretary's 
recommendation of a site to the President.

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B. DOE Promulgation of General Guidelines at 10 CFR Part 960

1. Overview of the General Guidelines
    Section 112(a) of the NWPA directed DOE to issue general guidelines 
for the recommendation of sites for characterization, in consultation 
with certain Federal agencies and interested Governors, and with the 
concurrence of the NRC. These general guidelines were to be comparative 
in nature, as DOE was required to consider various geologic media and 
such considerations as proximity to where spent fuel and high-level 
waste were stored. The general guidelines were also to consider non-
geologic factors, such as population density and distribution, that 
would not be examined in site characterization. No other procedural 
requirements were imposed on the issuance of these guidelines.
    DOE promulgated the section 112(a) guidelines by notice and comment 
rulemaking, in addition to the consultation and concurrence process 
specified in the NWPA. The DOE also conducted several public meetings 
on the guidelines. These additional activities, although not required 
by the NWPA, enabled DOE to receive comments from interested members of 
the public. The general guidelines were promulgated on December 6, 
1984, and codified in the Code of Federal Regulations at 10 CFR part 
960, General Guidelines for the Recommendation of Sites for the Nuclear 
Waste Repositories. 49 FR 47714.
2. Structure of the General Guidelines
    The Guidelines promulgated by DOE defined the basic technical 
requirements that candidate sites must meet, and specified how DOE 
would implement its site-selection process. The Guidelines were 
structured according to three categories: implementation guidelines, 
preclosure guidelines and postclosure guidelines. The implementation 
guidelines addressed general application of all the guidelines, and 
established the methodology for applying the guidelines during the 
various stages of the siting process: site screening and nomination, 
recommendation for characterization, and recommendation for repository 
development. The preclosure guidelines governed the siting 
considerations that dealt with the operation of a geologic repository 
before it is closed. The postclosure guidelines governed the siting 
considerations that dealt with the long-term behavior of a geologic 
repository after waste emplacement and closure.
    Both the preclosure and postclosure guidelines were organized under 
general categories of interest, for example, geohydrology and 
geochemistry. Each category was further divided into system guidelines 
and corresponding technical guidelines. The system guidelines addressed 
broad requirements for a geologic repository under preclosure and 
postclosure conditions; the corresponding technical guidelines 
specified conditions that would qualify or disqualify a site, and 
conditions that would be considered favorable or potentially adverse. 
49 FR 47724. In effect, the technical guidelines and the associated 
qualifying and disqualifying conditions imposed specific ``subsystem'' 
performance requirements; each subsystem requirement would be used to 
evaluate the merits of a site, independent of the other requirements.
    Section 112 of the NWPA described the minimum steps that DOE was to 
take during site screening and prior to site characterization. When 
promulgating the Guidelines in 1984, DOE determined that application of 
the Guidelines should extend beyond preliminary site screening to 
encompass site characterization activities and site recommendation to 
the President. Appendix III to the Guidelines explained how certain of 
the Guidelines would be applied at the principal decision points of the 
siting process: (1) identification of a site as being potentially 
acceptable under section 112(b); (2) nomination and recommendation of 
sites as suitable for characterization under sections 112(b) and (c); 
and (3) recommendation of a site for development as a repository 
(sections 113 and 114). 49 FR 47729-47730. With respect to the third 
decision point, which would be reached only after completion of site 
characterization activities and non-geologic data gathering activities, 
DOE did not promulgate separate Guidelines. Instead, DOE indicated that 
the preclosure and postclosure Guidelines would be applied to this 
decision, and appropriate findings issued, in the manner prescribed in 
Appendix III. Appendix III specified the types of findings that were to 
be issued from the application of the disqualifying and the qualifying 
conditions at each of the three decision points. The types of findings 
corresponded with the level of confidence required to make a finding; 
that is, a lower level finding required one degree of confidence in the 
finding, and a higher level finding required an increased level of 
confidence in the finding over the lower level. 49 FR 47728-47729. 
Appendix III included a table summarizing the level of the finding 
required at each of the three decision points.
    Appendix III represents the analytical process DOE would follow to 
issue findings relative to the disqualifying and qualifying conditions 
of a site, and use in its decision-making on site selection. This 
analytical process dictates a higher-level of confidence in the 
findings of qualifying or disqualifying conditions at the last stage of 
the siting process, site selection for repository development, compared 
to the initial stage of the siting process, site nomination for site 
characterization. DOE anticipated that the higher-level of confidence 
in its technical findings would be obtained through the site 
characterization process undertaken at the later stages of the 
selection process.
3. Bases for the Structure of the General Guidelines
    The structure and development of the Guidelines were based on four 
primary sources of information and considerations: (1) The direction in 
the NWPA, as originally enacted; (2) the extant understanding of 
geologic disposal in the scientific and technical community; (3) 
applicable regulations proposed by the NRC and the EPA governing the 
disposal of spent nuclear fuel and high-level radioactive waste in 
geologic repositories; and (4) public comments.
    DOE initiated the rulemaking process by assembling a task force of 
program experts. 49 FR 47718. The task force developed draft Guidelines 
based on criteria used earlier in the National Waste Terminal Storage 
Program, including program objectives, system performance criteria, and 
site performance criteria. At the time, the task force reviewed other 
criteria defined for geologic repositories by the National Academy of 
Sciences and the International Atomic Energy Agency.
    The task force also sought consistency with NRC regulations and 
proposed EPA regulations related to geologic repositories. 49 FR 47718. 
NRC is the statutory agency responsible for licensing the construction 
and operation of a geologic repository; EPA is the statutory agency 
responsible for setting public health and safety standards for a 
geologic repository. Consistency of the DOE Guidelines with these 
regulatory standards was essential, since any potential site would be 
evaluated based on its ability to meet applicable regulatory 
requirements. 49 FR 47721.
    In sum, the structure and content of the Guidelines was based on 
the state of knowledge in the late-1970s and early-

[[Page 67058]]

1980s in the regulatory community, as well as the national and 
international scientific community, regarding the development of 
geologic repositories.
    DOE sought and received extensive public comments on a draft of the 
Guidelines before submitting them to the NRC for concurrence. On 
February 7, 1983, the proposed Guidelines were published in the Federal 
Register (48 FR 5670) for public review and comment. In addition, DOE 
published a separate notice soliciting comment from the Governors of 
the six States with potentially acceptable sites, and then met 
individually with officials from each of these States. DOE also held a 
series of regional public hearings. After considering the comments 
received, DOE drafted a set of alternate Guidelines to address the 
comments. The alternate Guidelines and public comments were made 
available in a second notice on June 7, 1983 (48 FR 26441), followed by 
a second public comment period. Further regional meetings and 
consultations with Federal agencies were held before DOE submitted the 
Guidelines to NRC for concurrence on November 22, 1983. 49 FR 47718-
47719.
4. Consistency With NRC Technical and Procedural Conditions
    Of particular importance to DOE's formulation of the Guidelines was 
consistency with NRC licensing regulations for the disposal of waste in 
a geologic repository. 49 FR 47718. In June 1983, NRC amended its 
licensing regulations at 10 CFR part 60 with respect to subpart E, 
technical criteria addressing siting, design and performance objectives 
of a geologic repository. 48 FR 28194. NRC concurred in the Guidelines 
subject to conditions that would satisfy the overall need to maintain 
consistency between NRC regulations and the DOE Guidelines. Among the 
NRC conditions were: (1) DOE clarifications and deletions of certain 
limiting terms such as ``permanent'' and ``significant''; (2) DOE 
modifications for consistency with NRC criteria regarding anticipated 
processes and events, potentially adverse conditions, and the role of 
engineered barriers during the process for screening candidate sites 
for characterization; and (3) DOE revisions and additions to 
disqualifying conditions to ensure that unacceptable sites would be 
eliminated as early as practicable. 49 FR 47719-47722.
    NRC concurrence conditions also addressed general, procedural 
aspects of how the DOE was to apply the Guidelines. For example, NRC 
concurrence was conditioned on a lack of conflict between NRC 
regulations at 10 CFR part 60 and the Guidelines, recognition by DOE 
that NRC regulations were controlling in the event of any differences, 
and a commitment that DOE would obtain NRC concurrence on any future 
revisions to the Guidelines. 49 FR 47719-47720. NRC also requested DOE 
to specify in greater detail how the Guidelines would be applied at 
each siting stage. This specificity was provided by the addition of 
Appendix III to the Guidelines. Appendix III indicated how the 
Guidelines would be applied at all of the site selection stages, 
including the recommendations to the President for site 
characterization and for the development of a site as a repository.
    The NRC required additional changes after it met publicly with 
representatives of several interested states, Indian tribes, and DOE. 
After DOE committed to making those changes, the NRC voted to concur in 
the Guidelines. 49 FR 47720. Thus, the current Guidelines represent the 
substantial input provided by the NRC in 1984 through the statutory 
concurrence process.

C. DOE Application of the Guidelines

    Consistent with section 112(b) of the NWPA, DOE applied the 
Guidelines to: (1) Nominate five sites as suitable for 
characterization; and (2) recommend to the President three of those 
five nominated sites for characterization as candidate sites for the 
first repository. On May 27, 1986, the President approved each of the 
sites that had been recommended for characterization. Yucca Mountain 
was one of the three sites that DOE recommended. The recommendation to 
the President was documented in a DOE report, Recommendation by the 
Secretary of Energy for Site Characterization for the First 
Radioactive-Waste Repository (May 1986; DOE/S-0048). In addition, a 
draft environmental assessment was prepared for each of the five sites 
and final environmental assessments were prepared for each of the three 
sites that were recommended.
    This action concluded the process that had been established by the 
NWPA for identifying sites for characterization. The Guidelines' role 
of structuring DOE's process for identifying sites for characterization 
was completed in accordance with the Congressional directives to DOE. 
Under DOE's formulation of the Guidelines at that time, however, the 
Guidelines would remain relevant and applicable through the third 
principal siting decision point, the selection of a site to be 
recommended for the development of a repository.

D. 1987 Amendments to NWPA

    In 1987, Congress amended the NWPA to mandate Yucca Mountain as the 
sole site to be characterized. 42 U.S.C. 10172 (Supp. V 1987). The 
processes for site characterization under section 113 and site approval 
under section 114 were made applicable to only Yucca Mountain. Under 
sections 113(a) and (b), Yucca Mountain was designated as the site for 
which site characterization activities would take place, and a site 
characterization plan would be issued, respectively. Under section 
113(c), Congress amended the statute to name Yucca Mountain as the site 
for which the restrictions on site characterization activities would be 
applicable. That is, DOE was directed to conduct only such activities 
at Yucca Mountain that are necessary to evaluate the suitability of the 
site for an application to the NRC for a construction authorization, 
and to comply with requirements under the National Environmental Policy 
Act (NEPA). Section 114 was amended to restrict DOE's analysis of 
alternative sites in any environmental impact statement (EIS) that may 
be prepared for the Yucca Mountain site under NEPA. Any such EIS would 
analyze the Yucca Mountain site, and no other sites, for potential 
development of a geologic repository. Further, section 160(b) directed 
DOE to ``terminate all site specific activities (other than reclamation 
activities) at all candidate sites, other than the Yucca Mountain 
site.'' 42 U.S.C. 10172(a)(2).
    In sum, Congress made clear its intent for DOE to focus its 
resources on investigating Yucca Mountain, and only Yucca Mountain, as 
a potential site for a high-level radioactive waste repository.

E. Yucca Mountain Site Characterization Plan

1. Statutory Requirements
    Under sections 113 and 160 of the NWPA, as amended, DOE was 
authorized to conduct site characterization activities at the Yucca 
Mountain site. Prior to initiating site characterization under section 
113, DOE was required to prepare a general plan for site 
characterization activities at the Yucca Mountain site. DOE was 
required to submit the plan to the NRC and the State of Nevada for 
their review and comment [42 U.S.C. 10133(b)(1)], as well as to members 
of the public in the vicinity of Yucca Mountain [42 U.S.C. 
10133(b)(2)]. Certain contents of the

[[Page 67059]]

plan were mandated by section 113(b), including, among other things, a 
description of planned excavation and other testing activities, a 
description of the possible form or packaging of the high-level waste, 
and the criteria to be used to determine the suitability of the site 
for the location of a repository, developed pursuant to section 112(a). 
Section 113(b)(3) also required DOE to report every six months on the 
progress of site characterization activities at Yucca Mountain, and to 
provide the reports to the NRC, and the Governor and the legislature of 
the State of Nevada.
    DOE prepared the site characterization plan in draft form in 
January 1988. In preparing the plan, DOE followed NRC guidance, as 
specified in the document, Standard Format and Content of Site 
Characterization Plans for High Level Waste Geologic Repositories, 
Regulatory Guide 4.17 (NRC 1987). After review and comment by NRC, the 
State of Nevada, and interested members of the public, DOE finalized 
the Site Characterization Plan: Yucca Mountain Site, Nevada Research 
and Development Area, Nevada (December 1988; DOE/RW-0198) (hereinafter 
also the SCP), in December 1988.
2. Structure of the Site Characterization Plan
    ``Site characterization'' is defined in the NWPA to include 
research activities undertaken to establish the geologic condition of a 
site, for example, borings and surface excavations, and in situ testing 
necessary to evaluate the suitability of a candidate site for the 
location of a repository. 42 U.S.C. 10101(21). In the SCP, DOE 
described the purpose of its site characterization program at Yucca 
Mountain was to obtain the information necessary to determine whether 
the site is suitable for a repository, and could satisfy NRC licensing 
requirements (which must be consistent with EPA public health and 
safety standards). DOE also explained there that the information 
obtained from site characterization, such as the geologic, 
geoengineering, hydrologic, and climatological conditions at a site, 
would be used to develop and optimize repository design and to evaluate 
the performance of the site and the engineered barriers as an 
integrated system.
    The purpose of the SCP was threefold: (1) To describe the site, and 
the preliminary designs for the repository and the waste packages in 
sufficient detail to form the basis for the site characterization 
program; (2) identify issues to be resolved during site 
characterization and present the strategy for resolving the issues; and 
(3) describe the plans for the work needed to obtain the information 
deemed necessary and to resolve outstanding issues. The SCP was 
organized along two lines: (1) An issues hierarchy, which embodies the 
DOE, NRC and EPA regulations governing the repository system; and (2) 
an issue-resolution strategy.
    The issues hierarchy was a three-tiered framework laying out what 
must be known before the Yucca Mountain site could be selected and 
licensed. ``Issues'' were defined as questions related to performance 
of the repository that must be resolved to demonstrate compliance with 
applicable regulations of DOE, NRC and EPA. DOE identified four key 
issues to be addressed, based on regulatory requirements and the four 
system guidelines in part 960: (1) Postclosure performance; (2) 
preclosure performance; (3) environment, socioeconomic, and 
transportation impacts of a repository; and (4) ease and cost of 
repository siting, construction, operation and closure. DOE also 
explained that only the first, second, and part of the fourth key issue 
would be addressed in the site characterization program, since 
resolution of these other key issues (that is, key issue 3 and part of 
key issue 4) were not dependent on information from site 
characterization activities. The issue-resolution strategy consisted of 
four parts: Issue identification, performance allocation, data 
collection and analysis, and documentation of issue resolution. This 
framework was used to develop test programs and explain why the test 
programs were adequate and necessary. The object was to collect 
information to be used in a concluding set of analyses to resolve the 
issues, and to document resolution of the issues.
    As required by section 113(b)(1)(A)(iv), the SCP included criteria 
to determine the suitability of the site for development of a 
repository. Those ``criteria'' were the provisions within the 
Guidelines pertinent to site characterization activities, namely, the 
postclosure guidelines, and the preclosure guidelines related to 
radiological safety and technical feasibility of repository siting, 
construction and operation, to be applied in the manner described in 
Appendix III. Appendix III set out the level of findings DOE must make 
relative to the system and technical requirements found in the 
postclosure guidelines (subpart C) and preclosure guidelines (subpart 
D) at the final decision point of recommending a site for development 
as a repository. DOE believed that the information gained through site 
characterization and the issue resolution process would form the basis 
for these findings.
    DOE also explained in the SCP that not all of the Guidelines would 
be addressed as part of site characterization activities. The SCP would 
not address the environmental, socioeconomic and transportation 
guidelines, or certain guidelines related to ease and cost of 
repository siting, construction, operation, and closure, since DOE 
would not develop information related to those guidelines through site 
characterization activities. Those guidelines would be addressed in 
other investigations and plans to be conducted concurrently with the 
site characterization program. Also, in light of the 1987 amendments to 
the NWPA permitting site characterization to proceed only at Yucca 
Mountain, DOE stated in the SCP that the comparative portions of the 
Guidelines would not be applied in the site suitability determination 
to be made under section 113(b).
    In accordance with section 113(b)(3), approximately every six 
months DOE issues a report updating information on the conduct of site 
characterization activities at the Yucca Mountain site. Those reports 
briefly summarize the characterization activities undertaken at the 
site, the technical and scientific issues of key interest and their 
resolution, and issues that remain for further characterization and 
resolution. In addition, the semiannual reports provide references and 
a bibliography of other reports and documents containing more detailed 
information regarding site characterization activities. DOE provides 
the reports to the NRC, the Governor of Nevada, and the legislature of 
the State of Nevada.
    The progress reports reflect DOE's ongoing interaction with the 
NRC. In July 1986, the NRC amended its regulations at 10 CFR part 60 
(51 FR 27158) to establish the method of interaction between DOE and 
the NRC on the development and implementation of the site 
characterization plan. NRC established a system for DOE to report on 
the results of site characterization, identify issues, plan for 
additional studies, eliminate planned studies no longer necessary, and 
identify decision points reached. In this manner, the NRC established a 
clear pathway to interact with DOE in the management and direction of 
the site characterization program.
    Site characterization activities have continued up to and including 
the present, and are described in greater detail below in section II.G.

[[Page 67060]]

F. Energy Policy Act of 1992

    In 1992, Congress enacted certain provisions in the Energy Policy 
Act of 1992 (Pub. L. No. 102-486) impacting the nation's nuclear waste 
repository program. In section 801(a) of the Energy Policy Act of 1992 
(EPACT), Congress directed EPA to promulgate a new, health-based 
standard to ensure protection of the public health from high-level 
radioactive waste that may be disposed in a geologic repository located 
at Yucca Mountain. The new standards could depart from the generic EPA 
standards promulgated at 40 CFR part 191, and would be specific to 
Yucca Mountain. In section 801(b), Congress also directed the NRC, 
within one year of EPA adopting a new standard, to modify its technical 
requirements and criteria under section 121(b) of the NWPA [42 U.S.C. 
10141(b)] (i.e., 10 CFR part 60), as necessary, to be consistent with 
the new EPA standards.
    Before setting the new standard, however, EPA was required to 
contract with the National Academy of Sciences (NAS) to conduct a study 
to provide findings and recommendations on reasonable standards for 
protection of the public health and safety. Under section 801(a) of the 
EPACT, EPA was required to promulgate its new standards based on, and 
consistent with, the NAS findings and recommendations. Under the EPACT 
and accompanying congressional instruction, NAS's charge was to answer 
three specific questions embodied in section 801(a)(2), and to advise 
EPA on the technical basis for the health-based standards it was 
mandated to prepare. The three questions posed in section 801(a)(2) 
addressed: (1) Whether a health-based standard based on doses to 
individual members of the public would provide a reasonable basis for 
protecting public health and safety; (2) whether it is reasonable to 
assume that a system for postclosure oversight of the repository, using 
active institutional controls, will prevent an unreasonable risk of 
breaching the repository's engineered or natural barriers, or of 
increasing the exposure of individual members of the public to 
radiation beyond allowable limits; and (3) whether it is possible to 
make scientifically supportable predictions of the probability that the 
repository's engineered or natural barriers will be breached as a 
result of human intrusion over a period of 10,000 years.
    In August 1995, NAS published the statutorily mandated report, 
entitled Technical Bases for Yucca Mountain Standards. In sum, NAS 
issued findings that: (1) A health standard for Yucca Mountain based on 
risk to individuals of adverse health effects from releases from the 
repository (rather than EPA's generic standards which contain both 
individual dose and release limits) was an appropriate standard that 
would adequately protect the health and safety of the general public; 
(2) it is not reasonable to assume that a system for postclosure 
oversight can be developed, based on active institutional controls, 
which will itself prevent an unreasonable risk of breaching the 
repository's engineered barriers or of increasing the exposure of 
individual members of the public to radiation beyond allowable limits; 
and (3) it is not possible to make scientifically supportable 
predictions of the probability that a repository's engineered or 
geologic barriers will be breached as a result of human intrusion over 
a period of 10,000 years. Notwithstanding the latter two findings, the 
NAS recommended EPA include in its regulations a stylized human 
intrusion event. The NAS reasoned that such an analysis may provide 
useful insight into the degree to which the ability of a repository to 
protect the public health and safety would be degraded by an intrusion.
    In reaching its findings and recommendations, the NAS consulted 
with numerous entities, including local, state and federal government 
agencies, private organizations, and scientists and engineers, both 
national and international, familiar with the technical issues under 
study, and held five open technical meetings to ensure a thorough 
review of the scientific literature on the subject. In the Technical 
Bases for Yucca Mountain Standards, the NAS provides a detailed 
explanation of the assumptions and analyses underlying the study, and 
the reasons for NAS's findings and recommendations. Among the more 
important of these is the NAS assumption, confirmed by its technical 
review, that it is possible to conduct scientifically justifiable 
analyses of repository behavior over thousands of years in order to 
assess whether a repository can comply with the applicable public 
health standard. In addition, based on its analyses, the NAS concluded 
that the proper way to evaluate the risks of adverse health effects, 
and to compare those risks to the proposed standard, is to assess the 
estimated potential future behavior of the entire repository system and 
its potential effect on humans. The procedure used to perform this 
analysis is called performance assessment (alternately called total 
system performance assessment).
    In discussing the possible implications of its conclusions, the NAS 
noted that, if EPA issues standards based on individual risk (as 
recommended by the NAS), then the NRC would be required to revise its 
regulations embodied in 10 CFR part 60 to be consistent with EPA. This 
is because NRC's 10 CFR part 60 is directed in part to subsystem 
technical requirements, whereas the NAS concluded that it is the 
performance of the total system, rather than that of its individual 
elements in isolation, that is crucial in the context of a risk-based 
standard. Under a risk-based standard, imposing subsystem performance 
requirements might result in a deficient repository design even if each 
subsystem element meets or exceeds a certain performance standard. The 
NAS also observed that its recommendations, if adopted, implied the 
development by EPA of different regulatory and analytical approaches 
than those employed in the past, and that the process of establishing 
the new standards would require significant time and opportunity for 
public comment and review. Nevertheless, NAS noted that these potential 
changes should not impede site characterization work by DOE at Yucca 
Mountain.
    At present, EPA is in the process of preparing new standards 
pursuant to EPACT and in light of the NAS findings and recommendations. 
Those new standards have proposed in a rulemaking proceeding for public 
review and comment. Also consistent with EPACT, section 801(b), the NRC 
has proposed new regulations governing the technical requirements and 
criteria for licensing a potential geologic repository at the Yucca 
Mountain site based on the NAS findings and recommendations and in 
anticipation of new EPA standards. The EPA's and NRC's proposed 
regulations are discussed in greater detail below, in section II.J, and 
II.K, respectively.

