  Notice: This opinion is subject to formal revision before publication in the
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       United States Court of Appeals
                  FOR THE DISTRICT OF COLUMBIA CIRCUIT




Argued January 14, 2004                           Decided July 9, 2004

                               No. 01-1258

                  NUCLEAR ENERGY INSTITUTE, INC.,
                           PETITIONER

                                     v.

                ENVIRONMENTAL PROTECTION AGENCY,
                          RESPONDENT



                        Consolidated with
           01-1268, 01-1295, 01-1425, 01-1426, 01-1516,
           02-1036, 02-1077, 02-1116, 02-1179, 02-1196,
                         03-1009, 03-1058



             On Petitions for Review of Orders of the
               Environmental Protection Agency,
                   the Department of Energy,
             and the Nuclear Regulatory Commission
                             –————

 Bills of costs must be filed within 14 days after entry of judgment.
The court looks with disfavor upon motions to file bills of costs out
of time.
                              2

  Antonio Rossmann, Geoffrey Fettus, Martin G. Malsch,
and Charles J. Cooper argued the causes for petitioners State
of Nevada and Natural Resources Defense Council, et al.
With them on the briefs were Joseph R. Egan, Charles J.
Fitzpatrick, Howard K. Shapar, Brian Sandoval, Attorney
General, Attorney General’s Office of the State of Nevada,
Marta A. Adams, Senior Deputy Attorney General, Robert J.
Cynkar, Brian S. Koukoutchos, Vincent J. Colatriano, and
William H. Briggs Jr.
 John C. Martin argued the cause for petitioner Nuclear
Energy Institute, Inc. With him on the briefs were Jean V.
MacHarg, Susan M. Mathiascheck, Robert W. Bishop, and
Michael A. Bauser.
  Christopher S. Vaden, Michele L. Walter, and Ronald M.
Spritzer, Attorneys, U.S. Department of Justice, and Steven
F. Crockett, Special Counsel, U.S. Nuclear Regulatory Com-
mission, argued the causes for respondents. With them on
the briefs were Jeffrey B. Clark, Deputy Assistant Attorney
General, U.S. Department of Justice, G. Scott Williams, John
A. Bryson, and Greer S. Goldman, Attorneys, Karen D. Cyr,
General Counsel, U.S. Nuclear Regulatory Commission, John
F. Cordes Jr., Solicitor, E. Leo Slaggie, Deputy Solicitor, and
Marc Johnson, Deputy General Counsel, U.S. Department of
Energy. John C. Cruden, Assistant Attorney General, U.S.
Department of Justice, and Elizabeth A. Peterson, Attorney,
entered an appearance.
   Michael A. Bauser argued the cause for intervenor Nuclear
Energy Institute, Inc. With him on the briefs of interve-
nor/amicus Nuclear Energy Institute, Inc. and amicus Na-
tional Association of Regulatory Utility Commissioners were
Robert W. Bishop, James Bradford Ramsay, and Sharla M.
Barklind.
  Before: EDWARDS, HENDERSON, and TATEL, Circuit Judges.
  Opinion for the Court filed PER CURIAM.*
  * Judge Tatel wrote Parts I and II. Judge Edwards wrote Part
IV.
                            3

                 TABLE OF CONTENTS

 I. Background

II. The EPA Cases
    A. The EPA Rule: 40 C.F.R. part 197
    B. Challenges Brought by Nevada and Environmental
          Petitioners
        1. Jurisdiction
        2. The 10,000-Year Compliance Period
        3. The Controlled Area
        4. The Definition of ‘‘Disposal’’
    C. NEI’s Challenge to the Ground-Water Standard
        1. Standing
        2. Alleged Conflicts with the Energy Policy Act
        3. Arbitrary and Capricious Challenge

III. The NRC Cases
     A. Jurisdiction and Timeliness
     B. Nevada’s Merits Claims
         1. Primary Barrier and Multiple Barriers Claims
            a. The Primary Barrier Claim
            b. The Multiple Barriers Claims
         2. Compliance with EPA’s Part 197 in Construc-
              tion Authorization
         3. 10,000-Year Compliance Period
         4. Reviewability of DOE’s Peak Dose Calculations
         5. NRC’s ‘‘Reasonable Expectation’’ Standard

IV. The Site-Designation Cases
    A. The Constitutional Case
        1. Issue Preclusion
        2. Merits of the Constitutional Challenge
                                4

     B. The DOE Case
        1. DOE Criteria, Secretary’s Alleged Failure To
             Take Mandatory Actions, and Site Recommen-
             dations
        2. The Final Environmental Impact Statement

 V. Conclusion


   PER CURIAM: Having the capacity to outlast human civiliza-
tion as we know it and the potential to devastate public health
and the environment, nuclear waste has vexed scientists,
Congress, and regulatory agencies for the last half-century.
After rejecting disposal options ranging from burying nuclear
waste in polar ice caps to rocketing it to the sun, the scientific
consensus has settled on deep geologic burial as the safest
way to isolate this toxic material in perpetuity. Following
years of legislative wrangling and agency deliberation, the
political consensus has now selected Yucca Mountain, Nevada
as the nation’s nuclear waste disposal site.
   In this case, we consider challenges by the State of Nevada,
local communities, several environmental organizations, and
the nuclear energy industry to the statutory and regulatory
scheme devised to establish and govern a Yucca Mountain
nuclear waste repository. Petitioners challenge regulations
issued by the three agencies with responsibility for the site:
the Environmental Protection Agency (EPA), the Nuclear
Regulatory Commission (NRC or Commission), and the De-
partment of Energy (DOE). Petitioners also challenge the
constitutionality of the joint resolution through which Con-
gress selected Yucca Mountain as the repository site, as well
as certain actions of the President and Energy Secretary
leading to approval of the Yucca site.
  We conclude: (1) The 10,000-year compliance period select-
ed by EPA violates section 801 of the Energy Policy Act
(EnPA) because it is not, as EnPA requires, ‘‘based upon and
                              5

consistent with’’ the findings and recommendations of the
National Academy of Sciences. The remaining challenges to
the EPA regulation are without merit. (2) The Nuclear
Regulatory Commission’s licensing requirements are neither
unlawful nor arbitrary and capricious except to the extent
that they incorporate EPA’s 10,000-year compliance period.
(3) The congressional resolution selecting the Yucca site for
development represents an appropriate exercise of Congress’s
Article IV, section 3 authority over federal property. (4) The
Department of Energy’s and the President’s actions leading
to the selection of the Yucca Mountain site are unreviewable.
All but one of Nevada’s challenges to these actions are moot,
and the remaining challenge is unripe. Accordingly, we
vacate the EPA and NRC regulations insofar as they include
a 10,000-year compliance period. We deny or dismiss the
remaining petitions for review.

                      I.   BACKGROUND
  Since the dawn of the atomic age, the United States has
used nuclear fission to generate electricity. Today, approxi-
mately twenty percent of the nation’s electricity comes from
nuclear power. See Recommendation by the Secretary of
Energy Regarding the Suitability of the Yucca Mountain Site
for a Repository Under the Nuclear Waste Policy Act of 1982
at 1 (Feb. 2002), available at http://www.ocrwm.
doe.gov/ymp/sr/sar.pdf [hereinafter ‘‘Secretary’s Recommen-
dation’’]. Although nuclear power burns without emitting
harmful greenhouse gases, it produces a potentially deadly
and long-lasting byproduct: highly radioactive spent nuclear
fuel.
  At massive levels, radiation exposure can cause sudden
death. National Institutes of Health, Fact Sheet: What We
Know About Radiation, at http://www.nih.gov/health/
chip/od/radiation (last visited May 28, 2004). At lower doses,
radiation can have devastating health effects, including in-
creased cancer risks and serious birth defects such as mental
                              6

retardation, eye malformations, and small brain or head size.
See Environmental Radiation Protection Standards for Yucca
Mountain, Nevada, 64 Fed. Reg. 46,976, 46,978 (Aug. 27,
1999).
  Radioactive waste and its harmful consequences persist for
time spans seemingly beyond human comprehension. For
example, iodine-129, one of the radionuclides expected to be
buried at Yucca Mountain, has a half-life of seventeen million
years. See COMM. ON TECHNICAL BASES FOR YUCCA MOUNTAIN
STANDARDS, NAT’L RESEARCH COUNCIL, TECHNICAL BASES FOR
YUCCA MOUNTAIN STANDARDS 18-19 (1995) [hereinafter ‘‘NAS
REPORT’’]. Neptunium-237, also expected to be deposited in
Yucca Mountain, has a half-life of over two million years. Id.
at 19.
   As of 2003, nuclear reactors in the United States had
generated approximately 49,000 metric tons of spent nuclear
fuel. See Office of Civilian Radioactive Waste Management,
Fact Sheet, Nuclear Waste Explained: How Much Nuclear
Waste is in the United States, at http://www.
ocrwm.doe.gov/ymp/about/howmuch/shtml (last visited June 1,
2004) [hereinafter ‘‘How Much Nuclear Waste Is in the
United States’’]. Most of this waste is currently stored at
reactor sites across the country. See United States Environ-
mental Protection Agency, Public Health and Environmental
Radiation Protection Standards for Yucca Mountain, Nevada,
Final Background Information Document for Final 40 CFR
197 at 5-2 (June 2001) [hereinafter ‘‘Final Background Infor-
mation Document’’]. With more than 100 interim storage
locations sprinkled across thirty-nine states, over 161 million
people reside within seventy-five miles of a nuclear waste
storage facility. See Office of Civilian Radioactive Waste
Management, Fact Sheet, Nuclear Storage Explained: Cur-
rent Storage Methods For Radioactive Waste, at
http://www.ocrwm.doe.gov/ymp/about/storage.shtml (last visit-
ed June 1, 2004). By the year 2035, the United States will
have produced 105,000 metric tons of nuclear waste – approxi-
                               7

mately twice the current inventory. See How Much Nuclear
Waste Is in the United States.
   In 1982, responding to growing quantities of radioactive
waste and their potentially deadly health risks, Congress
enacted the Nuclear Waste Policy Act (NWPA), directing the
federal government to assume responsibility for permanently
disposing of the nation’s nuclear waste. Pub. L. No. 97-425,
96 Stat. 2201 (1982) (codified as amended at 42 U.S.C.
§§ 10101-10270 (2000)). The NWPA put the United States
on course to using geologic repositories buried deep below the
earth’s surface to house its nuclear waste. To finance the
creation and operation of such repositories, the NWPA estab-
lished the Nuclear Waste Fund to ensure that ‘‘the costs of
carrying out activities relating to the disposal of [radioactive]
waste and spent fuel will be borne by the persons responsible
for generating such waste and spent fuel.’’ 42 U.S.C.
§ 10131(b)(4) (2000). Accordingly, the NWPA required nu-
clear energy producers to pay assessments into the Fund
based on the amount of electricity they generate. See id.
§ 10222(a), (c) (2000).
  The NWPA assigned distinct regulatory roles to the De-
partment of Energy, the Environmental Protection Agency,
and the Nuclear Regulatory Commission. Congress charged
DOE with selecting, designing, and ultimately operating the
repository. See id. §§ 10132-10134 (2000). It required EPA
to establish generally applicable standards for protecting the
environment from releases of radioactive materials, id.
§ 10141(a) (2000), and directed NRC to assume responsibility
for licensing a DOE-proposed repository, id. § 10141(b).
   The NWPA also established a multi-stage process for DOE
to select an appropriate host site. The Act required the
Secretary of Energy to begin by issuing general site-selection
guidelines, id. § 10132(a), that DOE would then use to deter-
mine which candidate sites to recommend for intensive inves-
tigation, known as ‘‘site characterization,’’ id. § 10132(b).
Based on these guidelines, the Secretary was directed to
nominate at least five sites, id. § 10132(b)(1)(A), and then to
                               8

narrow the field to three for the President’s consideration, id.
§ 10132(b)(1)(B).
   Once the President approved the nominated sites, the
Secretary was required to undertake site-characterization
activities at each location. NWPA § 113(a) (codified as
amended at 42 U.S.C. § 10133(a)). The NWPA also directed
DOE, as part of its site-characterization program, to issue
‘‘criteria’’ for determining whether the candidate sites were
‘‘suitab[le]’’ for housing a waste repository. 42 U.S.C.
§ 10133(b)(1)(A)(iv). After completing the intensive site-
characterization process, the Secretary was authorized to
submit to the President, together with a final environmental
impact statement, a recommendation that he approve one of
the suitable sites for development. NWPA § 114(a)(1) (codi-
fied as amended at 42 U.S.C. § 10134(a)(1)).
  Under the NWPA, once the President approved a site, he
would then transmit his recommendation to Congress. Id.
§ 114(a)(2) (codified as amended at 42 U.S.C. § 10134(a)(2)).
The state within which the recommended site was located
could then submit a ‘‘notice of disapproval’’ to Congress, an
action that would effectively end the development process
with respect to that site unless Congress passed a joint
resolution overriding the state’s disapproval and approving
the site. See 42 U.S.C. § 10136(b)(2) (2000).
   Pursuant to this statutory regime, DOE promulgated site-
selection guidelines in 1984 and applied them to nominate five
candidate sites for characterization. Based on these guide-
lines, the Energy Secretary then recommended three sites to
the President: Deaf Smith County, Texas; Hanford, Wash-
ington; and Yucca Mountain, Nevada. See Nevada v. Wat-
kins, 939 F.2d 710, 713 (9th Cir. 1991). The President then
approved each for characterization. Id.
  In 1985, EPA promulgated 40 C.F.R. part 191, general
health and safety standards to govern an eventual waste
repository. EPA later revised these standards in response to
a First Circuit decision remanding aspects of the regulation.
See Natural Res. Def. Council, Inc. v. United States EPA,
                               9

824 F.2d 1258 (1st Cir. 1987) (NRDC v. EPA). NRC then
issued generic licensing standards in 10 C.F.R. part 60.
   In 1987, however, because characterizing three separate
sites was becoming both costly and time-consuming, Congress
departed from the NWPA’s original site-selection scheme and
directed, through the Nuclear Waste Policy Amendments Act
(NWPAA), that the nation’s nuclear waste program focus
exclusively on Yucca Mountain, Nevada. See Pub. L. No.
100-203, §§ 5001-5065, 101 Stat. 1330, 1330-227 to 1330-255
(1987) (codified in scattered sections of 42 U.S.C.). Located
in the arid Nevada desert approximately 100 miles northwest
of Las Vegas, Yucca Mountain sits on the Nevada Test Site,
the nation’s former nuclear bomb testing range. Under the
NWPAA, Yucca became the only site that DOE could lawfully
characterize. See 42 U.S.C. § 10133(a) (requiring the Energy
Secretary to ‘‘carry out TTT appropriate site characterization
activities at the Yucca Mountain site’’); id. § 10172(a)(1)-(2)
(2000) (‘‘The Secretary shall provide for an orderly phase-out
of site specific activities at all candidate sites other than the
Yucca Mountain site TTT [and] shall terminate all site specific
activities (other than reclamation activities) at all candidate
sites, other than the Yucca Mountain siteTTTT’’).
   In 1992, Congress directed DOE’s sister agencies, EPA and
NRC, to focus their regulatory attention on Yucca Mountain
as well. Through the Energy Policy Act, Congress required
EPA to promulgate, based on the recommendations of the
National Academy of Sciences, site-specific standards for
Yucca Mountain, and ordered NRC to modify its generic
technical requirements and criteria to bring them into con-
formity with EPA’s Yucca-specific rule. Pub. L. No. 102-486,
§ 801, 106 Stat. 2776, 2921-23 (1992) (codified at 42 U.S.C.
§ 10141 note (2000)). At about the same time, Congress
exempted the Yucca Mountain site from EPA’s part 191
generally applicable environmental regulations. See Waste
Isolation Pilot Plant Land Withdrawal Act, Pub. L. No. 102-
579, § 8, 106 Stat. 4777, 4786-88 (1992). With the enactment
of the NWPA, the NWPAA, and EnPA, the stage was set for
                               10

the promulgation of the regulations and the adoption of the
joint resolution challenged in this case.
   Acting pursuant to EnPA, both EPA and NRC promulgat-
ed standards to govern the Yucca Mountain repository. EPA
issued 40 C.F.R. part 197, establishing health and safety
standards that require DOE to limit radiation releases from
the repository for 10,000 years. See Public Health and
Environmental Radiation Protection Standards for Yucca
Mountain, NV, 66 Fed. Reg. 32,074 (June 13, 2001) (codified
at 40 C.F.R. pt. 197 (2004)). Shortly thereafter, NRC issued
Yucca-specific licensing standards in 10 C.F.R. part 63. See
Disposal of High-Level Radioactive Wastes in a Proposed
Geologic Repository at Yucca Mountain, Nevada, 66 Fed.
Reg. 55,732 (Nov. 2, 2001) (codified at 10 C.F.R. pt. 63 (2004)).
   DOE also focused its attention on the Nevada site, issuing
new site-suitability criteria specific to Yucca Mountain. See
10 C.F.R. pt. 963 (2004). Pursuant to these criteria and a
final environmental impact statement, the Energy Secretary
found Yucca Mountain suitable for a repository, concluding
that a Yucca facility is ‘‘likely to meet applicable radiation
protection standards.’’ Secretary’s Recommendation at 26.
Based on that finding, the Energy Secretary recommended
Yucca Mountain to the President for development as the
nation’s underground nuclear waste repository. Id. at 6.
Pursuant to NWPA procedures, the President then recom-
mended Yucca to Congress. Objecting, Nevada submitted a
notice of disapproval, to which Congress responded by pass-
ing a joint resolution approving the development of a reposi-
tory at Yucca Mountain. See Pub. L. No. 107-200, 116 Stat.
735 (2002) (codified at 42 U.S.C. § 10135 note (Supp. IV
2004)).
  As currently designed, the Yucca Mountain waste reposito-
ry will house up to 70,000 metric tons of radioactive waste
deep underground. See 66 Fed. Reg. at 32,081. DOE pro-
jects that ninety percent of the waste destined for Yucca
Mountain will be spent nuclear fuel from commercial nuclear
power plants. See id. The remaining ten percent will be
                              11

high-level radioactive waste left over from the nation’s nucle-
ar weapons program. See id.
   To isolate this waste for the epochal years required – by
comparison, human history has been recorded for only 5000
years, see id. at 32,099 – the disposal system’s overall design
contemplates two types of barriers. First, ‘‘engineered’’ bar-
riers, which include waste packages consisting of metal cylin-
ders protected by drip shields, will surround the waste and
protect it from water infiltration. See Office of Civilian
Radioactive Waste Management, Yucca Mountain Project,
Repository Concept: Engineered Barriers, at http://
www.ocrwm.doe.gov/ymp/about/ebarriers.shtml (last visited
June 1, 2004). These packages will sit in a complex of over
fifty horizontal tunnels, each over sixteen feet wide, 2000 feet
long, and reinforced with steel sets, rock bolts, and wire
mesh. See Office of Civilian Radioactive Waste Management,
Yucca Mountain Project, Repository Concept: Tunnel Layout
and Design, at http://www.ocrwm.doe.gov/ymp/about/tunnels.
shtml (last visited June 1, 2004). These tunnels are designed
not only to keep water and falling rocks from reaching the
waste canisters, but also to manage the heat the waste will
generate. See id. Second, the disposal system’s ‘‘natural’’
barriers, i.e., the characteristics of the rock formations under
Yucca Mountain, are intended to protect the waste from
water infiltration and to dilute radiation releases expected to
occur from leakage of the engineered barriers or from their
failure thousands of years from now. See Office of Civilian
Radioactive Waste Management, Fact Sheet, Nature and
engineering working together for a safe repository, at
http://www.ocrwm.doe.gov/factsheets/doeymp0203.shtml (last
visited June 1, 2004). DOE plans to construct the repository
tunnels in a thick layer of rock 1000 feet below the surface
and 1000 feet above the water table. See id. The Energy
Department expects that this surrounding rock will both limit
water from seeping into the waste packages and delay radio-
active particles from migrating into the human environment.
See id.; 66 Fed. Reg. at 32,087. Decades or even centuries
after beginning to bury waste at Yucca Mountain, DOE will
                              12

permanently close the repository by sealing off all openings to
the surface. See Secretary’s Recommendation at 7.
   Before us now are challenges to four aspects of the statuto-
ry and regulatory regime governing the Yucca Mountain
repository. First, the State of Nevada and various environ-
mental groups (Natural Resources Defense Council, Inc.,
Public Citizen, Citizen Alert, Nevada Nuclear Waste Task
Force, Nevada Desert Experience, Citizen Action Coalition of
Indiana, and the Nuclear Information and Resource Service)
challenge EPA’s radiation-protection regulation as insuffi-
ciently protective of public health and safety. The Nuclear
Energy Institute, Inc. (NEI), a trade association representing
the nuclear energy industry, challenges EPA’s ground-water
standard, claiming it to be both unnecessary and unlawful.
Second, Nevada, Clark County, and the City of Las Vegas
attack NRC’s licensing-criteria rule as arbitrary, capricious,
and contrary to law. Third, Nevada, Clark County, and the
City of Las Vegas challenge the constitutionality of the
congressional resolution selecting the Yucca Mountain site,
arguing that Congress impermissibly singled out the State to
bear the unique burden of housing the nation’s nuclear waste.
Fourth, Nevada, Clark County, and the City of Las Vegas
attack DOE’s part 963 site-suitability criteria, the Energy
Secretary’s and President’s decisions to recommend Yucca
Mountain for development as the nation’s waste repository,
and the Energy Department’s Final Environmental Impact
Statement. We consider each challenge in turn.

                    II.   THE EPA CASES
A.   The EPA Rule: 40 C.F.R. part 197
  Through the 1992 Energy Policy Act, Congress required
EPA to establish site-specific standards for a repository at
Yucca Mountain. The statute provides:
    [T]he [EPA] Administrator shall, based upon and
    consistent with the findings and recommendations of
    the National Academy of Sciences, promulgate, by
    rule, public health and safety standards for protec-
    tion of the public from releases from radioactive
                              13

    materials stored or disposed of in the repository at
    the Yucca Mountain site. Such standards shall pre-
    scribe the maximum annual effective dose equivalent
    to individual members of the public from releases to
    the accessible environment from radioactive materi-
    als stored or disposed of in the repository. The
    standards shall be promulgated not later than 1 year
    after the Administrator receives the findings and
    recommendations of the National Academy of Sci-
    ences TTT and shall be the only such standards
    applicable to the Yucca Mountain site.
EnPA § 801(a)(1).
  Acting pursuant to this authority, EPA promulgated a rule,
codified at 40 C.F.R. part 197, establishing a trio of public
health and safety standards to govern DOE’s nuclear waste
disposal activities at Yucca Mountain. Together, these stan-
dards are designed to protect both individuals living near the
disposal site and local ground-water supplies from excessive
radiation contamination.
   The rule begins by prescribing an ‘‘individual-protection
standard’’ that requires the Energy Department, as a condi-
tion of receiving an NRC license, to show that the Yucca
Mountain disposal system will sufficiently contain radiation to
protect a hypothetical person living adjacent to the site from
excessive exposure to radiation releases. The standard pro-
vides:
    The DOE must demonstrate, using performance as-
    sessment, that there is a reasonable expectation
    that, for 10,000 years following disposal, the reason-
    ably maximally exposed individual receives no more
    than an annual committed effective dose equivalent
    of 150 microsieverts (15 millirems) from releases
    from the undisturbed Yucca Mountain disposal sys-
    tem. The DOE’s analysis must include all potential
    pathways of radionuclide transport and exposure.
40 C.F.R. § 197.20 (2004). This ‘‘reasonably maximally ex-
posed individual’’ (RMEI) represents a theoretical person
                                14

living in the ‘‘accessible environment,’’ id. § 197.21 (2004), i.e.,
any point outside the ‘‘controlled area,’’ an area no greater
than 300 square kilometers around the repository, id.
§ 197.12 (2004). The RMEI is designed to have lifestyle
characteristics (such as water and food consumption habits)
that would expose him or her to ‘‘reasonably maximal’’ expo-
sure levels. See 66 Fed. Reg. at 32,092. The individual-
protection standard expresses the maximum doses the RMEI
may incur in terms of an ‘‘annual committed effective dose
equivalent,’’ a methodology that calculates an overall expo-
sure dose by assigning weighting factors to account for
organs’ relative sensitivities to radiation. See 40 C.F.R.
§ 197.2 (2004) (defining ‘‘effective dose equivalent’’ as ‘‘the
sum of the products of the dose equivalent received by
specified [human body] tissues following an exposure of, or an
intake of radionuclides into, specified tissues of the body,
multiplied by appropriate weighting factors’’).
   The rule’s second standard, the ‘‘human-intrusion stan-
dard,’’ requires DOE to show, among other things, a reason-
able expectation that the RMEI will receive no more than a
specified dose of radiation even if humans drill, intentionally
or otherwise, into a waste package during the 10,000-year
period immediately following disposal. Id. § 197.25(a) (2004).
   The third standard, the ‘‘ground-water-protection stan-
dard,’’ requires DOE to demonstrate that the Yucca Mountain
disposal system will contain radiation sufficiently well to
protect ground water outside the controlled area from exces-
sive contamination. Specifically, the rule provides:
     The DOE must demonstrate that there is a rea-
     sonable expectation that, for 10,000 years of un-
     disturbed performance after disposal, releases of
     radionuclides from waste in the Yucca Mountain
     disposal system into the accessible environment
     will not cause the level of radioactivity in the rep-
     resentative volume of ground water to exceed the
     limits in TTT Table 1.
Id. § 197.30 (2004). Table 1, in turn, specifies maximum
permitted contamination levels for three different types of
                              15

radionuclides, which correspond to the maximum contaminant
levels (MCLs) that EPA established under the Safe Drinking
Water Act (SDWA), 42 U.S.C. §§ 300f to 300j-26 (2000). See
66 Fed. Reg. at 32,106. For example, DOE must demon-
strate that ‘‘[c]ombined beta and photon emitting radionu-
clides’’ will not exceed four millirems per year. 40 C.F.R.
§ 197.30 (Table 1). Measured according to ‘‘critical organ
dose’’ methodology, these MCLs establish maximum radiation
doses by reference to the part of the body most sensitive to
the regulated radionuclide. See National Primary Drinking
Water Regulations; Radionuclides; Notice of Data Availabili-
ty, 65 Fed. Reg. 21,576, 21,603 (Apr. 21, 2000); National
Primary Drinking Water Regulations; Radionuclides, 65 Fed.
Reg. 76,708, 76,716 (Dec. 7, 2000); United States Environ-
mental Protection Agency, Public Health and Environmental
Radiation Protection Standards for Yucca Mountain, Nevada
(40 CFR Part 197) – Final Rule, Response to Comments
Document 6-21 (June 2001) [hereinafter ‘‘Response to Com-
ments’’]. The ‘‘representative volume’’ referred to in the
ground-water standard must include the highest concentra-
tion of radiation in the ‘‘plume of contamination’’ outside the
controlled area. 40 C.F.R. § 197.31(a)(1) (2004).
   To obtain a license to dispose of waste at Yucca Mountain,
the Energy Department ‘‘must demonstrate to NRC that
there is a reasonable expectation of compliance’’ with each of
these three protection standards. Id. § 197.13 (2004). To
account for changing conditions during the 10,000 years fol-
lowing disposal, EPA requires DOE to ‘‘vary factors related
to geology, hydrology, and climate based upon cautious, but
reasonable assumptions.’’ Id. § 197.15 (2004). In contrast,
the Energy Department must hold constant ‘‘changes in
society, the biosphere (other than climate), human biology, or
increases or decreases in human knowledge or technology.’’
Id.
   As to the period beyond the first 10,000 years, the rule
requires DOE to calculate the maximum radiation exposures
the RMEI will incur and then include the results of this
calculation in its environmental impact statement as an indi-
cator of long-term disposal system performance. Id. § 197.35
                               16

(2004). ‘‘No regulatory standard,’’ however, ‘‘applies to the
results of this analysis.’’ Id.
   In their petition for review, the State of Nevada, the
Natural Resources Defense Council (NRDC), and the other
environmental groups (throughout section II of this opinion,
we shall refer to this set of petitioners as either ‘‘Nevada’’ or
‘‘the State’’) first challenge part 197’s 10,000-year compliance
period, claiming that it both conflicts with EnPA and is
arbitrary and capricious. They also argue that EPA arbi-
trarily and capriciously drew the controlled area’s boundaries,
that the size of the controlled area violates the Safe Drinking
Water Act, and that the rule impermissibly defines the term
‘‘disposal.’’ For its part, the Nuclear Energy Institute chal-
lenges EPA’s decision to add a separate ground-water stan-
dard to part 197, arguing that the standard contravenes
EnPA and that it is arbitrary and capricious.
B.     Challenges Brought by Nevada and Environmental
       Petitioners
  1.    Jurisdiction
   Before addressing the merits of Nevada’s petition, we must
consider two jurisdictional issues. See Steel Co. v. Citizens
for a Better Env’t, 523 U.S. 83, 94-95, 101-02 (1998) (holding
that federal courts must ensure that they have jurisdiction
before considering the merits of a case). The first, relating
to subject matter jurisdiction, arises because although the
Hobbs Act, the jurisdictional statute invoked by all parties,
gives courts of appeals exclusive jurisdiction to review orders
issued by a host of federal agencies – including the Atomic
Energy Commission (AEC), the Federal Communications
Commission, and the Federal Maritime Commission – the Act
nowhere mentions the Environmental Protection Agency.
See 28 U.S.C. § 2342 (2000). Even so, we believe that the
Act’s conferral of jurisdiction over rules issued by the now-
defunct AEC gives us jurisdiction to entertain the petitions in
this case.
   The Hobbs Act authorizes courts of appeals to review ‘‘all
final orders of the Atomic Energy Commission made reviewa-
                              17

ble by section 2239 of title 42.’’ Id. § 2342(4). In turn,
section 2239 makes reviewable ‘‘[a]ny final order [of the
Atomic Energy Commission],’’ 42 U.S.C. § 2239(b) (2000),
that is entered in ‘‘any proceeding for the issuance or modifi-
cation of rules and regulations dealing with the activities of
licensees,’’ id. § 2239(a)(1)(A). The AEC’s authority to estab-
lish environmental standards to protect the public from radia-
tion exposure, however, has since been transferred to EPA,
and the AEC has been abolished. See Reorganization Plan
No. 3 of 1970, § 2(a)(6), reprinted in 5 U.S.C. App. 1 (2000)
(transferring to the EPA Administrator the ‘‘functions of the
Atomic Energy Commission TTT administered through its
Division of Radiation Protection Standards, to the extent that
such functions of the Commission consist of establishing
generally applicable environmental standards for the protec-
tion of the general environment from radioactive material’’);
42 U.S.C. § 5814(a) (2000) (abolishing the AEC). Given this
transfer of authority, at least three circuits have held that
EPA action undertaken pursuant to EPA’s AEC-transferred
authority is reviewable under the Hobbs Act as if undertaken
by the AEC itself. See Watkins, 939 F.2d at 712 n.4 (stating
that EPA’s generic health and safety standards for nuclear
waste repositories are reviewable under 42 U.S.C. § 2239(b));
NRDC v. EPA, 824 F.2d at 1267 n.7 (same); Quivira Mining
Co. v. United States EPA, 728 F.2d 477, 481-84 (10th Cir.
1984) (finding Hobbs Act jurisdiction over EPA regulations
addressing radiation releases from uranium fuel cycle opera-
tions). Going one step further, this circuit has held that
agency action that ‘‘derives’’ from transferred authority is
also reviewable under the Hobbs Act. See Aulenbeck, Inc. v.
Fed. Highway Admin., 103 F.3d 156, 164-65 (D.C. Cir. 1997)
(holding that the court had Hobbs Act jurisdiction to review
Transportation Department rules addressing certain safety
requirements because the agency’s power to issue those
requirements ‘‘derive[d] in part’’ from its transferred authori-
ty and because actions taken pursuant to that transferred
authority were subject to Hobbs Act review). This is just
such a case.
                               18

    In issuing its Yucca Mountain standards, EPA acted pursu-
ant to authority derived from its AEC-transferred powers.
When Congress, acting through EnPA section 801, required
EPA to issue Yucca-specific, radiation-protection standards, it
built on EPA authority – transferred from the AEC – to
promulgate generally applicable standards to protect the
public from radiation. See H.R. CONF. REP. NO. 102-1018, at
390 (1992), reprinted in 1992 U.S.C.C.A.N. 2472, 2481 (‘‘Sec-
tion 801 [of EnPA] builds upon [the] existing authority of the
[EPA] Administrator to set generally applicable [radiation-
protection] standardsTTTT’’). Because EPA’s authority to
promulgate its Yucca rule thus ‘‘derives’’ from its AEC-
transferred powers, we may consider petitioners’ challenge to
part 197 under our Hobbs Act jurisdiction. See Aulenbeck,
103 F.3d at 165.
    The second jurisdictional issue concerns EPA’s claim that
neither Nevada’s nor the environmental petitioners’ constitu-
tional standing is ‘‘self-evident.’’ Respondent’s Br. at 21. To
establish Article III standing to sue on behalf of their mem-
bers, NRDC and the other environmental petitioners must
show that ‘‘(a) [their] members would otherwise have stand-
ing to sue in their own right; (b) the interests [they] seek[ ]
to protect are germane to [their] purpose; and (c) neither the
claim asserted nor the relief requested requires the partic-
ipation of individual members in the lawsuit.’’ Hunt v. Wash.
State Apple Adver. Comm’n, 432 U.S. 333, 343 (1977). Under
the first element of this test, the environmental petitioners
must show that at least one of their members meets the
‘‘irreducible constitutional minimum’’ of standing, i.e., injury-
in-fact, causation, and redressability. Lujan v. Defenders of
Wildlife, 504 U.S. 555, 560-61 (1992). ‘‘The burden on a party
challenging an administrative decision in the court of appeals
is to show a substantial probability that it has been injured,
that the [respondent] caused its injury, and that the court
could redress that injury.’’ Rainbow/PUSH Coalition v.
FCC, 330 F.3d 539, 542 (D.C. Cir. 2003) (internal quotation
marks omitted). Moreover, the asserted injury must be both
‘‘concrete and particularized’’ as well as ‘‘actual or imminent.’’
Lujan, 504 U.S. at 560.
                              19

   To demonstrate standing, the environmental petitioners
rely on declarations by several of their members, including
one by Ed Goedhart, a member of petitioners Citizen Alert
and the Nuclear Information and Resource Service. See
Decl. of Ed Goedhart ¶ 1. Goedhart states that he lives and
works in Amargosa Valley, Nevada, eighteen miles from
Yucca Mountain. Id. ¶ 2. He alleges that EPA’s failure to
adopt more stringent radiation-protection standards will per-
mit hazardous radionuclides from the buried waste to contam-
inate his community’s ground-water supplies, causing adverse
health effects. See id. ¶¶ 2-7.
   These allegations are more than sufficient to give Goedhart
standing to sue in his own right. The claimed injury to his
ground-water supply is neither hypothetical nor conjectural.
Indeed, EPA itself acknowledges that ‘‘[t]he boundaries of the
town [of Amargosa Valley] include all of the area where the
highest potential doses from a repository at Yucca Mountain
are anticipatedTTTT’’ Final Background Information Docu-
ment at 8-13. Although radionuclides escaping from the
Yucca repository may not reach Goedhart’s community for
thousands of years, his injury is ‘‘actual or imminent,’’ for he
lives adjacent to the land where the Government plans to
bury 70,000 metric tons of radioactive waste – a sufficient
harm in and of itself. See La. Envtl. Action Network v.
United States EPA, 172 F.3d 65, 67-68 (D.C. Cir. 1999)
(holding that an environmental group established constitu-
tional standing where its members lived near a landfill into
which an EPA regulation allegedly would permit certain
hazardous wastes to be deposited). In addition, this harm is
‘‘fairly traceable,’’ Lujan, 504 U.S. at 560 (internal quotation
marks omitted), to EPA’s allegedly lax radiation-protection
standards, and favorable relief, i.e., requiring EPA to make
more stringent each aspect of the rule that petitioners chal-
lenge, would likely redress his harm.
   Nor have we any doubt that Goedhart has prudential
standing. To establish prudential standing, a party’s ‘‘griev-
ance must arguably fall within the zone of interests protected
or regulated by the statutory provision or constitutional guar-
antee invoked in the suit.’’ Bennett v. Spear, 520 U.S. 154,
                              20

162 (1997). Goedhart’s grievance clearly falls within the
Energy Policy Act’s ‘‘zone of interests,’’ for that Act seeks to
ensure that DOE operates the Yucca repository safely, i.e.,
without endangering the lives or health of the surrounding
population. See EnPA § 801(a)(1) (directing EPA to promul-
gate ‘‘public health and safety standards for protection of the
public from releases from radioactive materials’’).
   Because the Government does not argue that the environ-
mental petitioners fail either the germaneness or the individu-
al-participation element of associational standing, and because
‘‘we [too] have [no] reason to believe that [they] fail[ ] to
satisfy [these] latter two requirements,’’ Sierra Club v. EPA,
292 F.3d 895, 898 (D.C. Cir. 2002), we conclude that the
environmental petitioners have established standing to bring
their petition for review. And since only one petitioner
requires standing, we need not consider the Government’s
separate challenge to Nevada’s standing. See Military Tox-
ics Project v. EPA, 146 F.3d 948, 954 (D.C. Cir. 1998). We
thus turn to the merits of Nevada’s petition.
  2.   The 10,000-Year Compliance Period
   Nevada first challenges EPA’s decision to establish a com-
pliance period that extends only 10,000 years into the future.
According to Nevada, the 10,000-year marker violates EnPA
section 801(a) and is arbitrary and capricious under the
Administrative Procedure Act (APA), 5 U.S.C. § 706(2)(A)
(2000). We begin and end with Nevada’s EnPA challenge.
  Section 801(a) of the Energy Policy Act requires EPA to
promulgate public health and safety standards for Yucca
Mountain ‘‘based upon and consistent with the findings and
recommendations of the National Academy of Sciences.’’
Chartered by Congress during the Civil War, the National
Academy of Sciences (NAS or Academy) serves as the federal
government’s scientific adviser, convening distinguished
scholars to address scientific and technical issues confronting
society. See NAS REPORT at vi. EnPA directs EPA to
contract with NAS to conduct a study to provide ‘‘findings
and recommendations on reasonable standards for protection
of the public health and safety’’ from the potential hazards
                               21

posed by a Yucca Mountain repository. EnPA § 801(a)(2).
To undertake the necessary study, NAS convened a commit-
tee organized under the auspices of its principal operating
arm, the National Research Council. NAS REPORT at vi-vii.
That committee retained two consultants, conducted five open
meetings to which it invited over fifty scientists and engi-
neers, and reviewed publicly available research compiled by
federal, state, and local agencies, among others. Id. at vii-
viii.
   The Academy’s work culminated in a 1995 report entitled
‘‘Technical Bases for Yucca Mountain Standards.’’ With re-
spect to the length of the compliance period, NAS found ‘‘no
scientific basis for limiting the time period of the individual-
risk standard to 10,000 years or any other value.’’ Id. at 55.
According to the Academy, ‘‘compliance assessment is feasible
for most physical and geologic aspects of repository perform-
ance on the time scale of the long-term stability of the
fundamental geologic regime – a time scale that is on the
order of 106 [one million] years at Yucca Mountain.’’ Id. at 6.
NAS also explained that humans may not face peak radiation
risks until tens to hundreds of thousands of years after
disposal, ‘‘or even farther into the future.’’ Id. at 2. Given
these findings – and central to the issue before us – NAS
‘‘recommend[ed] that compliance assessment be conducted for
the time when the greatest risk occurs, within the limits
imposed by the long-term stability of the geologic environ-
ment.’’ Id. at 6 (emphasis omitted). That said, NAS ex-
plained that ‘‘although the selection of a time period of
applicability has scientific elements, it also has policy aspects
that we have not addressed,’’ such as the goal of establishing
consistent policies for managing various kinds of long-lived,
hazardous materials. Id. at 56.
   Following issuance of the NAS Report, EPA promulgated
its draft part 197 standards in which it proposed a 10,000-year
compliance period. In so doing, EPA ‘‘request[ed] comments
upon the reasonableness of adopting the NAS-recommended
compliance period or some other approach in lieu of the
10,000-year compliance period which we favorTTTT’’ 64 Fed.
Reg. at 46,995. DOE, responding to EPA’s request, sup-
                              22

ported the 10,000-year compliance period, claiming that a
‘‘significantly longer time period for assessing compliance
would be unprecedented, unworkable, and probably unimple-
mentable.’’ Letter from Lake H. Barrett, Acting Director,
Office of Civilian Radioactive Waste Management, to United
States Environmental Protection Agency 2 (Nov. 1999). By
contrast, Nevada submitted comments opposing the 10,000-
year marker, urging that EPA adopt a period of compliance
covering the time of projected peak doses, as NAS had
recommended. See Letter from Robert R. Loux, Executive
Director, Office of the Governor, Agency for Nuclear Pro-
jects, to United States Environmental Protection Agency 8
(Nov. 23, 1999).
   After the comment period closed, EPA promulgated its
final rule, in which it adopted a 10,000-year compliance peri-
od. Expressly acknowledging that NAS had recommended
that the compliance period cover the time when the greatest
risk of radiation exposure occurs and that the Academy had
found it scientifically possible to predict repository perform-
ance for approximately one million years, EPA nevertheless
concluded that ‘‘such an approach is not practical for regula-
tory decisionmaking.’’ 66 Fed. Reg. at 32,097. The agency
explained:
    Despite NAS’s recommendation, we conclude that
    there is still considerable uncertainty as to whether
    current modeling capability allows development of
    computer models that will provide sufficiently mean-
    ingful and reliable projections over a time frame up
    to tens-of-thousands to hundreds-of-thousands of
    years. Simply because such models can provide
    projections for those time periods does not mean
    those projections are meaningful and reliable enough
    to establish a rational basis for regulatory decision-
    making.
Id. Moreover, EPA maintained that selecting a compliance
period for the individual-protection standard ‘‘involves both
technical and policy considerationsTTTT In addition to the
technical guidance provided in the NAS Report, we consid-
                              23

ered several policy and technical factors that NAS did not
fully address, as well as the experience of other EPA and
international programs.’’ Id. at 32,098. According to EPA,
five considerations guided its decision: (1) the agency uses
10,000 years for programs involving the disposal of other
long-lived, hazardous materials, (2) the individual-protection
requirements in 40 C.F.R. part 191, EPA’s generally applica-
ble nuclear waste disposal standards, use such a time frame,
and ‘‘consistency [is] appropriate because both sets of stan-
dards apply to the same types of waste,’’ (3) many interna-
tional geologic disposal programs use 10,000 years, (4) setting
the standard to peak dose times ‘‘could lead to a period of
regulation that has never been implemented in a national or
international radiation regulatory program,’’ and focusing on
10,000 years forces more emphasis on features that humans
can control such as repository design, and (5) projecting
human exposure levels over long periods of time involves
great uncertainty. Id. at 32,098-99. On this last point, EPA
stated that ‘‘we believe that NAS might not have fully ad-
dressed two aspects of uncertainty,’’ specifically (1) ‘‘the
impact of long-term natural changes in climate and its effect
upon choosing an appropriate RMEI,’’ and (2) ‘‘the range of
possible biosphere conditions and human behavior.’’ Id.
   In the final rule’s preamble, EPA also explained why it
believed that part 197 complied with EnPA’s requirement
that the rule be ‘‘based upon and consistent with’’ NAS’s
findings and recommendations. Id. at 32,082-84. That man-
date, EPA stated, ‘‘does not bind us absolutely to follow the
NAS Report. Instead, we used it as a starting point for this
rulemakingTTTT [W]e do not believe the statute forces our
rulemaking to adopt mechanically NAS’s recommendations as
standards.’’ Id. at 32,083. Thus, because part 197 was
‘‘guided by the [Academy’s] findings and recommendations [in
light] of the special role Congress gave it,’’ id., EPA conclud-
ed that it had acted in accordance with EnPA’s directive.
  Challenging EPA’s determination, Nevada contends that
part 197’s 10,000-year compliance period deviates from the
NAS Report and that EPA therefore failed to promulgate a
                                24

rule ‘‘based upon and consistent with’’ NAS’s findings and
recommendations, as required by EnPA section 801(a). Be-
cause Congress has charged EPA with implementing section
801(a) of the Energy Policy Act, we analyze this claim under
the two-part test of Chevron U.S.A. Inc. v. Natural Re-
sources Defense Council, Inc., 467 U.S. 837 (1984). See
United States v. Mead Corp., 533 U.S. 218, 226-27 (2001).
Under Chevron’s first step, we ask ‘‘whether Congress has
directly spoken to the precise question at issue,’’ for if ‘‘the
intent of Congress is clear, that is the end of the matterTTTT
[T]he court, as well as the agency, must give effect to the
unambiguously expressed intent of Congress.’’ Chevron, 467
U.S. at 842-43. If the statute is ‘‘silent or ambiguous with
respect to the specific issue,’’ we proceed to Chevron’s second
step, asking whether the agency’s interpretation ‘‘is based on
a permissible construction of the statute.’’ Id. at 843. At
this stage, although we defer to agency statutory interpreta-
tions, ‘‘our judicial function is neither rote nor meaningless,’’
Natural Res. Def. Council, Inc. v. Daley, 209 F.3d 747, 752
(D.C. Cir. 2000), and we will reject an interpretation ‘‘that
diverges from any realistic meaning of the statute,’’ id. at 753
(quoting Massachusetts v. Dep’t of Transp., 93 F.3d 890, 893
(D.C. Cir. 1996)) (internal quotation marks omitted).
  Beginning at Chevron Step One, then, we ask whether
Congress’s directive that EPA issue standards ‘‘based upon
and consistent with the findings and recommendations of the
National Academy of Sciences’’ is clear and unambiguous. In
considering this question, we do not write on a clean slate.
In a recent case interpreting the Clean Air Act, we observed
that ‘‘[t]here is no question that the phrase ‘based on’ is
ambiguous.’’ Sierra Club v. EPA, 356 F.3d 296, 305-06 (D.C.
Cir. 2004), amended by No. 03-1084, 2004 WL 877850 (D.C.
Cir. Apr. 16, 2004). Although the words ‘‘based on’’ do not
necessarily mean ‘‘rest solely on,’’ we concluded, they prohibit
actions that ‘‘abandon[ ]’’ or ‘‘supplant[ ].’’ Id. at 306. In
another Clean Air Act case, we reached a similar conclusion
about the phrase ‘‘consistent with,’’ explaining that this ‘‘flexi-
ble statutory language’’ requires not ‘‘exact correspondence
TTT but only congruity or compatibility.’’ Envtl. Def. Fund,
                              25

Inc. v. EPA, 82 F.3d 451, 457 (D.C. Cir. 1996) (per curiam)
(describing the phrase ‘‘consistent with’’ as requiring the
court to defer to reasonable agency determinations), amended
by 92 F.3d 1209 (D.C. Cir. 1996). Likewise, in Natural
Resources Defense Council, Inc. v. Daley, we held that a
statute requiring fishing quotas to be (among other things)
‘‘consistent with’’ a fishery management plan was ambiguous.
209 F.3d at 754. Because ‘‘[t]he statute does not prescribe a
precise quota figure,’’ we reasoned, ‘‘there is no plain meaning
on this point.’’ Id. (‘‘[W]e TTT view this case as governed by
Chevron Step Two.’’). Given this case law, we are not free to
conclude that section 801(a) clearly and unambiguously an-
swers the precise question before us.
   Nor can we discern an unambiguous congressional com-
mand from EnPA’s legislative history. See id. at 752 (‘‘Under
the first step of Chevron, the reviewing court must exhaust
the traditional tools of statutory construction to determine
whether Congress has spoken to the precise question at
issue.’’ (internal quotation marks omitted)). The Conference
Report explains:
    The Conferees do not intend for the National Acade-
    my of Sciences, in making its recommendations, to
    establish specific standards for protection of the
    public but rather to provide expert scientific guid-
    ance on the issues involved in establishing those
    standards. Under the provisions of section 801, the
    authority and responsibility to establish the stan-
    dards, pursuant to a rulemaking, would remain with
    the [EPA] Administrator, as is the case under exist-
    ing law. The provisions of section 801 are not
    intended to limit the Administrator’s discretion in
    the exercise of his authority related to public health
    and safety issues.
H.R. CONF. REP. NO. 102-1018, at 391, reprinted in 1992
U.S.C.C.A.N. at 2482. Rather than answering the specific
question at hand, this discretion-conferring language supports
our view that nothing in section 801(a) specifies precisely how
EPA must use the NAS Report.
                              26