G. Evolution of the Site Characterization Program

    Since publication of the SCP in 1988, DOE's site characterization 
program at Yucca Mountain has made substantial progress in developing 
information and data about the site and resolving outstanding technical 
issues. Over time, the site characterization program has evolved and 
been driven by advances in science and technology, as well as 
legislative and managerial changes. The following summarizes the 
evolution and status of the site characterization program.

[[Page 67061]]

    Technical Components of the Site Characterization Program. The 
three main technical components of the site characterization program 
are testing, design, and performance assessment. Testing encompasses 
the investigation of natural features and processes at the site through 
field testing, conducted above and below ground, and laboratory testing 
of rock and water samples. Design refers to work on development of the 
description of a repository and waste packages tailored to the site 
features, supported by laboratory testing of candidate materials for 
waste packages and design-related testing in the underground tunnels 
similar to those in which waste would be emplaced. Performance 
assessment refers to the quantitative estimates of the performance of 
the total repository system, over a range of possible conditions and 
for different repository configurations, by means of computer modeling 
techniques that are based on site and materials testing data and 
accepted principles of physics and chemistry.
    Through the testing program, DOE has learned a great deal about the 
geologic conditions of the site. The single largest effort undertaken 
in this regard has been construction of the Exploratory Studies 
Facility (ESF). Construction of this facility began in 1992 and was 
completed in 1998. The ESF, a 4.9 mile long underground tunnel, has 
enabled DOE to conduct testing and exploration activities at the depth 
of the proposed repository. Utilization of this facility has formed the 
basis for increased knowledge and understanding of the mechanical and 
hydrologic characteristics of the geologic formation in which the 
repository would be constructed. Ongoing work at this facility will 
focus primarily on thermal and hydrologic testing in the cross drift to 
extend and, where necessary, modify this understanding of the 
properties of the host rock.
    The design component of the site characterization program comprises 
those activities aimed at developing concepts for the engineered 
components of the geologic repository. Design activities use 
information about the site gained through the testing program, and 
information about the engineered barrier system gained through other 
scientific investigations, to generate and develop design concepts that 
can meet the requirements placed on the engineered components of the 
repository. Site characterization activities are structured to acquire 
data needed to support the design. For example, a number of the site 
characterization program tests focus on the hydrological, geomechanical 
and thermal properties of Yucca Mountain. These tests are significant 
because they provide the fundamental information needed to specify the 
approach to be used in developing the geologic repository thermal 
loading and underground support schemes. Also, under the design 
program, DOE examines various approaches to meeting engineered facility 
requirements, and conducts comparative evaluations of the costs and 
benefits of different approaches to developing design concepts.
    The performance assessment component of site characterization 
represents the analytical method (i.e., computer modeling) DOE uses to 
forecast the performance of the repository within the Yucca Mountain 
setting and assess that performance against regulatory standards. Put 
in simplified terms, performance assessment uses the information and 
data collected under the testing and design programs to feed computer 
models that describe how the site would behave in the presence of a 
repository and how the engineered system would behave within the 
environmental setting of the mountain. Each model, called a process 
model, is designed to describe the behavior of individual and coupled 
physical and chemical processes. A total system performance assessment 
(TSPA) links the results of individual process models to construct a 
computer model of the repository system and surrounding environment 
that are important to assessment of overall repository performance. 
With the TSPA model, DOE can estimate releases of radionuclides from a 
repository under a range of conditions, over thousands of years, and 
forecast the consequent probable doses to persons.
    Performance assessment (or TSPA), as described above, is an 
accepted method to assess the performance of a repository at Yucca 
Mountain. DOE's use of performance assessment models began even before 
issuance of the SCP in 1988. Since that time, however, significant 
advancements have been made in the technical capability, acceptance, 
and use of this analytical tool. In 1991, the Nuclear Energy Agency 
Radioactive Waste Management Committee and the International Atomic 
Energy Agency International Radioactive Waste Management Advisory 
Committee confirmed that TSPA provides an adequate means to evaluate 
long-term radiological impacts of a waste disposal system. On a 
national level, the NRC, the NAS and the Nuclear Waste Technical Review 
Board (a Congressionally mandated committee of experts chartered to 
evaluate the technical and scientific validity of activities undertaken 
by DOE to characterize Yucca Mountain to determine its suitability as a 
location for a repository) have acknowledged the value of this method 
for evaluating postclosure performance for a repository at Yucca 
Mountain.
    A significant portion of the DOE site characterization program has 
been aimed at developing the scientific bases that serve as the 
foundation for the process models used in performance assessment. DOE 
developed performance assessment models and conducted benchmark 
performance assessments of the total repository system in 1991, 1993 
and 1995. Between these benchmark assessments, DOE conducted many 
performance assessments to evaluate selected features of the site and 
the evolving design. DOE used these total system and subsystem 
performance assessments to evaluate design options and to determine 
further data needed from site investigations. The most recent TSPA was 
conducted in 1998, the results of which are contained in the report, 
Viability Assessment of a Repository at Yucca Mountain (December 1998; 
DOE/RW-0508).
    Redirection of the Site Characterization Program. In 1994, DOE 
conducted extensive internal and external reviews of the program. As a 
result of those reviews, documented in the Civilian Radioactive Waste 
Management Program Plan (December 1994; DOE/RW-0458) (Program Plan), 
DOE identified cost-cutting measures to reduce the cost of completing 
site characterization. In response to Congressional concern with the 
1994 Program Plan, DOE submitted a revised Program Plan to Congress 
that was designed to maintain scientific investigations at the site, 
and retain target dates for determining site suitability and 
recommendation for construction authorization. Civilian Radioactive 
Waste Management Program Plan, Revision 1 (May 1996; DOE/RW-0458). As 
part of the revised strategy, DOE redirected project efforts to address 
the major unresolved technical questions and to complete an assessment 
of the viability of licensing and constructing a repository at Yucca 
Mountain. Congress indicated its approval of the revised Program Plan 
in the Conference Report on the Energy and Water Development 
Appropriations Act, 1997, H.R. Rep. No. 782, 104th Cong., 2d Sess. 82 
(1996), by directing that the appropriated funds be used in accordance 
with the revised Program Plan issued by DOE in May 1996.

[[Page 67062]]

    In the Fiscal Year 1997 Energy and Water Development Appropriations 
Act (Pub. L. No. 104-206), Congress directed DOE to provide the 
viability assessment of the Yucca Mountain site, referenced in DOE's 
revised Program Plan, to Congress and the President as a basis for 
making future decisions on program funding and direction. DOE issued 
the Viability Assessment of a Repository at Yucca Mountain (Viability 
Assessment) in December 1998. Drawing on 15 years of scientific 
investigation and design work, the Viability Assessment summarizes a 
large technical basis of field investigations, laboratory tests, 
models, analyses and engineering. The Viability Assessment also 
identifies major uncertainties relevant to the technical defensibility 
of DOE's analyses and designs, the approach to managing these 
uncertainties, and the status of work relative to the target dates of 
2001 for a determination on recommendation of Yucca Mountain and 2002 
for submittal of a license application to NRC. The Viability Assessment 
also includes the most recent iteration of the TSPA, and the results of 
that process.
    Coordination with NRC. DOE's implementation of its site 
characterization program and the issue resolution strategy embodied in 
the SCP has been conducted in close coordination with the NRC. In 1995, 
the NRC revised its prelicensing repository program as a result of 
changes in the DOE civilian radioactive waste management program, the 
findings of a NAS committee recommending changes to the public health 
standard for a potential Yucca Mountain repository, and budgetary 
constraints imposed by Congress. The NRC adjusted the scope of its 
program to focus only on those topics most critical to repository 
performance, termed ``key technical issues.'' These issues were 
intended to be a vehicle to communicate to DOE those technical matters 
for which the NRC had remaining unanswered questions regarding the 
performance of the Yucca Mountain site, or the data needed to assess 
that performance. DOE's management of the site characterization program 
includes activities to obtain information to address the NRC key 
technical issues. DOE has structured the site characterization program 
such that one of its goals is for DOE and NRC to reach consensus that 
the remaining key technical issues have been addressed adequately, or 
that adequate plans are in place to address the issues.

H. The 1993-1995 Public Dialogue on the Guidelines

    In the SCP, issued in December 1988, DOE described how it would 
apply the Guidelines as part of the site characterization program to 
evaluate the suitability of the site. DOE indicated in the SCP that the 
Guidelines related to site characterization activities would be applied 
as the suitability criteria. DOE also indicated there that the 
comparative provisions of those requirements would not be applied in 
light of the 1987 amendments to the NWPA limiting site characterization 
activities to Yucca Mountain. Notwithstanding this explanation, a 
number of interested parties suggested it remained unclear how DOE 
would apply the Guidelines in the future. Because of this continuing 
stated uncertainty, the DOE instituted an ongoing dialogue with 
external parties on the Guidelines.
    In October 1993, DOE briefed the representatives of the affected 
units of local government and the State of Nevada on its plans for 
activities related to site suitability evaluation. DOE followed this 
briefing with a Notice of Inquiry in the Federal Register (59 FR 
19680), dated April 25, 1994, eliciting the views of the public on the 
appropriate role of the Guidelines. A public meeting was held on May 
21, 1994 in Las Vegas, Nevada. The purposes of the meeting were to 
follow-up on a previous public meeting held in August 1993; to update 
the public on site characterization activities; and to provide an 
opportunity to discuss the development of a process to evaluate site 
suitability. DOE then published a second Federal Register notice (59 FR 
39766) on August 4, 1994, announcing that it intended to use the 
Guidelines as currently written, subject to the programmatic 
reconfiguration directed in the 1987 NWPA amendments. Through that 
notice, DOE also announced the availability of a draft description of 
the proposed process and its intention to hold two additional public 
meetings to discuss the matter. Although several options were 
discussed, DOE discerned no clearly preferred option from this public 
comment process. In response to public comments at the meetings, DOE 
committed to provide background information and its rationale for 
maintaining the use of the Guidelines as originally promulgated, with 
modification to eliminate application of the comparative portions of 
the Guidelines. In September 1995, DOE published in the Federal 
Register the background information and its rationale, as committed to 
in previous public meetings. 60 FR 47737.
    In the September 1995 public notice, DOE explained that amending 
the Guidelines, either to remove those portions that are primarily used 
for comparative purposes or to develop guidelines tailored to 
evaluation of the suitability of the Yucca Mountain site, was not 
required at that time. DOE recognized then that the Guidelines might 
have to be amended at some future date to be consistent with any 
changes to EPA or NRC requirements. 60 FR 47740. Among the options 
considered in the 1993-1995 public dialogue was abandonment of the 
Guidelines and adoption of the NRC siting criteria in 10 CFR 60.122. 
DOE noted that the Guidelines were expressly derived from, and are tied 
to, the part 60 siting criteria. In addition, DOE noted that, should 
any differences between 10 CFR part 960 and 10 CFR part 60 be 
identified, 10 CFR part 60 would prevail in the licensing process. 
While recognizing that much of 10 CFR 960 subpart B, the implementation 
guidelines, was no longer applicable, DOE concluded that the Guidelines 
could be selectively interpreted to avoid the comparative aspects while 
applying the relevant provisions of subparts C and D, the postclosure 
and preclosure guidelines.

I. The 1996 Notice of Proposed Rulemaking

    For many of the reasons described earlier in this notice, including 
changes in congressional direction of the repository program and 
advancements in site characterization, on December 16, 1996, DOE 
published in the Federal Register a notice of proposed rulemaking for 
10 CFR part 960. 61 FR 66158. In that notice, DOE proposed to clarify 
and focus the Guidelines and to add a new, site-specific subpart E to 
the Guidelines. Subpart E would apply only to the Yucca Mountain site, 
and would contain preclosure and postclosure system guidelines, each 
with a single qualifying condition. 61 FR 66163. In each of the 
periods, the qualifying condition would be that a repository at Yucca 
Mountain be capable of limiting radiological releases within applicable 
standards to be set by EPA and implemented by the NRC through the 
repository licensing process. DOE would demonstrate this capability 
through performance assessments. 61 FR 66164. These performance 
assessments would forecast the performance of a proposed geologic 
repository at Yucca Mountain and compare the results of the assessments 
to the applicable regulatory standards to

[[Page 67063]]

determine whether the site would be suitable for development as a 
repository.
    The 1996 proposal was consistent with the system-level evaluation 
originally envisioned for the conclusion of site characterization. DOE 
recognized in 1984 in the Guidelines that, only after the entire 
process of narrowing the number of potentially acceptable sites to one 
and after site characterization, would it be possible to conduct 
complete performance assessments. Such assessments require detailed 
information that can be obtained only during site characterization. 49 
FR 47717. In addition, the 1996 proposal was consistent with DOE's 
longstanding position that the Guidelines must complement and not 
conflict with EPA and NRC regulations, since the ability to meet 
applicable public health and safety standards and develop information 
adequate to support a license application has always been central to 
the site suitability determination.
    The 1996 proposal attracted a wide variety of comments from members 
of the public, the NRC, the EPA, and the Nuclear Waste Technical Review 
Board. The major issues that emerged from the public comment process 
are discussed in detail later in this Supplementary Information. For 
reasons also explained below, these comments persuaded DOE to reassess 
the clarity of the proposed regulations and the legal and policy basis 
for them.

J. Proposed NRC Regulation, 10 CFR Part 63

1. Background
    On February 22, 1999, the NRC published in the Federal Register a 
proposed new rule, 10 CFR part 63, containing licensing criteria for 
disposal of spent nuclear fuel and high-level radioactive waste in the 
proposed geologic repository at Yucca Mountain, along with proposed 
revisions to 10 CFR part 60 and other related regulations. 64 FR 8640. 
The proposed licensing criteria at part 63 would apply exclusively to 
Yucca Mountain; part 60 would be revised to make it applicable to any 
geologic repository other than one at Yucca Mountain. NRC's proposal 
seeks to establish a new system of risk-informed, performance-based 
regulation. Under this approach, risk insights, engineering analysis 
and judgment, and performance history are used to: (1) Focus attention 
on the most important activities; (2) establish objective criteria 
based upon risk insights for evaluating performance; (3) develop 
measurable or calculable parameters for monitoring system and licensee 
performance; (4) provide flexibility to determine how performance 
criteria are met; and (5) focus on results as the primary basis for 
regulatory decision-making. 64 FR 8643.
    The NRC's rationale for proposing part 63 stems from the 
requirements of the EPACT. 64 FR 8641-8643. Section 801(b) of EPACT 
requires that, within one year after EPA promulgates its new standards 
for protection of public health and safety, the NRC must modify its 
technical requirements and criteria for repository licensing (i.e., 
part 60) to be consistent with the new EPA standards. In addition, the 
EPACT requires NRC to include in its modifications, consistent with the 
NAS findings and recommendations, certain assumptions that are 
specified in the EPACT with regard to the effectiveness of DOE's 
postclosure oversight of the repository.
    The NAS issued its findings and recommendations in the report, 
Technical Bases for Yucca Mountain Standards, August 1995. The NAS 
findings and recommendations reported there, along with consultation 
NRC has had with EPA, provide the basis for NRC's proposed 
modifications. 64 FR 8641, 8643. The NAS recommended approach to 
setting a public health and safety standard has a different objective 
from the NRC approach reflected in the existing part 60 requirements 
and criteria. 64 FR 8643. Accordingly, the modifications proposed by 
the NRC, based on the NAS report, and the subsequently proposed EPA 
rule marked a change in methodology and licensing philosophy.
2. Structure of Proposed Part 63
    Preclosure Requirements. Proposed part 63 would require DOE to 
demonstrate compliance with the applicable preclosure regulatory 
standards by the use of an integrated safety analysis. 64 FR 8652. An 
integrated safety analysis is a systematic examination of the geologic 
repository operations area's hazards and their potential for initiating 
events (for example, accidents), the potential consequences of the 
events, and the site, structures, systems, components, equipment and 
activities of personnel. The analysis would be conducted to ensure that 
all relevant hazards that could result in unacceptable consequences 
have been adequately evaluated and appropriate protective measures have 
been identified. ``Integrated'' means joint consideration of safety 
measures that otherwise might conflict, including such measures as fire 
protection, radiation safety, criticality safety, and chemical safety. 
The results of the analysis would be used to support a finding of 
compliance with a performance objective for the preclosure period of 
limiting radiation exposures and releases within a dose limit of 25 
millirem (mrem) to any member of the public beyond the site boundary.
    Postclosure Requirements. While certain parts of proposed part 63 
are similar to part 60, in particular with respect to many procedural 
and administrative regulations, the substance of the regulations 
governing postclosure performance objectives is fundamentally 
different. The part 60 technical criteria for postclosure rely on 
several quantitative, subsystem performance objectives. In 1983-4, NRC 
believed this approach was best suited to meet its statutory 
requirement under section 121(b)(1)(B) of the NWPA to prescribe 
criteria that would involve use of a system of multiple barriers in the 
design of the repository. 64 FR 8648. At the time part 60 was written, 
NRC's technical opinion was that compliance with this requirement could 
be best demonstrated by specifying subsystem technical requirements, 
thereby assuring multiple, independent and redundant systems and 
barriers. Given advancements in technical understanding and analytical 
capability, and information acquired through site-characterization at 
Yucca Mountain, the NRC no longer believes this approach is an optimal 
and reliable approach to assure compliance with public health and 
safety standards. 64 FR 8648-8649.
    Part 63 does not contain subsystem performance requirements, or 
analogs for those requirements, as found in part 60. The part 63 
requirements are based on only one quantitative standard--demonstrating 
compliance with an individual dose limit. The part 63 technical 
criteria are compatible with the NRC's philosophy of risk-informed, 
performance-based regulation. This approach is consistent with NAS 
recommendations that would require compliance with a health-based 
standard established in consideration of risk to a hypothetical 
critical group as the only quantitative standard for postclosure 
repository performance. 64 FR 8643. The NRC concept of critical group 
means the hypothetical group of individuals reasonably expected to 
receive the greatest exposure to radioactive materials potentially 
released from a geologic repository at Yucca Mountain. The EPA proposes 
in its rule (described in section II. K) the use of a reasonably 
maximally exposed individual (RMEI). The RMEI is a hypothetical 
individual having certain characteristics that include where the RMEI 
lives, what the RMEI's diet would consist of and the amount of water 
consumed by the RMEI on daily basis.

[[Page 67064]]

For the purposes of this proposed rule, the term receptor is used in 
lieu of either the EPA or NRC concept. A receptor is intended to 
represent a member of the public, either an individual or group, that 
could be exposed to releases of radiation from a repository at Yucca 
Mountain. When the suitability determination is made, DOE would 
implement the regulatory concept applicable at that time.
    This approach is also consistent with NRC's obligation to ensure a 
multiple barrier system by requiring DOE to demonstrate that the 
natural barriers and the engineered barriers will work in combination 
to enhance overall performance of the repository.
    Part 63 would require DOE to demonstrate compliance with the 
applicable postclosure regulatory standard by the use of performance 
assessment. 64 FR 8650. Performance assessment is a systematic analysis 
that identifies the features, events, and processes that might affect 
performance of the geologic repository, examines their effects on 
performance, and estimates the resulting expected annual dose. 
Demonstrating compliance with the postclosure performance of 10 CFR 
part 63 would require a performance assessment to quantitatively 
estimate the expected annual dose, over the compliance period, to the 
average member of the critical group. The critical group would be a 
hypothetical group of individuals reasonably expected to receive the 
greatest exposure to radioactive materials released from the geologic 
repository. Consistent with the EPACT and the 1995 NAS report, the NRC 
proposed that the results of the performance assessment be the sole 
quantitative measure used to demonstrate compliance with the individual 
dose limit. 64 FR 8650.
    Because of the importance of the performance assessment, part 63 is 
structured to establish certain minimum requirements governing the 
content and validation methods for the performance assessment. 64 FR 
8650-8651. For example, DOE would be required to include in the 
performance assessment data related to the geology, hydrology and 
geochemistry of Yucca Mountain, as well as data related to the design 
of the engineered barrier system; to account for uncertainties and 
variabilities in the data used to model performance of the repository; 
to provide the technical basis for either inclusion or exclusion of 
specific features, events, and processes of the geologic setting; and 
to provide the technical basis for the models used in the overall 
performance assessment by providing, for example, comparisons of the 
output of detailed process-level models and empirical observations. In 
addition, part 63 would prescribe the characteristics of the reference 
biosphere and receptor to be used in the performance assessment. DOE 
also would be required to conduct a separate performance assessment 
based on a limited human intrusion scenario prescribed by the NRC.