  For its part, EPA insists that Congress actually intended it
to adopt a 10,000-year compliance period. In support of this
argument, EPA relies on EnPA section 801(a)(2)(C), which
directed the agency to engage NAS to examine whether it is
possible to predict the probability that humans will breach
Yucca Mountain’s engineered or geologic barriers over a
10,000-year period. EPA also points out that at the time
Congress enacted EnPA, the First Circuit had upheld a
10,000-year compliance period contained in EPA’s generic
part 191 standards. See NRDC v. EPA, 824 F.2d at 1292-93.
By failing to specify an alternate time frame in the Energy
Policy Act, EPA argues, Congress tacitly endorsed 10,000
years.
  EPA misreads EnPA’s contextual clues. Although EnPA
mentions 10,000 years in section 801(a)(2), section 801(a)(1) –
the provision that requires EPA to issue a Yucca-specific
rule – tells the agency exactly how to set any compliance
period, i.e., it must be ‘‘based upon and consistent with’’
NAS’s recommendations. In view of this express directive,
moreover, Congress’s failure to establish a compliance period
cannot be viewed as tacit approval of the part 191 time frame.
   Given section 801’s ambiguity, Nevada’s challenge turns on
whether EPA’s 10,000-year compliance period can be reason-
ably described as ‘‘based upon and consistent with’’ NAS’s
findings and recommendations. We think it cannot. It would
have been one thing had EPA taken the Academy’s recom-
mendations into account and then tailored a standard that
accommodated the agency’s policy concerns. But that is not
what EPA did. Instead, it unabashedly rejected NAS’s find-
ings, and then went on to promulgate a dramatically different
standard, one that the Academy had expressly rejected. Al-
though section 801’s ‘‘based upon and consistent with’’ stan-
dard does not require EPA to walk in lock-step with the
Academy, we think it entirely unreasonable for EPA to have
acted inconsistently with NAS findings and recommenda-
tions. As in Daley, ‘‘[t]his case presents a situation in which
the [agency’s action] so completely diverges from any realistic
                              27

meaning of the [statute] that it cannot survive scrutiny under
Chevron Step Two.’’ 209 F.3d at 753.
   To begin with, there is little question that EPA’s 10,000-
year compliance period deviates dramatically from the Acade-
my’s findings. Most important, NAS unequivocally recom-
mended a standard pegged to the time when radiation doses
reach their peak:
     We believe that compliance assessment is feasible
     for most physical and geologic aspects of repository
     performance on the time scale of the long-term
     stability of the fundamental geologic regime – a time
     scale that is on the order of 106 [one million] years at
     Yucca Mountain – and that at least some potentially
     important exposures might not occur until after
     several hundred thousand years. For these reasons,
     we recommend that compliance assessment be con-
     ducted for the time when the greatest risk occurs,
     within the limits imposed by long-term stability of
     the geologic environment.
NAS REPORT at 6-7. NAS reiterated this conclusion through-
out its report: ‘‘[W]e recommend TTT [t]hat compliance with
the standard be measured at the time of peak risk, whenever
it occurs,’’ id. at 2 (footnote omitted); ‘‘we have recommended
that the standard for individual risk should apply at times
when the peak potential risks might occur,’’ id. at 55-56; ‘‘we
see no technical basis for limiting the period of concern to a
period that is short compared to the time of peak risk or the
anticipated travel time,’’ id. at 56; ‘‘[t]he period over which
this level of protection should be assessed should extend over
the period of duration of hazard potential of the repository,
that is, until the time at which the highest critical group risk
is calculated to occur, within the limits imposed by the long-
term stability of the geologic environment at Yucca Mountain,
which is on the order of [one million] years,’’ id. at 67.
   Not only did NAS recommend that EPA set its compliance
period based on peak risk, but it expressly rejected 10,000
years as a proper benchmark: ‘‘The current EPA standard
[in part 191] contains a time limit of 10,000 years for the
                               28

purpose of assessing compliance. We find that there is no
scientific basis for limiting the time period of an individual-
risk standard in this way.’’ Id. at 6; see also id. at 55 (‘‘[W]e
believe that there is no scientific basis for limiting the time
period of the individual-risk standard to 10,000 years or any
other value.’’). A 10,000-year limitation, NAS explained,
‘‘might be inconsistent with protection of public health.’’ Id.
at 55. NAS continued:
    [A]s noted in a previous National Research Council
    study, EPA’s 10,000-year time limit TTT makes com-
    pliance rather easy. This we do not support because
    TTT we see no valid justification for this time lim-
    itTTTT Th[is] TTT calculational approach may seem
    to simplify licensing, but we do not understand how
    such an exercise can support the finding, required in
    licensing, that there be no unreasonable risk to the
    health and safety of the public.
Id. (internal quotation marks omitted) (second and third
omissions in original).
  Describing its recommendation as differing from a 10,000-
year standard, NAS went on to state:
    Perhaps the most significant difference between our
    recommendations and 40 CFR 191 concerns the time
    period over which the standard is applicable. In 40
    CFR 191, the standard applies for a period of 10,000
    years. In our proposal, we have specified that the
    basis for the standard should be the peak risk,
    whenever it occurs [within the limits imposed by the
    long-term stability of the geologic environment].
    Based on performance assessment calculations pro-
    vided to us, it appears that for some reasonable
    combinations of parameters, peak risks are likely to
    occur after 10,000 years.
Id. at 119 (footnote omitted) (emphasis added); see also id. at
2 (same).
   EPA’s own explanation of its treatment of the NAS Report
also reveals that the agency consciously and outrightly reject-
                               29

ed the Academy’s findings and recommendations. For exam-
ple, in the final rule’s preamble, EPA acknowledged that NAS
had found ‘‘no scientific basis for limiting the time period of
the individual-risk standard to 10,000 years or any other
value,’’ but ‘‘[d]espite NAS’s recommendation,’’ it concluded
that a 10,000-year standard was appropriate. 66 Fed. Reg. at
32,097 (internal quotation marks omitted) (emphasis added);
see also id. (concluding that NAS’s recommended peak dose
standard is ‘‘not practical for regulatory decisionmaking,
which involves more than scientific performance projections
using computer models’’).
   This case is quite similar to Daley, where, as we explained
above, see supra at 25, we held that a statute directing that
agency fishing quotas be ‘‘consistent with’’ applicable fishery
management plans was not free from ambiguity. See 209
F.3d at 753-54. Because the agency’s quota in that case had
only an eighteen percent likelihood of achieving its conserva-
tion target, we held that it failed Chevron’s Step-Two reason-
ableness test. Id. ‘‘Only in Superman Comics’ Bizarro
world, where reality is turned upside down,’’ we explained,
‘‘could the [agency] reasonably conclude that a measure that
is at least four times as likely to fail as to succeed offers [the
requisite degree of] confidence.’’ Id. at 754 (internal quota-
tion marks omitted). So too here. Only in a world where
‘‘based upon’’ means ‘‘in disregard of’’ and ‘‘consistent with’’
means ‘‘inconsistent with’’ could EPA’s adoption of a 10,000-
year compliance period be considered a permissible construc-
tion of section 801.
   EPA nevertheless insists that it acted consistently with the
Academy’s conclusions because it based the 10,000-year com-
pliance period on several policy concerns beyond the ken of
NAS’s technical expertise. In support of this argument, EPA
relies on NAS’s acknowledgment that agency standard-
setting implicates policy considerations: ‘‘[W]e note that al-
though the selection of a time period of applicability has
scientific elements,’’ NAS stated, ‘‘it also has policy aspects
that we have not addressed. For example, EPA might
choose to establish consistent policies for managing risks
from disposal of both long-lived hazardous nonradioactive
                                30

materials and radioactive materials.’’      NAS REPORT at 56
(citations omitted).
   We think the Academy’s statement far too thin a reed on
which to find that EPA reasonably interpreted EnPA’s
‘‘based upon and consistent with’’ command. Simply stating
that standard-setting has ‘‘policy aspects’’ cannot transform
NAS’s statement that ‘‘we recommend that compliance as-
sessment be conducted for the time when the greatest risk
occurs, within the limits imposed by long-term stability of the
geologic environment,’’ id. at 6-7 (emphasis omitted), into, as
EPA would seemingly have it, ‘‘we recommend that compli-
ance assessment be conducted for the period that lacks
scientific basis but that best meets EPA’s policy goals.’’
Furthermore, NAS’s conclusion that EPA ‘‘might choose to
establish consistent policies’’ is of little importance here, given
that this court – not the Academy – is charged with determin-
ing whether EPA has exercised its rulemaking discretion in
compliance with EnPA. And although our case law makes
clear that a phrase like ‘‘based upon and consistent with’’ does
not require EPA to hew rigidly to NAS’s findings, EnPA
section 801(a) cannot reasonably be read to allow a regulation
wholly inconsistent with NAS recommendations.
   EPA also claims that it complied with EnPA because it
based the 10,000-year compliance period on the Academy’s
finding that ‘‘there is no scientific basis for prediction of
future states [of human activity], and the limit of our ability
to extrapolate with reasonable confidence is measured in
decades, or at most, a few hundreds of years.’’ Id. at 55.
This statement helps EPA not at all, for NAS nonetheless
concluded that despite this uncertainty, limiting the compli-
ance period to 10,000 years was inappropriate. Id.
    Finally, at oral argument, EPA counsel insisted that part
197 is consistent with NAS’s findings because it requires
DOE to ‘‘calculate the peak dose of the reasonably maximally
exposed individual that would occur after 10,000 years follow-
ing disposal but within the period of geologic stability’’ and to
‘‘include [those] results and their bases in the environmental
impact statement for Yucca Mountain as an indicator of long-
                               31

term disposal system performance.’’ 40 C.F.R. § 197.35; see
also Oral Argument Tr. at 32 (‘‘[W]e certainly think that the
ultimate result was consistent with the NAS recommenda-
tions insofar as the projections out to time of peak dose are
required to be performed and submitted in the [Environmen-
tal Impact Statement].’’). Although EPA’s addition of this
provision might well represent a nod to NAS, it hardly makes
the agency’s regulation consistent with the Academy’s find-
ings. NAS recommended that the compliance period extend
to the time of peak risk, yet EPA’s rule requires only that
DOE calculate peak doses and expressly provides that ‘‘[n]o
regulatory standard applies to the results of this analysis.’’
40 C.F.R. § 197.35; see also 66 Fed. Reg. at 32,096 (‘‘The rule
does not TTT require that DOE meet a specific dose limit
after 10,000 years.’’).
   In sum, because EPA’s chosen compliance period sharply
differs from NAS’s findings and recommendations, it repre-
sents an unreasonable construction of section 801(a) of the
Energy Policy Act. Although EnPA’s ‘‘based upon and con-
sistent with’’ mandate leaves EPA with some flexibility in
crafting standards in light of NAS’s findings, EPA may not
stretch this flexibility to cover standards that are inconsistent
with the NAS Report. Had EPA begun with the Academy’s
recommendation to base the compliance period on peak dos-
age and then made adjustments to accommodate policy con-
siderations not considered by NAS, this might be a very
different case. But as the foregoing discussion demonstrates,
EPA wholly rejected the Academy’s recommendations. We
will thus vacate part 197 to the extent that it requires DOE to
show compliance for only 10,000 years following disposal. On
remand, EPA must either issue a revised standard that is
‘‘based upon and consistent with’’ NAS’s findings and recom-
mendations or return to Congress and seek legislative author-
ity to deviate from the NAS Report. It was Congress that
required EPA to rely on NAS’s expert scientific judgment,
and given the serious risks nuclear waste disposal poses for
the health and welfare of the American people, it is up to
Congress – not EPA and not this court – to authorize
departures from the prevailing statutory scheme.
                               32

   Because EPA’s 10,000-year compliance period violates
EnPA section 801, we have no need to consider Nevada’s
alternative argument that the standard is arbitrary and capri-
cious under the APA.
  3.   The Controlled Area
   Nevada next attacks part 197’s controlled area. Part 197
contemplates that the Yucca Mountain disposal system will
include not just a repository in which the waste packages are
placed, but also a controlled area surrounding the repository.
Under the rule, the controlled area may extend five kilome-
ters from the repository in every direction, except that to-
ward the south – the direction in which ground water flows –
the area may extend to a specified geographic coordinate that
is roughly eighteen kilometers away. See 40 C.F.R. § 197.12;
66 Fed. Reg. at 32,094.
   The controlled area serves three distinct functions. First,
it operates as the natural barrier portion of the disposal
system, the land dedicated to isolating and diluting radionu-
clides released from the waste packages. See 66 Fed. Reg. at
32,117. Second, it designates the area that EPA will make
off-limits to human settlement through ‘‘institutional controls’’
such as signs or guards. Id. Third, and central to Nevada’s
challenge here, the controlled area’s borders establish the
maximum distance from the repository that the Energy De-
partment may locate the reasonably maximally exposed indi-
vidual for purposes of demonstrating compliance with the
individual-protection standard, see 40 C.F.R. §§ 197.20-
197.21, as well as the greatest distance from the repository
that DOE may place the point of compliance for the ground-
water-protection standard, see id. §§ 197.30, 197.31(a)(1).
Under the individual-protection standard, DOE must show
that the RMEI living in the ‘‘accessible environment,’’ defined
as any point outside the controlled area, id. § 197.12, and
specifically, ‘‘above the highest concentration of radionuclides
in the plume of contamination,’’ id. 197.21(a), will incur radia-
tion doses no greater than prescribed by the rule, id.
§ 197.20. Under the ground-water-protection standard, DOE
must show that radiation levels in the representative volume
                              33

of water, including ‘‘the highest concentration level in the
plume of contamination’’ outside the controlled area, id.
§ 197.31(a)(1), do not exceed maximum contaminant limits, id.
§ 197.30.
   In the final Yucca rule, EPA selected a point approximately
eighteen kilometers south of the repository as the presumed
location of the RMEI and the ground-water standard’s point
of compliance. EPA explained that after considering loca-
tions ranging from a few kilometers to roughly thirty kilome-
ters from the repository, it selected the eighteen-kilometer
point as the RMEI’s location for two primary reasons. First,
after warning signs and other institutional controls lapse with
the passage of time (the Academy was unable to predict how
long such controls would last, see NAS REPORT at 106), rural
residents – those with the lifestyle traits upon which EPA
chose to model its RMEI, see 66 Fed. Reg. at 32,090 – are
unlikely to settle farther north because living conditions
become less hospitable the closer one gets to the repository.
In particular, terrain becomes rougher, and depth to ground
water increases. See id. at 32,094. Second, EPA concluded
that even if individuals, notwithstanding these conditions,
chose to live closer to Yucca Mountain, they would incur less
overall exposure than rural residents at eighteen kilometers
away, so placing the RMEI at the eighteen-kilometer point
would provide greater overall protection than a more norther-
ly location. Id. ‘‘[E]ven though the ground water nearer the
repository could contain higher concentrations of radionu-
clides,’’ EPA explained, if individuals lived closer to the
repository, they would incur lower overall doses. Id. at
32,093. According to the agency:
    [Such individuals] would be unlikely to withdraw
    water from the significantly greater depth for other
    than domestic use, and in the much larger quantities
    needed for gardening or farming activities because
    of the significant cost of finding and withdrawing the
    ground water. It is possible, therefore, for an indi-
    vidual located closer to the repository to incur expo-
                             34

    sures from contaminated drinking water, but not
    from ingestion of contaminated food.
Id. Based on these findings, EPA concluded, ‘‘the exposure
for an RMEI located approximately 18 [kilometers] south of
the repository (where ingestion of locally grown contaminated
food is a reasonable assumption) actually would be more
conservative than an RMEI located much closer to the reposi-
tory who is exposed primarily through drinking water.’’ Id.
   With respect to the ground-water standard’s point of com-
pliance, EPA explained:
    [A]s one gets closer than about 18 [kilometers] to
    the repository footprint, the depth to water begins to
    increase dramatically from about 100 [meters] at a
    distance of 20 [kilometers] to a few hundred meters
    at a distance of 5 [kilometers]. Given the expecta-
    tion of future population growth and the precious
    nature of ground water resources in the area, it is
    reasonable to assume that a small group may annu-
    ally extract the representative volume of ground
    water at a distance slightly closer than 20 [kilome-
    ters]TTTT This approach is protective of the ground
    water resources reasonably anticipated to be ac-
    cessed in the vicinity of Yucca Mountain.
Id. at 32,119-20.
   Nevada contends that EPA’s factual assumptions lack rec-
ord support and that the agency therefore acted arbitrarily
and capriciously in allowing the controlled area’s southern
boundary to extend eighteen kilometers from the repository.
In particular, Nevada argues that the record shows that
humans are likely to settle and grow food at locations much
closer to the repository and that individuals living nearer to
the buried waste will incur greater radiation exposure than
those a full eighteen kilometers away. Based on this view of
the record, Nevada claims that EPA’s controlled area is both
irrational and insufficiently protective of public health and
safety. We disagree.
                              35

   To begin with, contrary to Nevada’s assertion, record evi-
dence supports EPA’s finding that humans are unlikely to
cultivate crops within the controlled area. The Final Back-
ground Information Document, which explains much of the
technical basis for EPA’s rule, shows not only that costs for
drilling water increase as depth to water increases, but also
that drilling and pumping water for irrigation purposes at
depths exceeding 300 feet is economically infeasible, i.e., that
when ‘‘[c]ombining TTT pumping cost estimates TTT with TTT
capital cost estimates TTT, the marginal value of water for
irrigation is exceeded at depths to water greater than 300
feet.’’ Final Background Information Document at IV-12;
see also id. at IV-10, IV-12 (estimating the costs of drilling
wells and pumping water for irrigation purposes at various
depth-to-water levels). EPA therefore concluded that access-
ing water for irrigation is cost-prohibitive at locations closer
than eighteen kilometers. In reaching this conclusion, EPA,
relying on the Academy’s recommendation, found that since it
was ‘‘impossible to predict either human activities or econom-
ic imperatives,’’ it would assume ‘‘current conditions’’ would
persist indefinitely. 66 Fed. Reg. at 32,094 (‘‘[W]e followed
NAS’s recommendation to use current conditions to avoid
highly speculative scenarios.’’). Because Nevada does not
challenge this odd aspect of EPA’s reasoning and because
depth to water generally surpasses 300 feet at points closer to
the repository than the eighteen-kilometer mark, see Final
Background Information Document at 8-33, EPA’s conclusion
that humans would be unlikely to pursue agricultural activi-
ties in such unfavorable terrain seems reasonable to us.
  We also think it reasonable for the agency to have found
that humans will likely choose to settle outside the controlled
area. Although the record does show that a community could
feasibly settle within the controlled area and use local water
for domestic (as opposed to agricultural) purposes, see id. at
IV-11 to IV-12, and that institutional controls cannot deter
settlement within the controlled area for the entire compli-
ance period, see id. at 8-89, EPA’s Final Background Infor-
mation Document demonstrates that the costs of settling
nearer to the repository are substantially higher than estab-
                              36

lishing a community farther away, see id. at IV-8 to IV-9. In
any event, to satisfy the APA’s rational-decisionmaking stan-
dard, EPA need not prove that humans will never settle
within the controlled area; the agency needs only a reason-
able basis for believing that they are unlikely to do so. See
City of Waukesha v. EPA, 320 F.3d 228, 247 (D.C. Cir. 2003)
(per curiam) (‘‘[W]e will give an extreme degree of deference
to the agency when it is evaluating scientific data within its
technical expertise.’’ (internal quotation marks omitted)). In-
deed, deciding where to locate the RMEI and the ground-
water standard’s point of compliance involves a complex line-
drawing judgment to which we owe great deference. See
Sinclair Broad. Group, Inc. v. FCC, 284 F.3d 148, 159 (D.C.
Cir. 2002) (‘‘Where issues involve elusive and not easily
defined areas TTT, our review is considerably more deferen-
tial, according broad leeway to the [agency’s] line-drawing
determinations.’’ (citation and internal quotation marks omit-
ted)).
   EPA’s conclusion that individuals who could settle closer to
the repository will incur less radiation exposure than those
living eighteen kilometers away, though seemingly counterin-
tuitive, also finds support in the record. Although ground
water nearer to the repository could contain higher radiation
concentrations than ground water farther away, see 66 Fed.
Reg. at 32,093, well-drilling data in the record and the
Energy Department’s analysis of relative radiation-exposure
levels support EPA’s ultimate RMEI-location decision. As
discussed above, EPA’s well-drilling cost estimates show that
individuals who may settle closer to the repository are unlike-
ly to extract water for agricultural purposes. Record data
also demonstrate that individuals living closer to the reposito-
ry who consume smaller quantities of more highly contami-
nated water (water for drinking alone) will experience less
overall exposure than those living farther from the repository
who consume greater amounts of less contaminated water
(water for both drinking and agriculture). DOE’s draft envi-
ronmental impact statement projects that the mean peak dose
rate for an individual at five kilometers, whose radiation
intake is through drinking contaminated water alone, will be
lower than that for a person at twenty kilometers who
                                37

consumes contaminated drinking water and contaminated
food. See United States Department of Energy, Draft Envi-
ronmental Impact Statement for a Geologic Repository for
the Disposal of Spent Nuclear Fuel and High-Level Radioac-
tive Waste at Yucca Mountain, Nye County, Nevada 5-26 to
5-36 (July 1999).
   Nevada’s remaining challenges to EPA’s well-drilling data
are without merit. Although it is true that EPA found it
‘‘difficult to reconcile’’ cost figures in a particular set of well-
construction cost estimates, Final Background Information
Document at IV-2, the agency did not rely on those analyses,
resting its conclusions instead on calculations that estimated
the overall cost of water based on construction and pumping
costs for wells of various depths, see id. (stating that the
agency estimated ‘‘the significance of drilling costs on the
overall cost of water TTT by estimating the costs of various
wells (different uses and depths) from the data available and
then calculating the capital cost per acre-foot’’); see also id.
at IV-11 (describing the mathematical equation used to com-
pute water-pumping costs). And despite the State’s claim to
the contrary, the fact that DOE itself uses two wells within
the proposed controlled area to support its Yucca site-
investigation activities, see id. at 8-80; 66 Fed. Reg. at 32,123,
provides no basis for questioning EPA’s reasoning, for how a
government agency chooses to allocate public funds tells us
little (if anything) about how individuals, motivated by eco-
nomic and personal considerations, decide where to live.
   Finally, Nevada contends that the rule’s controlled area
boundaries violate what the State describes as the ‘‘non-
endangerment’’ provision of the Safe Drinking Water Act. 42
U.S.C. § 300h(b)(3)(C) (2000) (‘‘Nothing in this section shall
be construed to alter or affect the duty to assure that
underground sources of drinking water will not be endan-
gered by any underground injection.’’). Although conceding
both that EPA need not apply the SDWA to ground water
within the controlled area and that EPA has imported its
SDWA-based, maximum-contaminant-level standards to regu-
late ground water outside the controlled area, Nevada never-
theless insists that the SDWA compels EPA to draw a
                              38

smaller controlled area. This argument fails for a simple
reason: SDWA standards do not apply to the Yucca Moun-
tain repository. On this score, EnPA could not be clearer:
‘‘[EPA’s Yucca standards] shall be the only [public health and
safety] standards applicable to the Yucca Mountain site.’’
EnPA § 801(a)(1); see also H.R. CONF. REP. NO. 102-1018, at
390, reprinted in 1992 U.S.C.C.A.N. at 2481 (‘‘[T]he standards
established by the authority in this section would be the only
such standards for protection of the public from releases of
radioactive materials as a result of the disposal of spent
nuclear fuel or high-level radioactive waste in a repository at
the Yucca Mountain site.’’). Thus, even assuming that the
SDWA applies to nuclear waste disposal at Yucca Mountain,
Congress, acting through EnPA, exempted the Nevada repos-
itory from that statute. Therefore, the SDWA cannot limit
the size of Yucca’s controlled area, and because ‘‘the intent of
Congress is clear, that is the end of the matter.’’ Chevron,
467 U.S. at 842.
  4.   The Definition of ‘‘Disposal’’
   For its final challenge to part 197, Nevada claims that EPA
exceeded its statutory authority by adopting a definition of
the term ‘‘disposal’’ that deviates from the one contained in
the NWPA. While the NWPA defines ‘‘disposal’’ as ‘‘the
emplacement in a repository of high-level radioactive waste,
spent nuclear fuel, or other highly radioactive material with
no foreseeable intent of recovery, whether or not such em-
placement permits the recovery of such waste,’’ 42 U.S.C.
§ 10101(9) (2000), EPA’s rule adds a ‘‘for as long as reason-
ably possible’’ qualifier, 40 C.F.R. § 197.12. The rule defines
‘‘disposal’’ as ‘‘the emplacement of radioactive material into
the Yucca Mountain disposal system with the intent of isolat-
ing it for as long as reasonably possible and with no intent of
recovery, whether or not the design of the disposal system
permits the ready recovery of the material.’’ Id. According
to Nevada, the additional ‘‘for as long as reasonably possible’’
language ‘‘could be read as requiring only temporary delay of
radiation releases with engineered barriers to qualify as
‘disposal,’ mark[ing] a departure from the [c]ongressional
                              39

objective in the NWPA to base repository siting primarily on
the principle of long-term geologic isolation.’’ Nev. Br. at 2.
   Nevada’s claim fails, again for a simple reason: EnPA, the
statute pursuant to which EPA promulgated part 197, does
not require the agency to use NWPA definitions. See EnPA
§ 801(a)(1) (requiring EPA to promulgate standards to gov-
ern Yucca Mountain ‘‘[n]otwithstanding’’ other authority of
the agency to issue generally applicable standards); see also
id. § 801(a)(3) (stating that only EnPA, ‘‘rather than any
other authority of the Administrator to set generally applica-
ble standards for radiation protection,’’ applies to the Yucca
Mountain site). Rather, EnPA is silent as to the meaning of
‘‘disposal,’’ and Nevada has failed to show that in filling that
statutory gap, EPA acted unreasonably. See Chevron, 467
U.S. at 843 (stating that administering a congressionally
created program requires ‘‘the making of rules to fill any gap
left, implicitly or explicitly, by Congress’’).
C. NEI’s Challenge to the Ground-Water Standard
   The Nuclear Energy Institute, a trade association repre-
senting the nuclear energy industry, also takes issue with
part 197. Specifically, it challenges EPA’s inclusion of a
separate ground-water-protection standard. See 40 C.F.R.
§ 197.30. As NEI sees it, requiring DOE to demonstrate
compliance with a distinct ground-water standard is unneces-
sary because the rule’s individual-protection standard already
limits overall radiation exposure, including exposure received
through contaminated ground water.
  1.   Standing
   Before addressing the merits of NEI’s challenge, we must
consider EPA’s claim that the organization lacks standing.
To maintain its petition for review, NEI, like the environmen-
tal petitioners, must demonstrate that it satisfies both associ-
ational and prudential standing requirements. See Hunt, 432
U.S. at 343 (articulating the standing requirements for associ-
ations); Reytblatt v. United States Nuclear Regulatory
Comm’n, 105 F.3d 715, 720 (D.C. Cir. 1997) (stating that the
Hobbs Act, which authorizes ‘‘[a]ny party aggrieved’’ to chal-
                              40

lenge final agency orders, 28 U.S.C. § 2344 (2000), requires
parties to demonstrate both constitutional and prudential
standing).
   NEI claims that it has associational standing because part
197’s ground-water standard will complicate and delay the
completion of the Yucca Mountain repository. According to
NEI, EPA’s addition of a separate ground-water requirement
will force the Energy Department to expend additional re-
sources – both time and money – which will in turn inflict
concrete harm on NEI members who, under the NWPA, not
only bear the cost of storing their spent nuclear fuel until the
Yucca Mountain repository is constructed, but also foot the
repository’s bill through fee assessments paid into the Nucle-
ar Waste Fund. See 42 U.S.C. § 10131(a)(5) (stating that
nuclear waste generators ‘‘have the primary responsibility to
provide for, and the responsibility to pay the costs of, the
interim storage of [nuclear] waste TTT until [it] is accepted by
the Secretary of Energy’’ for disposal); id. § 10222 (requiring
nuclear waste generators to pay fees into the Nuclear Waste
Fund to finance the building and operation of the Govern-
ment’s underground repository). Affidavits submitted by
NEI state (1) that nuclear power plants spend millions of
dollars constructing and operating storage facilities, see Decl.
of Eileen M. Supko ¶¶ 16, 18-21, and (2) that imposition of a
ground-water standard will require DOE to undertake addi-
tional work at the characterization, design, and licensing
stages – which will both delay the date on which the Energy
Department will take stored waste off NEI members’ hands
and increase repository costs, see Decl. of Steven P. Kraft
¶¶ 8-11.
   Disputing these contentions, EPA argues that the separate
ground-water standard imposes no additional cost on the
repository program because the data and analysis required to
assess compliance with the ground-water standard are the
same as those required for the individual-protection standard.
See United States Environmental Protection Agency, Public
Health and Environmental Radiation Protection Standards
for Yucca Mountain, Nevada – Final 40 CFR 197: Evaluation
of Potential Economic Impacts of 40 CFR Part 197 (Economic
                              41

Impact Assessment) at ES-1 to ES-2, 6-5, 7-1 (June 2001);
see also Decl. of Ronald A. Milner ¶ 10 (‘‘[I]t is speculative
whether compliance with the final EPA groundwater stan-
dard would increase costs to the [Nuclear Waste] Fund so as
to require an increase to the TTT per kilowatt-hour fee in the
future or whether compliance with the standard would cause
delays in the construction of a repositoryTTTT’’). Moreover,
the agency argues that NEI’s requested relief – striking the
ground-water standard from part 197 – will not redress the
organization’s alleged injury because, with or without a sepa-
rate ground-water standard, DOE will retain the same reposi-
tory design.
   Based on the record before us, we conclude that NEI has
standing to bring its petition for review. As to injury-in-fact,
we have no doubt that delaying the opening of the Yucca
Mountain repository would inflict concrete harm on NEI
members, for as NEI’s affidavit explains, NEI members
expend substantial sums to operate their own storage facili-
ties. See Supko Decl. ¶¶ 16, 19. We likewise think NEI has
shown a ‘‘substantial probability,’’ Rainbow/PUSH Coalition,
330 F.3d at 542, that the addition of a separate ground-water
standard will cause these delays and that the organization’s
requested relief will likely redress this harm. As NEI points
out, part 197 requires DOE to demonstrate compliance with a
separate ground-water standard in NRC licensing proceed-
ings, see 40 C.F.R. §§ 197.13, 197.30 – a requirement that
both DOE and NAS found could complicate the licensing
process, see Letter from Lake H. Barrett, to United States
Environmental Protection Agency at B-4 (‘‘[T]he proposed
separate, single-pathway, groundwater standard could, de-
pending on how it was implemented, prohibitively complicate
licensingTTTT’’); Letter from Michael Kavanaugh, Chair and
John Ahearne, Vice Chair, Board on Radioactive Waste Man-
agement, National Research Council, to Carol M. Browner,
Administrator, Environmental Protection Agency 11 (Nov. 26,
1999) [hereinafter ‘‘NAS Comments’’] (‘‘Such separate
[ground-water] limits may greatly complicate the licensing
processTTTT’’); see also Kraft Decl. ¶ 10 (asserting that dur-
                               42

ing the NRC licensing process, DOE and NRC will have to
spend time and resources ensuring that the repository com-
plies with the separate ground-water standard). Moreover,
although EPA vigorously disputes NEI’s claim that the
ground-water standard will increase the cost of repository
design and construction, the agency says virtually nothing
about possible delays in the licensing process. Given this
record, NEI has carried its burden of satisfying Article III’s
‘‘irreducible constitutional minimum.’’ Finally, pursuing liti-
gation to speed the licensing of a permanent repository is
‘‘germane to the organization’s purpose[,] and TTT neither the
claim asserted nor the relief requested requires the partic-
ipation of individual members in the lawsuit.’’ Hunt, 432 U.S.
at 343. EPA never suggests otherwise.
    To demonstrate prudential standing, NEI must show that
its members’ ‘‘grievance[s] TTT arguably fall within the zone
of interests protected or regulated by the statutory provision
TTT invoked in the suit.’’ Bennett, 520 U.S. at 162. This test
is ‘‘not meant to be especially demanding. Indeed, a petition-
er is outside the statute’s zone of interests only if [the
petitioner’s] interests are so marginally related to or inconsis-
tent with the purposes implicit in the statute that it cannot
reasonably be assumed that Congress intended to permit the
suit.’’ Nat’l Petrochemical & Refiners Ass’n v. EPA, 287
F.3d 1130, 1147 (D.C. Cir. 2002) (per curiam) (citation and
internal quotation marks omitted). Furthermore, ‘‘there does
not have to be an indication of congressional purpose to
benefit the would-be [petitioner].’’ Nat’l Credit Union Ad-
min. v. First Nat’l Bank & Trust Co., 522 U.S. 479, 492 (1998)
(internal quotation marks omitted). To analyze prudential
standing, we look ‘‘to the particular provision of law upon
which the [petitioner] relies,’’ Bennett, 520 U.S. at 175-76;
‘‘Congress’s purposes in enacting the overall statutory
scheme are relevant only insofar as they may help reveal its
purpose in enacting the particular provision,’’ Grand Council
of the Crees v. FERC, 198 F.3d 950, 956 (D.C. Cir. 2000).
    EPA contends that NEI falls outside the ‘‘zone of inter-
ests’’ that EnPA section 801(a) protects or regulates because
that provision was designed to safeguard public health and
                              43

safety, not to minimize regulatory burdens. Although EPA is
correct that Congress enacted section 801(a) to protect the
public from radiation releases at Yucca Mountain, we think it
equally obvious that Congress intended section 801(a) to
facilitate construction of a permanent nuclear waste reposito-
ry – the very interest that NEI advances here. As evinced in
the NWPA and later in EnPA, Congress viewed EPA stan-
dards as a basic prerequisite for developing an underground
repository. Indeed, because section 801(a) focuses exclusive-
ly on a disposal facility at Yucca Mountain – the statute
regulates no preexisting environmental or health threat – the
required EPA standards would have no purpose whatsoever
were repository construction not to move forward. Finally,
section 801’s requirement that EPA promulgate health and
safety standards no later than one year after receiving NAS’s
recommendations further demonstrates Congress’s intent to
move the federal government expeditiously toward licensing
and operating a repository at Yucca Mountain. In light of
this congressional purpose, NEI’s interests ‘‘arguably’’ fall
within section 801(a)’s zone of interests, thus giving the
organization prudential standing to pursue its petition for
review. We therefore turn to the merits.
   2. Alleged Conflicts with the Energy Policy Act
   NEI argues that EPA’s inclusion of a separate ground-
water standard conflicts with EnPA’s plain language in three
ways. First, NEI claims that by relying on the ‘‘critical
organ dose’’ methodology, EPA’s ground-water standard vio-
lates EnPA section 801(a) because, according to the associa-
tion, that section authorizes EPA to promulgate only stan-
dards that protect individual members of the public based on
the ‘‘effective dose equivalent’’ (EDE) methodology. EnPA
section 801(a)(1) contains three sentences: The first states
that ‘‘the Administrator shall, based upon and consistent with
the findings and recommendations of the National Academy
of Sciences, promulgate, by rule, public health and safety
standards for protection of the public from releases from
radioactive materials stored or disposed of in the repository
at the Yucca Mountain site’’; the second sentence, empha-
sized by NEI, then says, ‘‘[s]uch standards shall prescribe the
                               44

maximum annual effective dose equivalent to individual mem-
bers of the public from releases to the accessible environment
from radioactive materials stored or disposed of in the reposi-
tory’’; the third sentence concludes, ‘‘[t]he standards shall be
promulgated not later than 1 year after the Administrator
receives the findings and recommendations of the National
Academy of Sciences TTT and shall be the only such standards
applicable to the Yucca Mountain site.’’
   Parsing this language, NEI argues that the provision’s
second sentence – ‘‘[s]uch standards shall prescribe the maxi-
mum annual effective dose equivalent to individual members
of the public’’ – defines the scope of the ‘‘public health and
safety standards’’ that the first sentence requires EPA to
promulgate. Therefore, NEI argues, in executing Congress’s
mandate to issue public health standards, the agency may
promulgate only EDE-based safety rules that protect the
public, not rules using a different methodology that protect
ground water. If Congress had thought of EDE standards as
merely a subset of EPA’s overall public health standards,
NEI continues, then it would have used the word ‘‘include’’ in
section 801(a)(1)’s second sentence, not ‘‘prescribe.’’ NEI
also claims that the third sentence’s phrase, ‘‘shall be the only
such standards applicable to the Yucca Mountain site,’’ limits
EPA’s authority to promulgation of the EDE-based standards
referenced in the preceding sentence. In other words, each
time Congress used the term ‘‘standards,’’ NEI argues, it
meant only the EDE standards described in section
801(a)(1)’s second sentence.
   In Chevron terms, the ‘‘precise question’’ presented by
NEI’s challenge is this: Did Congress clearly authorize EPA
to promulgate more than just individual-protection, EDE-
based standards? Unlike NEI, we think it did. To begin
with, section 801(a)(1)’s first sentence expressly requires EPA
to develop ‘‘public health and safety standards’’ – not just
‘‘EDE-based standards.’’ The second sentence’s directive –
that EPA’s standards ‘‘shall prescribe the maximum annual
effective dose equivalent to individual members of the pub-
lic’’ – neither restates nor defines the first sentence’s di-
rective that the agency promulgate ‘‘public health and safety
                              45

standards for protection of the public.’’ Rather, the two
sentences, read together, require EPA to establish a set of
health and safety standards, at least one of which must
include an EDE-based, individual-protection standard. In-
deed, NEI’s reading of section 801(a)(1) would render much
of that provision’s first sentence superfluous, for if Congress
had intended to delegate to EPA authority to adopt an EDE
standard only, it would not have directed the agency to
promulgate ‘‘public health and safety standards for protection
of the public.’’ For essentially the same reason, section
801(a)(1)’s third sentence, which provides that ‘‘[t]he stan-
dards TTT shall be the only such standards applicable to the
Yucca Mountain site,’’ offers no support for NEI’s position.
As we have explained, Congress required EPA to promulgate
‘‘public health and safety standards,’’ not just EDE-based
standards. Therefore, the limitation contained in section
801(a)(1)’s third sentence cannot plausibly be read as refer-
ring to the second sentence’s EDE-based standards.
   NEI also calls our attention to EnPA section 801(a)(3),
which provides that ‘‘[t]he provisions of this section shall
apply to the Yucca Mountain site, rather than any other
authority of the Administrator to set generally applicable
standards for radiation protection.’’ According to NEI, this
section ‘‘precludes the Government’s interpretation of the
first sentence of (a)(1) as giving [it] general authority to
prescribe any health and safety standards.’’ Oral Argument
Tr. at 73. This argument begs the question: Precisely what
authority does section 801(a)(1) delegate to the agency? The
answer, as we just explained, is that section 801 authorizes
EPA to promulgate not merely EDE-based standards, but
rather ‘‘public health and safety standards for protection of
the public.’’
   For its second statutory argument, NEI, echoing Nevada’s
challenge to the 10,000-year compliance period, contends that
part 197’s ground-water standard violates EnPA’s require-
ment that EPA’s rule be ‘‘based upon and consistent with the
findings and recommendations of the National Academy of
Sciences.’’ EnPA § 801(a)(1). As NEI sees it, EPA imper-
missibly promulgated a separate ground-water standard, like
                             46

the one in the generic part 191 standards, despite what NEI
regards as NAS’s conclusion that adding such a standard to
regulate Yucca Mountain waste disposal is unnecessary and
lacks scientific foundation.
   Although we concluded earlier in this opinion that EPA
violated section 801’s ‘‘based upon and consistent with’’ re-
quirement by adopting a 10,000-year compliance period, see
supra at 20-31, we reach the opposite conclusion here because
NAS treated the compliance-period and ground-water issues
quite differently. Whereas NAS expressly rejected a 10,000-
year compliance period, it said nothing at all about the need
to add a separate ground-water standard. The NAS Report
states:
     40 CFR 191 includes a provision to protect ground
     water from contamination with radioactive materials
     that is separate from the 40 CFR 191 individual-dose
     limits. These provisions have been added to 40
     CFR 191 to bring it into conformity with the Safe
     Drinking Water Act, and have the goal of protecting
     ground water as a resource. We make no such
     recommendation, and have based our recommenda-
     tions on those requirements necessary to limit risks
     to individuals.
NAS REPORT at 121. In other words, the Academy never
even considered a ground-water standard. As EPA ex-
plained:
     In its report, NAS did not recommend specifically
     that we include a separate ground water protection
     provision in our environmental protection standards
     for Yucca Mountain. Neither, however, did NAS
     state that we should not include such a provi-
     sionTTTT Our decision to include separate ground
     water standards is a policy decision that we make
     pursuant to our statutory authority under the Ener-
     gy Policy Act.
66 Fed. Reg. at 32,107; see also Response to Comments at 6-
16 (stating that the ground-water standard is not inconsistent
with NAS’s findings because ‘‘NAS clearly identified the
                              47

ground-water pathway as one of the significant pathways of
exposure’’ and because the Academy did not ‘‘make a specific
recommendation that EPA either include or not include a
separate ground-water protection provision’’). Put another
way, NAS made no ‘‘finding’’ or ‘‘recommendation’’ that
EPA’s regulation could fail to be ‘‘based upon and consistent
with.’’ We thus agree with EPA that section 801 left it free
to add a ground-water standard.
   NEI points out that the Academy sharply criticized EPA’s
ground-water standard in a letter submitted during part 197’s
notice-and-comment period. See NAS Comments at 10-12.
But EnPA does not require EPA to conform its rule to
comments that NAS submits during the rulemaking process.
Instead, EnPA section 801(a)(1) requires EPA to base its
standards on the Academy’s ‘‘findings and recommendations.’’
EnPA section 801(a)(2), in turn, requires EPA to obtain those
findings through a formal study conducted by the Academy:
‘‘[T]he [EPA] Administrator shall contract with the National
Academy of Sciences to conduct a study to provide TTT
findings and recommendations on reasonable standards for
protection of the public health and safetyTTTT’’ EnPA
§ 801(a)(2) (emphasis added). Reading these provisions to-
gether, we think it clear that Congress directed EPA to
conform its rule to those ‘‘findings and recommendations’’
that appear in the NAS Report. See Gustafson v. Alloyd
Co., 513 U.S. 561, 570 (1995) (‘‘[I]dentical words used in
different parts of the same act are intended to have the same
meaning.’’). Indeed, NAS itself stated that its ‘‘[f]indings and
recommendations to EPA on the technical bases for Yucca
Mountain standards were provided in the [NAS Report].’’
NAS Comments at 2. Given that report’s silence on the need
for a separate ground-water standard, EPA’s decision to add
distinct ground-water protections rests on ‘‘a permissible
construction’’ of EnPA section 801. See Chevron, 467 U.S. at
843.
   NEI’s final statutory argument requires little discussion.
Pointing out that EnPA directs EPA to protect ‘‘the public
from releases from radioactive materials stored or disposed of
in the repository at the Yucca Mountain site,’’ EnPA
                              48

§ 801(a)(1), NEI argues that the regulation impermissibly
applies not just to ‘‘releases,’’ but to preexisting background
radiation as well. It is true, as NEI observes, that the
ground-water standard caps the permissible level of radiation
contamination by requiring inclusion of ‘‘natural background’’
radiation in the calculation of ‘‘[c]ombined radium-226 and
radium-228’’ as well as ‘‘[g]ross alpha activity.’’ 40 C.F.R.
§ 197.30 (Table 1); see also 66 Fed. Reg. at 32,114 (requiring
that ‘‘DOE combine certain estimated releases from the Yuc-
ca Mountain disposal system with the pre-existing naturally
occurring or man-made radionuclides to determine the con-
centration in the representative volume [of ground water]’’).
Part 197, however, does not regulate background radiation.
See 40 C.F.R. § 197.30 (requiring DOE to demonstrate that
‘‘releases of radionuclides from waste in the Yucca Mountain
disposal system into the accessible environment will not cause
the level of radioactivity TTT to exceed the limits in TTT Table
1.’’ (emphasis added)). As EPA explains, the rule requires
only that DOE take background levels into account when
measuring permissible releases of radionuclides from the
repository. See id. (Table 1). Therefore, part 197 could not
possibly run afoul of EnPA’s focus on released radiation.
  3.   Arbitrary and Capricious Challenge
   NEI also attacks EPA’s ground-water standard as arbi-
trary and capricious. Part 197 requires DOE to show that
the level of radioactivity in the ground water outside the
designated controlled area will not exceed the maximum
contaminant levels for radionuclides that the agency estab-
lished under the Safe Drinking Water Act. See id.; 66 Fed.
Reg. at 32,106. Challenging these MCL limits, NEI claims
that their underlying ‘‘critical organ dose’’ methodology rests
on obsolete science, yields erratic health risks beyond the
high and low limits of EPA’s risk range, and conflicts with
other federal radiation-protection standards. NEI advances
a number of highly complex scientific arguments in support of
these attacks, but we need not address them here because we
rejected the same arguments last year in City of Waukesha v.
EPA.
                              49

   In City of Waukesha, we denied NEI’s challenge to EPA’s
Safe Drinking Water Act regulations, finding the agency’s
chosen methodology for its beta/photon MCLs consistent with
the SDWA’s ‘‘best available science’’ requirement and reason-
able under the APA. See 320 F.3d at 255-57. Specifically,
we saw ‘‘nothing unreasonable about EPA’s assertion that
[its] approach was consistent with the ‘best available science,’
and nothing arbitrary about its decision to [use older MCL
standards] under these circumstances.’’ Id. at 256. NEI’s
‘‘obsolete science’’ claim therefore cannot prevail here. Nor
can we accept NEI’s second argument – that EPA acted
arbitrarily by failing to choose a methodology for the Yucca
Mountain site that would yield consistent risk levels – be-
cause City of Waukesha upheld EPA’s decision to use the
selected MCLs despite their failure to provide uniform pro-
tection levels. See id. at 256-57 (concluding that the agency
acted reasonably in declining to promulgate uniform stan-
dards because risk variations in virtually all cases were
confined to the acceptable range). NEI’s third argument –
that EPA’s Yucca rule conflicts with other federal radiation-
protection standards – likewise founders in light of City of
Waukesha, which concluded that EPA’s MCL standards re-
lied on prevailing federal radiation guidance. See id. at 255-
56. Finally, even if City of Waukesha had not disposed of
this issue and even were there some inconsistency between
part 197’s ground-water standard and other official radiation-
protection guidance, NEI has nonetheless failed to show why
any such inconsistency would make EPA’s use of these stan-
dards at Yucca unreasonable. See id. at 248 (‘‘We may reject
an agency’s choice of scientific model only when the model
bears no rational relationship to the characteristics of the
data to which it is applied.’’ (internal quotation marks omit-
ted)).
   NEI also contends that EPA acted arbitrarily by justifying
its decision to adopt a ground-water standard on cost grounds
without first conducting a cost-benefit analysis. The pream-
ble to part 197’s final version states that ‘‘[b]ecause of the
expenses and difficulties associated with remediation of con-
taminated ground water, it is prudent and cost-effective to
                              50

prevent the occurrence of such contamination.’’ 66 Fed. Reg.
at 32,106. In our view, however, EPA adequately explained
its reasons for adopting the ground-water standard: Not only
did the agency conclude (unremarkably) that an ounce of
prevention is worth a pound of cure, but it explained that
adding a ground-water standard would produce other salu-
tary effects, i.e., ‘‘encourag[ing] a robust containment and
isolation design that will not result in unacceptable contami-
nation during the regulatory time frame.’’ Id. at 32,108; see
also Response to Comments at 6-12 (‘‘We believe that
ground-water protection standards will confer greater protec-
tion to aquatic or biological communities [than an individual-
protection standard alone] by limiting the contamination of
ground water that would discharge to the surface, such as
springs or seep areas.’’).
   Finally, NEI contends that EPA acted unreasonably by
regulating ground water with MCLs that were designed to
apply ‘‘at the tap,’’ i.e., after treatment. But even if the
MCLs were intended to apply ‘‘at the tap’’ in the SDWA
context, NEI gives us no basis for second-guessing EPA’s
decision to import these standards to the Yucca Mountain
site. As we have explained, EPA has offered an entirely
rational reason for protecting water resources while they
remain underground: Preventing ground water contamina-
tion is more cost-effective and environmentally protective,
and applying MCL standards will encourage a robust contain-
ment and isolation design. See 66 Fed. Reg. at 32,106-08.
By contrast, if the repository contaminates local ground wa-
ter, ‘‘future generations will have to decide whether to forego
use of the ground-water resource or to expend substantial
resources to clean [it] upTTTT This would violate one of the
primary principles in radioactive waste management TTT that
radioactive waste disposal should place no undue burdens
upon future generations.’’ Response to Comments at 6-13.