K. Proposed EPA Regulation, 40 CFR Part 197

1. Background
    On August 27, 1999, the EPA published in the Federal Register a 
proposed new rule, 40 CFR part 197, to establish public health and 
safety standards governing the storage and disposal of spent nuclear 
fuel and high level waste in a potential repository at Yucca Mountain, 
Nevada. 64 FR 46975. EPA is promulgating this rulemaking pursuant to 
section 801(a) of the EPACT. As explained earlier in this preamble 
(section I.F.), in section 801(a)(1) of the EPACT Congress directed EPA 
to promulgate a health-based standard for the protection of the public 
from releases from radioactive materials stored or disposed of in a 
repository at the Yucca Mountain site. Also under EPACT, Congress 
directed that the EPA standard was to be the only standard applicable 
to the Yucca Mountain site, and that the EPA standard must be based 
upon and consistent with NAS' findings and recommendations.
    As directed by Congress in the EPACT, it is EPA's role to establish 
the public health and safety standard, and NRC's role to implement that 
standard in any licensing process NRC may conduct for a repository at 
Yucca Mountain. It is anticipated that NRC would conform its proposed 
licensing regulation at 10 CFR part 63 to the final EPA radiation 
protection standards, as necessary and appropriate.
2. Structure of Proposed Part 197
    The proposed EPA rule is structured in two parts. Part A of the 
rule would establish the environmental standards for storage of spent 
nuclear fuel and high level waste at Yucca Mountain; part B would 
establish the environmental standards for disposal of spent nuclear 
fuel and high level waste at Yucca Mountain. The following is an 
overview of the main components of EPA's proposed rule; in many areas 
of the rule EPA has proposed alternative language and requirements for 
public review and consideration. For simplicity, not all of those 
alternative considerations will be presented here.
    For storage of spent nuclear fuel and high level waste, EPA 
proposes a standard limiting the annual committed effective dose 
equivalent (CEDE) to no more than 15 millirems to any member of the 
public in the general environment. This limit would apply to releases 
from the combination of management and storage of spent nuclear fuel 
and high level waste that is within the Yucca Mountain repository 
(below ground) and outside the Yucca Mountain repository but within the 
Yucca Mountain site (aboveground). EPA proposes this standard to be 
consistent with the risk level set in its generic standards for 
management and storage of spent nuclear fuel, high level waste, and 
transuranic waste, codified at subpart A of 40 CFR part 191 and with 
its interpretation of section 801 of EPACT requiring it to set site-
specific standards for storage of waste at Yucca Mountain. In EPA's 
view, storage of waste, whether inside the Yucca Mountain repository or 
outside the Yucca Mountain repository but within the Yucca Mountain 
site, presents the same technical situation and is analogous to the 
storage of radioactive waste at other facilities covered by 40 CFR part 
191. Accordingly, EPA proposes the storage standard for Yucca Mountain 
be essentially the same as the standard applicable to other facilities 
subject to subpart A of 40 CFR part 191.
    For disposal of spent nuclear fuel and high level waste, EPA 
proposes essentially three standards--an individual protection 
standard, a human intrusion standard, and a groundwater standard--that 
DOE would need to demonstrate to the satisfaction of the NRC to ensure 
protection of public health and safety. Under the individual protection 
standard, DOE would demonstrate that there is a reasonable expectation 
that for 10,000 years following disposal the reasonably maximally 
exposed individual (RMEI) receives no more than an annual committed 
effective dose equivalent (CEDE) of 15 millirems (mrem) from releases 
from the undisturbed Yucca Mountain disposal system. All potential 
pathways must be included in this analysis. In proposing this 
individual protection standard, EPA concluded that radiation release 
limits, such as those embodied in 40 CFR part 191, were not necessary 
in order to protect members of the general public from releases from a 
repository at Yucca Mountain.
    For the proposed human intrusion standard, EPA proposes two 
alternative rules, one of which would impose a CEDE limit of 15 mrem to 
a RMEI based on an assumed human intrusion event,

[[Page 67065]]

while the alternative rule would impose the dose limit if complete 
waste package penetration can be shown to occur before 10,000 years 
after disposal. EPA also proposes a rule outlining the elements of the 
human intrusion scenario to be used in the analysis.
    Under the proposed groundwater protection standard, EPA would 
require DOE to provide in its license application a reasonable 
expectation that for 10,000 years of undisturbed performance after 
disposal, releases of radionuclides from radioactive material in the 
Yucca Mountain disposal system will not cause the level of 
radioactivity in the representative volume of ground water at the point 
of compliance to exceed certain limits (e.g., combined beta and photon 
emitting radionuclides cannot exceed a limit of 4 millirems per year to 
the whole body or any organ). EPA presents for public review and 
comment several alternatives for the selection of the representative 
volume of water and for the location of the point of compliance.
    EPA's proposed approach to setting public health and safety 
standards for a repository at Yucca Mountain follows the NAS 
recommendations and findings, and the regulatory approach proposed by 
the NRC in its proposed licensing regulations. Although EPA has 
proposed some requirements in its rulemaking that differ from certain 
NAS findings and recommendations and NRC's proposed licensing 
regulations, (for example, EPA proposes use of a dose standard instead 
of a risk standard, and use of the RMEI concept instead of critical 
group), EPA's proposed rule is consistent with the primary NAS findings 
and recommendations that a public health standard based on risk or dose 
to an individual member of the public can be protective of general 
public health and safety, and that the Yucca Mountain-related physical 
and geologic processes are sufficiently quantifiable and the related 
uncertainties sufficiently boundable that the performance can be 
assessed over certain time frames.
    EPA assumes, and, in the case of the individual protection 
standard, EPA would expressly require DOE to use performance assessment 
to calculate the dose limits established in its proposed radiation 
protection standards for disposal. Although EPA generally would not 
prescribe requirements on how the performance assessments would be 
conducted, it would impose certain limitations. For example, proposed 
section 197.40 would limit consideration by DOE in its performance 
assessments of events that are estimated to have less than one chance 
in 10,000 of occurring within 10,000 years of disposal. In addition, 
EPA, similar to the NRC, acknowledges certain inherent limitations in 
DOE's ability to demonstrate compliance with the public health and 
safety standard through use of performance assessment, but nevertheless 
mandates the use of that method of assessment. EPA's rule recognizes, 
through the concept of reasonable expectation, that, among other 
things, there are inherent uncertainties in making long-term 
projections of the performance of the Yucca Mountain disposal system, 
that performance assessments and analyses should be focused upon the 
full range of defensible and reasonable parameter distributions, and 
that assessments should not exclude important parameters simply because 
they are difficult to precisely quantify to a high degree of 
confidence.

III. Basis for Proposal

A. Legal Authority and Necessity To Amend the Guidelines and Criteria

1. Overview
    Section 112(a) of the NWPA explicitly establishes DOE authority to 
``issue general guidelines for the recommendation of sites for 
repositories'' and to ``use [the] guidelines established under this 
subsection in considering candidate sites for recommendation under 
subsection (b).'' Subsection (b) of section 112 provides for a process, 
to be conducted following promulgation of the guidelines that would 
result in: (1) the nomination of 5 potential sites for 
characterization; and (2) the selection of 3 of those 5 sites for 
recommendation to the President as suitable for site characterization 
activities. Section 112(a) also includes explicit authority to revise 
the guidelines, from time to time, consistent with the provisions of 
112(a).
    Shortly after the enactment of the NWPA, DOE promulgated the 
Guidelines (codified at 10 CFR part 960) to implement section 112. The 
approach taken at that time was to structure the Guidelines to provide 
a framework not only for the section 112 decisions (for which it was 
statutorily required) but also for subsequent steps in the site 
selection process. Consistent with this view, the Guidelines as 
originally promulgated also addressed actions to be taken under 
sections 113 and 114. The rationale permitting that approach was the 
provision in section 113(b) that DOE include in its site 
characterization plan ``criteria to be used to determine the 
suitability of [a] site for the location of a repository, developed 
pursuant to section 112(a).'' 49 FR 47730. DOE reasoned that, since the 
site characterization plan was to be an element supporting any 
Secretarial recommendation of one site for development under section 
114, the Guidelines were ``intended to be used in deciding which among 
the characterized sites is to be recommended to the President, the 
Congress, and finally to the NRC for appropriate approvals.'' 47 FR 
47730. That approach was understandable in 1984 when DOE anticipated 
the need to evaluate by comparison multiple characterized sites, a 
comparison similar to the choosing of sites for characterization for 
which the Guidelines were required by section 112(a) of the NWPA. After 
the 1987 amendments to the NWPA designated Yucca Mountain as the only 
site to be characterized, DOE chose to apply some, but not all, of the 
Guideline provisions in the Site Characterization Plan prepared under 
section 113(b) of the NWPA as criteria to determine site suitability. 
DOE/RW-0199 (1988). In 1995, DOE reconsidered the Guidelines in the 
context of evaluating the suitability of the Yucca Mountain site under 
the Site Characterization Plan. DOE decided then that ``[b]ecause DOE 
need apply only the relevant provisions'' of the Guidelines, amending 
or supplanting them with ``Guidelines specifically tailored'' to 
evaluating the suitability of the Yucca Mountain site was ``not 
required at this time.'' 60 FR 47737, 47740 (1995).
    As discussed in greater detail below, DOE now has determined that a 
new approach is called for in light of the cumulative effect of the 
intervening legislative, regulatory, and technical developments that 
have occurred since 1984. DOE now proposes to develop criteria, using 
section 112(a) in the development of the criteria, but not adopting the 
particular section 112(a) Guidelines as those criteria, to form the 
basis for a determination of the suitability of the Yucca Mountain site 
for the location of a repository. The rationale for this approach stems 
from the basic analysis recommended by the National Academy of 
Sciences, which differed from that embedded in the 1984 Guidelines, and 
the advent of new regulations proposed by the NRC that, under the 
NWPA's structure, must define the areas and methodology of DOE's 
inquiries into Yucca Mountain's suitability.
    Accordingly, DOE today proposes to revise the existing Guidelines 
at 10 CFR part 960 to limit their application to only the initial site 
selection process set forth in section 112. DOE may make additional 
revisions to the Guidelines if, in the future, circumstances were to

[[Page 67066]]

change and DOE were to reinitiate a preliminary site screening process 
under section 112. Further, DOE proposes today to promulgate a new 
rule, consistent with section 113(b)(1)(A)(iv), to establish criteria 
to be used to determine the suitability of Yucca Mountain for the 
location of a geologic repository. The criteria identified in this new 
rule are based on the geologic factors and considerations referenced in 
section 112(a), as they relate to DOE's current scientific 
understanding and methodology for assessing the suitability of the 
Yucca Mountain site as a location for a repository.
2. Section 112
    DOE's approach in today's proposal is grounded on the text of 
section 112(a) and the basic structure of the NWPA, as originally 
enacted and as amended. As originally enacted, the NWPA set up a 
sequential process for selecting, comparing, and evaluating potential 
sites for the development of a geologic repository for high-level 
waste. The 1987 amendments eliminated any continued comparison of 
sites; only Yucca Mountain is authorized for site characterization 
activities leading to possible recommendation as a repository site. 
Beyond the first step in the process, recommendation of multiple sites 
for site characterization (section 112), there is no explicit direction 
in the Act (in its original enactment or amendment) whether or how to 
utilize the Section 112(a) Guidelines in the succeeding site selection 
processes (sections 113 and 114). Instead, section 112(a) specifies the 
intended use of the Guidelines: ``[t]he Secretary shall use guidelines 
established under this subsection in considering sites to be 
recommended for site characterization under section 112(b).'' Likewise, 
the environmental assessment of the various sites nominated for 
characterization pursuant to section 112 is to include ``evaluation'' 
of each nominated site under each Guideline not requiring 
characterization for its application and all the Guidelines pertinent 
to whether a site is ``suitable for site characterization.'' 42 U.S.C. 
10132(b)(1)(D)(i)&(ii). Nowhere in its text does section 112 require 
any additional use of the Guidelines.
    In sum, the text of section 112 and its relation to other 
provisions in the NWPA indicate that the Guidelines are to govern the 
process of selecting and comparing among potential sites to determine 
which sites are appropriate to proceed to the next, more detailed 
evaluation stage, site characterization. In contrast, nothing in the 
text of section 112 specifies that the Guidelines are also to govern 
the process for determining site suitability and site recommendation 
under sections 113 and 114.
3. Section 113
    Section 113 of the NWPA requires DOE to prepare a site 
characterization plan for a candidate site selected under section 112 
for site characterization activities. A required element of a site 
characterization plan is ``criteria to be used to determine the 
suitability of such candidate site for the location of a repository, 
developed pursuant to section 112(a).'' 42 U.S.C. 10133(b)(1)(A)(iv) 
(emphasis added). The NWPA does not define the term ``criteria.'' The 
NWPA does, however, define the term ``site characterization'' as 
activities ``undertaken to establish the geologic condition'' of a 
candidate site. 42 U.S.C. 10101(21)(B). This definition indicates that 
the required scope of the general site characterization plan and 
therefore of the section 113(b) ``criteria'' is limited to geologic 
considerations. This reading of section 113(b) is reinforced by the 
provisions of section 112(a) in which the only usage of the term 
``criteria'' in that section are the ``primary criteria'' that are 
explicitly equated to ``geological considerations.''
    Section 113(b) requires that the ``criteria'' to be included in the 
Site Characterization Plan be ``developed pursuant to section 112(a)'' 
of the NWPA. Because section 112(a) of the NWPA is devoted to the 
``Guidelines'' for selecting candidate sites while section 113(b) is 
devoted to the ``criteria'' under which selected candidate sites 
subsequently are to be characterized, it is necessary to consider how 
the Guidelines are required to relate to the criteria by section 113's 
requirement that the criteria be ``developed pursuant to section 
112(a).''
    It is unlikely that the Congress intended to require the 
``criteria'' to be the Guidelines themselves. It would have been simple 
enough for Congress to have legislated that policy in section 113(b) by 
a straightforward requirement that the Site Characterization Plan 
specify that the ``Guidelines developed pursuant to section 112(a)'' 
would be used ``to determine the suitability of each candidate site.'' 
Compare 42 U.S.C. 10133(b)(1)(A)(iv). Had Congress intended this policy 
result it is unlikely that it would have chosen such an elliptical and 
opaque way of expressing it as the actual statutory text that does not 
use the term ``Guidelines'' at all. And a construction of section 
113(b) requiring the suitability ``criteria'' to be the same as the 
section 112 Guidelines would risk tension with section 113(c)'s 
restriction that limits DOE to conducting ``only'' characterization 
activities ``necessary to provide the data required'' to prepare an NRC 
license application. The NRC, of course, is not required to base its 
licensing standards on the Guidelines adopted by DOE under section 
112(a) of the NWPA (although it was required to concur in them), nor 
does section 112 afford the NRC the ability to compel DOE to 
reformulate the Guidelines should the NRC determine to amend or 
supplant its licensing standards.
    Section 112(a) contains specific procedural mandates required to be 
employed by DOE in issuing or revising the Guidelines. Before DOE may 
promulgate the Guidelines DOE must consult with several specified 
federal agencies and with ``interested Governors.'' 42 U.S.C. 10132(a). 
In addition, the NRC must ``concur[]'' in the issuance of the 
Guidelines. Id. These distinctive procedural requirements obviously are 
tailored to the particular circumstances of site decision-making under 
the NWPA and therefore specify procedural requirements that would not 
otherwise obtain under the rulemaking provisions of the Administrative 
Procedure Act or the rulemaking provisions of the Department of Energy 
Organization Act that were in force when the NWPA was adopted.
    The requirement of section 113(b) that the SCP's ``criteria'' for 
characterizing sites be ``developed pursuant to section 112(a)'' 
therefore is best understood as mandating observance of the special 
procedural requirements of section 112(a) in formulating or altering 
the section 113(b) ``criteria.'' This understanding of the statutory 
text seems the most faithful to its explicit terms and the larger 
statutory context in which it occurs. Moreover, it seems the only 
understanding of section 113(b) that is consistent with the 1987 
changes to the NWPA (which mandated exclusive characterization work for 
the Yucca Mountain site without amending section 113(b) despite 
amending the statute elsewhere to remove the element of comparing 
sites, to which the Guidelines of section 112(a) were devoted). This 
understanding of the requirements of section 113(b) also comports with 
DOE's prior understanding, as was described in the 1995 notice, that 
not all the original Guideline elements need be applied in site 
characterization under section 113 of the NWPA.

[[Page 67067]]

B. Events Necessitating Amendment of the Guidelines and Criteria

1. Congressional Redirection of the Program
    Since the NWPA was enacted in 1982 and the Guidelines promulgated 
in 1984, Congress has made major changes to the framework for 
developing a geologic repository. Those changes are described below 
and, in part, form the basis for the revisions to 10 CFR part 960 and 
the promulgation of a new 10 CFR part 963 proposed in this notice.
    1987 Amendments to the NWPA. Congress amended the NWPA in 1987 to 
select Yucca Mountain as the only site to be characterized. In support 
of that decision, Congress directed DOE to terminate site-specific 
activities at the two other sites that had been recommended for site 
characterization in 1986. 42 U.S.C. 10172. Further, Congress restricted 
DOE's characterization activities at Yucca Mountain to only those the 
Secretary considers necessary to provide the data required for 
evaluation of the suitability of the site for NRC construction 
authorization (i.e., license application), and for compliance with the 
National Environmental Policy Act of 1969. A provision was added to the 
NWPA to provide for termination of site characterization activities at 
Yucca Mountain if at any time the Secretary determines that Yucca 
Mountain is unsuitable for development as a repository.
    Although the 1987 amendments to the Act were decisive in focusing 
the repository program and DOE's efforts on one specific site, for many 
years DOE maintained that these changes were not so significant as to 
warrant amendment of the Guidelines. Instead, DOE believed the 
Guidelines, for the most part, could be applied to Yucca Mountain for 
purposes of determining the suitability of the site (because Yucca 
Mountain already had been found suitable for characterization under 
other provisions of the Guidelines) in support of a possible site 
recommendation by the Secretary. The only changes to the Guidelines 
necessitated by the 1987 amendments were to eliminate consideration of 
those parts of the Guidelines related to comparative analysis. 
Similarly, the NRC had not made significant modifications to its 
technical requirements and criteria in 10 CFR part 60 as a result of 
the 1987 amendments to the Act.
    1992 Energy Policy Act. In the 1992 Energy Policy Act, Congress 
reinforced its intent that Yucca Mountain was the exclusive focus of 
the nation's repository program, not only for DOE, but also for the 
other federal agencies, EPA and NRC, with authority and responsibility 
over the repository program. Section 801 of the EPACT directed the EPA 
to promulgate, by rule, new public health and safety standards for the 
protection of the public from releases from radioactive materials 
stored or disposed of in a repository at the Yucca Mountain site. 
Unlike the previous standard, which was generic to geologic 
repositories and included limits on radioactive releases to the 
environment, the new standards were required to prescribe maximum 
annual radioactive dose limits to individual members of the public 
based on releases to the accessible environment from materials stored 
or disposed of at Yucca Mountain. To aid EPA in this process, Congress 
directed a National Academy of Sciences (NAS) study to provide findings 
and recommendations on reasonable standards for protection of the 
public health and safety. EPA was required to base its new rule on the 
findings and recommendations of the NAS. For Yucca Mountain, these 
standards would replace the generally applicable standards for the 
protection of the general environment that the EPA had promulgated at 
40 CFR part 191 under the authority of section 121 of the NWPA.
    The EPACT also directed the NRC to modify its technical 
requirements and criteria, as necessary, to be consistent with the 
EPA's new standards. In addition, NRC was directed to ensure that, 
consistent with the NAS findings and recommendations, its requirements 
and criteria for postclosure oversight of a Yucca Mountain repository 
would be sufficient to prevent any activities at the site posing an 
unreasonable risk of breaching the engineered and natural barriers of 
the site, and to prevent any increase in exposure of individual members 
of the public beyond allowable limits.
    These changes were significant because they set the stage for 
future regulatory changes governing the standards a Yucca Mountain 
repository must meet to ensure public health and safety, and to obtain 
a license for construction. The ability to meet regulatory standards 
has always been a dominant factor in the site selection process. This 
requirement is reflected in the structure of the Guidelines, is 
reinforced by the 1987 amendments to the Act, and is a prime focus of 
DOE's site characterization program. Thus, the Congressional mandate in 
the EPACT directing new and revised regulations governing geologic 
disposal at Yucca Mountain necessarily impacts DOE's formulation of the 
criteria that will be used to determine the suitability of Yucca 
Mountain as a site for development of a repository. Until recently, 
however, the full extent and nature of those impacts have not been 
defined. The NRC's recent proposal to amend 10 CFR part 60, its 
technical requirements and criteria for licensing a repository, to add 
a new part 63 specific to Yucca Mountain, provides DOE with an outline 
of anticipated regulatory changes, and signals for DOE how and why it 
must conform its Guidelines and criteria for determining the 
suitability of the Yucca Mountain site for the location of a 
repository.
    Fiscal Years 1996 and 1997 Appropriations Acts and the Viability 
Assessment. Finally, in response to budgetary concerns, the Conference 
Report on the Energy and Water Development Appropriations Act, 1996 
(Pub. L. No. 104-46) (H.R. Rep. No. 293, 104th Cong., 1st Sess. 68 
(1995)) directed the DOE to focus on only those activities necessary to 
assess the performance of a repository at the Yucca Mountain site and 
to collect the scientific information needed to determine the site's 
suitability. DOE responded by revising its Program Plan for 1996 in 
which it indicated that, among other changes, DOE would complete a 
viability assessment of the Yucca Mountain site in 1998, and would 
develop a proposal to amend the Guidelines and develop new regulations 
specific to the Yucca Mountain site. Congress indicated its approval of 
the changes by directing that appropriated funds be used in accordance 
with the revised program plan. Congress reinforced this direction in 
the Fiscal Year 1997 Energy and Water Appropriations Act, where it 
mandated that DOE provide to the Congress and the President a viability 
assessment of the Yucca Mountain site in 1998.
    These changes in budget for DOE's civilian radioactive waste 
management program indicate congressional intent for DOE to focus site 
characterization activities on assessing the viability and suitability 
of Yucca Mountain, and to complete those activities in the near term. 
In light of this congressional direction, it is reasonable for DOE to 
amend the Guidelines in a manner that acknowledges Yucca Mountain as 
the only site at which site characterization has occurred and for which 
DOE would need to conduct a suitability evaluation under section 
113(b).
2. Consistency Between DOE and NRC Regulations
    Procedural Consistency. The DOE's site characterization suitability 
criteria must be consistent with the NRC's

[[Page 67068]]

licensing criteria if the DOE is to present a potentially successful 
license application to the NRC. Such consistency originally was 
attained in the Guidelines through the NRC's concurrence process, as 
required by section 112(a) of the NWPA. DOE will preserve this 
consistency in these proposed suitability criteria by ensuring that 
they reflect the changes to the licensing criteria that recently have 
been proposed by the NRC in a new rule to be codified at 10 CFR part 
63, and by soliciting NRC concurrence on DOE's proposed amendments to 
the Guidelines and the promulgation of a new regulation at 10 CFR part 
963.
    Substantive Consistency. NRC's proposed new rule establishing the 
technical requirements and criteria for repository licensing at Yucca 
Mountain, proposed 10 CFR part 63, is different from its existing 
general rule on repository licensing, 10 CFR part 60. DOE now has 
little choice but to propose site suitability criteria that are 
consistent with the NRC's proposed licensing requirements. The 
suitability of a site for the location of a repository is a function of 
the DOE's ability to demonstrate the site can meet applicable 
regulatory requirements. DOE has conducted the site characterization 
program at Yucca Mountain with the statutory objective [42 U.S.C. 
10133(c)] of demonstrating its ability to obtain construction 
authorization from the NRC (i.e., to meet NRC licensing requirements 
and EPA health and safety standards, as implemented by NRC through the 
license). DOE could not scientifically and technically support a 
suitability determination, and, hence, a license application, without 
conforming its criteria for suitability to the proposed NRC technical 
requirements and criteria for a repository license. Such conforming 
criteria are proposed in this notice.
    The NRC proposed rule part 63 is a departure from the philosophy 
and technical requirements of 10 CFR part 60. The new rule would be 
based on the 1995 NAS report recommending a risk-limit standard for a 
repository at Yucca Mountain. The NRC timed publication of its proposal 
now to ensure NRC has sufficient time, once EPA issues its new 
standard, to put the new licensing standards in effect. The proposed 
rule embodies a new approach of risk-informed, performance-based 
regulation, and is specific to Yucca Mountain. The old rule relied on 
subsystem performance objectives and a release limit standard. Under 
the proposed rule, the performance of a Yucca Mountain repository would 
be evaluated against a health-based standard in consideration of risk 
to a hypothetical critical group and this standard would be the only 
quantitative standard for the postclosure performance of the 
repository. The new rule would require DOE to demonstrate compliance 
with postclosure technical criteria through performance assessments, 
and preclosure criteria through an integrated safety analysis. The new 
approach embodied in the proposed rule would eliminate current part 60 
design and siting criteria, as well as quantitative subsystem 
requirements, but would add specific requirements for the content of 
performance assessments to ensure their sufficiency and adequacy. In 
other words, a proposed Yucca Mountain repository would be evaluated as 
an entire system, not by assessing its individual parts in isolation, 
in order to determine whether it meets applicable standards to protect 
public health and safety.
    Once the proposal is finalized, the current structure of DOE's 
technical guidelines, which is premised on a demonstration of system 
and subsystem technical requirements, will no longer be consistent 
with, and in some cases may conflict with, the NRC technical 
requirements to support a license application. For example, several of 
DOE's technical guidelines require compliance with the siting and 
design requirements set forth in 10 CFR parts 60.113, 60.122 and 
60.133. Those requirements would not exist in proposed part 63 and 
would not be applicable to Yucca Mountain under proposed amendments to 
part 60. Those requirements are subsystem performance requirements that 
are inconsistent with the NRC's new approach of evaluating the 
technical merits of a potential site based on the performance of the 
repository system as an integrated whole, and not on the performance of 
each part independent of the other parts.
    A good example of this is the geohydrology guideline at 960.4-2-1. 
Under this guideline, DOE set qualifying and disqualifying conditions 
for the geohydrology of a site. The qualifying condition for 
geohydrology requires a site be capable of compliance with radionuclide 
release limits set by EPA in 40 CFR part 191, and by NRC in 10 CFR part 
60.112, as well as compliance with DOE subsystem performance 
requirements that mirror NRC requirements in 60.113. At present, there 
is no applicable release limit set by EPA under 40 CFR part 191, and 
the NRC's proposed amendments to 10 CFR part 60 would nullify the 
applicability of 60.113 to Yucca Mountain and create a new part 63 for 
which there is no analogous release limit or subsystem performance 
objective for geohydrology. Accordingly, it would be illogical for DOE 
to reach a finding relative to this qualifying condition, as required 
by Appendix III, based on regulatory requirements that no longer would 
be applicable to the Yucca Mountain site and would not support a 
determination of site suitability for the Yucca Mountain site.
    The DOE Guideline 960.4-2-1 also contains a disqualifying 
condition. Under this condition, DOE would disqualify a site if the 
pre-waste emplacement ground water travel time from the disturbed zone 
to the accessible environment is expected to be less than 1,000 years 
along any pathway of likely and significant radionuclide travel. Under 
the analogous NRC provision, 60.113, there is a performance objective 
directing that the pre-waste emplacement ground water travel time along 
the fastest path of likely radionuclide travel from the disturbed zone 
to the accessible environment must be at least 1,000 years or such 
other travel time as approved by the NRC. Under NRC's proposed 
revisions to its regulations, this subsystem performance requirement 
would no longer apply to a repository at Yucca Mountain under part 60, 
and it would not exist, nor would there be any requirement similar to 
it, under new part 63. Accordingly, it would be illogical for DOE to 
reach a finding relative to this disqualifying condition, as required 
by Appendix III, based on regulatory requirements that no longer would 
be applicable to the Yucca Mountain site and would not support a 
determination of site suitability for the Yucca Mountain site.
    Below is a table further illustrating the inconsistencies between 
the current Guidelines and the proposed part 63. Table 1 provides a 
cross walk between the technical guidelines to be applied as the 
criteria under section 113(b), their analog in existing part 60, and 
their analog, if any, in proposed part 63.