                    III.   THE NRC CASES
  Nevada and two of its political subdivisions – Clark County
and the City of Las Vegas (collectively, Nevada or the
                             51

State) – challenge two NRC actions in separate cases which
we have consolidated for review. In case number 02-1116,
Nevada petitions for review of the requirements and criteria
promulgated by NRC in part 63 of its regulations for licens-
ing the Department of Energy’s planned repository at Yucca
Mountain for the disposal of spent nuclear fuel and high-level
radioactive waste. See Disposal of High-Level Radioactive
Wastes in a Proposed Geologic Repository at Yucca Moun-
tain, NV, 66 Fed. Reg. 55,732 (final rule Nov. 2, 2001)
(codified at 10 C.F.R. pt. 63) [hereinafter part 63]. In a
related case, number 03-1058, Nevada petitions for review of
NRC’s denial of its petition for rulemaking (submitted eight
months after NRC published part 63 in the Federal Register)
seeking various amendments to NRC’s requirements and
criteria, all of which were directed at ensuring that DOE, as
part of the anticipated licensing process, demonstrate that
Yucca Mountain’s geologic makeup provides the ‘‘primary’’
barrier for isolating radioactive waste from the human envi-
ronment. See State of Nevada; Denial of a Petition for
Rulemaking, 68 Fed. Reg. 9023 (Feb. 27, 2003). Although
Nevada’s two cases take different tacks, both essentially
challenge NRC’s requirements and criteria for licensing a
radioactive waste repository at Yucca Mountain.
   Nevada challenges part 63 on multiple grounds. First,
Nevada claims that NRC violated the NWPA by permitting
the licensing of a repository that does not isolate waste
primarily by geologic means and does not provide multiple,
independent barriers to prevent the escape of radionuclides
from the repository. As part of this claim Nevada further
maintains that, by abandoning the so-called multiple-barrier
approach, NRC acted arbitrarily and capriciously, in violation
of the Administrative Procedure Act. Second, Nevada claims
that NRC violated EnPA by failing to require that DOE’s
planned repository comply with EPA’s part 197. See Public
Health and Environmental Radiation Protection Standards
for Yucca Mountain, NV, 66 Fed. Reg. 32,074 (June 13, 2001)
(codified at 40 C.F.R. pt. 197) [hereinafter part 197]. Next,
Nevada claims that NRC violated the NWPA, the Atomic
Energy Act (AEA), 42 U.S.C. §§ 2011 et seq. (2000), and the
                                  52

National Environmental Policy Act (NEPA), 42 U.S.C.
§§ 4321 et seq. (2000), by precluding challenges to DOE’s
peak radiation dose calculations required by part 63 and
violated the APA by limiting the period for evaluating the
repository’s performance to 10,000 years following the place-
ment of waste there. Finally, Nevada claims that NRC
violated the APA by adopting a ‘‘lax’’ ‘‘reasonable expecta-
tion’’ standard of proof for assessing the repository’s ultimate
performance. See Petitioners’ Br. at 66-75.
   For the reasons set forth below, we grant Nevada’s petition
for review in part and deny it in part. Before we turn to the
merits of Nevada’s claims, however, we must address NRC’s
assertion that, for the most part, we lack jurisdiction to do so.
A. Jurisdiction and Timeliness
   NRC contends that we lack jurisdiction to entertain Neva-
da’s petition for review of the part 63 licensing requirements
and criteria (case No. 02-1116) because it was untimely filed
under the Hobbs Act, 28 U.S.C. § 2342, which allows 60 days
for filing a petition for review of final agency action, id.
§ 2344. See Respondent’s Br. at 18-25. NRC argues that
Nevada is not entitled to the benefit of the NWPA’s longer,
180-day window for commencing a civil action challenging
agency action taken ‘‘under’’ subtitle A of the Act provided in
section 119,1 42 U.S.C. § 10139(c), because in promulgating
part 63 NRC did not take action ‘‘under’’ the NWPA.
  1   Section 119 of the NWPA provides in pertinent part:
      [T]he United States courts of appeals shall have original
      and exclusive jurisdiction over any civil action –
        (A) for review of any final decision or action of the
        Secretary, the President, or the Commission under
        this part;
        (B) alleging the failure of the Secretary, the Presi-
        dent, or the Commission to make any decision, or take
        any action, required under this part; [or]
        (C) challenging the constitutionality of any decision
        made, or action taken, under any provision of this
        partTTTT

42 U.S.C. § 10139(a)(1)(A)-(C) (emphases added).
                                   53

   NRC first observes that, while the NWPA requires NRC to
promulgate ‘‘technical requirements and criteria,’’ it directs
NRC to do so ‘‘pursuant to authority under other provisions
of law.’’2 42 U.S.C. § 10141(b)(1)(A) (emphasis added). NRC
next points out that the NWPA manifests that NRC’s author-
ity under ‘‘other provisions of law’’ refers to the AEA and the
Energy Reorganization Act of 1974 (ERA), 42 U.S.C. §§ 5801
et seq. (2000). Because the NWPA directs NRC to promul-
gate ‘‘requirements and criteria’’ under preexisting authority
conferred by the AEA, NRC did not promulgate part 63
‘‘under’’ the NWPA but ‘‘under’’ the AEA. Therefore, as
NRC regulations issued under the AEA are reviewable under
the Hobbs Act, 42 U.S.C. § 2239(a)-(b), which requires a
petition for review to be filed within sixty days following
issuance of the agency’s final rule, see 28 U.S.C. §§ 2342,
2344, Nevada’s petition – filed 160 days after NRC issued its
final licensing criteria – is untimely. NRC does concede that
we retain jurisdiction to address the sole claim made in
Nevada’s second petition for review (case No. 03-1058) – i.e.,
that the NWPA requires Yucca Mountain’s geology to serve
as the repository’s primary mechanism for isolating radioac-
tive waste from the human environment – because ‘‘in the
  2   Section 121 of the NWPA provides in pertinent part:
      [T]he Commission, pursuant to authority under other pro-
      visions of law, shall, by rule, promulgate technical require-
      ments and criteria that it will apply, under the Atomic
      Energy Act of 1954 (42 U.S.C. 2011 et seq.) and the
      Energy Reorganization Act of 1974 (42 U.S.C. 5801 et
      seq.), in approving or disapproving –
         (i) applications for authorization to construct reposito-
         ries;
         (ii) applications for licenses to receive and possess
         spent nuclear fuel and high-level radioactive waste in
         such repositories; and
         (iii) applications for authorization for closure and de-
         commissioning of such repositories.
42 U.S.C. § 10141(b)(1)(A).
                              54

Hobbs Act context this [c]ourt has approved the petition for
rulemaking device to trigger a new opportunity to seek
substantive judicial review of agency rules.’’ Respondent’s
Br. at 28; see also Nat’l Mining Ass’n v. DOI, 70 F.3d 1345,
1350 (D.C. Cir. 1995) (‘‘[O]ur cases TTT have permitted chal-
lenges to rules beyond the statutory period. We have re-
peatedly recognized that such challenges may be brought as
petitions for a new rule and thereafter as petitions for review
of an agency denial.’’). We do not accept NRC’s theory and,
as set forth below, hold that Nevada’s petition for review of
NRC’s part 63 – case No. 02-1116 – was timely filed under
section 119 of the NWPA. See 42 U.S.C. § 10139(c).
   Statutes providing for judicial review, including section 119
of the NWPA, 42 U.S.C. § 10139, ‘‘are jurisdictional in nature
and must be construed with strict fidelity to their terms.’’
Stone v. INS, 514 U.S. 386, 405 (1995); accord Slinger
Drainage, Inc. v. EPA, 237 F.3d 681, 682-83 (D.C. Cir. 2001).
While the NWPA’s judicial review provisions admittedly are
far from a ‘‘model of clarity,’’ Natural Res. Def. Council v.
Abraham, 244 F.3d 742, 743 (9th Cir. 2001); accord Tennes-
see v. Herrington, 806 F.2d 642, 647 (6th Cir. 1986) (‘‘NWPA’s
provisions on judicial review are unclear.’’), we conclude that
NRC issued part 63 ‘‘under’’ section 121 of the NWPA as we
understand that section’s use of this critical term. See 42
U.S.C. § 10139(a)(1)(A)-(C). NRC, relying on the Ninth Cir-
cuit’s decision in Natural Res. Def. Council v. Abraham, 244
F.3d at 746-47, maintains that ‘‘the sine qua non of NWPA
jurisdiction is that the agency action come ‘at least under the
Act.’ ’’ Respondent’s Br. at 20 (emphasis in original (citing
and quoting Natural Res. Def. Council v. Abraham, 244 F.3d
at 747)). We have no quarrel with the commonsensical
proposition that section 119 brings within judicial purview
only those final agency actions embraced by the express
language of the NWPA. See Natural Res. Def. Council v.
Abraham, 244 F.3d at 747 (‘‘NWPA’s provision for judicial
review is limited to decisions ‘under’ the part, or at least
under the Act when the decision is pursuant to a part of the
Act and relates to the purposes of the part in which the
                               55

judicial review provision is placed.’’ (emphases in original));
Herrington, 806 F.2d at 647 (section 119 provides for review
of ‘‘certain actions arising under the Act’’ (emphasis added));
Gen. Elec. Uranium Mgmt. Corp. v. DOE, 764 F.2d 896, 901
(D.C. Cir. 1985) (section 119 provides for review of ‘‘any final
decision or action ‘under’ ’’ the NWPA (quoting 42 U.S.C.
§ 10139(a)(1)(A))). We do, however, part company with NRC
when it asserts that NRC’s challenged actions ‘‘implicated’’
the NWPA but were not taken ‘‘under’’ it. Respondent’s Br.
at 19-20.
  Section 121 of the NWPA provides that NRC
      pursuant to authority under other provisions of law,
      shall, by rule, promulgate technical requirements
      and criteria that it will apply, under the [AEA] TTT
      and the [ERA] TTT, in approving or disapproving –
        (i) applications for authorization to construct
        repositories;
        (ii) applications for licenses to receive and pos-
        sess spent nuclear fuel and high-level radioac-
        tive waste in such repositories; and
        (iii) applications for authorization for closure
        and decommissioning of such repositories.
42 U.S.C. § 10141(b)(1)(A). NRC seizes on section 121’s
instruction that NRC use authority granted ‘‘under other
provisions of law’’ – as well as its explicit reference to those
authorities (the AEA and the ERA) – to accomplish what the
section commands it to do: promulgate ‘‘requirements and
criteria’’ to apply to the three types of listed applications. In
focusing on section 121’s reference to ‘‘authority under other
provisions of law,’’ however, NRC overlooks the fact that
section 121 itself – and not any of NRC’s preexisting authori-
ty under the AEA and the ERA – specifically directs NRC to
adopt ‘‘requirements and criteria’’ to review the specified
applications. See id. § 10141(b).
  NRC likewise ignores that, in addition to directing NRC to
adopt ‘‘requirements and criteria,’’ section 121 imposes con-
straints on the form the ‘‘requirements and criteria’’ may
take. Id. § 10141(b)(1)(B)-(C). Section 121 provides, for
example, that the ‘‘requirements and criteria’’ promulgated by
                              56

NRC ‘‘shall provide for the use of a system of multiple
barriers in the design of the repository and shall include such
restrictions on the retrievability of the solidified high-level
radioactive waste and spent fuel emplaced in the repository
as the Commission deems appropriate.’’ Id. § 10141(b)(1)(B).
Section 121 also requires that NRC’s ‘‘requirements and
criteria shall not be inconsistent with any comparable stan-
dards promulgated by’’ EPA. Id. § 10141(b)(1)(C).
   Our conclusion that NRC promulgated its licensing criteria,
at least in part, ‘‘under’’ the NWPA is buttressed by section
801 of EnPA. See EnPA § 801(b)(1). That section, in the
plainest of language, directs NRC to ‘‘modify its technical
requirements and criteria under section 121(b) of the
[NWPA], as necessary, to be consistent with [EPA’s] stan-
dards.’’ Id. (emphasis added). Therefore, it is simply impos-
sible for us to say, as NRC would have us do, that NRC did
not act ‘‘under’’ the NWPA, at least in part, when it promul-
gated part 63.
   NRC insists that NRC’s authority to regulate the DOE’s
disposal of high-level radioactive wastes predated the passage
of the NWPA and therefore NRC had no need to, and did
not, act ‘‘under’’ the NWPA in promulgating part 63. Specifi-
cally, NRC alleges that section 202 of the ERA, 42 U.S.C.
§ 5842, (not the NWPA) ‘‘gave the NRC the power (and the
obligation) to regulate DOE’s proposed Yucca Mountain re-
pository.’’ Respondent’s Br. at 22. NRC’s argument, howev-
er, is somewhat beside the point. That Congress may have
authorized NRC to regulate DOE’s disposal of radioactive
waste before it enacted the NWPA, compare 42 U.S.C.
§ 5842(3) (providing for licensing and related regulatory au-
thority over ‘‘[f]acilities used primarily for the receipt and
storage of high-level radioactive wastes resulting from activi-
ties licensed under such Act’’); Disposal of High-Level Radio-
active Wastes in Geologic Repositories: Licensing Proce-
dures, 46 Fed. Reg. 13,971 n.1 (final rule Feb. 25, 1981) (‘‘The
Commission interprets ‘storage’ as used in the [ERA] to
include disposal.’’), with 42 U.S.C. § 10134(d) (under the
NWPA ‘‘[t]he Commission shall consider an application for a
construction authorization for all or part of a repository in
                              57

accordance with the laws applicable to such applications’’),
hardly negates the fact that in the NWPA Congress specifi-
cally directed NRC to issue ‘‘requirements and criteria’’ for
evaluating repository-related applications and, not insignifi-
cantly, how to do so.
   We also think that NRC’s reliance on the First Circuit’s
decision in NRDC v. EPA, 824 F.2d 1258 (1st Cir. 1987), is
misplaced. There, the First Circuit decided to exercise
Hobbs Act jurisdiction regarding a petition for review of
standards promulgated by EPA ‘‘pursuant to the directive of
the NWPA’’ because the Hobbs Act authorizes ‘‘judicial re-
view of final orders under the [AEA].’’ Id. at 1263, 1267 n.7.
NRC says a similar result should occur here because the
First Circuit based the exercise of Hobbs Act jurisdiction on
Congress’s instruction to EPA to promulgate its standards
‘‘pursuant to authority under other provisions of law,’’ which
is the precise instruction it gave NRC in section 121 of the
NWPA. See Respondent’s Br. at 20. But the First Circuit
did not confront the issue we confront; section 119 expressly
authorizes judicial review of actions taken by NRC under the
NWPA but does not do so for those taken by EPA. See 42
U.S.C. § 10139(a)(1)(A)-(B). Thus, the First Circuit in
NRDC v. EPA had no occasion to, and in fact did not, choose
between NWPA and Hobbs Act jurisdiction. See 824 F.2d at
1267 n.7. Nor has any other court addressed precisely this
issue so far as the parties or we can tell.
   Section 119 requires that ‘‘any civil action’’ seeking review
of a final NRC ‘‘decision or action’’ under the NWPA, as well
as any action challenging NRC’s failure to make a decision or
take an action under the Act, must be filed ‘‘not later than the
180th day’’ following the challenged decision, action or failure
to act. 42 U.S.C. § 10139(a), (c). Nevada filed its petition
for review of part 63 on April 11, 2002, 160 days after NRC
published part 63 in the Federal Register. See 66 Fed. Reg.
55,732. Because Nevada filed its petition for review of NRC’s
action in promulgating part 63 – an action it took ‘‘under’’ the
NWPA – well within the time allowed by section 119, see 42
U.S.C. § 10139(c), we conclude that its petition is timely.
                              58

   Having found Nevada’s petition for review in case number
02-1116 timely, we accordingly turn now to its merits. Be-
cause we address (and reject) the sole claim raised in Neva-
da’s petition for review in case number 03-1058 – that is, its
challenge to NRC’s denial of its petition for rulemaking – in
reviewing its first petition, however, we need not separately
address that petition.
B. Nevada’s Merits Claims
   We review NRC’s challenged actions under the familiar
administrative law standards noted above. We defer to
NRC’s interpretation of the NWPA under Chevron, 467 U.S.
at 842-43. See Op. supra at 24; see also Barnhart v. Walton,
535 U.S. 212, 218 (2002). Outside the arena of statutory
interpretation, we will affirm the Commission’s action unless
it is ‘‘arbitrary, capricious, an abuse of discretion, or other-
wise not in accordance with law[.]’’ 5 U.S.C. § 706(2)(A); see
City of Brookings Mun. Tel. Co. v. FCC, 822 F.2d 1153, 1164
(D.C. Cir. 1987). We require only that the agency ‘‘examine
the relevant data and articulate a satisfactory explanation for
its action including a ‘rational connection between the facts
found and the choice made.’ ’’ Motor Vehicle Mfrs. Ass’n v.
State Farm Mut. Auto. Ins. Co., 463 U.S. 29, 43 (1983)
(quoting Burlington Truck Lines v. United States, 371 U.S.
156, 168 (1962)). We are ‘‘extreme[ly]’’ deferential, however,
to an agency ‘‘ ‘evaluating scientific data within its technical
expertise.’ ’’ Huls Am. Inc. v. Browner, 83 F.3d 445, 452
(D.C. Cir. 1996) (quoting Int’l Fabricare Inst. v. EPA, 972
F.2d 384, 389 (D.C. Cir. 1992)). With the exception of the
selection of a 10,000-year compliance period, discussed below,
see Op. infra at 72-74, the NRC actions under review meet
these standards.
   1. Primary Barrier and Multiple Barriers Claims
     a. The Primary Barrier Claim
  Nevada first charges that part 63 flouts Congress’s unam-
biguous directive that Yucca Mountain’s geologic features
must serve as the repository’s primary means of isolating
radioactive waste from the human environment. Nevada
acknowledges that part 63 provides that the ‘‘geologic reposi-
                               59

tory must include multiple barriers, consisting of both natural
barriers and an engineered barrier system.’’ 10 C.F.R.
§ 63.113(a). Likewise, it recognizes that part 63 requires
DOE to identify the features ‘‘that are considered barriers
important to waste isolation’’ of both the natural geologic
setting and the engineered barrier system and to describe,
with technical support, their respective capabilities to isolate
waste. Id. § 63.115(a)-(c). Nevada argues that part 63 is
nevertheless flawed, however, because nowhere does it re-
quire that Yucca Mountain’s geologic features provide ‘‘inde-
pendent or primary waste isolation capabilities.’’ Petitioners’
Br. at 43.
   Nevada calls to our attention various provisions of the
NWPA that it believes demonstrate that Congress intended
the geologic features of the DOE’s planned repository to act
as the primary barrier for isolating waste from the human
environment. The NWPA defines ‘‘repository’’ as ‘‘any sys-
tem’’ for ‘‘the permanent deep geologic disposal of high-level
radioactive waste and spent nuclear fuel.’’ 42 U.S.C.
§ 10101(18). Nevada also invokes sections 112 and 113 of the
NWPA which, in its view, ‘‘emphasize the central importance
of a site’s physical characteristics to determining its suitabili-
ty [as a repository].’’ Petitioners’ Br. at 45. Nevada points
out that section 112 requires ‘‘geologic considerations’’ to
serve as the ‘‘primary criteria for the selection of sites in
various geologic media.’’ 42 U.S.C. § 10132(a). It also notes
that section 113 contemplates that DOE may find a candidate
site ‘‘unsuitable’’ for development as a repository, see 42
U.S.C. § 10133(c)(3), a finding it believes would not make
sense ‘‘unless the site itself, without engineered barriers,
could fail to meet disposal safety requirements.’’ Petitioners’
Br. at 45. Based on these statutory references, Nevada
concludes that ‘‘[i]t would make little sense for Congress to
require that DOE focus on a site’s physical characteristics in
analyzing the site’s suitability, only to be indifferent to wheth-
er NRC reduced such characteristics to an afterthought in
any subsequent licensing proceedings.’’ Id.
                              60

   Nevada further explains that section 113 requires that, in
determining a candidate site’s suitability as a repository,
DOE must conduct site-characterization activities in accor-
dance with section 112, 42 U.S.C. § 10133(b)(1)(A)(iv), which
section provides that ‘‘geologic considerations TTT shall be
[the] primary criteria.’’ Id. § 10132(a). Moreover, because
the NWPA limits DOE’s site-characterization activities to
those necessary to evaluate the site’s suitability to apply to
NRC for construction authorization, see id. § 10133(c)(1),
Nevada maintains that it necessarily follows that NRC’s
licensing criteria must also require that a repository’s geolog-
ic features serve as the ‘‘primary’’ means for isolating waste.
Otherwise, according to Nevada, ‘‘it would have made no
sense for Congress to have required DOE to make this the
primary factor in determining whether’’ to file an application
with NRC. Petitioners’ Br. at 46 (emphasis in original).
   NRC initially faults Nevada for failing to take up this
statutory claim with the Commission before raising it on
review. It maintains that Nevada never asserted during
NRC’s public comment period that the NWPA requires the
repository’s geologic features to serve as the primary barrier
and, consequently, Nevada has waived that argument. We
conclude, however, that Nevada adequately raised the pri-
mary barrier claim to avoid the consequences of our waiver
doctrine. ‘‘Absent special circumstances, a party must initial-
ly present its comments to the agency during the rulemaking
in order for the court to consider the issue.’’ Tex Tin Corp.
v. EPA, 935 F.2d 1321, 1323 (D.C. Cir. 1991) (emphasis
added); accord Nebraska v. EPA, 331 F.3d 995, 997 (D.C.
Cir. 2003). ‘‘As a general rule, claims not presented to the
agency may not be made for the first time to a reviewing
court.’’ Omnipoint Corp. v. FCC, 78 F.3d 620, 635 (D.C. Cir.
1996). To preserve a legal or factual argument, we require
its proponent to have given the agency a ‘‘fair opportunity’’ to
entertain it in the administrative forum before raising it in
the judicial one. Wash. Ass’n for Television & Children v.
FCC, 712 F.2d 677, 681 (D.C. Cir. 1983); see Nat’l Ass’n of
Mfrs. v. DOI, 134 F.3d 1095, 1111 (D.C. Cir. 1998).
                                61

   Nevada has the better of this argument; we believe that it
did not waive its primary barrier claim. It contends that it,
and others, made the claim to NRC during the public com-
ment period which closed on June 30, 1999. See 66 Fed. Reg.
at 55,732-33. As far as we can tell from the two record
citations the State offers us, however, neither it nor any other
commenter advanced the argument it presses here during
NRC’s public comment period. See Tr. of Proceedings, Unit-
ed States of America, Nuclear Regulatory Commission, Public
Meeting on Proposed Regulations (10 Part 63) For a High-
Level Waste Repository at Yucca Mountain, NV, June 16,
1999, at 82-84, reprinted in Joint Appendix (J.A.) 76-78
(stating that DOE definition of defense-in-depth3 originally
meant that ‘‘geologic barriers were supposed to supply the
main barrier to transport of radioactive waste once the repos-
itory started leaking’’ and inquiring of NRC staff whether
DOE could ‘‘acceptabl[y]’’ rely primarily on man-made con-
tainers to secure waste); Comments of the Inst. for Energy
& Env’t Research on the Draft NRC Rule on Disposal of
High-Level Radioactive Wastes in a Proposed Repository at
Yucca Mountain, NV, June 30, 1999, at 1-2, reprinted in J.A.
108-09 (‘‘Allowing primary reliance on engineered barriers for
waste isolation would be inappropriate.’’ (emphasis added)).
   Nevada did raise the argument it advances here during a
public meeting NRC held on November 2, 1999 to discuss the
defense-in-depth notion ‘‘as applied to a possible high-level
waste repository at Yucca Mountain.’’ Official Tr. of Pro-
ceedings, United States of America, Nuclear Regulatory
Commission, Pubic Meeting – A Facilitated Roundtable Dis-
cussion on Defense in Depth as Applied to a Possible High-
Level Waste Repository at Yucca Mountain, NV, Nov. 2,
1999, at 1, 76-77, reprinted in J.A. 113, 119-20 (capitalization
altered). There, a representative of the Nevada Agency for
  3 NRC uses ‘‘defense-in-depth’’ to mitigate the uncertainties in-
volved in ensuring the safety of complex facilities by requiring
multiple and redundant safety barriers. See 64 Fed. Reg. at 8647;
see also Op. infra at 68.
                                  62

Nuclear Projects observed that NRC had to follow the
NWPA’s command, expressed in section 112, that ‘‘geologic
factors shall be primary’’ in evaluating both Yucca Mountain’s
natural features and DOE’s engineered barriers and their
respective roles in waste isolation. See id. at 119-20. This is
in essence the same point Nevada raises here.
   NRC maintains, however, that the statement does not
count because it came too late. It asserts that the Nevada
representative made the statement during a public meeting
that occurred several months after the public comment period
closed and that NRC had made clear that the meeting was
not intended to reopen that period. But NRC’s representa-
tions were far more equivocal than NRC would lead us to
believe and, taken together, indicate that the public comments
it received during the meeting would in fact figure in its
decision-making process. Compare J.A. 122 (‘‘[T]his is not an
extra public comment period. It is a way to help us make
more clear what we’ve put out in our proposal and to under-
stand better the comments that we’ve receivedTTTT’’), with
J.A. 117 (‘‘[W]e’re here in the process of responding to public
comments on Part 63, and we are here to get your input on
this particular issue [the defense-in-depth issue] as we final-
ize Part 63.’’ (emphasis added)); J.A. 126 (‘‘[T]hat comment,
as well as all of the other very fine comments that we’ve
heard today, will be carried back [to NRC].’’). Our conclu-
sion is further bolstered by NRC’s own words. In the
Supplemental Information accompanying the final version of
part 63, NRC referred to this very meeting in a context which
plainly suggests that it considered what occurred there in
developing its regulation.4 See 66 Fed. Reg. at 55,732-33.
  Accordingly, we conclude that Nevada gave NRC a ‘‘fair
opportunity’’ to pass on its primary barrier claim. See Wash.
Ass’n for Television & Children, 712 F.2d at 681. The State
  4  NRC explained that ‘‘[i]n developing this final rule, [it] consid-
ered comments received at’’ various public meetings, noting that it
‘‘also held a facilitated round table discussion on defense in depth as
applied to a possible repository at Yucca Mountain on November 2,
1999, in Las Vegas.’’ 66 Fed. Reg. at 55,733.
                              63

made its point – more than two years before part 63 was
published – during a public meeting held, as we have noted,
for the express purpose of discussing defense-in-depth. And
NRC expressly acknowledged that meeting in the Supple-
mental Information. See Op. supra at note 4. Nevada wins
the battle, however, only to lose the war.
    Under Chevron Step One, we use the customary statutory
construction tools of text, structure and purpose. See Ca.
Metro Mobile Communications, Inc. v. FCC, 365 F.3d 38, 44-
45 (D.C. Cir. 2004). Using those tools, we find nothing that
unambiguously prohibits NRC from deciding not to require
DOE to build a repository that relies on the repository’s
geologic setting to provide the primary mechanism for isolat-
ing waste from the human environment. Indeed, the
NWPA’s language instructs otherwise. In section 121 Con-
gress specifically directs NRC to issue ‘‘technical require-
ments and criteria’’ that ‘‘provide for the use of a system of
multiple barriers in the design of the repository.’’ 42 U.S.C.
§ 10141(b)(1)(B) (emphasis added). The NWPA contains no
language indicating that NRC is to assign a rating to any
single barrier – whether natural or artificial – in a repository
with a ‘‘system of multiple barriers.’’ Id.; cf. id. § 10101(12)
(‘‘ ‘[E]ngineered barriers’ means manmade components of a
disposal system designed to prevent the release of radionu-
clides into the geologic medium involved.’’); id. § 10101(18)
(‘‘ ‘[R]epository’ means any system licensed by the Commis-
sion that is intended to be used for, or may be used for, the
permanent deep geologic disposal of high-level radioactive
waste and spent nuclear fuelTTTT’’ (emphasis added)).
   Nor does section 121 say anything about the barrier the
repository’s geologic composition must provide in the ‘‘system
of multiple barriers.’’ Id. § 10141(b). Congress did, howev-
er, circumscribe NRC’s rulemaking authority in section 121 in
three significant respects, only one of which is directly rele-
vant here – i.e., NRC must require a repository to ‘‘use TTT a
system of multiple barriers.’’ Id. § 10141(b)(1)(B). We find
it telling that Congress refrained from further delimiting
NRC’s authority in section 121. If Congress had intended to
                              64

mandate that the ‘‘requirements and criteria’’ give primacy to
a repository’s geologic makeup, it would have expressly so
provided – especially given that such an additional restriction
on NRC’s authority would be significant. See Indep. Ins.
Agents of Am., Inc. v. Hawke, 211 F.3d 638, 643-44 (D.C. Cir.
2000) (relying on expressio unius est exclusio alterius canon
to find provision of National Bank Act expressly authorizing
banks in smaller locales to sell insurance ‘‘strongly con-
firm[ed] the view that the more general grant in [a second
provision of the Act] did not include broad insurance pow-
ers’’). We are therefore hard pressed to conclude that Con-
gress ‘‘has directly spoken to the precise question at issue’’
here and decline to do so. Chevron, 467 U.S. at 842. Accord-
ingly, we move to Chevron Step Two and defer to NRC’s
interpretation of section 121 so long as it is based on a
permissible construction. See Chevron, 467 U.S. at 842-43;
Barnhart, 535 U.S. at 218.
   Section 121 authorizes NRC to adopt ‘‘requirements and
criteria’’ to license a waste repository at Yucca Mountain
subject to the limitations outlined above. See 42 U.S.C.
§ 10141(b); see generally 10 C.F.R. § 63.113(a) (‘‘The geolog-
ic repository must include multiple barriers, consisting of
both natural barriers and an engineered barrier system.’’);
see also id. § 63.113(b)-(d) (‘‘engineered barriers TTT, working
in combination with natural barriers,’’ must meet certain
specific performance standards). None of the restrictions,
however, specifies how the requirements and criteria ‘‘shall
provide for the use of a system of multiple barriers in the
design of the repository’’ or the role that any particular
barrier must play in the system. 42 U.S.C. § 10141(b)(1)(B).
While Congress contemplated that the repository’s geologic
makeup was to play a significant role in isolating radioactive
waste, see id. §§ 10101(18), 10132(a), we cannot say that NRC
acted unreasonably in declining to read into section 121’s
otherwise plain wording a requirement that it serve as the
repository’s principal barrier for isolating waste. See id.
§ 10141(b)(1)(B).
   Not surprisingly, Nevada eschews reliance on section 121 –
which speaks directly to NRC’s duty to issue requirements
                              65

and criteria for licensing a repository – in favor of other
provisions of the NWPA. None of the provisions to which it
directs our attention, however, even remotely compels NRC
to adopt requirements and criteria that put the greatest
burden for isolating waste on a repository’s geologic barrier
potential. In fact, the State relies on NWPA provisions that
govern actions taken by DOE, not NRC. It relies principally
on section 112 of the NWPA, which directs the DOE Secre-
tary to issue ‘‘general guidelines for the recommendation of
sites for repositories TTT [that] specify detailed geologic con-
siderations that shall be primary criteria for the selection of
sites in various geologic media.’’ Id. § 10132(a); see also id.
§§ 10133(b)(1)(A)(iv) (DOE to submit criteria used to deter-
mine a site’s suitability), 10133(c)(3)(A)-(F) (describing DOE’s
obligations upon determining site unsuitable).
   The argument Nevada puts together from various provi-
sions of the NWPA – i.e., that NRC’s licensing criteria must
track DOE’s site-selection criteria emphasizing the site’s geol-
ogy – is similarly flawed in relying on the NWPA’s commands
to DOE. Of course, it would be strange for Congress in one
breath to require DOE to select a site suitable for a reposito-
ry based on geologic considerations, while in the next autho-
rizing NRC to ignore them. Congress’s directives to the
agencies were plainly intended to be complementary not
contradictory. NRC acknowledges as much. See 68 Fed.
Reg. at 9027 (‘‘It may be readily acknowledged that it would
make little sense for Congress to establish a system for
selecting a repository where DOE guidelines for selection of
sites and NRC regulations for licensing a repository would
contradict each other.’’). But complementary duties do not
have to be identical. No statutory language requires it and
there is nothing contradictory about Congress requiring DOE
to recommend a suitable repository site based on geologic
considerations, while instructing NRC to issue requirements
and criteria for licensing a repository based on the use of a
system of multiple barriers, including but not emphasizing,
the geologic barrier. See 68 Fed. Reg. at 9028.
   Indeed, NRC’s requirements and criteria to license a re-
pository designed by DOE come into play only after DOE
                                 66

selects a suitable site based on geologic considerations. See
42 U.S.C. §§ 10132(a); 10133(b); 10134; see also 68 Fed.
Reg. at 9027. Under the scheme the NWPA establishes,
DOE submits an application for authorization to construct a
repository with NRC after it selects a site under section 112
based on guidelines ‘‘specify[ing] detailed geologic consider-
ations that shall be primary criteria for selection of sites in
various geologic media,’’ 42 U.S.C. § 10132(a), and performs
characterization activities under section 113 to determine the
‘‘suitability of [the] site for the location of a repository,’’ id.
§ 10133(b)(1)(A)(iv). Thus, by statutory design, NRC’s li-
censing regulations are used to evaluate a repository pro-
posed by DOE at a site also selected by DOE after DOE has
considered the site’s geologic makeup. See id. §§ 10132(a),
10133(b)(1)(A)(iv). As NRC itself recognized, Congress had
‘‘no need to require, and did not require, NRC to issue
regulations making geologic considerations the ‘primary’ cri-
teria for approval of DOE’s license application for the reposi-
tory.’’ 68 Fed. Reg. at 9027.
   Nevada’s non-textual contentions are equally unconvincing.
It relies on the First Circuit’s decision in NRDC v. EPA,
which declared that in the NWPA ‘‘Congress ordered that
these highly dangerous wastes be placed underground with
the intent that the surrounding geologic formations would be
the major component of the containment mechanism.’’ 824
F.2d at 1279. The court made the statement, however, in
treating a different issue – namely, whether EPA departed
from the ‘‘non-endangerment’’ mandate of the Safe Drinking
Water Act by permitting groundwater contamination within
the repository’s ‘‘controlled area.’’ Id. at 1276-79. Because
the court’s observation came in resolving EPA’s apparently
conflicting obligations under the SDWA and the NWPA, it
offers minimal support for Nevada’s contention.5 Id. at 1279.
  5 The State also resorts to the legislative history of the NWPA,
asserting that it ‘‘leaves no doubt about the primacy of geologic
isolation.’’ Petitioners’ Br. at 46. But Nevada’s proffered citations
say not a word about whether Congress intended NRC to ensure
that the repository’s geologic features provide the primary barrier
for isolating waste from the human environment. See, e.g., H.R.
                                67

    For the foregoing reasons, we conclude that NRC’s ‘‘re-
quirements and criteria’’ to license a nuclear waste repository
reasonably and permissibly implement section 121 of the
NWPA.
    b. The Multiple Barriers Claims
    Nevada next argues that NRC violated the NWPA’s re-
quirement that a repository incorporate a ‘‘multiple barriers’’
system by failing to include ‘‘any specific requirement for any
barrier to provide any degree of protection that is substan-
tially independent of the others.’’ Petitioners’ Br. at 49. In
not providing ‘‘safety redundancy’’ by specifying minimum
performance standards for each of the multiple barriers,
Nevada maintains, NRC ‘‘deprived’’ the multiple barriers
requirement of any ‘‘vitality.’’ Petitioners’ Br. at 49. We
disagree.
    Although Congress statutorily required NRC’s ‘‘technical
requirements and criteria’’ to provide for multiple barriers, 42
U.S.C. § 10141(b)(1)(B), it did not address this precise issue.
See Chevron, 467 U.S. at 842-43. Nevertheless we find that
NRC’s interpretation of section 121 is ‘‘based on a permissible
construction of’’ the section. See Chevron, 467 U.S. at 843.
Pursuant to section 121, NRC must adopt technical require-
ments and criteria that ‘‘provide for the use of a system of
multiple barriers in the design of the repository.’’ 42 U.S.C.
§ 10141(b)(1)(B) (emphasis added). This is just what NRC
did. Section 63.113 of the NRC regulations requires that
‘‘[t]he geologic repository must include multiple barriers,
consisting of both natural barriers and an engineered barrier
system.’’ 10 C.F.R. § 63.113(a); see also id. § 63.102(h)
(‘‘uncertainties are addressed by requiring the use of a multi-
ple barrier approach; specifically, an engineered barrier sys-
tem is required in addition to the natural barriers provided
REP. NO. 97-491, pt. 1, at 30 (1982) (‘‘Commitment to a waste
disposal technology relying on primary geologic containment provid-
ed by a solid rock formation located deep underground, together
with containment by engineered barriers including the form and
packaging of the nuclear waste, which will provide safe containment
of the waste without reliance on human monitoring and mainte-
nanceTTTT’’ (emphasis added)).
                              68

by the geologic setting’’). The NRC regulations also require
that the ‘‘engineered barriers, working in combination with
natural barriers’’ meet certain performance standards. Id.
§ 63.113(b)-(d). Furthermore, in order to comply with sec-
tion 63.113, DOE must identify the design features of the
engineered barriers and the natural features of the reposito-
ry’s geologic makeup ‘‘that are considered barriers important
to waste isolation’’ as well as describe – backed by technical
support – their capabilities ‘‘to isolate waste, taking into
account uncertainties in characterizing and modeling the be-
havior of the barriers.’’ Id. § 63.115(a)-(c). Section 121 does
not, as Nevada contends, require that each barrier type
provide a quantified amount of protection or, indeed, indepen-
dent protection. See 42 U.S.C. § 10141(b)(1)(B). Its silence
instead gives NRC flexibility in determining how best to
‘‘provid[e] for the use of a system of multiple barriers in the
design of the repository.’’ See id. We think that NRC, in
implementing this requirement in the manner discussed
above, acted reasonably and permissibly. See Chevron, 467
U.S. at 843.
   Nevada next asserts that even if section 121 does not
require barrier-by-barrier performance assessment, NRC ar-
bitrarily and capriciously abandoned its longstanding regula-
tory philosophy of ‘‘defense-in-depth.’’ See Petitioners’ Br. at
50-54. The defense-in-depth concept ensures that a geologic
repository system is robust; that is, that the system is
capable of withstanding unanticipated failures and other chal-
lenges to its integrity through the deployment of multiple and
redundant safety barriers. Specifically, Nevada contests
NRC’s use of defense-in-depth at the proposed Yucca Moun-
tain repository through an overall system performance as-
sessment rather than using the approach of its older regula-
tions, which approach tests the individual performance of the
repository’s ‘‘system elements.’’ See Disposal of High-Level
Radioactive Wastes in a Proposed Geologic Repository at
Yucca Mountain, NV, 64 Fed. Reg. 8640, 8648 (proposed rule
Feb. 22, 1999. (‘‘Commission opted to prescribe minimum
performance standards for each of the major system ele-
ments’’ in part 60)); see 10 C.F.R. § 60.113 (performance
standards for particular barriers). At bottom, Nevada main-
                              69

tains that NRC failed to explain adequately its departure
from the approach it took in part 60, which governs the
disposal of high-level radioactive wastes in geologic reposito-
ries other than Yucca Mountain and uses the sort of subsys-
tem performance assessment that part 63 eschews. See 10
C.F.R. § 60.113. We do not agree.
  An agency is free to discard precedents or practices it no
longer believes correct. See, e.g., Motor Vehicle Mfrs. Ass’n,
463 U.S. at 57 (‘‘[A]n agency changing its course must supply
a reasoned analysis.’’); Ramaprakash v. FAA, 346 F.3d 1121,
1124-25 (D.C. Cir. 2003). Indeed we expect that any agency
may well change its past practices with advances in knowl-
edge in its given field or as its relevant experience and
expertise expands. See Ramaprakash, 346 F.3d at 1124. If
an agency decides to change course, however, we require it to
supply a ‘‘reasoned analysis indicating that prior policies and
standards are being deliberately changed, not casually ig-
nored.’’ Greater Boston Television Corp. v. FCC, 444 F.2d
841, 852 (D.C. Cir. 1970); see also Ramaprakash, 346 F.3d at
1124-25. And NRC has done so.
   NRC set out its rationale in opting to evaluate the pro-
posed Yucca Mountain repository based on a total system
performance assessment in the Supplemental Information
accompanying both the proposed and the final part 63. See
66 Fed. Reg. at 55,758-59; 64 Fed. Reg. at 8647-50. NRC
initially observed that advances in knowledge of the earth
sciences undermined the need, reflected in part 60, to com-
pensate for the major uncertainties inherent in assessing the
long-term performance of geologic repositories. See 64 Fed.
Reg. at 8648-49. NRC stated that ‘‘experience and improve-
ments in the technology of performance assessment, acquired
over more than [fifteen] years, now provide significantly
greater confidence in the technical ability to assess compre-
hensively overall repository performance, and to address and
quantify the corresponding uncertainty.’’ Id. at 8649. More-
over, NRC noted that its early approach, adopted at a time
when quantitative techniques for assessing repository per-
formance were in their infancy, had failed to ‘‘gain[ ] broad
                              70

acceptance in the technical community’’; it cited both the
National Academy of Sciences and its own Advisory Commit-
tee as holding views critical of its approach. Id. According-
ly, NRC concluded that ‘‘advances in performance assessment
technology support the use of performance assessment re-
sults for estimating long term repository performance’’ and
that these advances ‘‘obviate[d] TTT the need to prescribe
arbitrary, minimum performance standards for subsystems to
build confidence in a system’s overall performance.’’ 66 Fed.
Reg. at 55,758.
   Moreover, NRC expressed concern that, based on its fif-
teen years’ experience working with part 60, the application
of part 60’s subsystem performance standards ‘‘may impose
significant additional expenditure of resources on the nation’s
[high level waste] program, without producing any commen-
surate increase in the protection of public health and safety.’’
64 Fed. Reg. at 8649. NRC thus determined in the final rule
to give DOE ‘‘flexibility for deciding the extent and focus of
site characterization’’ and concluded that DOE, as the reposi-
tory’s designer, ‘‘may place greater or lesser reliance on
individual components of the repository system when deciding
how best to achieve the overall safety objective.’’ 66 Fed.
Reg. at 55,758.
   Finally, NRC explained that part 60’s subsystem criteria,
as originally conceived, were ‘‘intended to be separate, ‘inde-
pendent,’ easily-determined measures of subsystem perform-
ance, determination of which would require only application of
technology that was readily available.’’ 64 Fed. Reg. at 8649.
According to NRC, however, ‘‘[e]xtensive experience with
site-specific performance assessment has shown [the subsys-
tem criteria] to be none of these.’’ Id. Indeed, as NRC
explained in the final rule, ‘‘[e]stimates of subsystem perform-
ance are subject to many, if not all, of the same sources of
uncertainty as are estimates of overall system performance’’
and concluded that ‘‘[i]t is questionable, therefore, whether
the subsystem criteria in part 60, or any other criteria, could
provide truly independent assurance of total system perform-
ance.’’ 66 Fed. Reg. at 55,758. In light of NRC’s detailed
analysis supporting its decision to evaluate the performance
of the Yucca Mountain repository based on the barrier sys-
                               71

tem’s overall performance, we believe that it adequately
explained its change in course. See, e.g., Motor Vehicle Mfrs.
Ass’n, 463 U.S. at 57. Accordingly, we conclude that NRC
acted neither arbitrarily nor capriciously in rejecting part 60’s
subsystem performance approach in favor of the overall per-
formance approach.
   2. Compliance With EPA’s Part 197 in Construction
       Authorization
   Nevada alleges that NRC violated the NWPA and EnPA
by permitting construction of the Yucca Mountain repository
without first determining that there is a reasonable expecta-
tion that the repository will comply with the EPA standards.
Nevada maintains that, because NRC is required under both
the NWPA and EnPA to promulgate licensing requirements
and criteria that are consistent with the EPA standards,
NRC must ensure that the proposed repository will meet
those standards before it authorizes construction. According
to Nevada, however, NRC’s pertinent regulation, section
63.31, does not require the Commission to find that DOE’s
application for construction authorization complies with the
EPA standards set out in part 197, see 40 C.F.R. pt. 197, or
that the application satisfies the EPA standards as incorpo-
rated in part 63. Nevada points to paragraph 63.31(a)(3)(ii),
which provides that, in making its construction authorization
decision, NRC must simply ‘‘consider’’ whether ‘‘the site and
design comply with the performance objectives and require-
ments contained in subpart E’’ (requiring compliance with
EPA standards set forth in subpart L of part 63, see 10
C.F.R. § 63.113(b)). In Nevada’s view, NRC has ‘‘[c]learly
TTT unlawfully reserved for itself the discretion to authorize
repository construction even in the face of authoritative evi-
dence that it will not comply with NRC’s own (and EPA’s)
safety requirements.’’ Petitioners’ Br. at 56.
   NRC in turn asserts that Nevada offered ‘‘no hint’’ of this
argument during NRC’s rulemaking proceedings and, as a
consequence, cannot now challenge section 63.31 on this
ground. Respondent’s Br. at 26. While Nevada does not
deny that it failed to raise the argument below, offering no
citation in the voluminous record where it did so, it counters
                              72

that it did not have to. Petitioners’ Reply Br. at 12-13.
Nevada maintains that its oversight was ‘‘both understanda-
ble and excusable’’ in that EPA did not propose its standards
until after the window for public comment on part 63 had
closed, and thus, the timing of NRC’s rulemaking proceedings
‘‘discourag[ed]’’ the public from commenting ‘‘on the interre-
lationship’’ of the two agencies’ regulations. Petitioners’ Re-
ply Br. at 12-13. We are unconvinced.
   It is a hard and fast rule of administrative law, rooted in
simple fairness, that issues not raised before an agency are
waived and will not be considered by a court on review. See
United States v. L.A. Trucker Truck Lines, Inc., 344 U.S. 33,
37 (1952) (‘‘Simple fairness to those who are engaged in the
tasks of administration, and to litigants, requires as a general
rule that courts should not topple over administrative deci-
sions unless the administrative body not only has erred but
has erred against objection made at the time appropriate
under its practice.’’); see also Nat’l Wildlife Fed’n v. EPA,
286 F.3d 554, 562 (D.C. Cir. 2002) (‘‘[T]here is a near absolute
bar against raising new issues – factual or legal – on appeal in
the administrative context.’’); Nat’l Ass’n of Mfrs., 134 F.3d
at 1111 (‘‘ ‘Our cases TTT require complainants, before coming
to court, to give the [agency] a fair opportunity to pass on a
legal or factual argument.’ ’’ (quoting Wash. Ass’n for Televi-
sion & Children, 712 F.2d at 681 (alteration and emphasis in
original))). The rule applies with no less force to a statutory
interpretation claim not brought to an agency’s attention:
‘‘[R]espect for agencies’ proper role in the Chevron frame-
work requires that the court be particularly careful to ensure
that challenges to an agency’s interpretation of its governing
statute are first raised in the administrative forum.’’ Natural
Res. Def. Council v. EPA, 25 F.3d 1063, 1074 (D.C. Cir. 1994);
see also Ohio v. EPA, 997 F.2d 1520, 1528 (D.C. Cir. 1993);
Linemaster Switch Corp. v. EPA, 938 F.2d 1299, 1308-09
(D.C. Cir. 1991). Nevada failed to raise this claim before
NRC and consequently waived it.
   3. 10,000-Year Compliance Period
   Nevada next alleges that NRC breached its duty under the
AEA and the NWPA to safeguard the public health and
                              73

safety and arbitrarily and capriciously limited the period for
evaluating the repository’s performance to 10,000 years fol-
lowing the placement of waste there. According to Nevada,
NRC chose – based on political realities rather than hard
science – to assess the repository’s performance only for the
period preceding the time the repository will pose the great-
est health risk to future generations, ignoring the advice of
experts that there are no technical impediments to evaluating
the repository’s performance for a much longer period as well
as its own recognition that such an evaluation is feasible.
Nevada claims that it is unreasonable for NRC to require
DOE to compute the peak dose of radiation much further out
but for NRC not to consider the repository’s performance at
that time, claiming that the uncertainties related to human
behavior and exposure pathways in predicting the reposito-
ry’s performance during the 10,000 years following waste
placement can be addressed as well in assessing its perform-
ance thereafter. Nevada additionally faults NRC’s decision
to confine its evaluation of the repository’s performance to
10,000 years because, Nevada claims, NRC knows that a
reasonably maximally exposed individual will ‘‘likely’’ receive
a peak dose of radiation that exceeds NRC’s and EPA’s
limits. Petitioners’ Br. at 59.
   In its proposed rule, NRC named three factors in propos-
ing the 10,000-year compliance period: (1) it ‘‘correspond[ed]
to the time period when the waste is inherently most hazard-
ous’’; (2) it ‘‘is sufficiently long, such that a wide range of
conditions will occur which will challenge the natural and the
engineered barriers, providing a reasonable evaluation of the
robustness of the geologic repository’’; and (3) it ‘‘is consis-
tent with other regulations involving geologic disposal of long-
lived hazardous materials, including radionuclides.’’ 64 Fed.
Reg. at 8647. In the Supplemental Information accompany-
ing part 63 in its final form, NRC used the same three factors
as the basis for adopting a 10,000-year compliance period.
See 66 Fed. Reg. at 55,760. In addition, in rejecting NAS’s
recommendation that ‘‘the time over which compliance should
be assessed should include the time when greatest risk oc-
curs, within the limits imposed by the stability of the geologic
system,’’ NRC acknowledged that its judgment involved poli-
                              74

cy as well as technical considerations. Id. at 55,759. It
explained:
     The fact that it is feasible to calculate performance
     of the engineered and geologic barriers making up
     the repository system for periods much longer than
     10,000 years does not mean that it is possible to
     make realistic or meaningful projections of human
     exposure and risk, attributable to releases from the
     repository, over comparable time frames.
Id. at 55,760. NRC therefore concluded that for periods
approaching one million years, as NAS had suggested, ‘‘sig-
nificant climatic and even human evolution would almost
certainly occur’’ rendering it ‘‘all but impossible to make
useful and informed assumptions about human behaviors and
exposure pathways.’’ Id. at 55,760.
   NRC contends that Nevada waived its AEA claim, see
Respondent’s Br. at 26, but we need not decide the waiver
issue or the merits of the State’s challenge to NRC’s choice of
a 10,000-year compliance period now. In light of NRC’s
obligation under EnPA to maintain licensing criteria that are
consistent with the public health and safety standards pro-
mulgated by EPA, see EnPA § 801(b)(1); see also 64 Fed.
Reg. at 8647 (‘‘Should EPA issue final standards for Yucca
Mountain TTT that specify a different compliance period, the
NRC will amend its criteria at 10 CFR Part 63, as necessary,
to comply with EnPA requirements for consistency with final
EPA standards.’’), and our holding above vacating EPA’s
selection of a 10,000-year period for assessing compliance
with its public health and safety standards, see Op. supra at
II.B.2, we likewise vacate NRC’s identical compliance period
in part 63 and direct NRC to reconsider the period on
remand once EPA has complied with our opinion.
  4.   Reviewability of DOE’s Peak Dose Calculations
   Nevada next challenges NRC’s decision to require DOE to
‘‘calculate the peak dose of the reasonably maximally exposed
individual that would occur after 10,000 years following dis-
posal but within the period of geologic stability,’’ 10 C.F.R.
§ 63.341, while ‘‘categorically’’ prohibiting any challenge to
                               75

the calculation during the upcoming licensing hearing on the
Yucca Mountain repository. See Petitioners’ Br. at 57-65.
Nevada bases this claim, not surprisingly, on NRC’s state-
ment to this effect in the Supplemental Information accompa-
nying part 63: ‘‘[T]here is no finding that the NRC must
make with respect to these peak dose calculations nor may
they be the subject of litigation in any NRC licensing pro-
ceedings for a repository at Yucca Mountain.’’ 66 Fed. Reg.
at 55,760. Nevada contends that, in so providing, NRC
violated the NWPA, see 42 U.S.C. § 10134(f)(4), the AEA, see
id. § 2077(c), the NEPA, see id. § 4332(2)(C), and its own
regulations promulgated thereunder, see 10 C.F.R.
§ 51.109(a)(2), as well as our precedent, see Union of Con-
cerned Scientists v. NRC, 735 F.2d 1437 (D.C. Cir. 1984), cert.
denied sub nom. Ark. Power & Light Co. v. Union of
Concerned Scientists, 469 U.S. 1132 (1985). While NRC
intimates that Nevada waived the argument by failing to raise
it during NRC’s rulemaking proceedings, NRC has plainly,
and wisely, retreated from its position that DOE’s peak dose
calculations are unassailable.
   In its brief NRC states that parties to the future proceed-
ings on the Yucca Mountain repository will be permitted to
challenge DOE’s peak dose calculations under certain circum-
stances. Respondent’s Br. at 44-45. While NRC correctly
points out that it is obligated under the NWPA to adopt
DOE’s environmental impact statement (EIS) ‘‘to the extent
practicable,’’ 42 U.S.C. § 10134(f)(4), it concedes that it has
imposed no ‘‘ ‘categorical’ limitation’’ on any challenge to
DOE’s peak dose calculations and that, under its regulations,
parties to the proceeding may challenge the practicability of
adopting aspects of DOE’s EIS, including the peak dose
calculations, based on ‘‘substantial new information’’ to the
contrary. Respondent’s Br. at 44; see also 10 C.F.R.
§ 51.109(c)(2) (adoption practicable unless, inter alia, ‘‘[s]ig-
nificant and substantial new information or new consider-
ations render such [EIS] inadequate’’); id. at § 63.341 (‘‘DOE
must include the results and their bases in the [EIS] for
Yucca Mountain’’). NRC has, in fact, abandoned the state-
ment in the Supplemental Information that provides the sole
footing for Nevada’s argument. See Respondent’s Br. at 45.
It explains that the challenged statement is ‘‘not part of the
                               76