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    As demonstrated in the above table, in most cases there is no 
analog between the DOE Guidelines and NRC's proposed part 63. In 
addition, the Guidelines could not continue to reference and rely on 
revised part 60, since NRC's proposed revisions to part 60 would make 
them inapplicable to a repository at Yucca Mountain. Under the 
circumstances, it would be irrational and difficult, if not impossible, 
for DOE to apply the Guidelines in their current form.
    Under these changed circumstances, DOE must act to propose 
amendments to its outdated Guidelines and conform its site suitability 
criteria to the NRC proposed rule for licensing a Yucca Mountain 
repository.
3. Improvements in Analytical Methods
    DOE's proposed changes will also serve to conform the rules for 
assessing the suitability of a site with the current scientific and 
technical methods developed and utilized by DOE in its site 
characterization program. The proposed changes in the regulatory scheme 
reflect the advances in the scientific and technological understanding 
of the processes relevant to assessing the long-term performance of a 
geologic repository. The regulatory revisions proposed by EPA, NRC and 
DOE, mark a change from generic regulations based on limited 
information about geologic disposal developed early in the Nation=s 
quest for sites for geologic disposal, to regulations promulgated 
specifically for the Yucca Mountain site that reflect over 20 years of 
data collection and intensive site characterization activities at the 
Yucca Mountain site. It would be irrational for DOE to ignore these 
changes, and continue to rely on technical requirements that are not 
aligned with, and are not supported by, the prevailing scientific 
knowledge and understanding.
    As recognized by the NRC in its proposed part 63, during the more 
than 15 years since the NRC promulgated its initial technical criteria 
at 10 CFR part 60 (and DOE promulgated matching technical requirements 
in 10 CFR part 960), there has been considerable evolution in the 
capability of technical methods for assessing the performance of a 
geologic repository at Yucca Mountain. 64 FR 8640-8641. These advances 
result from both improved computer capability and better analytical 
methods. Indeed, these changes for the first time enable the vast 
quantities of data that have been collected through site 
characterization to all be used in models that more accurately model 
site performance. NRC stated that these new methods were not envisioned 
when the part 60 criteria were established, and that their 
implementation allows for the use of more effective and efficient 
methods of analysis for evaluating conditions at Yucca Mountain than do 
the existing NRC generic criteria in part 60. 64 FR 8641. Moreover, NRC 
believes that implementation of these new analytical methods for 
evaluating Yucca Mountain will avoid the imposition of unnecessary, 
ambiguous, or potentially conflicting criteria that could result from 
the application of some of the generic requirements of 10 CFR part 60. 
64 FR 8641.
    The evolution in performance assessment methodology formed the 
basis for DOE's 1996 proposal to amend the Guidelines. In that 
proposal, DOE explained that only by assessing how specific design 
concepts will work within the natural system at Yucca Mountain and 
comparing the results of these assessments to the applicable regulatory 
standards, can DOE reach a meaningful conclusion regarding the site's 
suitability for development as a repository. The proposed amendments to 
the Guidelines would have required a comprehensive evaluation focused 
on whether a geologic repository at Yucca Mountain would adequately 
protect the public and the environment from the hazards posed by high-
level radioactive waste and spent nuclear fuel (61 FR 66160). DOE 
explained that recent results in four major areas have advanced the 
ability to evaluate the Yucca Mountain site, and geologic disposal, to 
the point that a system approach is now appropriate. These four areas 
are: (1) Analysis and integration of data collected from surface-based 
testing and regional studies; (2) examination of the potential 
repository horizon made possible by the excavation of the Exploratory 
Studies Facility; (3) the site-specific conceptual design of the 
engineered facilities; and (4) performance assessment analyses (61 FR 
66161).
    As with the NRC, DOE recognizes that this improved understanding 
now allows the reconsideration of general Guidelines that may be 
unnecessary, ambiguous, or potentially conflicting for Yucca Mountain. 
Based on the DOE's accumulated knowledge, and significantly enhanced 
understanding, DOE has determined that a system performance approach 
provides the most meaningful method for evaluating whether the Yucca 
Mountain site is suitable for development as a repository. In this 
revised proposal, DOE expands on its earlier proposal to modify the 
Guidelines and incorporate performance assessment as the appropriate 
approach to assess the forecasted performance of a repository, and to 
serve as the basis for site characterization suitability criteria. This 
revised proposal provides greater detail, comprehension and 
transparency of information describing the performance assessment 
methodology, and how it serves as a foundation for site 
characterization suitability criteria.

IV. Response to Public Comments on the 1996 Proposal

    DOE requested public comments and announced a public hearing on the 
proposed amendments to the Guidelines in the Notice of Proposed 
Rulemaking published in the Federal Register on December 16, 1996. 61 
FR 66157.
    DOE received written and oral comments on the proposed amendments 
to the Guidelines from numerous organizations including Federal, state, 
and local government agencies; citizen and environmental groups; a 
nuclear industry group; a Native American group; and from individual 
citizens. Oral comments were also received during the January 23, 1997, 
public hearing in Las Vegas, Nevada. DOE received many comments 
concerned with issues that are not related to the proposed amendments 
to the Guidelines, such as issues that pertain to activities at the 
Nevada Test Site, the continued use of nuclear power, the broad powers 
of the federal government, as well as activities related generally to 
the civilian radioactive waste program but not at issue in this 
rulemaking, such as consideration of alternatives to geologic disposal, 
the Western Shoshone claims to land under the Ruby Valley Treaty, and 
opposition to or support of geologic disposal and the study of Yucca 
Mountain. Because these issues lie outside the scope of the proposed 
amendments to the Guidelines, they are not addressed in this notice. 
DOE notes that many of the comments received, especially from 
individuals, expressed a strong opposition to the selection of Yucca 
Mountain as the only site to be characterized. As explained in section 
II above, in the 1987 amendments to the NWPA, Congress limited DOE to 
characterizing only the site at Yucca Mountain. The wisdom of that 
decision is not the subject of this rulemaking proceeding.
    The following discussion summarizes the issues emerging from the 
comments that bear on DOE's current proposal, and DOE's response to 
those comments. All issues and comments on the 1996 proposal may not be 
addressed here in light of DOE's decision in this notice to revise the 
1996 proposal and provide a

[[Page 67071]]

full public comment period on the revised proposal.

A. Legal Authority.

    Several commenters, including the State of Nevada, stated that 
DOE's proposal to amend the Guidelines is contrary to section 112(a) of 
the Act and cited the following three decisions by the U.S. Court of 
Appeals for the Ninth Circuit as support for this view: Nevada versus 
Watkins, 914 F.2d 1545 (9th Cir. 1990) (Watkins I), Nevada versus 
Watkins, 939 F.2d 710 (9th Cir. 1991) (Watkins II), and Nevada versus 
Watkins, 943 F.2d 1080 (9th Cir. 1991) (Watkins III). Specifically, the 
Attorney General of Nevada stated at the public hearing that section 
112(a) of the Act and the Watkins I and II decisions stand for the 
proposition that the Guidelines were to be used to determine the 
suitability of the site, and at the time of a suitability determination 
the validity of the current Guidelines would be subject to review by 
the Court.
    DOE recognizes that it did not set forth in the 1996 Notice of 
Proposed Rulemaking a full legal analysis of the statutory basis for 
the proposed rule, nor did DOE address the rulings of the 9th Circuit 
Court of Appeals in the three ``Watkins'' decisions cited by the State. 
In this notice, DOE has included an extensive discussion entitled 
``Legal Authority and the Necessity to Amend the Guidelines and 
Criteria'' in order to more fully explain to the public DOE's 
interpretation of the pertinent sections of the NWPA and why DOE 
believes that it not only may but must amend the Guidelines and 
promulgate a new part 963. While DOE believes that the ``Watkins'' 
rulings are instructive in interpreting various provisions of the NWPA, 
DOE does not believe that these rulings support the contention that DOE 
may not amend the Guidelines, or that the criteria used for the 
suitability determination under section 113 must be identical to the 
conditions in the Guidelines that are used for site selection under 
section 112.

B. Relationship between DOE suitability determination and NRC licensing 
requirements.

    Nye County expressed the view that due to funding cuts DOE was 
attempting to cut corners and accelerate the process toward licensing. 
Nye County was concerned that this would mask what it views as the 
distinction between site suitability and NRC licensing. Several 
individual commenters stated that DOE appeared to be: (1) Dropping the 
NRC licensing requirements for Yucca Mountain; (2) lowering the 
licensing requirements; or (3) deleting some of the NRC requirements.
    The following responds to the Nye County comments. First, although 
DOE suffered funding shortages in 1996, funding shortages were not the 
reason for the decision to propose amendments to the Guidelines in 
1996. DOE stated the reasons for the 1996 proposal in the Federal 
Register notice announcing the proposal, and included DOE's intent to 
focus and clarify the site suitability evaluation of the Yucca Mountain 
site to reflect anticipated regulatory changes and the most current 
scientific and technical methods for assessing the expected performance 
of a geologic repository at Yucca Mountain.
    Second, the 1996 proposed amendments to the Guidelines, as well as 
those proposed in this notice, are not an attempt to accelerate the 
licensing process, or otherwise mask the distinction between site 
suitability and licensing. Rather, they are an attempt to carry out the 
site characterization program for its intended purpose, that is, to 
determine if the site is suitable and potentially licensable. The site 
suitability criteria developed by DOE within the context of the site 
characterization program, and proposed here as new rule 963, are 
closely linked to the determination of the site's potential 
licensability, as they must be. DOE must conduct its site 
characterization process in accordance with section 113(c) of the NWPA, 
which provides that DOE may conduct only such site characterization 
activities as DOE considers necessary to provide the data required for 
evaluation of the suitability of such site for an application to be 
submitted to the NRC for a construction authorization (often referred 
to as a ``license'') at such site, and for compliance with NEPA. 42 
U.S.C. 10133(c). Therefore, DOE is required to base its site 
characterization activities on NRC licensing requirements and the 
environmental impact statement to be conducted under NEPA.
    While today's proposal relies, in part, on newly proposed NRC 
licensing requirements, it is completely consistent with the letter and 
the purpose of the NWPA. Although DOE is utilizing NRC's proposal to 
develop DOE's own proposal, DOE is not attempting to accelerate the 
licensing process. DOE must first complete all the steps in section 113 
and section 114(a)(1) of the NWPA before making a recommendation to the 
President, and receive presidential and congressional approval before 
submitting an application for a construction authorization to the NRC. 
Then, DOE would have to participate in the licensing process outlined 
by NRC in its regulations. DOE, as a potential licensee subject to NRC 
regulation, has no authority to accelerate the licensing process; only 
NRC is authorized to do that.
    The following responds to concerns raised by other commenters that 
DOE's proposal to change to part 960 is an attempt to eliminate or 
degrade NRC licensing requirements. That was not DOE's intent in the 
1996 proposal, nor in today's proposal. To the contrary, DOE's proposed 
amendments to the Guidelines and new part 963 are designed to better 
align DOE's suitability criteria with newly proposed NRC licensing 
requirements. The NRC's recent proposed amendments to 10 CFR part 60 
and proposed new part 63 are based on its own legal responsibilities 
and technical judgment. DOE has no authority to amend NRC requirements. 
DOE's objective in promulgating a new part 963 is to conform to, rather 
than deviate from, NRC requirements so that DOE can determine whether 
NRC is likely to approve an application from DOE for a construction 
authorization for a repository at Yucca Mountain.

C. The rules should not be changed to fit the site.

    Some commenters stated their belief that Yucca Mountain would be 
disqualified under the existing Guidelines and therefore DOE is 
attempting to change the rules to fit the site.
    DOE is not proposing to amend part 960 and adopt a new part 963 
because it believes Yucca Mountain cannot satisfy the conditions in the 
current Guidelines. Rather, this proposal is intended to implement the 
statutory mandate in section 113 in a rational manner, consistent with 
the current regulatory framework and technical basis for assessing the 
performance of a geologic repository as an integrated system. DOE is 
convinced that the transition to a system performance approach will not 
result in a lower level of protection of public health and safety. 
DOE's reasons for proposing amendments to the Guidelines in 1996 were 
provided in the notice announcing that proposal. In this notice, DOE 
provides an extensive discussion of the basis and reasons for its 
revised proposal to amend part 960 and add new part 963.
    Notwithstanding these explanations, DOE recognizes that many 
commenters believe that DOE is changing the Guidelines because of the 
fear that those requirements cannot be met. In particular, several 
commenters stated

[[Page 67072]]

their belief that the site could not meet the ground-water travel time 
disqualifying condition in the Guidelines (Sec. 960.4-2-1(d)).
    DOE has not reached a conclusion on this issue. The disqualifying 
condition at Sec. 960.4-2-1(d) requires disqualification if DOE 
determines that the pre-waste emplacement ground-water travel time is 
expected to be less than 1,000 years along any pathway of likely and 
significant radionuclide travel. Calculations performed in 1998 as part 
of the total system performance assessment for the Viability Assessment 
indicate that the average ground-water travel time is greater than 
1,000 years. Based on investigations and calculations to date, DOE has 
not determined whether the ground-water travel time along any pathway 
of likely and significant radionuclide travel is less than 1,000 years. 
DOE continues to investigate and conduct research on ground-water 
travel time at Yucca Mountain to reduce uncertainties, to the extent 
possible, and to gain confidence in its calculations. In the meantime, 
DOE believes that there is no basis at this time to find that this 
disqualifying condition exists at Yucca Mountain.
    In addition, under NRC's proposed changes to its licensing criteria 
and requirements for high-level waste repositories, the analogous 
provision to 960.4-2-1 in existing 10 CFR part 60 would no longer be 
applicable to a geologic repository at Yucca Mountain, and new 10 CFR 
part 63 would not contain such a condition, or any condition similar to 
it. As previously explained in section III.B.2. of this Supplementary 
Information, it would be illogical--and questionable in view of the 
characterization restrictions contained in section 113(a)(1) of the 
NWPA--for DOE to apply the Guidelines as currently written, including 
this particular guideline, in light of these proposed regulatory 
changes by the NRC.

D. Any amendments to the Guidelines should continue to address all the 
pre-and post-closure factors, as well as the qualifiers and 
disqualifiers.

    Several commenters requested that DOE leave the Guidelines 
virtually intact and apply all of the pre-or post-closure guidelines. 
Some suggested that DOE only amend those specific guidelines that need 
to be amended. Some commenters were concerned that by eliminating 
certain individual guidelines and the qualifiers and disqualifiers, DOE 
was trying to ensure that Yucca Mountain would be found suitable for a 
repository even if it is an inadequate site.
    As explained in previous sections of this Supplementary 
Information, DOE is proposing revisions to the Guidelines that are 
permissible under the NWPA, and that are intended to conform the 
Guidelines to anticipated changes in EPA and NRC regulations, and to 
the current state of scientific understanding of how to assess the 
suitability of a repository at Yucca Mountain. Nevertheless, in 
response to the comments about maintaining the pre-and post-closure 
factors in the Guidelines, DOE has structured the proposed suitability 
criteria to make transparent what characteristics and traits of a 
geologic repository at Yucca Mountain are most important to determining 
the suitability of the site during the preclosure and postclosure 
periods. The suitability criteria address and reflect the geologic 
considerations identified in section 112(a) that are relevant to and 
informed by site characterization activities. Siting considerations 
that are not addressed in the suitability criteria developed under 
section 113 (that is, as part of the site characterization program) 
would be addressed elsewhere by the Secretary when deciding whether to 
recommend the site to the President under section 114 of the NWPA. For 
example, environmental, transportation, and socioeconomic impacts would 
be considered in the EIS; the technical feasibility of constructing, 
operating, and closing a repository at the site would be included in 
the design work required for recommending the site. In sum, the 
considerations listed in section 112(a) of the NWPA and in the current 
Guidelines that are not addressed in either the preclosure or 
postclosure site suitability criteria proposed in part 963 would be 
addressed during the section 114 site recommendation process.
    With respect to qualifying and disqualifying conditions, DOE 
believes that it is not reasonable or necessary to maintain these 
conditions in a proposed new rule. DOE proposes eliminating individual 
disqualifiers, since maintaining them would mask how the system as an 
integrated whole would function, and would be inconsistent with the NRC 
proposal. The only appropriate disqualifier is the applicable public 
health and safety standard.
    As explained previously, the prevailing scientific view is that the 
most appropriate method for evaluating whether a site is suitable for a 
repository is through TSPAs. Under the proposed 10 CFR part 963, DOE 
would use the total system performance assessment method to evaluate 
whether a repository at the Yucca Mountain site is likely to meet 
applicable NRC regulations, and thus is suitable for development of a 
repository.
    In response to the 1996 proposal, several commenters expressed the 
common view that use of TSPA is appropriate and the Guidelines should 
be revised to match current technical understandings. For example, the 
NWTRB commented that the proposal's linking of suitability directly and 
unambiguously to overall system performance is a sounder approach than 
the approach in the original Guidelines. Also, the U.S. Department of 
the Interior (DOI) commented that the original guidelines are a relic 
of the early 1980s and now impose an unnecessary burden on the program. 
DOI observed that it makes little sense to comply with existing 
Guidelines based on EPA and NRC regulations that no longer apply to 
Yucca Mountain.

E. DOE rationale for changing its position on the need to revise the 
Guidelines.

    In 1994, DOE issued a Federal Register notice stating that it had 
decided not to revise the Guidelines (59 FR 39766), despite the 1987 
amendments to the NWPA. In a 1995 Federal Register notice, following 
continued public dialogue on this issue, DOE provided its rationale for 
not revising the Guidelines ``at this time.'' 60 FR 47737. Ignoring the 
qualifying phrase ``at this time,'' some commenters argued that by 
issuing the 1996 Notice of Proposed Rulemaking, DOE reversed its 
position from the 1994 and 1995 notices without a credible and 
persuasive explanation.
    DOE has reassessed its 1994 and 1995 positions and has determined 
that now is the proper time to amend the Guidelines. DOE believes that 
events have transpired since the 1994 and 1995 notices were published 
and the 1996 amendments proposed, in particular NRC's proposed changes 
to its licensing regulations, that present DOE with a situation in 
which the most responsible and appropriate action is for DOE to amend 
the Guidelines. The nature of those amendments and the reasons for 
DOE's proposal to amend are provided in this notice. The public will be 
provided a full and fair opportunity to comment on DOE's proposal, and 
DOE will respond to those comments.

F. Public participation process.

    The NWTRB suggested that DOE formally connect its site suitability 
determination to a public process for making the decision on whether to 
recommend to the President that Yucca Mountain be developed as a 
repository.

[[Page 67073]]

    Such a process is provided for in section 114(a) of the NWPA. 
Before recommending the site for development as a repository, DOE must 
hold public hearings in the vicinity of the Yucca Mountain site to 
inform residents of the area and to receive their comments regarding 
the possible site recommendation. The preliminary suitability 
evaluation conducted under this proposed part 963 would be part of the 
information provided for public comment. In addition to these 
subsection 114(a) consideration hearings, the public will have 
opportunities to comment on the DOE's analyses of the potential impacts 
of developing a repository at the Yucca Mountain site during the 
repository EIS process.
    Further, the site recommendation must be accompanied by a 
comprehensive statement of DOE's basis for the recommendation that will 
include the final EIS and the views and comments of the Governor and 
legislature of any State, or the governing body of any Indian tribe, 
together with the Secretary's response to those views. This 
comprehensive statement must be made available to the public, as well 
as submitted to the President. As further required by section 114 of 
the Act, the Secretary will notify the Governor and legislature of the 
State of Nevada of a decision to recommend the site at least 30 days 
before submitting a recommendation to the President.

G. Clarification of, and suggested modifications to, the performance 
assessment methodology.

    A number of commenters asked for clarification or further 
explanation of the method and process for implementing the proposed 
total system performance assessment approach. The EPA and the NWTRB 
noted that a comprehensive explanation of TSPA would provide 
transparency and verifiability to DOE's evaluation process.
    DOE has decided not to finalize the proposed Subpart E of the 
Guidelines but, instead, to propose a new part 963 that provides the 
level of detail, transparency and verifiability requested by the 
commenters. In this preamble, in particular sections II.G and VI, DOE 
provides a more comprehensive explanation of the background and 
evolution of the TSPA methodology and approach, and a description of 
how this methodology will be implemented in the postclosure suitability 
evaluation, than was provided for proposed Subpart E. In addition, DOE 
has structured the 963 rule itself to contain more specific 
requirements than those enunciated in proposed Subpart E as to how and 
what must be evaluated in the TSPA analysis of postclosure suitability. 
For example, section 963.16 would require that DOE determine 
postclosure suitability based on TSPA analyses of repository 
performance in cases with and without a stylized human intrusion event. 
That section also enumerates certain required elements of those 
analyses, such as, inclusion of data related to the suitability 
criteria specified in 963.17, an accounting of uncertainties and 
variabilities in parameter values, identification of the natural and 
engineered barriers important to waste isolation, demonstration of the 
technical bases for the models used in the TSPA, and the conduct of 
appropriate sensitivity analyses. Moreover, DOE's proposed method and 
process for implementing the TSPA approach in part 963 is consistent 
with the TSPA concepts and requirements proposed by the NRC in section 
63.102 and 63.114, as well as the implementation requirements proposed 
by EPA in proposed 40 CFR 197.13. DOE believes that conducting the TSPA 
analysis in the manner prescribed by the requirements of proposed 963 
are responsive to public comments on the TSPA approach, and will 
provide a level of transparency and verifiability comparable to that 
proposed by the regulatory requirements of NRC and EPA.
    Role of Natural and Engineered Barriers. Some commenters suggested 
that the proposed approach should include explicit requirements for 
performance of the natural and engineered barriers. The EPA recommended 
that the site suitability evaluation approach should distinguish 
contributions of site features to performance for extended periods of 
time and should make the role of natural barriers in containing waste 
clear to the public. The NWTRB also commented that the DOE should 
assess the relative roles of natural and engineered barriers and their 
interactions, but noted that specific requirements for individual 
components of the system could be arbitrary and unworkable.
    DOE has responded to this comment by providing the specifications 
for how it will conduct a TSPA in support of determining site 
suitability. The relative contribution of the natural and engineered 
barriers to the waste containment and their interaction will be 
demonstrated through the conduct of the TSPA. Through the TSPA, the 
requirements of which are contained in proposed part 963, DOE can 
examine the contributions of site features important to performance and 
the relative roles of the natural and engineered barriers. For example, 
by conducting sensitivity analyses, DOE can examine a specific feature, 
whether natural or engineered, and thereby determine its relative 
impact on the performance of the total repository system.
    Robust Compliance. The NWTRB suggested that, in responding to 
comments that the proposed amendments ``change the rules in the middle 
of the game,'' DOE should modify the amendments to strengthen 
confidence in the technical validity of the overall system performance 
assessment. The NWTRB submitted that the TSPA should not only show that 
the repository system complies with a standard, but does so 
``robustly.'' The NWTRB suggested three indicators of robust 
compliance: (1) Address uncertainties fully and accurately; (2) 
describe the results of sensitivity studies; and (3) specify a margin 
of safety, i.e., require performance in excess of applicable radiation 
protection standards.
    In conducting and documenting the TSPA under the proposed rule, DOE 
would identify the processes used to carry out the performance 
assessment, state the assumptions used in the assessments, address all 
uncertainties fully and accurately, and describe the results of 
sensitivity studies. By so doing, DOE would address two of the three 
indicators the NWTRB identified for showing robust compliance.
    The NWTRB's third indication of robust compliance would be for DOE 
to require performance in excess of applicable standards. The EPA is 
required to establish radiological protection standards that are 
adequately protective of public health and safety. DOE believes that 
compliance with the required applicable standards, as described in this 
proposed rule, is a sufficient basis for evaluating the Yucca Mountain 
site's suitability for development. However, DOE would indicate, in its 
underlying technical documentation, by what margin the expected 
performance of the repository exceeds the applicable radiation 
protection standards.
    Specific Level of Confidence. The NWTRB also suggested that DOE 
should modify the amendments to strengthen confidence in the technical 
validity of the overall system performance assessment. The NWTRB 
suggested that DOE specify the level of confidence that must be reached 
in its performance calculation before it is prepared to make a positive 
site suitability determination.

[[Page 67074]]

    In the proposed rule, DOE is defining the criteria that would be 
considered in conducting the overall total system performance 
assessment. In this way, DOE believes that overall confidence in the 
calculation will be increased because the key building blocks 
(criteria) of the TSPA would each be identified and considered.
    Moreover, while DOE appreciates the importance of the NWTRB comment 
that there should be a level of confidence in the performance 
calculation, DOE does not believe it is appropriate or most effective 
to address that comment by specifying or quantifying a level of 
confidence as part of the proposed rule. The reasons not to quantify 
the level of confidence in the rule are threefold. First, at this time, 
there is no universally accepted or standard technical basis for DOE to 
rely upon to quantify that level of confidence for inclusion in the 
proposed rule for a first of its kind facility for spent fuel and high-
level waste; to adopt such a quantitative standard could 
inappropriately constrain the Secretary's determination of site 
suitability. Second, through the TSPA described in the proposed rule, 
DOE will generate, and the public will have access to, information 
about the probabilistic distribution of values around the expected 
value in order to assess the level of confidence in the performance 
calculation. Finally, in its proposed regulations at part 63 (which 
serve as the model for the TSPA method described in this proposed 
rule), the NRC does not specify or require a quantitative level of 
confidence to be shown in order to determine whether the Yucca Mountain 
site would meet applicable radiation protection standards. Taken 
together, these reasons suggest the better course is for DOE to not 
quantify the level of confidence for the performance calculation, but 
to utilize other mechanisms, such as defining the criteria that would 
be considered, to strengthen confidence in the technical completeness 
and validity of the performance calculation.
    Defense-in-Depth. Another specific NWTRB comment was that DOE 
should demonstrate in its performance assessment how the repository 
system preserves the principle of defense-in-depth using multiple 
barriers.
    In response, DOE believes that the issue of defense-in-depth will 
be addressed by the NRC's proposed requirements for using multiple 
barriers for the repository. Those requirements include descriptions of 
site characteristics and design components, process and performance 
assessment model analyses, and sensitivity studies. However, DOE does 
not believe that it is appropriate for part 963 to articulate an 
explicit defense-in-depth strategy nor to require significant 
redundancy in repository design. The DOE rejected this approach in 1984 
when the general Guidelines were promulgated (49 FR 47721) in choosing 
not to set numerical limits on individual site characteristics. The 
NRC, in its proposed part 63, also has rejected explicit, subsystem 
performance requirements as a means to demonstrate defense-in-depth.

H. Data requirements for performance assessment.

    Two commenters expressed concern that, if DOE issues amended 
Guidelines prior to the EPA's promulgation of radiological standards 
specific to Yucca Mountain, the DOE may not have a full understanding 
of the health and safety standards, may need additional data collection 
and analysis, and may need to alter the Guidelines again after the EPA 
standards are issued. The EPA also commented that the new standards may 
warrant gathering different or additional data to provide the basis for 
compliance with the standards.
    DOE responds to these comments by including in the proposed part 
963 criteria that must be considered in a TSPA that are important to 
assessing the ability of a repository at the Yucca Mountain site to 
meet applicable NRC standards for the preclosure and postclosure 
periods, which will implement applicable EPA public health and safety 
standards. DOE believes that the criteria in proposed part 963 are 
related sufficiently to the data and analytical needs to address the 
proposed EPA standard as to warrant proposing it at this time. In 
addition, NRC's proposed part 63 is based on a dose standard, and 
includes data and analytical requirements necessary to meet that 
standard. DOE has structured the proposed part 963 based on NRC's 
proposed Part 63 and consistent with EPA's proposed 40 CFR part 197. 
Therefore, DOE believes that part 963 could be implemented without 
substantial revision.
    In a similar vein, a variety of commenters questioned the state of 
DOE's understanding of the site and the potential repository system at 
Yucca Mountain. Some commenters indicated that the DOE does not yet 
know enough about the site to make the proposed changes to the 
Guidelines, others questioned whether the DOE would know enough at the 
planned time for a site recommendation, and others contended that the 
DOE could never know enough to apply a total system performance 
assessment approach to a suitability evaluation.
    In response, DOE notes that, although it is advantageous to limit 
uncertainties and strive to gain as much data and scientific 
understanding as practicable, the prevailing scientific view is that 
certainty, in the normal sense of that word, is not possible to achieve 
with respect to assessing the postclosure performance of a geologic 
repository intended to last for tens of thousands of years. The NRC's 
existing regulations at part 60 and proposed regulations at part 63 
require ``reasonable assurance'' that the public and environment will 
be adequately protected from the radiation hazards posed by a 
repository. That standard reflects that there are inherent 
uncertainties in understanding the evolution of the geologic setting, 
the reference biosphere, and an engineered barrier system. Performance 
assessments are necessarily probabilistic; they can only analyze future 
repository performance in terms of the probabilities of different 
events and results.
    Equally important, EPA recognizes the inherent uncertainty in this 
process in its proposed public health and safety standards. EPA would 
have the NRC implement the public health standard based on ``reasonable 
expectation.'' According to EPA, reasonable expectation ``means that 
the Commission is satisfied that compliance will be achieved based upon 
the full record before it. Reasonable expectation (a) requires less 
than absolute proof because absolute proof is impossible to attain for 
disposal due to the uncertainty of projecting long-term performance; 
(b) is less stringent than the reasonable assurance concept that NRC 
uses to license nuclear power plants; (c) takes into account the 
inherently greater uncertainties in making long-term projections of the 
performance of the Yucca Mountain disposal system; (d) does not exclude 
important parameters from assessments and analyses simply because they 
are difficult to precisely quantify to a high degree of confidence; and 
(e) focuses performance assessments and analyses upon the full range of 
defensible and reasonable parameter distributions rather than only upon 
extreme physical situations and parameter values.''

I. The ability to understand results of total systems performance 
assessment.

    The NWTRB commented that the performance assessment should be 
carried out in a manner that is highly transparent to the technical 
community, regulators, and interested members of the general public. 
Some commenters

[[Page 67075]]

stated that total system performance assessment would not likely be 
easily understood. Other commenters asserted that the approach in the 
1996 proposed rule would be misleading or mask uncertainties and, 
therefore, not recognize potentially insufficient waste isolation 
capabilities of the site.
    DOE has developed proposed part 963 taking into account these 
considerations. Proposed part 963 includes specific site suitability 
criteria and a description of the evaluation method to ensure the 
public is informed of how and what DOE will consider in reaching a 
suitability evaluation for completion of site characterization. DOE 
will conduct performance assessments in a manner that is transparent, 
valid and verifiable. In other words, these assessments will be clear, 
logical, technically defensible and adequately documented. A 
transparent system performance assessment will be clear not only to the 
technical analysts, but also to readers who are familiar with the 
particular aspects of the assessment, such as the fundamental 
scientific and engineering principles, numerical analytical methods, or 
regulatory implications.
    In addition, DOE is currently using several methods to increase the 
traceability of these analyses. Analyses are traceable to the extent 
that a complete and unambiguous record exists of decisions and 
assumptions, and of models and data, and their use in arriving at the 
results of the analyses. These methods include abstraction workshops to 
ensure the completeness of models and approaches used in performance 
assessment, detailed documentation of each model, formal expert 
elicitations, and a participatory external peer review of the 
development, documentation, and results of the performance assessment 
for the Viability Assessment. The results of this peer review will be 
considered, as will be the comments of all oversight groups, to assist 
DOE's development of a TSPA for a possible site recommendation and 
subsequent license application. These actions should enhance confidence 
in the analyses and help communicate the complexities of predicting 
system behavior to a wide range of audiences.
    A related concern is that system analyses could dilute or somehow 
mask the importance of specific, independent technical characteristics. 
On the contrary, it is the system analyses that assess the significance 
of any independent technical characteristic. The Yucca Mountain total 
system performance assessment is not a single computer model or 
analysis, but the integrated result of several discrete process models, 
each of which in turn is supported by a group of more detailed data 
sets, models, and analyses. The total system performance assessment 
method permits evaluation of how certain individual characteristics, 
either alone or in combination, could cause the site to fail to meet 
the applicable standards, and how such failures are related to the 
performance of the total system. By not placing reliance on any single 
component of the system, the total system performance assessment method 
supports a multiple barriers approach, as required by NRC licensing 
regulations in order to provide reasonable assurance that the 
repository system will perform adequately.

J. The relation of DOE and NRC requirements.

    The NRC commented that its regulations have a broader role than 
just to implement the EPA standards. They contain the technical 
criteria and requirements for licensing a geologic repository, as 
provided by subsection 121(b) of the NWPA. The NRC recommended that the 
DOE proposed postclosure guideline be changed to reflect that broader 
role and proposed that it be revised to read, `` * * * repository shall 
perform in accordance with both the EPA standards established 
specifically for the Yucca Mountain site and NRC's regulations 
applicable to the Yucca Mountain site.''
    DOE understands that the applicable NRC regulations containing the 
technical requirements and criteria for construction, operation, and 
closure of a geologic repository, as provided for by section 121 of the 
NWPA, will have a broader role regarding Yucca Mountain than just to 
implement the EPA standards for the Yucca Mountain site. The NRC 
regulations will govern the licensing process if the Yucca Mountain 
site is recommended by the Secretary to the President, approved by the 
President, and is designated by Congress under section 115 of the Act.
    The use of the phrase ``likely to meet applicable radiation 
protection standard'' in the proposed part 963 is meant to clarify the 
role of NRC and EPA regulations in evaluating suitability and reaching 
a suitability determination. DOE would refer to applicable health and 
safety standards, both those promulgated by EPA and NRC, in determining 
site suitability in the preclosure and postclosure periods. In 
recognition of NRC's broader role in the licensing process, and in 
anticipation of submitting an application for a license, DOE has 
structured its rule regarding the methods and procedure for evaluating 
suitability to be consistent with proposed NRC licensing criteria and 
requirements.
    Notwithstanding these similarities in DOE's and NRC's proposed 
rules, DOE's determination of suitability is not the equivalent of a 
licensing decision. DOE's assessment of whether the Yucca Mountain site 
is suitable is a more preliminary assessment than the subsequent NRC 
licensing decision. Proposed part 963 would include many but not all 
NRC licensing requirements in the suitability determination; the intent 
is to provide the Secretary with sufficient information to determine 
whether the site should be recommended to the President based on, among 
other things, the likelihood the site would meet applicable regulatory 
standards for licensing.

K. Definition of closure.

    Nye County, Nevada, suggested that the language of the general 
guidelines should allow for the possibility of having an open, 
naturally ventilated repository, to ensure that regulatory flexibility 
exists if such a design provides for greater protection of the public's 
health and safety and the environment. The County proposed that the 
definition of ``closure'' at Sec. 960.2 be amended to eliminate 
reference to the ``sealing of shafts'' and add an explicit reference to 
``any extended period of natural ventilation.''
    DOE agrees that, during the design process, it would be appropriate 
to consider the potential benefits and consequences of maintaining a 
ventilated repository for an extended period of time. Any decision of 
whether and how to continue ventilation of the repository will consider 
the costs and benefits of that option, in light of the information 
available at that time. In response to this comment, DOE has modified 
the prior definition of ``closure'' by proposing in Sec. 963.2 a 
definition including the phrase ``except those openings that may be 
designed for ventilation or monitoring'' to ensure that the option of a 
ventilated repository is not foreclosed.

V. Description of Proposal--10 CFR Part 960

A. Subpart A--General Provisions

    This section of the Guidelines contains the statement of 
applicability and definitions. The proposed revisions to section 960.1, 
Applicability, would limit the application of the Guidelines to 
evaluations of the suitability of sites for site characterization under 
section 112(b) of the NWPA. The revisions

[[Page 67076]]

would eliminate the applicability of the Guidelines to determinations 
of suitability of a site at the site characterization stage under 
section 113, or the site recommendation stage under section 114. These 
revisions would clarify the applicability of the Guidelines to the 
preliminary site screening stage, which entails a comparative analysis 
process, and thereby better align the application of the Guidelines 
with the structure of the NWPA, as originally enacted and as amended in 
1987. The revisions to the third and fourth sentences would update the 
reference to other regulatory requirements of the NRC and EPA, in light 
of the current status of applicable NRC and EPA regulations relative to 
high-level waste geologic repositories. The fifth through seventh 
sentences would remain unchanged.
    The proposed revisions to the definitions section would make the 
terms consistent with the NWPA and with the other proposed revisions to 
the Guidelines limiting applicability of subparts B, C, and D of the 
Guidelines to determinations of site suitability for site 
characterization under section 112 of the NWPA.

B. Subpart B--Implementation Guidelines

    The proposed revisions to the Implementation Guidelines would limit 
the procedures and basis for application of the postclosure and 
preclosure guidelines of subparts C and D, respectively, to evaluations 
of the suitability of sites for site characterization.
    Section 960.3, Implementation Guidelines, would be revised to 
eliminate the sentences in that section setting forth the procedures 
and basis for application of subparts C and D in evaluations and 
determinations of the suitability of a site under section 113 and 
section 114 of the NWPA. These revisions would remove section 960.3-1-
4-4, Site Recommendation for Repository Development, in its entirety. 
That section pertains to the procedure and evidence required to make a 
site recommendation decision under section 113 and 114. Those decisions 
would not be governed by the Guidelines, and therefore reference to 
them would be removed. Section 960.3-1-5, Basis for Site Evaluation, 
would be revised to eliminate all references to Appendix III and the 
application of the requirements of that section in making suitability 
determinations at the site characterization or site recommendation 
stages. Only the last sentence of section 960.3-2, Siting Process, 
would be revised. This revision would limit the applicability of the 
siting process to the recommendation of sites for site 
characterization. Section 960.3-2-4, Recommendation of Sites For the 
Development of Repositories, would be removed in its entirety. That 
section pertains to the comparison of characterized sites, leading to a 
recommendation by the Secretary to the President of a site for 
development as a repository. The proposed revisions would eliminate 
that decision process from evaluation under the Guidelines, and the 
section in its entirety would be removed.

C. Appendix III

    The proposed revisions to Appendix III would remove and eliminate 
the applicability of this Appendix to decisions for repository site 
selection and siting decisions. The qualifying and disqualifying 
conditions of the technical guidelines in subparts C and D would apply 
only to the decision point for selecting sites for site 
characterization. All references to the site selection and site 
recommendation decisions under sections 113 and 114 would be removed, 
including the tabular column in Appendix III referencing the repository 
site selection siting decision.
    With respect to the guidelines listed in Appendix III that apply to 
environmental quality, socioeconomics and transportation 
considerations, DOE considered whether to propose continuing to require 
their applicability to a Yucca Mountain site recommendation under 
section 114 of the NWPA. DOE decided not to do so because the issues 
addressed by these guidelines will be covered in the environmental 
impact statement for the Yucca Mountain site, and section 114(a)(1)(D) 
requires that the final environmental impact statement be part of the 
comprehensive statement of the basis for a site recommendation to the 
President. 42 U.S.C. 10134(a)(1)(D). Members of the public concerned 
about the analysis of environmental quality, socioeconomics and 
transportation issues will have ample opportunity to comment on these 
issues as part of the public review and comment process on the draft 
environmental impact statement and in additional public hearings 
required by section 114. In sum, DOE is of the view that the 
environmental quality, socioeconomics and transportation guideline 
requirements are substantially and unnecessarily duplicative of 
requirements under the procedures for developing an environmental 
impact statement and for formulating and informing a site 
recommendation under section 114.

VI. Description of Proposal--10 CFR Part 963

    The purpose of this part of the Supplementary Information is to 
explain the meaning and basis for those provisions of proposed part 963 
that are not self-explanatory. The following is a section by section 
analysis of the proposed rule, and the accompanying explanation.

A. Subpart A--General Provisions

    Subpart A comprises two parts, the statement of Purpose, section 
963.1, and Definitions, section 963.2.
    (a) Purpose--section 963.1. The purpose of the proposed rule is as 
stated in this section: to establish the methods and criteria for 
determining the suitability of the Yucca Mountain site for the location 
of a geologic repository in completing DOE's site characterization 
program activities to be conducted under section 113(b) of the NWPA. 
The suitability evaluation methods to be used by DOE are consistent 
with the methods proposed by the NRC for assessing the potential of a 
geologic repository at the Yucca Mountain site to meet licensing 
criteria and requirements. The suitability criteria relate to the 
geologic considerations identified in section 112(a) as they reflect 
current scientific understanding and regulatory expectations (both NRC 
and EPA) regarding the performance and safety of a geologic repository 
during the preclosure and postclosure periods of operation. Because the 
suitability criteria are part of the site characterization program, 
these criteria relate to site characterization activities. Site 
characterization activities relate to scientific and technical 
investigations of the site to determine its natural properties and 
features, for example, studying the geohydrology and geochemistry of 
the site, as distinct from consideration of other features, such as 
cost, socioeconomics and transportation of waste to the repository. An 
explanation of how the suitability criteria were derived is provided 
below.
    The proposed rule does not address the site recommendation process 
in its entirety. Other information required under section 114 of the 
NWPA that must be considered and submitted to the President and made 
available to the public if the site is recommended for development as a 
geologic repository is not addressed by the proposed rule. Regarding 
any repository site recommendation the Secretary of Energy shall make 
available to the public, and submit to the President, a comprehensive 
statement of the basis of

[[Page 67077]]

such recommendation, including the following: (a) A description of the 
proposed repository, including preliminary engineering specifications 
for the facility; (b) a description of the waste form or packaging 
proposed for use at such repository, and an explanation of the 
relationship between the waste form or packaging and the geologic 
medium of the site; (c) a discussion of data, obtained in site 
characterization activities, relating to the safety of such site; (d) a 
final environmental impact statement prepared for the Yucca Mountain 
site; (e) the preliminary comments of the NRC concerning the extent to 
which the at-depth site characterization analysis and the waste form 
proposal for such site seem to be sufficient for inclusion in any 
application to be submitted by the Secretary for licensing of such site 
as a repository; (f) the views and comments of the Governor and 
legislature of any State, or the governing body of any affected Indian 
tribe, as determined by the Secretary, together with the response of 
the Secretary to such views; (g) such other information as the 
Secretary considers appropriate; and (h) any impact report submitted 
under section 116(c)(2)(B) of the NWPA [42 U.S.C. 10136(c)(2)(B)] by 
the State of Nevada.
    (b) Definitions--section 963.2. The proposed rule includes 
definitions of certain words and terms. The definitions clarify DOE's 
intent and meaning in the context of this rule. The definitions are 
also intended to make the terms consistent with proposed NRC regulation 
governing the construction and licensing of a repository at the Yucca 
Mountain site. Several of the terms are important to understanding the 
suitability evaluation process, and are addressed here.
    Criteria are those characterizing traits that are relevant to 
assessing the performance of a geologic repository at the Yucca 
Mountain site. The criteria relate to the geologic considerations 
identified in section 112(a) of the NWPA that are relevant to the 
assessment of the performance of a geologic repository at the Yucca 
Mountain site. The geologic repository includes the natural barriers of 
the geologic setting and the engineered barriers of the repository 
design. The suitability criteria of the proposed rule are specific 
characterizing traits of the Yucca Mountain site that, through the site 
characterization process, DOE has identified as important indicators of 
the performance of the total repository system (that is, the integrated 
natural and engineered barrier systems).
    Consistent with varying definitions in standard dictionaries, DOE 
considered narrowly defining the term ``criteria'' as benchmark, pass-
fail standards rather than more broadly as ``characterizing traits.'' 
DOE decided not to adopt the more narrow definition for four reasons. 
First, in section 112(a) of the NWPA, the term ``primary criteria'' is 
used synonymously with the term ``detailed geologic considerations,'' a 
term that does not necessarily imply any benchmark. Second, as used in 
context in section 113 of the NWPA, the term ``criteria'' appears to 
refer to the considerations for evaluating whether a repository in a 
particular geologic medium is likely to meet applicable NRC standards, 
thus indicating that the site suitability criteria and the NRC 
standards are not one and the same. Third, section 121 of the NWPA 
(which addresses NRC's regulatory responsibilities) distinguishes 
between ``criteria'' and ``standards,'' a distinction which implies 
that ``criteria'' are not necessarily benchmark standards themselves. 
Finally, although some are inclined to define the term ``criteria'' 
narrowly, that inclination is not universal. For example, in 10 CFR 
part 50, the NRC sets forth quality assurance ``criteria'' that are in 
the nature of considerations, rather than benchmark, pass-fail 
standards.
    The performance of the total system is evaluated using a computer 
modeling tool called total system performance assessment. Total system 
performance assessment identifies the features, events and processes 
that might affect the performance of a repository, as well as the 
probabilities and significance of occurrence. Total system performance 
assessment examines the effects of those features, events and processes 
on that performance by estimating the expected annual dose to the 
receptor as a result of releases from the repository.
    For the preclosure period, suitability would be evaluated through a 
preclosure safety evaluation method. The preclosure safety evaluation 
would consider site characteristics and preliminary engineering 
specifications to assess the adequacy of the repository facilities to 
perform their intended functions and to mitigate the effects of design 
basis events, or credible accidents that could affect the ability of 
the geologic repository to operate safely. Design basis events are 
categorized in two ways: (1) those events, both natural and human-
induced, that are expected to occur one or more times before permanent 
closure; or (2) those events, both natural and human-induced, that have 
at least one chance in 10,000 of occurring before permanent closure. 
The preclosure safety evaluation would assess the ability of the 
geologic repository to meet the applicable radiation protection 
standard for the preclosure period under both categories of design 
basis events.
    DOE's evaluation of the suitability of a geologic repository at the 
Yucca Mountain site would be based on consideration of a preliminary 
design for the geologic repository. The design is the description of 
the potential geologic repository, which includes multiple barriers to 
the release and transport of radionuclides. These multiple barriers 
consist of both the natural barriers and an engineered barrier system. 
The geologic repository includes not only the facilities and areas 
where radioactive wastes are handled, but also that portion of the 
geologic setting that provides isolation of the radioactive wastes. As 
used in the proposed rule, and in NRC's proposed part 63, isolation 
means inhibiting the movement of radioactive material from the 
repository to the location where the receptor resides, so that 
radiation exposures will be less than the radiation dose limits 
prescribed in NRC's proposed regulation.