rule itself and must be construed in a manner consistent with
NRC regulations’’ – namely, the ones expressly allowing
parties to the proceeding to challenge DOE’s dose calcula-
tions as part of a challenge to the ‘‘practicability’’ of adopting
DOE’s EIS. Respondent’s Br. at 45 (citing 10 C.F.R.
§§ 51.109, 63.341). NRC’s volte face apparently satisfies
Nevada, see Petitioners’ Reply Br. at 29, and we need not
treat it further.
  5.   NRC’s ‘‘Reasonable Expectation’’ Standard
   Finally, Nevada challenges NRC’s adoption of a ‘‘reason-
able expectation’’ standard for evaluating whether, in a future
licensing proceeding, DOE’s proposed repository complies
with the post-closure performance requirements set forth in
the NRC regulations.         See 10 C.F.R. §§ 63.31(a)(2),
63.101(a)(2), 63.303; 66 Fed. Reg. at 55,739-40. Nevada
argues that in other contexts NRC requires ‘‘reasonable
assurance’’ that the licensed activity adequately protects the
public health and safety and that, in jettisoning the time-
tested and Supreme Court-approved standard, see Power
Reactor Dev. Corp. v. Int’l Union of Elec., Radio & Mach.
Workers, 367 U.S. 396, 407-08 (1961), in favor of a ‘‘vague’’
‘‘reasonable expectation’’ standard, NRC ‘‘overt[ly]’’ violated
the AEA and the NWPA and otherwise acted arbitrarily and
capriciously. Petitioners’ Br. at 69-70. We need not, howev-
er, resolve this matter.
   NRC explained in its brief that there is ‘‘no consequential
difference’’ between the reasonable assurance and reasonable
expectation standards and that the two are, in fact, ‘‘[v]irtual-
ly [i]ndistinguishable.’’ Respondent’s Br. at 47-48. More-
over, during oral argument, counsel for NRC confirmed that
the two standards are substantively identical. See Oral Argu-
ment Tr. at 106-07. Nevada deemed NRC’s representation
sufficient to satisfy its claim. See Petitioners’ Reply Br. at 29
(noting NRC’s ‘‘welcome’’ concession that reasonable assur-
ance and reasonable expectation are ‘‘identical’’ standards).
   To summarize briefly, then, Nevada prevails on only one of
its challenges in these cases. Because NRC must set licens-
                              77

ing requirements and criteria that are consistent with the
EPA standards, and because we have determined that EPA’s
10,000-year compliance period is not ‘‘based upon and consis-
tent with’’ the NAS recommendations, we vacate NRC’s
identical standard in part 63 for reconsideration once EPA
reviews its standard. We reject, on the merits, Nevada’s
argument that the NWPA required NRC to provide that the
geologic composition of DOE’s proposed repository must con-
stitute the primary barrier for isolating waste from the
human environment. So, too, do we reject Nevada’s multiple
barriers claims. Section 121 of the NWPA requires that
NRC promulgate requirements and criteria that provide for
the use of multiple barriers and this NRC did. We conclude,
moreover, that NRC adequately explained its decision to
evaluate the performance of the proposed repository based on
a total system performance assessment rather than on the
performance of the repository’s individual subsystems.
   Of Nevada’s remaining arguments, the State waived one of
them and the parties resolved the other two inter se. Nevada
waived its contention that NRC acted unlawfully in permit-
ting construction of the Yucca Mountain repository without
first finding a reasonable expectation that the repository
complies with the EPA standards because Nevada did not so
contend at the agency level. Nevada’s challenges to NRC’s
original assertion that DOE’s peak dose calculations cannot
be assailed in a future licensing hearing and to NRC’s
‘‘reasonable expectation’’ standard have been resolved by the
parties.

              IV.   THE SITE–DESIGNATION CASES
   On February 14, 2002, the Secretary of Energy submitted
to the President his recommendation that the Yucca Moun-
tain site be developed as a repository. The recommendation
was based in part upon the Secretary’s determination that the
Yucca site satisfied DOE’s site-suitability criteria and in part
upon a final environmental impact statement (FEIS), devel-
oped by DOE pursuant to § 114(f) of the NWPA. The day
after receiving the Secretary’s recommendation, the Presi-
                              78

dent submitted to Congress his recommendation that the
Yucca site be developed.
  Nevada exercised its right under sections 115 and 116 of
the NWPA to submit to Congress a timely ‘‘notice of disap-
proval.’’ In the absence of further congressional action, this
notice would have nullified the President’s site designation.
See 42 U.S.C. § 10135(b). After legislative hearings at which
Nevada and other parties testified and submitted documenta-
ry evidence, Congress enacted a joint ‘‘resolution of reposito-
ry siting approval’’ (Resolution) overriding Nevada’s notice of
disapproval and approving the Yucca site for a repository.
See 42 U.S.C. § 10135(a), (c) (prescribing the form and effect
of the Resolution). The Resolution was enacted pursuant to
the legislative procedures prescribed by the NWPA, see 42
U.S.C. § 10135(d), (e), and was signed into law by the Presi-
dent on July 23, 2002. The legislation provides:
    Resolved by the Senate and House of Representa-
    tives of the United States of America in Congress
    assembled, That there hereby is approved the site at
    Yucca Mountain, Nevada, for a repository, with re-
    spect to which a notice of disapproval was submitted
    by the Governor of the State of Nevada on April 8,
    2002.
Pub. L. No. 107-200, 116 Stat. 735 (2002).
  In State of Nevada v. United States Department of Energy
(No. 01-1516 and consolidated cases) (DOE Case), Nevada
challenges the actions of the Secretary of Energy and the
President leading to the approval of the Yucca site. In other
words, Nevada does not challenge the legislation itself, but,
rather, agency and executive branch actions that preceded
the passage of the Resolution.
   Nevada’s primary claim is that DOE’s site-suitability crite-
ria violate the NWPA by failing to incorporate certain geolog-
ical considerations set forth in § 112(a) of the statute. In
addition, Nevada asserts that the Secretary violated the
NWPA by failing to complete site-characterization activities
at Yucca before recommending the site and by failing to take
                              79

certain mandatory actions after allegedly determining that
the Yucca site was unsuitable. Finally, Nevada challenges
the FEIS, claiming that DOE violated procedural and sub-
stantive requirements of the National Environmental Policy
Act of 1969 and its implementing regulations. Nevada re-
quests, on the basis of these alleged defects, that we set aside
the site-suitability criteria, the Secretary’s site recommenda-
tion, the FEIS, and the President’s site designation.
   In State of Nevada v. United States (No. 03-1009), Nevada
challenges the constitutionality of the Resolution approving
the Yucca site. Nevada asserts that the Constitution re-
quires Congress, when it regulates federal lands in a manner
that imposes a unique burden on a particular state, to do so
by means of facially neutral and generally applicable criteria.
Nevada claims that the Resolution violates this asserted
‘‘equal treatment’’ requirement and accordingly should be set
aside.
  We will address Nevada’s challenge to the Resolution’s
constitutionality first. We reject Nevada’s claim and uphold
the Resolution. Yucca Mountain is located on federal land,
and Congress has the authority under the Property Clause to
designate the site for development as a repository. To the
extent that the Constitution requires that legislation regulat-
ing federal lands have a rational basis, the Resolution meets
this standard. In exercising its Property Clause power to
enact the Resolution, Congress has not regulated Nevada’s
activities so as to infringe upon State sovereignty interests of
the type recognized under the Tenth Amendment. We find
no viable basis in the Constitution supporting Nevada’s claim
that Congress must in all instances exercise its Property
Clause powers solely pursuant to neutral criteria that are
generally applicable to all federal lands. Nevada cites no
case law that endorses such a sweeping proposition and we
have found none.
  Turning to the DOE Case, we hold that Congress’s enact-
ment of the Resolution – which independently approved the
Yucca site for development – was a final legislative action
once it was signed into law by the President. The passage of
                                80

this law rendered moot Nevada’s challenges to the preceding
site-selection-related actions of executive branch officials, fed-
eral agencies, the Secretary, and the President. Whatever
the legal infirmities vel non of those actions, the Resolution is
law and cannot be set aside absent a constitutional defect.
Having found no such defect, we conclude that Nevada’s
claims are moot. Congress has settled the matter, and we, no
less than the parties, are bound by its decision. If DOE or
NRC uses the FEIS to support future decisions relating to
the Yucca project, Nevada may challenge the substance of the
FEIS in the relevant proceedings. But any such challenge is
not yet ripe and must await another day.
A.        The Constitutional Case
     1.    Issue Preclusion
   Before turning to Nevada’s constitutional challenge, we
address the Government’s claim that the Ninth Circuit’s
decision in Nevada v. Watkins, 914 F.2d 1545 (9th Cir. 1990),
cert. denied, 499 U.S. 906 (1991), precludes consideration of
the issues Nevada seeks to raise. In Watkins, Nevada
challenged the constitutionality of the 1987 amendments to
the NWPA, which limited site-characterization activities un-
der the statute to Yucca Mountain. The Ninth Circuit held
that Congress had the constitutional authority under the
Property Clause to enact the 1987 amendments. Id. at 1553.
The court went on to hold that none of the other constitution-
al provisions or doctrines relied upon by Nevada – including
the Tenth Amendment, the Federal Enclave Clause, the
Privileges and Immunities Clause, the Port Preference
Clause, and the equal footing doctrine – precluded Congress
from exercising its Property Clause authority in this manner.
Id. at 1554-58. We have no disagreement with the Ninth
Circuit’s resolution of the claims at issue in Watkins. Indeed,
many of the basic principles articulated in that decision are
central to our resolution of the case before us. But we cannot
agree that Watkins precludes us from considering the issues
now raised by Nevada.
 For issue preclusion to apply, the same issue now raised
must have been contested by the parties and submitted for
                              81

judicial determination in the prior case, the issue must have
been ‘‘actually and necessarily determined,’’ and preclusion
must not ‘‘work a basic unfairness’’ to the party that would be
bound by resolution of the issue in the prior case. Yamaha
Corp. of Am. v. United States, 961 F.2d 245, 254 (D.C. Cir.
1992), cert. denied, 506 U.S. 1078 (1993). The issues Nevada
now seeks to raise simply are not precisely the same as those
decided in Watkins. Nevada’s claim in the instant case
requires us to determine whether the Constitution requires
that a national nuclear waste repository site on federal land
be selected on the basis of facially neutral, generally applica-
ble criteria, and, if so, whether the Resolution violates this
asserted ‘‘equal treatment’’ requirement. No such issue was
or could have been decided in Watkins. Most important, the
two cases involve different statutes with different effects.
The statute at issue in Watkins limited site-characterization
activities under the NWPA to Yucca but did not select the
site for development as a repository. The legislation chal-
lenged in this case, by contrast, approved the Yucca site for
development and authorized DOE to seek a license to con-
struct and operate a repository there. Moreover, the consti-
tutional claims at issue in the two cases are distinct. Nevada
did not challenge the 1987 amendments on the basis of the
purported ‘‘equal treatment’’ requirement that it now asserts.
The Watkins court therefore had no opportunity to pass on
the precise issues raised by the claim now before us.
   We are aware of no precedent – and the Government has
cited none – remotely suggesting that a prior decision ad-
dressing the constitutionality of one statute bars consider-
ation of a later challenge, on different constitutional grounds,
to a different statute with different effects. In short, Wat-
kins did not ‘‘actually and necessarily’’ determine the same
issues raised by Nevada’s claim in the case before us, and
therefore we are not precluded from considering and deciding
those issues on the merits.
  2.   Merits of the Constitutional Challenge
   The Property Clause of the U.S. Constitution provides that
‘‘Congress shall have Power to dispose of and make all
                               82

needful Rules and Regulations respecting the Territory or
other Property belonging to the United States.’’ U.S. CONST.
art. IV, § 3, cl. 2. Under the Clause, ‘‘Congress exercises the
powers both of a proprietor and of a legislature over the
public domain.’’ Kleppe v. New Mexico, 426 U.S. 529, 540
(1976). Indeed, the Supreme Court has repeatedly declared
that Congress’s power over federal lands is ‘‘without limita-
tions.’’ Cal. Coastal Comm’n v. Granite Rock Co., 480 U.S.
572, 580 (1987) (quoting Kleppe, 426 U.S. at 539). According-
ly, our role in reviewing Congress’s exercise of this power is
narrow. We must determine whether the Resolution ‘‘can be
sustained as a ‘needful’ regulation ‘respecting’ the public
lands.’’ Kleppe, 426 U.S. at 536. But in so doing, ‘‘we must
remain mindful that, while courts must eventually pass upon
them, determinations under the Property Clause are entrust-
ed primarily to the judgment of Congress.’’ Id.
   The Property Clause clearly provides an adequate source of
constitutional authority for Congress’s enactment of the Res-
olution. The disputed Resolution is a law ‘‘respecting’’ feder-
al property. And we defer to Congress’s judgment that the
Resolution is a ‘‘needful’’ regulation. See id.; United States
v. San Francisco, 310 U.S. 16, 29-30 (1940) (‘‘[I]t is not for the
courts to say how [the public trust over federal lands] shall be
administered. That is for Congress to determine.’’ (quoting
Light v. United States, 220 U.S. 523, 537 (1911))). Our review
extends, at most, to determining whether there is a rational
relationship between Congress’s stated end and its chosen
means. See Peter A. Appel, The Power of Congress ‘‘Without
Limitation’’: The Property Clause and Federal Regulation of
Private Property, 86 MINN. L. REV. 1, 82 (2001); see also
Kleppe, 426 U.S. at 535-36 (discussing the basis for Con-
gress’s enactment of the statute at issue); cf. Hodel v. Va.
Surface Mining & Reclamation Ass’n, Inc., 452 U.S. 264, 291
(1981) (‘‘The only limitation on congressional authority
[preemptively to regulate private activities under the Com-
merce Clause] is the requirement that the means selected be
reasonably related to the goal of regulating interstate com-
merce.’’). The Resolution easily passes this test.
                              83

   The Resolution is best understood as a step in the reposito-
ry-development process established by the NWPA two dec-
ades before. Congress enacted the NWPA on the basis of
findings that the accumulation of spent nuclear fuel and
radioactive waste had created a ‘‘national problem’’ and that
‘‘the Federal government has the responsibility to provide for
the permanent disposal of high-level radioactive waste and
such spent nuclear fuel as may be disposed of in order to
protect the public health and safety and the environment.’’
42 U.S.C. § 10131(a)(2), (4). One of the primary purposes of
the NWPA, therefore, was ‘‘to establish a schedule for the
siting, construction, and operation of repositories that will
provide a reasonable assurance that the public and the envi-
ronment will be protected from the hazards posed by’’ such
wastes. 42 U.S.C. § 10131(b)(1). The Senate Committee
Report on the Resolution referred back to the NWPA find-
ings and reaffirmed the judgment that ‘‘[a] geologic reposito-
ry is needed to isolate high-level radioactive waste and spent
nuclear fuel from the public and the environment.’’ S. REP.
NO. 107-159, at 4 (2002). The Report concluded that the
Administration had adequately demonstrated that the Yucca
site was likely to be suitable for development, subject to the
outcome of future NRC licensing proceedings. Id. at 13.
Approval of the site and continuation of the repository-
development process therefore was determined to be in the
national interest. Id. at 14.
   There clearly is a rational relationship between Congress’s
stated purpose – the development of a geologic repository for
the safe disposal of radioactive waste – and its decision to
approve the Yucca site. It is not for this or any other court
to examine the strength of the evidence upon which Congress
based its judgment. See Kleppe, 426 U.S. at 541 n.10 (‘‘What
appellees ask is that we reweigh the evidence and substitute
our judgment for that of Congress. This we must decline to
do.’’).
   It remains only to determine whether the Resolution vio-
lates some other provision of the Constitution. See Watkins,
914 F.2d at 1553-54 (citing Williams v. Rhodes, 393 U.S. 23,
29 (1968)). Nevada asserts that the Constitution requires
                                84

Congress, when it decides to use federal property in a
manner that imposes a unique burden on a particular State,
to choose the relevant site on the basis of facially neutral
criteria that are applicable nationwide. The Resolution runs
afoul of this ‘‘equal treatment’’ requirement, as Nevada styles
it, because Congress approved the Yucca site based on site-
suitability criteria that are applicable only to Yucca and that
allegedly ‘‘reduce[d] to a virtual irrelevancy the actual geolog-
ic characteristics of the site.’’ Petitioners’ Br. at 24.
   The so-called ‘‘equal treatment’’ claim Nevada asserts is not
based upon any specific provision of the Constitution, but
rather on principles of federalism ostensibly inherent in the
Constitution as a whole. Although Nevada purports to find
support for its claim in the Guarantee Clause, the Port
Preference Clause, the Uniformity Clause, the Bill of Attain-
der Clause, and the equal footing doctrine, its argument is
based primarily on the Supreme Court’s interpretation of the
Tenth Amendment in South Carolina v. Baker, 485 U.S. 505
(1988). In Baker, the Court suggested ‘‘the possibility that
some extraordinary defects in the national political process
might render congressional regulation of state activities inval-
id under the Tenth Amendment.’’ Id. at 512. Such a defect
might arise, the Court indicated, where a State ‘‘was singled
out in a way that left it politically isolated and powerless.’’
Id. at 513. Nevada argues that this occurs when Congress
legislates in violation of the asserted ‘‘equal treatment’’ princi-
ple: ‘‘A State can negotiate and politick with other States
when the issue before Congress is what general standards to
apply in deciding where to bury nuclear waste, because all
States have an interest in fair, reasonable and workable rules,
given that all are at risk of being stuck with an unpopular
burden.’’ Petitioners’ Br. at 53. Where, by contrast, Con-
gress is asked to give an up-or-down vote on a single pre-
announced site, ‘‘then the State where that site is located
loses its natural allies in the national political process.’’ Id.
We find no basis in the Constitution for Nevada’s proposed
‘‘equal treatment’’ requirement. Accordingly, we reject Ne-
vada’s challenge to the Resolution.
                              85

   To begin with, the Resolution does not infringe upon state
interests of the kind protected by the Tenth Amendment.
Baker, upon which Nevada bases its claim, construed the
Tenth Amendment as broadly as possible to refer to ‘‘any
implied constitutional limitation on Congress’ authority to
regulate state activities, whether grounded in the Tenth
Amendment itself or in principles of federalism derived gen-
erally from the Constitution.’’ 485 U.S. at 511 n.5 (emphasis
added). Baker then unequivocally states that ‘‘the possibility
that some extraordinary defects in the national political pro-
cess might render congressional regulation TTT invalid under
the Tenth Amendment’’ would be an issue only with respect
to ‘‘congressional regulation of state activities.’’ 485 U.S. at
512 (emphasis added). Congress’s decision to designate Yuc-
ca Mountain for development as a repository does not in any
way regulate Nevada’s activities; it merely prescribes the use
of a particular piece of federal property. Nor, of course, does
the Resolution ‘‘commandeer’’ the state legislative process or
state officials so as to violate the Tenth Amendment con-
straint on federal powers recognized in New York v. United
States, 505 U.S. 144 (1992), and Printz v. United States, 521
U.S. 898 (1997). Congress’s decision to use the Yucca site as
a repository does preempt Nevada from adopting conflicting
legislation or regulations. But this is merely the natural and
constitutionally unobjectionable result of the Supremacy
Clause. See Kleppe, 426 U.S. at 543; see also Hodel, 452 U.S.
at 290 (‘‘Although such congressional enactments obviously
curtail or prohibit the States’ prerogatives to make legislative
choices respecting subjects the States may consider impor-
tant, the Supremacy Clause permits no other result.’’). In
short, while the designation of Yucca as a repository may
impose a burden on Nevada, it does not infringe upon state
sovereign interests of the limited type protected by the Tenth
Amendment.
  Moreover, the Tenth Amendment limitation adumbrated by
the Court in Baker applies to defects in the political process.
But the ‘‘equal treatment’’ claim asserted by Nevada plainly
goes to the substantive basis of congressional legislation over
federal property and does not involve the political process at
                               86

all. The Court made clear in Baker that ‘‘nothing in TTT the
Tenth Amendment [broadly construed] authorizes courts to
second-guess the substantive basis for congressional legisla-
tion. Where, as here, the national political process did not
operate in a defective manner, the Tenth Amendment is not
implicated.’’ 485 U.S. at 513 (citation omitted). If anything,
therefore, Baker appears positively to preclude us from sub-
jecting congressional legislation to the so-called ‘‘equal treat-
ment’’ requirement conjured up by Nevada.
   As noted above, Nevada purports to find support for its
‘‘equal treatment’’ claim in the Guarantee Clause, the Port
Preference Clause, the Uniformity Clause, the Bill of Attain-
der Clause, and the equal footing doctrine. Nevada does not
assert that the Resolution violates any of these provisions or
doctrines taken individually, and it is clear that any such
claim would fail. Rather, Nevada contends that these provi-
sions and doctrines express fundamental principles of state
equality and a general constitutional preference for legislation
based on neutral and generally applicable criteria. Nevada
attempts to distill these principles and to synthesize from
them a novel constitutional ‘‘equal treatment’’ requirement.
But in so doing, Nevada effectively discards the text, the
substantive context, and the jurisprudential history of each of
the individual provisions or doctrines upon which it relies.
The end product is an entirely new creation. It has no
textual basis in the Constitution. And, perhaps not surpris-
ingly, Nevada cites no juridical precedent or historical prac-
tice hinting at the existence of such a restraint on congres-
sional authority over federal lands.
   We are aware, of course, that the Supreme Court has
recognized – in the context of its state sovereign immunity
and ‘‘commandeering’’ decisions – constitutional limitations on
congressional authority that are not solely or strictly based
upon the text of the Constitution. See, e.g., Printz, 521 U.S.
at 918-25; Alden v. Maine, 527 U.S. 706, 713 (1999). Those
limitations, however, were rooted ‘‘in historical understanding
and practice, in the structure of the Constitution, and in the
jurisprudence of th[e Supreme] Court.’’ Printz, 521 U.S. at
905. The Court’s sovereign immunity decisions are premised
                              87

on the conclusion that, ‘‘as the Constitution’s structure, its
history, and the authoritative interpretations by this Court
make clear, the States’ immunity from suit is a fundamental
aspect of sovereignty which the States enjoyed before the
ratification of the Constitution.’’ Alden, 527 U.S. at 713.
This preexisting immunity was ‘‘confirmed TTT as a constitu-
tional principle’’ by the ratification of the Eleventh Amend-
ment. Id. at 728-29. The Court’s recognition of the anti-
commandeering principle similarly was rooted in the history
and structure of the Constitution, Printz, 521 U.S. at 905-23,
and, ‘‘most conclusively,’’ in the Court’s prior jurisprudence,
id. at 925.
   Nevada’s proposed ‘‘equal treatment’’ requirement has no
such roots in Supreme Court precedent or the history of the
Constitution. As for Nevada’s contention that the require-
ment is inherent in the Constitution’s structure, we have
already shown that the Tenth Amendment does not protect
the type of state interests implicated by this case. As the
following discussion makes clear, the inferential leap from the
remaining constitutional sources relied upon by Nevada to the
proposed ‘‘equal treatment’’ requirement is too great to be
plausible.
   The Uniformity Clause provides that ‘‘all Duties, Imposts
and Excises shall be uniform throughout the United States.’’
U.S. CONST. art. I, § 8, cl. 1. The Port Preference Clause
provides that ‘‘[n]o Preference shall be given by any Regula-
tion of Commerce or Revenue to the Ports of one State over
those of another.’’ U.S. CONST. art. I, § 9, cl. 6. These
provisions have been narrowly construed to prohibit certain
forms of direct discrimination between States within the
legislative spheres to which the provisions apply: taxation
and port-related commerce-and-revenue regulation, respec-
tively. See, e.g., United States v. Ptasynski, 462 U.S. 74, 85-
86 (1983) (upholding against a Uniformity Clause challenge
an oil taxation scheme that had the effect of giving a unique
exemption to Alaskan oil, on the grounds that the exemption
was based on ‘‘neutral factors’’ and was not intentionally
discriminatory); Pennsylvania v. Wheeling & Belmont
Bridge Co., 59 U.S. (18 How.) 421, 433-35 (1856) (holding that
                               88

the Port Preference Clause prohibits only ‘‘positive legisla-
tion by [C]ongress’’ that gives ‘‘a direct privilege or prefer-
ence to the ports of any particular State over those of
another,’’ not federal enactments that merely confer ‘‘inciden-
tal advantages’’ on one port over others). Nevada correctly
notes that the Supreme Court has upheld legislation chal-
lenged under these provisions on the grounds, inter alia, that
the legislation was based on neutral factors or only inciden-
tally burdened or benefitted a particular State. See id. The
conclusion that tax or port-related legislation having these
characteristics may be insulated from challenge under these
provisions, however, cannot plausibly be converted into a con-
stitutional mandate that all legislation whatsoever have such
characteristics.
   The equal footing doctrine, upon which Nevada also relies,
applies to the terms on which new states enter the Union.
Utah Div. of State Lands v. United States, 482 U.S. 193, 195-
96 (1987). Its principal application has been to guarantee
that newly admitted States take title to the bed of all naviga-
ble waters in their territories, just as did the original thirteen
States. Id. But the Supreme Court has made clear that the
doctrine ‘‘negatives any implied, special limitation of any of
the paramount powers of the United States in favor of a
State.’’ United States v. Texas, 339 U.S. 707, 717 (1950).
This includes, of course, Congress’s exercise of its Property
Clause powers. See Watkins, 914 F.2d at 1555 (rejecting
Nevada’s equal footing challenge to the 1987 amendments to
the NWPA).
   The other purported constitutional bases of the ‘‘equal
treatment’’ claim are even more tenuous. The Guarantee
Clause provides, in relevant part, that ‘‘[t]he United States
shall guarantee to every State in this Union a Republican
Form of Government.’’ U.S. CONST. art. IV, § 4. The Su-
preme Court has indicated that this provision is implicated
only where legislation poses some ‘‘realistic risk of altering
the form or method of functioning of [a State’s] government.’’
New York v. United States, 505 U.S. at 186. The Bill of
Attainder Clause, U.S. CONST. art. I, § 9, cl. 3, proscribes
legislation singling out individuals for punishment. See, e.g.,
                               89