B. Subpart B--Site Suitability Determination, Methods and Criteria

    (a) Scope--section 963.10. The scope of subpart B includes, for 
both the preclosure and postclosure periods, the basis for DOE's 
suitability determination for the Yucca Mountain site. There are 
separate sections of the proposed rule for the preclosure and 
postclosure time periods. The scope of these sections also includes the 
site suitability criteria to be applied in accordance with section 
113(b) of the NWPA, the methods for applying the criteria and 
evaluating suitability, and the basis for the resulting suitability 
determination.
    The proposed rule is divided into two sections corresponding to the 
preclosure and postclosure periods, and within each period, three 
subsections. The subsections present for each period: (1) the 
suitability determination; (2) the suitability evaluation method; and 
(3) the criteria to be used for the evaluation. The purpose of 
separating the preclosure and the postclosure periods is to make clear 
the differences in determining the suitability of a geologic repository 
during these two periods. This separation is consistent with the 
current structure of the Guidelines, and the structure of the current 
and proposed new NRC licensing regulations, which have separate 
performance objectives for the preclosure and the postclosure periods.

[[Page 67078]]

The preclosure method and criteria govern the suitability 
considerations that deal with the operation of the repository before it 
is closed, while waste is being received, stored and emplaced, and 
allow for the possibility of retrieval. These are the considerations 
important in protecting the public and repository workers from 
exposures to radiation during repository operations, especially if an 
accident should occur. The postclosure method and criteria govern the 
suitability considerations that deal with the long-term behavior of the 
repository. The behavior of interest here is after waste emplacement 
and repository closure.
    (b) Suitability determination--section 963.11. This section 
describes how DOE will determine the suitability of the site based on 
the information and data developed through the program of site 
characterization activities at Yucca Mountain. DOE may find the Yucca 
Mountain site suitable for the location of a repository based on its 
determinations relative to the preclosure and postclosure suitability 
evaluations under sections 963.12 and 963.15. Those determinations, in 
turn, entail assessment of preclosure and postclosure suitability using 
the designated evaluation method and criteria for each time period. The 
overall suitability determination, if affirmative, will be one part of 
the Secretary's decision, under section 114, whether to recommend the 
Yucca Mountain site to the President for development of a repository.
    (c) Preclosure suitability determination--section 963.12. The 
suitability evaluation of the Yucca Mountain site will consider the 
safety of the geologic repository during the operational or preclosure 
time period. The preclosure criteria to evaluate the suitability of a 
geologic repository operations area at Yucca Mountain will be 
considerations that are important to determining safety during 
construction and active operation and to demonstrating compliance with 
the applicable radiation protection standard.
    (d) Preclosure suitability evaluation method--section 963.13. The 
preclosure suitability criteria will be applied through a preclosure 
safety evaluation method. The preclosure safety evaluation would 
support the recommendation to approve the Yucca Mountain site for 
submittal of a license application. The NRC provides a framework 
indicating how to conduct this type of evaluation in proposed 10 CFR 
63.112. DOE designed the preclosure safety evaluation method proposed 
in this rule based on this NRC framework and a DOE assessment of what 
information would be necessary and sufficient to determine, at the site 
suitability stage, whether a proposed geologic repository at Yucca 
Mountain is likely to meet the applicable radiation protection 
standards for the preclosure period.
    The preclosure safety evaluation method, using preliminary 
engineering specifications, will assess the adequacy of the repository 
facilities to perform their intended functions and prevent or mitigate 
the effects of postulated design basis events that are deemed 
sufficiently credible to warrant consideration. The preclosure safety 
evaluation will consider: a preliminary description of the site 
characteristics, the surface facilities, and the underground 
facilities; a preliminary description of the expected design bases for 
the operating facilities and a preliminary description of any 
associated limits on operation; a preliminary description of potential 
hazards (for example, seismic activity, flooding and severe winds), 
event sequences, and their consequences; and, a preliminary description 
of the structures, systems, components, equipment, and operator actions 
intended to mitigate or prevent accidents. The purpose of the 
preclosure safety evaluation is to ensure that relevant hazards that 
could result in unacceptable consequences have been adequately 
evaluated and appropriate protective measures have been identified such 
that the geologic repository operations area will comply with the 
preclosure requirements for protection against radiation exposures and 
releases of radioactive material.
    The preclosure safety evaluation will emphasize performance 
requirements, analytical bases and technical justifications, and 
evaluations that show how safety functions will be accomplished. The 
adequacy of the facility design will be evaluated by consideration of 
postulated design basis events viewed as sufficiently credible that the 
facility should be designed to prevent or mitigate their effects. 
Design basis events are those natural and human-induced events that are 
either expected to occur before closure, or have one chance in 10,000 
of occurring before permanent closure. DOE will evaluate the 
probability of the event and the associated consequences. For events of 
high frequency, the consequences should be low. For less probable 
accidents that are potentially more severe, the allowable consequences 
are higher. In either case, the suitability determination will be 
supported by a design that DOE considers likely to meet the applicable 
radiation protection standard.
    (e) Preclosure suitability criteria--section 963.14. DOE will 
evaluate the suitability of the Yucca Mountain site during the 
preclosure period using the following criteria: (a) ability to contain 
and limit releases of radioactive materials; (b) ability to implement 
control and emergency systems to limit exposures to radiation; (c) 
ability to maintain a system and components that perform their intended 
safety functions; and (d) ability to preserve the option to retrieve 
wastes during the preclosure period. These criteria are considerations 
important to determining the performance of a potential repository at 
Yucca Mountain. For example, in applying the first criterion, DOE will 
ensure repository facilities are designed to keep the radioactive 
materials confined in order to limit releases of radioactive material. 
The second and third criteria address DOE's ability to ensure that 
emergency controls and procedures are developed to limit releases 
should an accident occur, and that the system and its components will 
perform their safety function as intended. The fourth and final 
criterion is also important to the safe functioning of a repository; 
that is, ensuring the capability to retrieve or recover the wastes from 
the repository should conditions warrant.
    These criteria also relate to certain geologic considerations in 
section 112(a) of the NWPA. The geologic considerations identified in 
section 112(a) that are relevant to the preclosure period are 
hydrology, geophysics, seismic activity, atomic energy defense 
activities, proximity to water supplies and proximity to populations. 
These considerations are relevant to the evaluation of preclosure 
suitability because they bear on the evaluation of repository system 
safety during the preclosure period. The hydrology and geophysics of 
the site are important to preclosure safety because they are indicators 
of possible initiating events for accidents. Seismic activity is also 
important in this regard, as it is an indication of the potential for 
earthquake activity to disrupt normal functioning of a repository 
surface facility. The location of atomic energy defense activities in 
relation to the Yucca Mountain site is important to preclosure safety 
and would be considered to the extent they exist and may impact 
operations of the repository facility. Proximity to water supplies and 
proximity to populations are important to preclosure safety because 
they relate to potential locations where people could eventually be 
exposed to

[[Page 67079]]

radionuclides either through airborne transport or through a water 
pathway.
    (f) Postclosure suitability determination--section 963.15. The 
postclosure suitability evaluation of the Yucca Mountain site will 
consider the safety of the geologic repository during the time after 
operations cease, the postclosure period. DOE will determine the 
suitability of the Yucca Mountain site for the postclosure period by 
examining the results of a TSPA conducted under section 963.16. If the 
results indicate a repository at Yucca Mountain is likely to meet the 
applicable radiation protection standard, then DOE may determine, on 
the basis of site characterization activities, that the site is 
suitable for the postclosure period.
    (g) Postclosure suitability evaluation method--section 963.16. DOE 
will evaluate the suitability of a potential repository at the Yucca 
Mountain site using the TSPA method (described in greater detail 
below). Using the TSPA method, DOE will estimate quantitatively the 
expected annual dose, over the compliance period, to the receptor. With 
this estimate, DOE will evaluate the performance of the repository and 
its ability to limit radiological exposures within the applicable 
radiation protection standard.
    (1) Section 963.16(a). Section 963.16(a) describes how DOE will 
conduct separate performance assessments in order to evaluate the 
postclosure performance of a geologic repository at Yucca Mountain. One 
TSPA will be conducted in accordance with the method described in 
963.16(b) and using all of the criteria identified in section 963.17, 
except the criterion assuming a human intrusion into the repository. A 
second TSPA will be conducted in accordance with the method described 
in 963.16(b) (except not all engineered and natural barriers will be 
considered), and using all of the criteria in section 963.17, including 
the criterion assuming a stylized human intrusion into the repository, 
as defined by NRC regulations. The results of each performance 
assessment will be examined by DOE to determine the suitability of the 
site for the postclosure period.
    The conduct of separate assessments is consistent with EPA's 
proposed 40 CFR part 197 and NRC's proposed regulations at 10 CFR part 
63. The proposed regulations, in turn, are based on NAS recommendations 
in the report, Technical Bases for Yucca Mountain Standards, on how 
best to assess the performance and resilience of a potential 
repository. Because the manner and likelihood of human intrusion 
occurring many hundreds or thousands of years into the future cannot be 
estimated reliably by examining either the historic or geologic record, 
the NAS recommended an approach that will assess how resilient the 
geologic repository would be against a postulated intrusion. The 
consequences of the assumed human intrusion event will be addressed in 
a ``stylized'' manner, that is, by assuming a particular human 
intrusion event occurs in a certain way, at a specified time. Proposed 
EPA and NRC regulations define different stylized human intrusion 
events to be examined by DOE. At the time of the suitability 
determination, DOE will conduct the human intrusion analysis within the 
framework of the applicable regulatory concept, and use the results of 
the performance assessment to evaluate the suitability of the site for 
the postclosure period.
    (2) Section 963.16(b). Section 963.16(b) provides an outline of the 
contents and manner in which DOE will conduct its performance 
assessments. As described previously in this notice, and briefly 
summarized here, performance assessment in this context is a method of 
forecasting how a system or parts of a system designed to contain 
radioactive waste will behave over time. Its goal is to aid in 
determining whether the system can meet established performance 
requirements. A TSPA is a type of performance assessment analysis in 
which the components of a system are integrated or linked into a single 
analysis.
    The TSPA treats both the engineered and natural system components. 
The engineered system is to some extent controllable, but the natural 
system generally is not. The responses of the total system extend over 
periods beyond those for which data have been or can be obtained. The 
relationship of the components of a TSPA is often described as a 
pyramid. The lowest level of the pyramid represents the complete suite 
of process and design data and information (that is, field and 
laboratory studies that are the first step in understanding the 
system). The next higher level indicates how the data feed into 
conceptual models that portray the operation of the individual system 
components. The next higher level represents the synthesis of 
information from the lower levels of the pyramid into computer models. 
The term abstraction often is used to indicate the extraction of 
essential information from large quantities of data. The TSPA models 
are usually referred to as abstracted models. At this point, the 
subsystem behavior may be described by linking models together into 
representations; this is the point at which performance assessment 
modeling is usually thought to begin. This is also the basis for the 
identification of the Yucca Mountain specific suitability criteria 
contained in the proposed rule.
    The upper level is the final level of distillation of information 
into the most significant aspects to represent the total system. At 
this point, the models are linked together. These are the models used 
to forecast system performance and estimate the likelihood that the 
performance will comply with regulations and ensure long-term safety.
    As information flows up the pyramid, it generally is distilled into 
progressively more simplified or essential forms, or becomes more 
abstracted. However, abstraction is not synonymous with simplification. 
If a particular component model cannot be simplified without losing 
essential aspects of the model, then the model becomes part of the TSPA 
calculation tool. Thus, an abstracted model in a TSPA may take the form 
of something as simple as a table of values that were calculated using 
a complex computer model, or the abstraction may take the form of a 
fully three dimensional computer simulation.
    The TSPA method described in section 963.16(b) is a systematic 
analysis that identifies the features, events, and processes (i.e., 
specific conditions or attributes of the geologic setting, degradation, 
deterioration, or alteration processes of engineered barriers, and 
interactions between the natural and engineered barriers) that might 
affect performance of the geologic repository; examines their effects 
on performance; and estimates the expected annual dose. The features, 
events, and processes considered in the TSPA will represent a wide 
range of effects on geologic repository performance. Those features, 
events, and processes expected to affect compliance significantly or be 
potentially adverse to performance are included, while events of very 
low probability can be excluded from the analysis. The expected annual 
dose to the receptor is estimated using the selected features, events, 
and processes, and incorporating the probability that the estimated 
dose will occur.
    The TSPA method described in section 963.16(b) is a systematic 
analysis that identifies the features, events, and processes (i.e., 
specific conditions or attributes of the geologic setting, degradation, 
deterioration, or alteration processes of engineered

[[Page 67080]]

barriers, and interactions between the natural and engineered barriers) 
that might affect performance of the geologic repository; examines 
their effects on performance; and estimates the expected annual dose. 
The features, events, and processes considered in the TSPA will 
represent a wide range of effects on geologic repository performance. 
According to proposed EPA and NRC regulations, those features, events, 
and processes expected to affect compliance significantly or be 
potentially adverse to performance are included, while events of very 
low probability (less than one chance in 10,000 of occurring within 
10,000 years of disposal) can be excluded from the analysis. The 
expected annual dose to the average member of the critical group is 
estimated using the selected features, events, and processes, and 
incorporating the probability that the estimated dose will occur.
    The TSPA that will be used to assess the postclosure performance of 
the Yucca Mountain repository will be conducted in the manner described 
in section 963.16(b). It will synthesize data and information into a 
set of models that simulate the behavior of the individual system 
components. DOE will abstract essential information from its initial 
models and refine them into linked models, including computer models, 
that represent important aspects of system performance. DOE will use 
these models to forecast system behavior and the likelihood of system 
compliance with the applicable radiation protection standard.
    The TSPA calculations will be used to address conditions in the 
natural and engineered components of a repository at Yucca Mountain 
over the time that the standards apply. The TSPA calculations will also 
be used to consider disruptive events that are improbable, but that are 
important to understanding the repository behavior in the future. A 
requirement for TSPA will be to identify the identification of those 
natural features of the geologic setting and the design features of the 
engineered barrier system that are considered barriers important to 
waste isolation. TSPA will be used to assess the capability of the 
barriers, identified as important to waste isolation, to isolate waste, 
taking into account uncertainties in characterizing and modeling the 
barriers. Sensitivity studies and the regulatory definition of very-low 
probability events will provide the technical basis for inclusion or 
exclusion of specific features, events, and processes of the geologic 
setting in the TSPA.
    Specific features, events, and processes of the geologic setting 
will be evaluated through sensitivity analyses to determine if the 
magnitude and time of the resulting expected annual dose would be 
significantly changed by their omission. Sensitivity analysis is a 
technique that is used to examine how a system responds if one of its 
components is changed. Systems are said to be sensitive to such a 
component if the results of the calculation are changed significantly 
in response to changes in that component's values. The sensitivity 
calculations will also provide the technical basis for either inclusion 
or exclusion of degradation or alteration processes of engineered 
barriers in the TSPA. Degradation or alteration processes will be 
evaluated further if the magnitude and timing of the resulting expected 
annual dose would be significantly changed by their omission.
    Using the TSPA results, DOE can examine the sensitivity of one or 
more components of the calculations in the assessment. DOE can examine 
the response of the geologic repository system with regard to 
sensitivities of the system to the suitability criteria, in order to 
evaluate whether the geologic repository meets the applicable radiation 
protection standard.
    As part of the TSPA, DOE will account for uncertainties and 
variabilities in both calculations and data, and provide the technical 
bases for parameter ranges, probability distributions, and bounding 
values. The reason for this accounting is that it is recognized, by the 
NRC and others, that there are inherent uncertainties in the 
understanding of the evolution of the geologic setting, biosphere, and 
engineered barrier system. Under the circumstances, proof that the 
geologic repository will be in conformance with the applicable 
radiation protection standard is not to be had in the ordinary sense of 
the word. Instead, DOE will demonstrate compliance and the performance 
of the potential repository using sophisticated, complex predictive 
models that are supported by limited data from field and laboratory 
tests, site-specific monitoring, and natural analog studies that may be 
supplemented with expert judgment.
    Another aspect of DOE's conduct of the TSPA is the analysis of 
alternative models of features and processes. Under 963.16(b)(3), DOE 
will consider alternative models of features and processes that are 
consistent with available data and current scientific understanding, 
and evaluate the effects that alternative models would have on the 
estimated performance of the geologic repository. In this regard, if 
other interested persons suggest and present to DOE alternative models 
that are consistent with available data and current scientific 
understanding, DOE will evaluate those other models. In implementing 
this requirement, however, DOE does not believe it would be 
scientifically or technically useful, and may be administratively 
burdensome, to require that, in every case, DOE provide the bases for 
not using an alternative model suggested by another party. Other 
interested persons may suggest any number of alternative models, some 
of which may not be consistent with available data and current 
scientific thinking and therefore not add significant value to the TSPA 
analysis. Nevertheless, DOE may decide, on a case-by-case basis, to 
document consideration of alternative models that were suggested by 
other interested persons, but not used because, among other things, the 
model is not consistent with available data and current scientific 
understanding.
    (h) Postclosure suitability criteria--section 963.17. The 
postclosure criteria to evaluate the suitability of a geologic 
repository at Yucca Mountain will be considerations that reflect both 
the processes and the models used to simulate those processes that are 
important to the total system performance of the geologic repository. 
These criteria are characterizing traits that are relevant and 
important in the processes to be modeled in the TSPA that evaluates the 
suitability of the Yucca Mountain site for the postclosure period. 
These criteria also are related to the section 112(a) geologic 
considerations identified in the NWPA. Following is a description of 
how the section 112(a) geologic considerations relate to the 
postclosure suitability criteria, as well as a discussion of the 
criteria as they relate to the processes and computer models to be used 
in evaluating the performance of a geologic repository in the 
postclosure period.
    (1) Section 112(a) geologic considerations. The geologic 
considerations identified in section 112(a) of the NWPA that are 
relevant to the postclosure performance of a repository at Yucca 
Mountain are: location of valuable natural resources, hydrology, 
geophysics, seismic activity, proximity to water supplies, and 
proximity to populations. These considerations are relevant to 
postclosure performance because they impact components and processes of 
the repository system related to potential transport of radionuclides 
via ground water to members of the public.
    The location of valuable natural resources is a relevant geologic

[[Page 67081]]

condition for postclosure performance because the presence of these 
resources in the geologic setting of Yucca Mountain could lead to 
exploratory drilling or excavation and a consequent breach of the 
repository's safety barriers. Hydrology- and geophysics-related 
conditions are relevant because they describe some of the geologic 
features of the site that are related to safety and the physical 
characteristics that are related to potential transport of 
radionuclides to the biosphere. Seismic activity is relevant to 
postclosure performance because it is related to the potential for 
changes in geologic structures that could lead to enhanced transport of 
radionuclides. Proximity to water supplies and populations are relevant 
to postclosure performance because they are related to potential 
locations where people could eventually be exposed to radionuclides in 
their water.
    Table 2 provides a cross-reference between the section 112(a) 
factors related to geologic considerations, and the postclosure 
suitability criteria. As previously stated, the postclosure suitability 
criteria largely represent the process model components of the total 
system performance assessment that DOE will use to evaluate the 
performance of the repository during the postclosure period. DOE has 
identified these processes as pertinent to assessing the performance of 
a repository at Yucca Mountain through information and data developed 
under its site characterization program. These processes also are 
related to, and impacted by, the geologic considerations found in 
section 112(a) of the NWPA.

                                 Table 2
------------------------------------------------------------------------
                                             Postclosure suitability
       NWPA Sec.  112(a) factors                     criteria
------------------------------------------------------------------------
(a) Processes pertinent to total system
 performance:
    Hydrology, geophysics, seismic       (1) Site characteristics.
     activity.
    Hydrology, geophysics, seismic       (2) Unsaturated-zone flow
     activity.                            characteristics.
    Hydrology, geophysics, seismic       (3) Near-field environment
     activity.                            characteristics.
    Hydrology, geophysics, seismic       (4) Engineered barrier system
     activity.                            degradation characteristics.
    Hydrology, geophysics, seismic       (5) Waste form degradation
     activity.                            characteristics.
    Hydrology, geophysics, seismic       (6) Engineered barrier system
     activity.                            degradation, flow, and
                                          transport characteristics.
    Hydrology, geophysics, seismic       (7) Unsaturated-zone flow and
     activity.                            transport characteristics.
    Hydrology, geophysics, seismic       (8) Saturated-zone flow and
     activity.                            transport characteristics.
    Hydrology, proximity to water        (9) Biosphere characteristics.
     supplies, proximity to populations.
(b) Disruptive processes and events:
    Hydrology, geophysics..............  (1) Volcanism.
    Seismic activity, geophysics.......  (2) Seismic events.
    Hydrology, geophysics, seismic       (3) Nuclear criticality.
     activity.
    Location of valuable natural         (4) Inadvertent human
     resources, proximity to              intrusion.
     populations.
------------------------------------------------------------------------

    (2) Suitability criteria. DOE has developed its site 
characterization program to address those processes of the repository 
system that are pertinent to understanding how a repository at Yucca 
Mountain would comply with applicable radiation protection standards. 
The program also has been developed to better understand these 
processes, and resolve or put in place methods to resolve issues 
related to those processes. DOE has described these processes, and the 
methods to resolve issues related to the processes, in the SCP, semi-
annual progress reports on site characterization program activities, in 
several TSPAs conducted over the years, and most recently in the 
Viability Assessment. These processes are simulated through performance 
assessment models; those models are integrated and refined to a point 
resulting in a representation of the performance of the system in 
total.
    Put in simple terms, the processes that are pertinent to 
understanding the performance of a repository at Yucca Mountain, and 
that form the basis for the numerical models in the TSPA and the 
suitability criteria in section 963.17, are those physical processes of 
water falling on Yucca Mountain as rain and snow, moving into the 
mountain, down through the unsaturated zone to the potential repository 
level, from the repository level to the saturated zone, and from there 
to the outside environment. At the repository level, the water would be 
affected by the physical processes associated with the repository and 
with the waste packages and the waste forms. Eventually, the water 
could move out of the repository horizon and further downward through 
the unsaturated zone. Subsequently, it could move into the saturated 
zone where it could be transported to a point where humans could be 
exposed to any radionuclides carried in the water. Disruptive events 
could potentially affect these processes and, therefore, need to be 
considered. This set of physical processes is simulated in the 
numerical modeling method of the TSPA that will be used to assess 
quantitatively the radionuclide releases to the public and, 
consequently, the safety and suitability of the Yucca mountain site.
    The suitability criteria proposed in this rule are derived from 
these pertinent physical processes. These criteria represent the 
characteristic traits pertinent to assessing the performance of a 
geologic repository at the Yucca Mountain site. They also reflect and 
represent in a larger sense the geologic considerations identified in 
section 112(a) of the NWPA such as hydrology, geophysics, seismic 
activity, and proximity to water supplies and populations.
    The sequence in which the suitability criteria are presented in the 
proposed rule generally corresponds to the process of water flow 
presented above. In general, the criteria can be thought of as building 
blocks; each criterion in the sequence is evaluated on its own, with 
the results of that evaluation incorporated into the evaluation of the 
succeeding criteria, and so on until the final analysis. As the site 
characterization program evolves, DOE may refine these process models 
to better reflect and assess the processes pertinent to performance of 
a geologic repository at the Yucca Mountain site. It is possible that 
the processes, as well as the design selected, could dictate other ways 
to arrange the information included under the individual criteria. 
While the individual components of the process models may vary 
according to improvements in data and information, DOE's resultant 
suitability

[[Page 67082]]

determination would be based on an evaluation of each of the 
postclosure suitability criteria.
    The criteria are separated into two categories. The first category, 
presented in section 963.17(a), represent those criteria important to 
the total system performance assessment without accounting for 
disruptive processes and events that could impact that performance. The 
second category, presented in section 963.17(b), are those criteria 
representing disruptive processes and events that could adversely 
affect the characteristics of the repository system, and consequently 
release radionuclides to the human environment. Each criterion in the 
first category is linked to a specific TSPA model component that will 
be used to evaluate the performance of that criterion. Each criterion 
in the second category is generally treated as an effect imposed on the 
system at a time that reflects the probability of occurrence of the 
disruptive event.
    Under section 963.17(a), the first and a fundamental criterion that 
will be modeled to assess performance of a repository at the Yucca 
Mountain site is the representation of pertinent site characteristics. 
The criterion of site characteristics includes: (a) The geologic 
properties of the site--for example, stratigraphy, rock type and 
physical properties, and structural characteristics; (b) the hydrologic 
properties of the site--for example, porosity, permeability, moisture 
content, saturation, and potentiometric characteristics; (c) the 
geophysical properties of the site--for example, thermal properties, 
densities, velocities and water contents, as measured or deduced from 
geophysical logs, and (d) the geochemical properties of the site--for 
example, precipitation, dissolution characteristics, and sorption 
properties of mineral and rock surfaces. Together, as reflected in the 
performance assessment, these characteristics enable a representative 
simulation of the behavior of a geologic repository at the Yucca 
Mountain site.
    The second criterion, unsaturated zone flow characteristics, 
relates to the processes affecting the limitations and amount of water 
entering the unsaturated zone above the repository and contacting 
wastes in the repository. Unsaturated zone flow characteristics 
include: (a) Climate--for example, precipitation and postulated future 
climatic conditions; (b) infiltration--for example, precipitation 
entering the mountain in excess of water returned to the atmosphere by 
evaporation and plant transpiration; (c) unsaturated-zone flux--for 
example, water movement through the pore spaces, or flowing along 
fractures or through perched water zones above the repository; and (d) 
seepage--for example, water dripping into the underground repository 
openings from the surrounding rock. Together, the first and second 
criteria define the temporal and spatial distribution of water flow 
through the unsaturated zone above the water table at Yucca Mountain, 
and the temporal and spatial distribution of water seepages into the 
underground openings of the repository.
    The third criterion, near field environment characteristics, also 
relates to processes important to limiting the amount of water that 
could contact wastes. This criterion includes: (a) Thermal hydrology--
for example, effects of heat from the waste on water flow through the 
site, and the temperature and humidity at the engineered barriers; and, 
(b) near-field geochemical environment--for example, the chemical 
reactions and products resulting from water contacting the waste and 
the engineered barriers materials. The thermal regime generated by the 
decay of the radioactive wastes can mobilize water over the first 
hundreds to thousands of years. For these reasons, the amount of water 
flowing in the rock and seeping into drifts is expected to vary with 
time.
    The fourth criterion, engineered barrier system degradation 
characteristics, relates to the processes important to long waste 
package lifetimes. This criterion includes: (a) engineered barrier 
system component performance--for example, drip shields, backfill, 
coatings, or chemical modifications; and (b) waste package 
degradation--for example, the corrosion of the waste package materials 
within the near-field repository environment. This criterion and the 
first criterion, site characteristics, define the spatial and temporal 
distribution of the time periods when waste packages are expected to 
breach. The thermal, hydrologic, and geochemical processes acting on 
the waste package surface are the most important environmental factors 
affecting the waste package lifetime. In addition, the degradation 
characteristics of the waste package materials significantly impact the 
timing of waste package breaches.
    The fifth criterion, waste form degradation characteristics, 
addresses the initial aspects of low rate of release of radionuclides. 
This criterion includes: (a) cladding degradation--for example, 
corrosion or break-down of the cladding on the individual spent fuel 
pellets; and, (b) waste form dissolution--for example, the ability of 
individual radionuclides to dissolve in water penetrating breached 
waste packages. This criterion is important to understanding how and in 
what manner the waste forms will break down, permitting the release of 
radionuclides to the immediately surrounding environment.
    The sixth criterion, engineered barrier system degradation, flow, 
and transport characteristics, addresses the processes important to the 
manner in which radionuclides can begin to move outward once the 
engineered barrier system has been degraded. This criterion includes : 
(a) colloid formation and stability--for example, the formation of 
colloidal particles and the ability of radionuclides to adhere to these 
particles as they may be washed through the remaining barriers; and (b) 
engineered barrier transport--for example, the movement of 
radionuclides dissolved in water or adhering to colloidal particles to 
be transported through the remaining engineered barriers and in the 
underlying unsaturated zone. This criterion and the first criterion, 
site characteristics, lead to a determination of the spatial and 
temporal distribution of the mass of radioactive wastes released from 
the waste packages. Each characteristic depends on the thermal, 
hydrologic, and geochemical conditions inside the waste package, which 
change with time.
    The next two criteria--unsaturated zone flow and transport 
characteristics (criterion seven), and saturated zone flow and 
transport characteristics (criterion eight)--relate to processes 
important to radionuclide concentration reduction during transport. To 
assess the movement of radionuclides away from the degraded engineered 
barrier system, the first important process to understand is the 
unsaturated zone flow characteristics in combination with the 
unsaturated zone transport characteristics. The unsaturated zone flow 
and transport characteristics criterion includes: (a) unsaturated-zone 
transport--for example, the movement of water with dissolved 
radionuclides or colloidal particles through the unsaturated zone 
underlying the repository, including retardation mechanisms such as 
sorption on rock or mineral surfaces; and (b) thermal hydrology--for 
example, effects of heat from the waste on water flow through the site. 
The next criterion, saturated zone flow and transport characteristics, 
addresses similar radionuclide transport processes, only in the 
saturated zone. This criterion includes: (a) saturated zone transport--
for example, the movement of water with dissolved

[[Page 67083]]

radionuclides or colloidal particles through the saturated zone 
underlying and beyond the repository, including retardation mechanisms 
such as sorption on rock or mineral surfaces; and (b) dilution--for 
example, diffusion of radionuclides into pore spaces, dispersion of 
radionuclides along flow paths, and mixing with non-contaminated ground 
water.
    The ninth criterion, biosphere characteristics, addresses the 
characteristics that describe the lifestyle and habits of individuals 
who potentially could be exposed to radioactive material at a future 
time. Because of the difficulty in predicting the lifestyles and habits 
of future generations, such assessments are to be based on 
representative current conditions. Both the EPA and the NRC have 
proposed rules that would require DOE to apply current conditions in 
assessments of the reference biosphere. This criterion includes: (a) a 
reference biosphere and receptor defined, for example, by considering 
pathways, location and behavior representative of current conditions; 
and (b) biosphere transport and uptake--for example, the consumption of 
ground or surface waters through direct extraction or agriculture, 
including mixing with non-contaminated waters and exposure to 
contaminated agricultural products.
    Together, the criteria of unsaturated zone flow and transport 
characteristics, saturated zone flow and transport characteristics, and 
biosphere characteristics, address the spatial and temporal variations 
of radionuclide concentrations in ground water. The ground water 
concentration ultimately yields the mass of radionuclides that may be 
ingested or inhaled by individuals exposed to that ground water, which 
in turn leads to a level of radiological dose or risk associated with 
that potential exposure. The concentration depends on both the mass 
release rate of the radionuclides as well as the volumetric flux of 
water along the different pathways in the different components.
    Section 963.17(b) presents four final criteria (separately 
enumerated from section 963.17(a)) under the category of disruptive 
processes and events. These criteria relate to disruptive processes and 
events that could potentially release radionuclides directly to the 
human environment, or otherwise adversely affect the characteristics of 
the system. The criteria pertinent to assessing repository performance 
relative to this attribute include: (1) Volcanism--for example, the 
probability and potential consequences of a volcanic eruption 
intersecting the repository; (2) seismic events--for example, the 
probability and potential consequences of a earthquake on the 
underground facilities or hydrologic system; and (3) nuclear 
criticality--for example, the probability and potential consequences of 
a self-sustaining nuclear reaction as a result of chemical or physical 
processes affecting the waste either in or after release from breached 
waste packages.
    The last of the four disruptive processes and events criteria, 
inadvertent human intrusion, is a special criterion to be applied and 
assessed in its own performance assessment. Although characterization 
of the Yucca Mountain site and region indicates that it is not a likely 
choice for future exploration for natural resources, the NRC has 
identified the examination of a human intrusion scenario through 
drilling as a requirement for a TSPA in its proposed part 63. 
Accordingly, inadvertent human intrusion--for example, consequences to 
repository system performance following a stylized human intrusion 
scenario, is included in the criteria for disruptive processes and 
events, although it will be treated in a separate performance 
assessment. In making its suitability determination, DOE would apply 
the regulatory concept for human intrusion applicable at that time.

VII. Opportunity for Public Comment

A. Participation in Rulemaking

    Interested persons are invited to participate in this proposed 
rulemaking by submitting written data, views, or comments with respect 
to the subject set forth in this notice. The Department encourages the 
maximum level of public participation possible in this rulemaking. 
Individuals, coalitions, states or other government entities, and 
others are urged to submit written comments on the proposal.

B. Written Comment Procedures

    The DOE invites public comments on the proposed rule. Written 
comments should be identified on the outside of the envelope, and on 
the comments themselves, with the designation: ``Site Characterization 
Suitability Criteria NOPR, Docket Number [RW-RM-99-963]'' and must be 
received by the date specified at the beginning of this notice in order 
to be considered. In the event any person wishing to submit written 
comments cannot provide them directly, alternative arrangements can be 
made by calling [(800) 967-3477]. All comments received on or before 
the date specified at the beginning of this notice and other relevant 
information will be considered by the DOE before final action is taken 
on the proposed rule. All comments submitted will be available for 
examination in the Rule Docket File in the Yucca Mountain Science 
Center in Las Vegas, Nevada, and the DOE's Freedom of Information 
Reading Room. Pursuant to the provisions of 10 CFR 1004.11, any person 
submitting information or data that is believed to be confidential, and 
which may be exempt by law from public disclosure, should submit one 
complete copy, as well as two copies from which the information 
considered confidential has been deleted. The Department of Energy will 
make its own determination of any such claim and treat it according to 
its determination.

C. Hearing Procedures

    At the beginning of this notice, DOE indicated that there would be 
a separate Federal Register Notice informing the public of the time and 
location of the public hearings on this supplemental notice of proposed 
rulemaking. For obvious reasons, DOE will hold these hearings in the 
vicinity of Yucca Mountain because nearby residents would be especially 
impacted by the location of a nuclear waste repository at Yucca 
Mountain. These hearings will not be trial-type evidentiary hearings 
that require a lawyer. They will be informal, and DOE intends to use a 
facilitator in an effort to ensure they are fair and productive.
    DOE is considering a format wherein DOE officials would make a 
presentation that summarizes the supplemental notice of proposed 
rulemaking, and members of the public would have the opportunity to 
make oral comments. Prior to or following the hearing, DOE officials 
may be available to answer technical questions about the proposed 
regulation articulated in this notice. However, the DOE officials could 
not make any commitments about the final rule, and in some instances, 
they might be limited to taking the oral comments under advisement. In 
fairness to all commenters, decisions about the final rule must await 
the close of the comment period and consideration by DOE senior policy 
makers.

VIII. Regulatory Review

A. Review for Compliance with the National Environmental Policy Act 
(NEPA)

    The issuance of these amendments to the guidelines is a preliminary 
decision-making activity pursuant to subsection 112(d) and 113(d) of 
the Act and therefore does not require the preparation of an 
environmental impact statement pursuant to subsection

[[Page 67084]]

102(2)(C) of the NEPA or any other environmental review under 
subsection 102(2)(E) or (F) of the NEPA.

B. Review under the Regulatory Flexibility Act

    The Regulatory Flexibility Act, 5 U.S.C. 601 et seq., was enacted 
by Congress to ensure that a substantial number of small entities do 
not unnecessarily face significant negative economic impact as a result 
of Government regulations. The DOE certifies that the rule amending the 
guidelines will not have a significant impact on a substantial number 
of small entities. The final rule will not regulate or otherwise 
economically burden anyone outside of the DOE. It merely articulates 
considerations for the Secretary of Energy to use in determining 
whether the Yucca Mountain site is suitable for development as a 
repository. Moreover, in response to the initial notice of proposed 
rulemaking , a few entities who commented were small entities, and none 
of them identified economic burdens that the proposed regulations would 
impose. Accordingly, no regulatory flexibility analysis is required 
under the Regulatory Flexibility Act.

C. Review under the Paperwork Reduction Act

    The DOE has determined that this rule, as proposed, contains no new 
or amended record keeping, reporting, or application requirements, or 
any other type of information collection requirements subject to the 
Paperwork Reduction Act (Pub. L. No. 96-511).

D. Review under Unfunded Mandates Reform Act

    The Unfunded Mandates Reform Act of 1995 (Pub. L. No. 104-4) 
generally requires Federal agencies to closely examine the impacts of 
regulatory actions on State, local, and tribal governments. Subsection 
101(5) of Title I of that law defines a Federal intergovernmental 
mandate to include any regulation that would impose an enforceable duty 
upon State, local, or tribal governments, except, among other things, a 
condition of Federal assistance or a duty arising from participating in 
a voluntary federal program. Title II of that law requires each Federal 
agency to assess the effects of Federal regulatory actions on State, 
local, and tribal governments, in the aggregate, or to the private 
sector, other than to the extent such actions merely incorporate 
requirements specifically set forth in a statute. Section 202 of that 
title requires a Federal agency to perform a detailed assessment of the 
anticipated costs and benefits of any rule that includes a Federal 
mandate which may result in costs to State, local, or tribal 
governments, or to the private sector, of $100 million or more. Section 
204 of that title requires each agency that proposes a rule containing 
a significant Federal intergovernmental mandate to develop an effective 
process for obtaining meaningful and timely input from elected officers 
of State, local, and tribal governments.
    This rule, as proposed, is not likely to result in any Federal 
mandate that may result in the expenditure by State, local, and tribal 
governments in the aggregate, or by the private sector, of $100 million 
or more in any one year. Further, the guidelines in 10 CFR part 960, 
the proposed amendments to part 960 and the proposed part 963 largely 
incorporate requirements specifically provided in Sections 112 and 113 
of the Act. Moreover, Sections 112, 113 and 114 of the Act provide for 
meaningful and timely input from elected officials of State, local and 
tribal governments. Accordingly, no assessment or analysis is required 
under the Unfunded Mandates Reform Act of 1995.

E. Review under Executive Order 12612

    Executive Order 12612, 52 FR 41685, requires that regulations, 
rules, legislation, and any other policy actions be reviewed for any 
substantial direct effect on States, on the relationship between the 
Federal government and the States, or in the distribution of power and 
responsibilities among various levels of government. If there are 
substantial effects, then the Executive Order requires a preparation of 
a Federalism assessment to be used in all decisions involved in 
promulgating and implementing policy action.
    The rule, as proposed in this notice, will not have a substantial 
direct effect on the institutional interests or traditional functions 
of the States. Accordingly, no assessment or analysis is required under 
Executive Order 12612.

F. Review under Executive Order 12866

    Section 1 of Executive Order 12866 (``Regulatory Planning and 
Review''), 58 FR 51735, establishes a philosophy and principles for 
Federal agencies to follow in promulgating regulations. Section 1(b)(9) 
of that Order provides: ``Wherever feasible, agencies shall seek views 
of appropriate State, local, and tribal officials before imposing 
regulatory requirements that might significantly or uniquely affect 
those governmental entities. Each agency shall assess the effects of 
Federal regulations on State, local, and tribal governments, including 
specifically the availability of resources to carry out those mandates, 
and seek to minimize those burdens that uniquely or significantly 
affect such governmental entities, consistent with achieving regulatory 
objectives. In addition, agencies shall seek to harmonize Federal 
regulatory actions with regulated State, local and tribal regulatory 
and other governmental functions.''
    Section 6 of Executive Order 12866 provides for a review by the 
Office of Information and Regulatory Affairs (OIRA) of a ``significant 
regulatory action,'' which is defined to include an action that may 
have an effect on the economy of $100 million or more, or adversely 
affect, in a material way, the economy, competition, jobs, 
productivity, the environment, public health or safety, or State, 
local, or tribal governments. The Department has concluded that this 
proposed rule is a significant regulatory action that requires a review 
by the OIRA. DOE submitted this rule for OIRA clearance, and OIRA has 
completed its review.

G. Review under Executive Order 12875

    Executive Order 12875 (``Enhancing Intergovernmental 
Partnership''), provides for reduction or mitigation, to the extent 
allowed by law, of the burden on State, local and tribal governments of 
unfunded Federal mandates not required by statute. The analysis under 
the Unfunded Mandates Reform Act of 1995, above, satisfies the 
requirements of Executive Order 12875. Accordingly, no further analysis 
is required under Executive Order 12875.

H. Review under Executive Order 12988

    With respect to the review of existing regulations and the 
promulgation of new regulations, section 3(a) of Executive Order 12988, 
``Civil Justice Reform,'' 61 FR 4729 (February 7, 1996), imposes on 
Executive agencies the general duty to adhere to the following 
requirements: (1) Eliminate drafting errors and ambiguity; (2) write 
regulations to minimize litigation; and (3) provide a clear legal 
standard for affected conduct rather than a general standard and 
promote simplification and burden reduction. With regard to the review 
required by section 3(a), section 3(b) of Executive Order 12988 
specifically requires that Executive agencies make every reasonable 
effort to ensure that the regulation: (1) Clearly specifies the 
preemptive effect, if any; (2) clearly specifies any effect on existing 
Federal law or regulation; (3) provides a clear legal standard for 
affected conduct while promoting

[[Page 67085]]

simplification and burden reduction; (4) specifies the retroactive 
effect, if any; (5) adequately defines key terms; and (6) addresses 
other important issues affecting clarity and general draftsmanship 
under any guidelines issued by the Attorney General. Section 3(c) of 
Executive Order 12988 requires Executive agencies to review regulations 
in light of applicable standards in section 3(a) and section 3(b) to 
determine whether they are met or it is unreasonable to meet one or 
more of them. The DOE has completed the required review and determined 
that, to the extent permitted by law, the rule, as proposed, meets the 
relevant standards of Executive Order 12988.

I. Review under Executive Order 13084

    Under Executive Order 13084, ``Consultation and Coordination with 
Indian Tribal Governments,'' DOE may not issue a discretionary rule 
that significantly or uniquely affects Indian tribal governments and 
imposes substantial direct compliance costs. This proposed rulemaking 
would not have such effects. Accordingly, Executive Order 13084 does 
not apply to this rulemaking.

J. Review Under the Treasury and General Government Appropriations Act, 
1999

    Section 654 of the Treasury and General Government Appropriations 
Act, 1999 (Public Law 105-277) requires Federal agencies to issue a 
Family Policymaking Assessment for any proposed rule or policy that may 
affect family well-being. Today's proposal would not have any impact on 
the autonomy or integrity of the family as an institution. Accordingly, 
DOE has concluded that it is not necessary to prepare a Family 
Policymaking Assessment.

List of Subjects in 10 CFR Parts 960 and 963

    Environmental protection, Geologic repositories, Nuclear energy, 
Nuclear materials, Radiation protection, Waste disposal.

    Issued in Washington, D.C. on November 19, 1999.
Lake H. Barrett,
Acting Director, Office of Civilian Radioactive Waste Management.
    For the reasons stated in the preamble, DOE hereby proposes to 
amend part 960, and to add a new part 963 to, Chapter II of Title 10 of 
the Code of Federal Regulations as follows:

PART 960--GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF 
POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY

    1. The authority for 10 CFR part 960 is revised to read as follows:

    Authority: 42 U.S.C. 2011, et seq., 42 U.S.C. 7101, et seq., 42 
U.S.C. 10101. et seq.

    2. The part heading for Part 960 is revised to read as set forth 
above:


Sec. 960.1  [Amended]

    3. Section 960.1 is amended by removing the phrase ``for the 
development of repositories'' from the first sentence and removing the 
phrase ``and any preliminary suitability determinations required by 
Section 114(f)'' from the second sentence.
    4. Section 960.2 is amended by revising the definitions of ``Act,'' 
``Application'' and ``Determination'' to read as follows:


Sec. 960.2  Definitions.

* * * * *
    Act means the Nuclear Waste Policy Act of 1982, as amended.
* * * * *
    Application means the act of making a finding of compliance or 
noncompliance with the qualifying or disqualifying conditions specified 
in the guidelines of subparts C and D of this part.
* * * * *
    Determination means a decision by the Secretary that a site is 
suitable for site characterization for the selection of a repository, 
consistent with applications of the guidelines of subparts C and D of 
this part in accordance with the provisions set forth in subpart B of 
this part.
* * * * *


Sec. 960.3  [Amended]

    5. Section 960.3 is amended by removing the phrase ``for the 
development of repositories'' from the first sentence.


Sec. 960.3-1-4-4  [Removed]

    6. Section 960.3-1-4-4 is removed.
    7. Section 960.3-1-5 is revised to read as follows:


Sec. 960.3-1-5  Basis for site evaluations.