United States v. Brown, 381 U.S. 437, 447 (1965). The Clause
cannot be invoked on behalf of a State. South Carolina v.
Katzenbach, 383 U.S. 301, 324 (1966).
   We find it beyond serious dispute that Nevada’s proposed
‘‘equal treatment’’ requirement cannot reasonably be inferred
from the provisions and doctrines upon which Nevada pur-
ports to rely. We fail to see, moreover, how the constraints
demanded by Nevada’s claim would be consistent with the
plenary nature of Congress’s Property Clause authority or
the considerable deference that we accord to Congress’s
judgment in exercising that authority. Under Nevada’s pro-
posed requirement, each time Congress decides to use federal
property in a manner that incidentally burdens a State – for
example by designating such property for use as a military
installation, a prison, a dam, a storage or disposal site, or a
conservation area – it must formulate neutral selection crite-
ria and apply those criteria to every piece of federal property
in the Nation before selecting a site. Courts presumably
would be required to scrutinize the substantive basis of the
legislation in question to ensure that the criteria were genu-
inely neutral and generally applied. This is far more intru-
sive than any requirement that there be a rational basis for
Congress’s judgment that a particular regulation respecting a
particular property is ‘‘needful.’’ The substantive constraint
on legislation and the judicial role implicit in Nevada’s ‘‘equal
treatment’’ requirement are, in our view, totally at odds with
the broad interpretation given to Congress’s Property Clause
powers. See Biodiversity Assoc. v. Cables, 357 F.3d 1152,
1161-62 (10th Cir. 2004) (rejecting a constitutional challenge
to legislation prescribing in ‘‘minute detail’’ the management
of a single national forest on the grounds that Congress, in
exercising its Property Clause powers, ‘‘is permitted to be as
specific as it deems appropriate’’ and that ‘‘[i]t would be
difficult if not impossible to control the use of federal lands
without reference to specific actions affecting specific tracts
of land’’); see also Nat’l Coalition to Save Our Mall v.
Norton, 269 F.3d 1092, 1097 (D.C. Cir. 2001) (finding no
constitutional objection to the specificity of legislation requir-
ing construction of a World War II Memorial on the National
                              90

Mall). As the Supreme Court declared long ago: ‘‘The power
over the public land TTT entrusted to Congress [under the
Property Clause] is without limitations. ‘And it is not for the
courts to say how that trust shall be administered. That is
for Congress to determine.’ ’’ San Francisco, 310 U.S. at 29-
30 (quoting Light, 220 U.S. at 537) (footnotes omitted).
  For all of the foregoing reasons, we reject Nevada’s consti-
tutional challenge to the Resolution. We now turn to Neva-
da’s challenge to the administrative and executive decisions
leading up to the Resolution’s enactment.
B.     The DOE Case
  1.    DOE Criteria, Secretary’s Alleged Failure to Take
        Mandatory Actions, and Site Recommendations
   Nevada’s challenges to DOE’s site-suitability criteria, the
Secretary’s recommendation, the FEIS, and the President’s
recommendation are all directed to the fundamental question
of whether the Yucca site was properly selected for develop-
ment as a repository. Congress’s enactment of the Resolu-
tion, however, has rendered that question moot. The Resolu-
tion affirmatively and finally approved the Yucca site for a
repository, thus bringing the site-selection process to a con-
clusion. No determination as to the soundness of the admin-
istrative and executive actions leading up to the Resolution’s
enactment would undo the Resolution’s binding effects. ‘‘It
has long been settled that a federal court has no authority ‘to
give opinions upon moot questions or abstract propositions, or
to declare principles or rules of law which cannot affect the
matter in issue in the case before it.’ ’’ Church of Scientology
v. United States, 506 U.S. 9, 12 (1992) (quoting Mills v.
Green, 159 U.S. 651, 653 (1895)). Where Congress enacts
intervening legislation that definitively resolves the issues a
litigant seeks to put before us, the claims are moot and we
are precluded from deciding them. See Cook Inlet Treaty
Tribes v. Shalala, 166 F.3d 986, 990 (9th Cir. 1999); Mobil
Oil Corp. v. EPA, 35 F.3d 579, 585 (D.C. Cir. 1994); State of
Nevada v. Watkins, 943 F.2d 1080, 1083-84 (9th Cir. 1991);
Bunker Ltd. P’ship v. United States, 820 F.2d 308, 311 (9th
Cir. 1987).
                              91

   There is no question that the Resolution is a law, enacted in
accordance with the bicameralism and presentment require-
ments of Article I, section 7, clause 3 of the Constitution. See
Bowsher v. Synar, 478 U.S. 714, 756 (1986) (Stevens, J.,
concurring in judgment) (‘‘The joint resolution, which is used
for ‘special purposes and TTT incidental matters,’ makes bind-
ing policy and ‘requires an affirmative vote by both Houses
and submission to the President for approval’ – the full
Article I requirements.’’ (citations omitted)); Consumer En-
ergy Council of Am. v. FERC, 673 F.2d 425, 459 n.140 (D.C.
Cir. 1982) (stating that joint resolutions become law upon
presentment to and approval by the President).
   As with any other statute, our interpretation of the Resolu-
tion begins with its text and the presumption that Congress
‘‘says in a statute what it means and means in a statute what
it says there.’’ Conn. Nat’l Bank v. Germain, 503 U.S. 249,
254 (1992); see also Ann Arbor R.R. Co. v. United States, 281
U.S. 658, 666 (1930) (stating that a joint resolution is con-
strued according to general rules of statutory construction).
Congress, in enacting the Resolution, spoke in concise and
unambiguous language: ‘‘[T]here hereby is approved the site
at Yucca Mountain, Nevada, for a repository, with respect to
which a notice of disapproval was submitted by the Governor
of the State of Nevada on April 8, 2002.’’ 116 Stat. 735
(2002), 42 U.S.C. § 10135 note. The Resolution’s meaning is
clear on its face: It overrides Nevada’s notice of disapproval
and affirmatively approves the Yucca site for the development
of a repository. The practical effect of the legislation is to
conclude the site-selection process and to permit DOE to seek
authorization from NRC to construct and operate a reposito-
ry at this site.
   The legislative history of the Resolution confirms this
interpretation. The Senate Committee Report on the Resolu-
tion states that ‘‘[t]he purpose of [the Resolution] is to
approve the site at Yucca Mountain, Nevada for the develop-
ment of a repository for the disposal of high-level radioactive
waste and spent nuclear fuel, pursuant to the Nuclear Waste
Policy Act of 1982.’’ S. REP. NO. 107-159, at 1 (2002). The
House Committee Report contains virtually identical lan-
                              92

guage. H.R. REP. NO. 107-425, at 2 (2002). Both Reports
state that the effect of the Resolution’s enactment will be to
allow DOE to go forward with its application for authorization
from NRC to build and operate the repository. See S. REP.
NO. 107-159, at 1 (2002); H.R. REP. NO. 107-425, at 7 (2002)
(Congressional Budget Office Estimate).
    The floor debate on the Resolution likewise confirms that
the members of Congress intended the Resolution to approve
the Yucca site, conclude the site-selection process, and permit
DOE to proceed to seek a license for the repository. See
generally 148 CONG. REC. H2180-H2205 (daily ed. May 8,
2002); 148 CONG. REC. S6444-S6491 (daily ed. July 9, 2002).
As Senator Murkowski, one of the Senate sponsors of the
Resolution, declared, ‘‘The resolution TTT reaffirms the pres-
ent recommendation of Yucca Mountain as a suitable site for
this Nation’s permanent geologic repository TTT [and] gives
the Department of Energy the go ahead to begin the licens-
ing process with the Nuclear Regulatory CommissionTTTT’’
148 CONG. REC. S5886 (daily ed. June 21, 2002). Representa-
tive Shimkus, one of the House sponsors, similarly stated that
‘‘[t]he vote that Congress will be taking today says that after
20 years of exhaustive scientific analysis the government is
ready to designate Yucca Mountain TTT a safe site and move
to the licensing phase for the development of an underground
disposal facility.’’ 148 CONG. REC. H2185 (daily ed. May 8,
2002).
    There is good reason, moreover, to conclude that both
Nevada and the Members of Congress understood that enact-
ment of the Resolution would render moot most of the claims
raised in this suit. Nevada, in its statement of the reasons
for its notice of disapproval, notified Congress of its pending
law suits challenging ‘‘the legal soundness of both the Secre-
tary’s and the President’s Yucca Mountain site recommenda-
tions.’’ Statement of Reasons Supporting the Governor of
Nevada’s Notice of Disapproval of the Proposed Yucca Moun-
tain Project 5-6 (Apr. 8, 2002), reprinted in Add. of Leg.
Materials at 10-11. Nevada asserted the central claim in the
case now before us: that DOE changed its site-suitability
criteria because Yucca could not meet the preexisting criteria.
                              93

Id. Nevada urged Congress to delay approval of the reposi-
tory until its legal claims were decided by the courts and
stated that direct legislative approval of the Yucca site would
mean that ‘‘DOE’s bogus site suitability determination could
never be reviewed on the technical merits.’’ Id.
   The Senate Committee Report considered and rejected
Nevada’s objections to approval of the Yucca site, including
the legal argument against the site-suitability criteria. S.
REP. NO. 107-159, at 6-13 (2002). The authors of the Report
reviewed the Administration’s case for selecting the Yucca
site and concluded that the Secretary’s recommendation and
the supporting documents and testimony ‘‘me[t] the burden of
going forward imposed by the [NWPA].’’ Id. at 13. Neva-
da’s arguments, the Committee declared, did not ‘‘outweigh
the national interest in proceeding’’ with the repository pro-
gram. Id. at 14. Despite Nevada’s public prediction that
approval of the Yucca site would render its site-selection-
related claims unreviewable, Congress ultimately enacted the
Resolution.
   In summary, everything in the text and legislative history
of the Resolution confirms that Congress intended affirma-
tively to approve the Yucca site, thus concluding the site-
selection process and permitting DOE to seek authorization
from NRC to build and operate a repository at the site. In
the absence of any constitutional defect in the Resolution, we
have no authority to review the substantive basis for this
decision. ‘‘Once the meaning of an enactment is discerned
and its constitutionality determined, the judicial process
comes to an end. We do not sit as a committee of review, nor
are we vested with the power of veto.’’ Tenn. Valley Auth. v.
Hill, 437 U.S. 153, 194-95 (1978). The Resolution’s meaning
is clear, and we have already rejected Nevada’s sole constitu-
tional challenge. There consequently remains nothing left for
us to decide. No pronouncement from this court as to the
legal soundness of the administrative and executive decisions
preceding the enactment of the Resolution could provide
Nevada with any effective relief. The Resolution is the law,
the Yucca site has been finally approved, and DOE has been
                                94

authorized to seek permission from NRC to construct and
operate the repository.
   Nevada concedes that its claims are moot to the extent that
the Resolution affirmatively approved the Yucca site for
development. Nevada argues, however, that the Resolution
is merely a ‘‘legislative veto’’ that ‘‘cancels’’ Nevada’s notice of
disapproval and restores the status quo ante. This narrow
construction is untenable and must be rejected. The Resolu-
tion’s text and legislative history make inescapably clear that
it not only ‘‘canceled’’ Nevada’s notice of disapproval but also
affirmatively approved the Yucca site. Nevada’s arguments
to the contrary are unpersuasive.
   First, the fact that the Resolution approves the Yucca site
‘‘with respect to which a notice of disapproval was submitted’’
cannot plausibly be read to limit the effect of the approval.
Rather, this secondary clause merely makes clear that Con-
gress intended its affirmative approval to override Nevada’s
notice of disapproval. Nevada’s narrow focus on this lan-
guage, by contrast, would render meaningless the Resolu-
tion’s primary clause: ‘‘There hereby is approved the site at
Yucca Mountain, Nevada, for a repository.’’
   Contrary to Nevada’s assertions, our interpretation of the
Resolution is entirely consistent with NWPA section 114(b).
That provision states that DOE shall submit a license applica-
tion to NRC if the President’s ‘‘site designation is permitted
to take effect under section [115].’’ 42 U.S.C. § 10134(b).
The President’s site designation may be ‘‘permitted to take
effect’’ under section 115 in one of two ways: without any
further action if Nevada does not submit a timely notice of
disapproval, or, if Nevada does submit such a notice, through
enactment of a joint resolution meeting the requirements of
section 115. See 42 U.S.C. § 10135(b), (c). Nevada submit-
ted a notice of disapproval. Under this scenario, the Presi-
dent’s original site designation was nevertheless ‘‘permitted
to take effect’’ precisely because Congress enacted a law
affirmatively adopting that designation.
  We find no merit in Nevada’s contention that our interpre-
tation of the Resolution somehow renders the NWPA’s judi-
                               95

cial review provision meaningless. Section 119 of the NWPA
gives the U.S. courts of appeals exclusive jurisdiction over,
inter alia, any civil action ‘‘for review of any final decision or
action of the Secretary [of Energy], the President, or the
[Nuclear Regulatory] Commission under this part.’’ 42
U.S.C. § 10139(a)(1). It is elementary that this provision
does not supercede Article III of the Constitution, which
requires that a case or controversy remain ‘‘live’’ in order for
this or any other court to have jurisdiction. See Church of
Scientology, 506 U.S. at 12 (‘‘[A] federal court has no authori-
ty ‘to give opinions upon moot questionsTTTT’ ’’). Section 119
contemplates the possibility of actions challenging decisions of
the Secretary and the President. But it does not follow that
the section is rendered meaningless when, as a result of
intervening legislation, a particular action challenging a par-
ticular decision becomes moot and therefore unreviewable.
It should be noted, moreover, that section 119 continues to
govern other suits challenging actions taken under the rele-
vant portion of the NWPA. Nevada’s constitutional challenge
to the Resolution, addressed on the merits above, was
brought pursuant to section 119(a)(1). And section 119 pre-
sumably will govern future actions including, for example, any
petitions for review of DOE’s final decision selecting an
alternative for transporting waste to Yucca Mountain and
NRC decisions relating to construction authorization or li-
censing.
   Finally, we reject Nevada’s contention that the Resolution’s
meaning or effect is cabined by the fact that it was enacted
pursuant to accelerated legislative procedures. We repeat:
The Resolution is a law, validly enacted under Article I,
section 7 of the Constitution, and its meaning is to be
interpreted according to standard tools of statutory interpre-
tation, beginning with its text. That the Resolution was
enacted pursuant to the special procedures set forth in the
NWPA has no particular bearing on our interpretation of its
content.
  2.   The Final Environmental Impact Statement
  DOE’s Final Environmental Impact Statement was used to
support the Secretary’s and the President’s recommendations
                              96

of the Yucca site. Insofar as Nevada’s instant challenge to
the FEIS is intended to reverse the decision to select the
Yucca site, the challenge is moot for the reasons stated above.
The Resolution approved the site, and no finding that the
FEIS is legally defective would change Congress’s final and
binding decision. Because the FEIS is expected to play a
continuing role in decision making related to the Yucca site,
however, we clarify the limits of our holding.
  Section 114(f)(4) of the NWPA provides, in relevant part,
that the DOE’s FEIS ‘‘shall, to the extent practicable, be
adopted by [NRC] in connection with the issuance by [NRC]
of a construction authorization and license for such reposito-
ry.’’ 42 U.S.C. § 10134(f)(4). To the extent NRC adopts the
FEIS, NRC’s responsibilities under the National Environ-
mental Policy Act shall be deemed satisfied and ‘‘no further
consideration shall be required.’’ Id. In addition, DOE is
expected to use the FEIS to support one or more future
decisions related to Yucca Mountain, including the selection of
an alternative for transporting waste to the site.
   We agree with DOE that any challenge to the FEIS,
insofar as it may be adopted in support of a future NRC
construction-authorization or licensing decision or used by
DOE in support of a future transportation-alternative selec-
tion, is not yet ripe for review. In determining ripeness, we
assess ‘‘both the fitness of the issue for judicial decision and
the hardship to the parties of withholding court consider-
ation.’’ AT&T Corp. v. FCC, 349 F.3d 692, 699 (D.C. Cir.
2003) (quoting Abbott Labs. v. Gardner, 387 U.S. 136, 149
(1967)). In examining the fitness of an issue for our consider-
ation, we are primarily concerned with whether the claims
raise ‘‘purely legal questions [that] would TTT be presumptive-
ly suitable for judicial review,’’ or whether the court and the
agency would instead benefit from postponing review until
the agency’s policy has ‘‘crystallized’’ through implementation
in a concrete factual setting. AT&T Corp., 349 F.3d at 699-
700 (quoting Better Gov’t Ass’n v. Dep’t of State, 780 F.2d 86,
92 (D.C. Cir. 1986)). Where an issue is not yet fit for judicial
review, we must weigh the benefits of postponing review
                              97

against the hardship suffered by the petitioner as a result of
such delay. See id. at 700.
   Nevada’s substantive claims against the FEIS will not be
fit for judicial review until the FEIS is used to support a
concrete and final decision. DOE has not yet selected a
transportation alternative or sought to use the existing FEIS
to support such a decision. We do not yet know whether or
to what extent NRC will adopt DOE’s FEIS in support of any
decision to authorize construction or license the operation of a
repository at Yucca. NRC has indicated that it may require
that DOE supplement the FEIS, or it may itself supplement
the FEIS. See NEPA Review Procedures for Geologic Re-
positories for High-Level Waste, 53 Fed. Reg. 16,131, 16,142-
43 (May 5, 1988) (Proposed Rule); 10 C.F.R. § 51.109(a)
(2003). In the face of such uncertainty, it is clear that the
relevant agency positions have not yet ‘‘crystallized.’’ Our
review of the FEIS therefore would benefit from postponing
consideration until the FEIS has been used to support a
specific, concrete, and final decision. See Ohio Forestry
Ass’n, Inc. v. Sierra Club, 523 U.S. 726, 733-37 (1998) (with-
holding consideration of a forest management plan where it
was uncertain whether and to what extent the plan would be
used to support specific future logging decisions).
   Turning to the second prong of our ripeness inquiry, we
conclude that withholding consideration of Nevada’s substan-
tive claims at this time imposes no hardship on Nevada.
Nevada itself has not sought immediate review of the FEIS
insofar as it may relate to future DOE or NRC decisions.
Putting the now-unreviewable site-selection decisions to one
side, the effect of the FEIS will not be felt in a concrete way
by Nevada until it is used to support some other final decision
of DOE or NRC. Nevada may raise its substantive claims
against the FEIS if and when NRC or DOE makes such a
final decision. Our decision to postpone consideration of
Nevada’s claims therefore works no hardship on Nevada
sufficient to render its claims ripe. See id. at 735 (holding
that requiring a party to participate in further administrative
or judicial proceedings is not a hardship sufficient to outweigh
                              98

a determination that an issue is unfit for review); AT&T
Corp., 349 F.3d at 700 (same).
   In reaching this conclusion as to hardship, we rely on the
assurances of counsel for both NRC and DOE at oral argu-
ment that Nevada will be permitted to raise its substantive
challenges to the FEIS in any NRC proceeding to decide
whether to adopt the FEIS and in any DOE proceeding to
select a transportation alternative. Oral Argument Tr. at
149-52, 169-71. It was noted at oral argument that an NRC
decision to adopt the FEIS may present special concerns,
because NRC is required under the NWPA to adopt the
FEIS ‘‘to the extent practicable.’’           See 42 U.S.C.
§ 10134(f)(4). In setting forth regulations to govern review
of DOE’s FEIS, NRC has acknowledged that it would not be
‘‘practicable’’ to adopt the FEIS unless it meets the standards
for an ‘‘adequate statement’’ under the NEPA and the Coun-
cil for Environmental Quality’s NEPA regulations. See 53
Fed. Reg. at 16,142. We agree. The NWPA’s mandate that
the FEIS be adopted by NRC ‘‘to the extent practicable’’ is
intended to avoid duplication of the environmental review
process. See H.R. REP. NO. 97-491, pt. 1, at 48, 53-54 (1982).
But it cannot reasonably be interpreted to permit NRC to
premise a construction-authorization or licensing decision
upon an EIS that does not meet the substantive requirements
of the NEPA or the Council on Environmental Quality’s
NEPA regulations. See id. at 48 (‘‘The Committee intends
that throughout the repository development program, the
Secretary and other agencies meet the general requirements
and the spirit of NEPA.’’ (emphasis added)).
   NRC’s current regulation governing review of DOE appli-
cations for construction authorization or licensing of a reposi-
tory states that adoption of the DOE’s FEIS shall be deemed
‘‘practicable’’ unless:
     (1) TTT The action proposed to be taken by [NRC]
     differs from the action proposed in the license appli-
     cation submitted by the Secretary of Energy[,] and
     [t]he difference may significantly affect the quality
     of the human environment; or (2) Significant and
                              99

    substantial new information or new considerations
    render such environmental impact statement inade-
    quate.
10 C.F.R. § 51.109(c) (2003). The regulation also notes that,
if the FEIS is adopted in accordance with this requirement,
‘‘no further consideration under NEPA or this subpart shall
be required.’’ 10 C.F.R. § 51.109(d) (2003). When ques-
tioned at oral argument about the meaning of this regulation,
Government counsel assured the court that NRC will not
construe the ‘‘new information or new considerations’’ re-
quirement to preclude Nevada from raising substantive
claims against the FEIS in administrative proceedings. Oral
Argument Tr. at 171.
   On January 15, 2004, following oral argument, counsel for
NRC purported to clarify the Government’s position in a
letter submitted to the court. Letter from Steven F. Crock-
ett, Office of the General Counsel, U.S. Nuclear Regulatory
Commission (Jan. 15, 2004). The letter states that the rele-
vant NRC regulations, including 10 C.F.R. § 51.109(c), ‘‘af-
fect[ ] issues that can be raised and litigated at NRC admin-
istrative hearings, not issues that can be raised on judicial
review.’’ Id. The suggested distinction makes no sense.
Nevada’s claims have not been adjudicated on the merits here
and presumably will not have been passed upon by any court
prior to the relevant NRC proceedings. The claims thus
would certainly raise ‘‘new considerations’’ with regard to any
decision to adopt the FEIS. Moreover, as noted above, any
substantive defects in the FEIS clearly would be relevant to
the ‘‘practicability’’ of adopting the FEIS. Government coun-
sel’s unequivocal representation to the court during oral
argument that Nevada will not be foreclosed from raising
substantive claims against the FEIS in administrative pro-
ceedings comports with the terms of the regulation and
reflects a reasonable and compelling interpretation. There-
fore, on the record at hand, there is no reason to assume that
the regulation will bar consideration of Nevada’s substantive
claims in the relevant NRC administrative proceedings.
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                       V. CONCLUSION
   In sum, we vacate 40 C.F.R. part 197 to the extent that it
incorporates a 10,000-year compliance period because, con-
trary to EnPA section 801(a), that compliance period is not
‘‘based upon and consistent with’’ the recommendations of the
National Academy of Sciences. The remaining challenges to
the EPA rule are without merit. We vacate the NRC rule
insofar as it incorporates EPA’s 10,000-year compliance peri-
od. In all other respects, we deny Nevada’s petition for
review challenging the NRC rule. We also reject the State’s
challenge to the constitutionality of the resolution approving
the Yucca Mountain site, and we dismiss the State’s petition
attacking the Department of Energy’s and the President’s
actions leading to passage of that resolution, as those actions
are unreviewable.
                                                   So ordered.