    (a) Evaluations of individual sites and comparisons between and 
among sites shall be based on the postclosure and preclosure guidelines 
specified in subparts C and D of this part, respectively. Except for 
screening for potentially acceptable sites as specified in Sec. 960.3-
2-1, such evaluations shall place primary significance on the 
postclosure guidelines and secondary significance on the preclosure 
guidelines, with each set of guidelines considered collectively for 
such purposes. Both the postclosure and the preclosure guidelines 
consist of a system guideline or guidelines and corresponding groups of 
technical guidelines.
    (b) The postclosure guidelines of subpart C of this part contain 
eight technical guidelines in one group. The preclosure guidelines of 
subpart D of this part contain eleven technical guidelines separated 
into three groups that represent, in decreasing order of importance, 
preclosure radiological safety; environment, socioeconomics, and 
transportation; and ease and cost of siting, construction, operation, 
and closure.
    (c) The relative significance of any technical guideline to its 
corresponding system guideline is site specific. Therefore, for each 
technical guideline, an evaluation of compliance with the qualifying 
condition shall be made in the context of the collection of system 
elements and the evidence related to that guideline, considering on 
balance the favorable conditions and the potentially adverse conditions 
identified at a site. Similarly, for each system guideline, such 
evaluation shall be made in the context of the group of technical 
guidelines and the evidence related to that system guideline.
    (d) For purposes of recommending sites for development as 
repositories, such evidence shall include analyses of expected 
repository performance to assess the likelihood of demonstrating 
compliance with 40 CFR part 191 and 10 CFR part 60, in accordance with 
Sec. 960.4-1. A site shall be disqualified at any time during the 
siting process if the evidence supports a finding by the DOE that a 
disqualifying condition exists or the qualifying condition of any 
system or technical guideline cannot be met.
    (e) Comparisons between and among sites shall be based on the 
system guidelines, to the extent practicable and in accordance with the 
levels of relative significance specified above for the postclosure and 
the preclosure guidelines. Such comparisons are intended to allow 
comparative evaluations of sites in terms of the capabilities of the 
natural barriers for waste isolation and to identify innate 
deficiencies that could jeopardize compliance with such requirements. 
If the evidence for the sites is not adequate to substantiate such 
comparisons, then the comparisons shall be based on the groups of 
technical guidelines under the postclosure and the preclosure 
guidelines, considering the levels of relative significance appropriate 
to the

[[Page 67086]]

postclosure and the preclosure guidelines and the order of importance 
appropriate to the subordinate groups within the preclosure guidelines. 
Comparative site evaluations shall place primary importance on the 
natural barriers of the site. In such evaluations for the postclosure 
guidelines of subpart C of this part, engineered barriers shall be 
considered only to the extent necessary to obtain realistic source 
terms for comparative site evaluations based on the sensitivity of the 
natural barriers to such realistic engineered barriers. For a better 
understanding of the potential effects of engineered barriers on the 
overall performance of the repository system, these comparative 
evaluations shall consider a range of levels in the performance of the 
engineered barriers. That range of performance levels shall vary by at 
least a factor of 10 above and below the engineered-barrier performance 
requirements set forth in 10 CFR 60.113, and the range considered shall 
be identical for all sites compared. The comparisons shall assume 
equivalent engineered barrier performance for all sites compared and 
shall be structured so that engineered barriers are not relied upon to 
compensate for deficiencies in the geologic media. Furthermore, 
engineered barriers shall not be used to compensate for an inadequate 
site; mask the innate deficiencies of a site; disguise the strengths 
and weaknesses of a site and the overall system; and mask differences 
between sites when they are compared. Releases of different 
radionuclides shall be combined by the methods specified in appendix A 
of 40 CFR part 191.
    (f) The comparisons specified above shall consist of two 
comparative evaluations that predict radionuclide releases for 100,000 
years after repository closure and shall be conducted as follows. 
First, the sites shall be compared by means of evaluations that 
emphasize the performance of the natural barriers at the site. Second, 
the sites shall be compared by means of evaluations that emphasize the 
performance of the total repository system. These second evaluations 
shall consider the expected performance of the repository system; be 
based on the expected performance of waste packages and waste forms, in 
compliance with the requirements of 10 CFR 60.113, and on the expected 
hydrological and geochemical conditions at each site; and take credit 
for the expected performance of all other engineered components of the 
repository system. The comparison of isolation capability shall be one 
of the significant considerations in the recommendation of sites for 
the development of repositories. The first of the two comparative 
evaluations specified in the preceding paragraph shall take precedence 
unless the second comparative evaluation would lead to substantially 
different recommendations. In the latter case, the two comparative 
evaluations shall receive comparable consideration. Sites with 
predicted isolation capabilities that differ by less than a factor of 
10, with similar uncertainties, may be assumed to provide equivalent 
isolation.
    8. In section 960.3-2, the last sentence is revised to read as 
follows:


Sec. 960.3-2  Siting process.

    * * * The recommendation of sites as candidate sites for 
characterization shall be accomplished in accordance with the 
requirements specified in Sec. 960.3-2-3.


Sec. 960.3-2-4  [Removed]

    9. Section 960.3-2-4 is removed.

Appendix III to Part 960 [Amended]

    10. Appendix III to Part 960 is amended as follows:
    In paragraph 1, introductory text, first sentence, revise the 
phrase ``the ``principal to read acertain''
    In paragraph 1, remove the definition (decision point) for 
``Repository Site Selection.''
    In paragraph 2, remove the definition for the numeral ``4'' and 
paragraphs ``(a)'' and ``(b)'' which follow.
    In the table, Findings Resulting From the Application of the 
Qualifying and Disqualifying Conditions of the Technical Guidelines at 
Major Siting Decisions, remove the column heading and corresponding 
entries for ``Repository Site Selection'' under the heading ``Siting 
Decision.''
    4. New part 963 is added to read as follows:

PART 963--YUCCA MOUNTAIN SITE SUITABILITY GUIDELINES

Subpart A--General Provisions

963.1  Purpose.
963.2  Definitions.

Subpart B--Site Suitability Determination, Methods and Criteria

963.10  Scope.
963.11  Suitability determination.
963.12  Preclosure suitability determination.
963.13  Preclosure suitability evaluation method.
963.14  Preclosure suitability criteria.
963.15  Postclosure suitability determination.
963.16  Postclosure suitability evaluation method.
963.17  Postclosure suitability criteria.

    Authority: 42 U.S.C. 2011 et seq.; 42 U.S.C. 7101 et seq.; 42 
U.S.C. 10101, et seq.

Subpart A--General Provisions


Sec. 963.1  Purpose.

    (a) The purpose of this part is to establish DOE methods and 
criteria for determining the suitability of the Yucca Mountain site for 
the location of a geologic repository. DOE will use these methods and 
criteria in analyzing the data from the site characterization 
activities required under section 113 of the Nuclear Waste Policy Act.
    (b) This part does not address other information that must be 
considered and submitted to the President, and made available to the 
public, by the Secretary under section 114 of the Nuclear Waste Policy 
Act if the Yucca Mountain site is recommended for development as a 
geologic repository.


Sec. 963.2  Definitions.

    For purposes of this Part:
    Barrier means any material, structure or process that prevents or 
substantially delays the movement of water or radionuclides.
    Cladding means the corrosion-resistant material, typically a 
zirconium alloy, that binds and contains the nuclear fuel material in 
individual fuel pellets.
    Closure means the final closing of the remaining open operational 
areas of the underground facility and boreholes after termination of 
waste emplacement, culminating in the sealing of shafts and ramps, 
except those openings that may be designed for ventilation or 
monitoring.
    Colloid means any fine-grained material in suspension, or any such 
material that can be easily suspended.
    Criteria means the characterizing traits relevant to assessing the 
performance of a geologic repository, as defined by this section, at 
the Yucca Mountain site.
    Design means a description of the engineered structures, systems, 
components and equipment of a geologic repository at Yucca Mountain 
that includes the engineered barrier system.
    Design basis event means:
    (1) Those natural and human-induced events that are expected to 
occur one or more times before permanent closure; or
    (2) Other natural and human-induced events that have at least one 
chance in 10,000 of occurring before permanent closure.
    DOE means the U.S. Department of Energy, or its duly authorized 
representatives.
    Engineered barrier system means the waste packages and the 
underground facilities.
    Expected means assumed to be probable on the basis of existing

[[Page 67087]]

evidence and in the absence of significant evidence to the contrary.
    Geologic repository means a system that is intended to be used for, 
or may be used for, the disposal of radioactive wastes in excavated 
geologic media including the engineered barrier system and the portion 
of the geologic setting that provides isolation of the radioactive 
waste.
    Geologic setting means geologic, hydrologic, and geochemical system 
of the region in which a geologic repository operations area at Yucca 
Mountain is or may be located.
    Infiltration means the flow of a fluid into a solid substance 
through pores or small openings; specifically, the movement of water 
into soil and fractured or porous rock.
    Near-field means the region where the adjacent natural 
geohydrologic system has been significantly impacted by the excavation 
of the repository and the emplacement of the waste.
    NRC means the U.S. Nuclear Regulatory Commission or its duly 
authorized representatives.
    Perched water means ground water of limited lateral extent 
separated from an underlying body of ground water by an unsaturated 
zone.
    Preclosure or preclosure period means the period of time before and 
during closure of the geologic repository.
    Preclosure safety evaluation means a preliminary assessment of the 
adequacy of repository support facilities to prevent or mitigate the 
effects of postulated design basis events (including fire, radiation, 
criticality, and chemical hazards), and the site, structures, systems, 
components, equipment, and operator actions that would be relied on for 
safety.
    Postclosure means the period of time after the closure of the 
geologic repository.
    Radioactive waste means high-level radioactive waste and other 
radioactive materials, including spent nuclear fuel, that are received 
for emplacement in the geologic repository.
    Reference biosphere means the description of the environment, 
inhabited by the receptor, comprising the set of specific biotic and 
abiotic characteristics of the environment, including, but not limited 
to, climate, topography, soils, flora, fauna, and human activities.
    Repository support facilities means all permanent facilities 
constructed in support of site characterization activities and 
repository construction, operation, and closure activities, including 
surface structures, utility lines, roads, railroads, and similar 
facilities, but excluding the underground facility.
    Seepage means the inflow of ground water moving in fractures or 
pore spaces of permeable rock to an open space in the rock such as an 
excavated drift.
    Sensitivity study means an analytic or numerical technique for 
examining the effects on outcomes, such as radionuclide releases, of 
varying specified parameters, such as the infiltration rate due to 
precipitation, when a model run is performed.
    Site characterization means activities, whether in the laboratory 
or in the field, undertaken to establish the geologic conditions and 
the ranges of the parameters of a candidate site relevant to the 
location of a repository, including borings, surface excavations, 
excavations of exploratory shafts, limited subsurface lateral 
excavations and borings, and in situ testing needed to evaluate the 
suitability of a candidate site for the location of a repository, but 
not including preliminary borings and geophysical testing needed to 
assess whether site characterization should be undertaken.
    Surface facilities means repository support facilities within the 
restricted area located on or above the ground surface.
    System performance means the complete behavior of a geologic 
repository system at Yucca Mountain in response to the conditions, 
processes, and events that may affect it.
    Total system performance assessment means a probabilistic analysis 
that is used to:
    (1) Identify the features, events and processes that might affect 
the performance of the geologic repository;
    (2) Examine the effects of such features, events, and processes on 
the performance of the geologic repository; and
    (3) Estimate the expected annual dose to the receptor as a result 
of releases from the geologic repository.
    Underground facility means the underground structure, backfill 
materials, if any, and openings that penetrate the underground 
structure (e.g., ramps, shafts and boreholes, including their seals)
    Waste is synonymous with ``radioactive waste.''
    Waste form means the radioactive waste materials and any 
encapsulating or stabilizing matrix.
    Waste package means the waste form and any containers, shielding, 
packing, and other absorbent materials immediately surrounding an 
individual waste container.
    Yucca Mountain site means the candidate site in the State of Nevada 
recommended by the Secretary to the President under section 
112(b)(1)(B) of the Nuclear Waste Policy Act of 1982 (NWPA) [42 U.S.C. 
1032(b)(1)(B)] on May 27, 1986.

Subpart B--Site Suitability Determination, Methods, and Criteria


Sec. 963.10  Scope.

    (a) The scope of this subpart includes the following for both the 
preclosure and postclosure periods:
    (1) The bases for the suitability determination for the Yucca 
Mountain site as a location for a geologic repository;
    (2) The suitability evaluation methods for applying the site 
suitability criteria to a geologic repository at the Yucca Mountain 
site; and
    (3) The site suitability criteria that DOE will apply in accordance 
with section 113(b)(1)(A)(iv) of the NWPA.
    (b) DOE will seek NRC concurrence on any future revisions to this 
subpart.


Sec. 963.11  Suitability determination.

    DOE will evaluate whether the Yucca Mountain site is suitable for 
the location of a geologic repository on the basis of the preclosure 
and postclosure determinations described in Secs. 963.12 and 963.15. If 
DOE's evaluation of the Yucca Mountain site for the location of a 
geologic repository under Secs. 963.12 and 963.15 shows that the 
geologic repository is likely to meet the applicable radiation 
protection standards for the preclosure and postclosure periods, then 
DOE may determine that the site is a suitable location for the 
development of such a repository.


Sec. 963.12  Preclosure suitability determination.

    DOE will apply the method and criteria described in Secs. 963.13 
and 963.14 to evaluate the suitability of the Yucca Mountain site for 
the preclosure period. If DOE finds that the results of the preclosure 
safety evaluation conducted under Sec. 963.13 show that the Yucca 
Mountain site is likely to meet the applicable radiation protection 
standard, DOE may determine the site suitable for the preclosure 
period.


Sec. 963.13  Preclosure suitability evaluation method.

    (a) DOE will evaluate preclosure suitability using a preclosure 
safety evaluation method. DOE will evaluate the performance of the 
geologic repository at the Yucca Mountain site using the method 
described in paragraph (b) of this section and the criteria in 
Sec. 963.14. DOE will consider the performance of the system in terms

[[Page 67088]]

of the criteria to evaluate whether the geologic repository is likely 
to comply with the applicable radiation protection standard.
    (b) The preclosure safety evaluation method, using preliminary 
engineering specifications, will assess the adequacy of the repository 
facilities to perform their intended functions and prevent or mitigate 
the effects of postulated design basis events that are deemed 
sufficiently credible to warrant consideration. The preclosure safety 
evaluation will consider:
    (1) A preliminary description of the site characteristics, the 
surface facilities and the underground operating facilities;
    (2) A preliminary description of the design bases for the operating 
facilities and a preliminary description of any associated limits on 
operation;
    (3) A preliminary description of potential hazards, event 
sequences, and their consequences; and
    (4) A preliminary description of the structures, systems, 
components, equipment, and operator actions intended to mitigate or 
prevent accidents.


Sec. 963.14  Preclosure suitability criteria.

    DOE will evaluate preclosure suitability using the following 
criteria:
    (a) Ability to contain radioactive material and to limit releases 
of radioactive materials;
    (b) Ability to implement control and emergency systems to limit 
exposure to radiation;
    (c) Ability to maintain a system and components that perform their 
intended safety functions; and
    (d) Ability to preserve the option to retrieve wastes during the 
preclosure period.


Sec. 963.15  Postclosure suitability determination.

    DOE will apply the method and criteria described in Secs. 963.16 
and 963.17 to evaluate the suitability of the Yucca Mountain site for 
the postclosure period. If DOE finds that the results of the total 
system performance assessments conducted under Sec. 963.16 show that 
the Yucca Mountain site is likely to meet the applicable radiation 
protection standard, DOE may determine the site suitable for the 
postclosure period.


Sec. 963.16  Postclosure suitability evaluation method.

    (a) DOE will evaluate postclosure suitability using the total 
system performance assessment method. DOE will conduct a total system 
performance assessment to evaluate the ability of the geologic 
repository to meet the applicable radiation protection standard under 
the following circumstances:
    (1) DOE will conduct a total system performance assessment to 
evaluate the ability of the geologic repository to limit radiological 
exposures in the case where there is no human intrusion into the 
repository. DOE will model the performance of the geologic repository 
at the Yucca Mountain site using the method described in paragraph (b) 
of this section and the criteria in Sec. 963.17, excluding the 
criterion in paragraph (b)(4) of Sec. 963.17. DOE will consider the 
performance of the system in terms of the criteria to evaluate whether 
the geologic repository is likely to comply with the applicable 
radiation protection standard.
    (2) Consistent with applicable NRC regulations regarding a stylized 
human intrusion case, DOE will conduct a total system performance 
assessment to evaluate the ability of the geologic repository to limit 
radiological exposures in a stylized limited human intrusion case. DOE 
will model the performance of the geologic repository at the Yucca 
Mountain site using the method described in paragraph (b) of this 
section and the criteria in Sec. 963.17. DOE will consider the 
performance of the system in terms of the criteria to evaluate whether 
the geologic repository is likely to comply with the applicable 
radiation protection standard. The human intrusion evaluation under 
this paragraph will be separate from the evaluation conducted under 
paragraph (a)(1) of this section.
    (b) In conducting a total system performance assessment under this 
section, DOE will:
    (1) Include data related to the suitability criteria in 
Sec. 963.17;
    (2) Account for uncertainties and variabilities in parameter values 
and provide the technical basis for parameter ranges, probability 
distributions, and bounding values;
    (3) Consider alternative models of features and processes that are 
consistent with available data and current scientific understanding, 
and evaluate the effects that alternative models would have on the 
estimated performance of the geologic repository;
    (4) Consider only events that have at least one chance in 10,000 of 
occurring over 10,000 years;
    (5) Provide the technical basis for either inclusion or exclusion 
of specific features, events, and processes of the geologic setting, 
including appropriate details as to magnitude and timing regarding any 
exclusions that would significantly change the expected annual dose;
    (6) Provide the technical basis for either inclusion or exclusion 
of degradation, deterioration, or alteration processes of engineered 
barriers, including those processes that would adversely affect natural 
barriers, (such as degradation of concrete liners affecting the pH of 
ground water or precipitation of minerals due to heat changing 
hydrologic processes), including appropriate details as to magnitude 
and timing regarding any exclusions that would significantly change the 
expected annual dose;
    (7) Provide the technical basis for models used in the total 
systems performance assessment such as comparisons made with outputs of 
detailed process-level models and/or empirical observations (for 
example, laboratory testing, field investigations, and natural 
analogs);
    (8) Identify natural features of the geologic setting and design 
features of the engineered barrier system important to isolating 
radioactive waste;
    (9) Describe the capability of the natural and engineered barriers 
important to isolating radioactive waste, taking into account 
uncertainties in characterizing and modeling such barriers;
    (10) Provide the technical basis for the description of the 
capability of the natural and engineered barriers important to 
isolating radioactive waste;
    (11) Use the reference biosphere and group receptor assumptions 
specified in applicable NRC regulations; and
    (12) Conduct appropriate sensitivity studies.


Sec. 963.17  Postclosure suitability criteria.

    (a) DOE will evaluate the postclosure suitability of a geologic 
repository at the Yucca Mountian site through suitability criteria that 
reflect both the processes and the models used to simulate those 
processes, that are important to the total system performance of the 
geologic repository. The applicable criteria are:
    (1) Site characteristics, which include:
    (i) Geologic properties of the site--for example, stratigraphy, 
rock type and physical properties, and structural characteristics;
    (ii) Hydrologic properties of the site--for example, porosity, 
permeability, moisture content, saturation, and potentiometric 
characteristics;
    (iii) Geophysical properties of the site--for example, densities, 
velocities and water contents, as measured or deduced from geophysical 
logs; and
    (iv) Geochemical properties of the site--for example, 
precipitation, dissolution characteristics, and sorption properties of 
mineral and rock surfaces.

[[Page 67089]]

    (2) Unsaturated zone flow characteristics, which include:
    (i) Climate--for example, precipitation and postulated future 
climatic conditions;
    (ii) Infiltration--for example, precipitation entering the mountain 
in excess of water returned to the atmosphere by evaporation and plant 
transpiration;
    (iii) Unsaturated zone flux--for example, water movement through 
the pore spaces, or flowing along fractures or through perched water 
zones above the repository;
    (iv) Seepage--for example, water dripping into the underground 
repository openings from the surrounding rock;
    (3) Near field environment characteristics, which include:
    (i) Thermal hydrology--for example, effects of heat from the waste 
on water flow through the site, and the temperature and humidity at the 
engineered barriers.
    (ii) Near field geochemical environment--for example, the chemical 
reactions and products resulting from water contacting the waste and 
the engineered barrier materials;
    (4) Engineered barrier system degradation characteristics, which 
include:
    (i) Engineered barrier system component performance--for example, 
drip shields, backfill, coatings, or chemical modifications, and
    (ii) Waste package degradation--for example, the corrosion of the 
waste package materials within the near-field environment;
    (5) Waste from degradation characteristics, which include:
    (i) Cladding degradation--for example, corrosion or break-down of 
the cladding on the individual spent fuel pellets;
    (ii) Waste from dissolution--for example, the ability of individual 
radionuclides to dissolve in water penetrating breached waste packages;
    (6) Engineered barrier system degradation, flow, and transport 
characteristics, which include:
    (i) Colloid formation and stability--for example, the formation of 
colloidal particles and the ability of radionuclides to adhere to these 
particles as they may be washed through the remaining barriers; and
    (ii) Engineered barrier transport--for example, the movement of 
radionuclides dissolved in water or adhering to colloidal particles to 
be transported through the remaining engineered barriers and in the 
underlying unsaturated zone;
    (7) Unsaturated zone flow and transport characteristics, which 
include:
    (i) Unsaturated zone transport--for example, the movement of water 
with dissolved radionuclides or colloidal particles through the 
unsaturated zone underlying the repository, including retardation 
mechanisms such as sorption on rock or mineral surfaces;
    (ii) Thermal hydrology--for example, effects of heat from the waste 
on water flow through the site;
    (8) Saturated zone flow and transport characteristics, which 
include:
    (i) Saturated zone transport--for example, the movement of water 
with dissolved radionuclides or colloidal particles through the 
saturated zone underlying and beyond the repository, including 
retardation mechanisms such as sorption on rock or mineral surfaces; 
and
    (ii) Dilution--for example, diffusion of radionuclides into pore 
spaces, dispersion of radionuclides along flow paths, and mixing with 
non-contaminated ground water;
    (9) Biosphere characteristics, which include:
    (i) Reference biosphere and receptor--for example, biosphere water 
pathways, location and behavior of receptor; and
    (ii) Biosphere transport and uptake--for example, the consumption 
of ground or surface waters through direct extraction or agriculture, 
including mixing with non-contaminated waters and exposure to 
contaminated agricultural products.
    (b) DOE will evaluate the postclosure suitability of a geologic 
repository at the Yucca Mountain site using criteria that consider 
disruptive processes and events important to the total system 
performance of the geologic repository. The applicable criteria related 
to disruptive processes and events include:
    (1) Volcanism--for example, the probability and potential 
consequences of a volcanic eruption intersecting the repository;
    (2) Seismic events--for example, the probability and potential 
consequences of an earthquake on the underground facilities or 
hydrologic system;
    (3) Nuclear criticality--for example, the probability and potential 
consequences of a self-sustaining nuclear reaction as a result of 
chemical or physical processes affecting the waste either in or after 
release from breached waste packages;
    (4) Inadvertent human intrusion--for example, consequences to 
repository system performance following a stylized human intrusion 
scenario.

[FR Doc. 99-30668 Filed 11-29-99; 8:45 am]
BILLING CODE 6450-01-P