[Federal Register Volume 70, Number 173 (Thursday, September 8, 2005)]
[Proposed Rules]
[Pages 53313-53320]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-17778]
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NUCLEAR REGULATORY COMMISSION
10 CFR Part 63
RIN 3150-AH68
Implementation of a Dose Standard After 10,000 Years
AGENCY: Nuclear Regulatory Commission.
ACTION: Proposed rule.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is proposing to
amend its regulations governing the disposal of high-level radioactive
wastes in a proposed geologic repository at Yucca Mountain, Nevada. The
proposed rule would implement the U.S. Environmental Protection
Agency's (EPA's) proposed standards for doses that could occur after
10,000 years but within the period of geologic stability. The proposed
rule also specifies a value to be used to represent climate change
[[Page 53314]]
after 10,000 years, as called for by EPA, and specifies that
calculations of radiation doses for workers use the same weighting
factors that EPA is proposing for calculating individual doses to
members of the public.
DATES: The comment period expires November 7, 2005. Comments received
after this date will be considered if it is practical to do so, but NRC
is able to assure consideration only for comments received on or before
this date.
ADDRESSES: You may submit comments by any one of the following methods.
Please include the following number (RIN 3150-AH68) in the subject line
of your comments. Comments on rulemakings submitted in writing or in
electronic form will be made available to the public in their entirety
on the NRC rulemaking Web site. Personal information will not be
removed from your comments.
Mail comments to: Secretary, U.S. Nuclear Regulatory Commission,
Washington, DC 20555-0001, ATTN: Rulemakings and Adjudications Staff.
E-mail comments to: [email protected]. If you do not receive a reply e-
mail confirming that we have received your comments, contact us
directly at (301) 415-1966. You may also submit comments via the NRC's
rulemaking Web site at http://ruleforum.llnl.gov. Address questions
about our rulemaking website to Carol Gallagher (301) 415-5905; e-mail
[email protected]. Comments can also be submitted via the Federal eRulemaking
Portal at http://www.regulations.gov.
Hand deliver comments to: 11555 Rockville Pike, Rockville, Maryland
20852, between 7:30 a.m. and 4:15 p.m. Federal workdays. (Telephone
(301) 415-1966).
Fax comments to: Secretary, U.S. Nuclear Regulatory Commission at
(301) 415-1101.
Publicly available documents related to this rulemaking may be
examined and copied for a fee at the NRC's Public Document Room (PDR),
Public File Area O1 F21, One White Flint North, 11555 Rockville Pike,
Rockville, Maryland. Selected documents, including comments, can be
viewed and downloaded electronically via the NRC rulemaking Web site at
http://ruleforum.llnl.gov.
Publicly available documents created or received at the NRC after
November 1, 1999, are available electronically at the NRC's Electronic
Reading Room at http://www.nrc.gov/NRC/ADAMS/index.html. From this
site, the public can gain entry into the NRC's Agencywide Document
Access and Management System (ADAMS), which provides text and image
files of NRC's public documents. If you do not have access to ADAMS or
if there are problems in accessing the documents located in ADAMS,
contact the NRC Public Document Room (PDR) Reference staff at 1-800-
397-4209, 301-415-4737, or by e-mail to [email protected].
FOR FURTHER INFORMATION CONTACT: Timothy McCartin, Office of Nuclear
Material Safety and Safeguards, U.S. Nuclear Regulatory Commission,
Washington, DC 20555-0001, telephone (301) 415-7285, e-mail
[email protected]; Janet Kotra, Office of Nuclear Material Safety and
Safeguards, U.S. Nuclear Regulatory Commission, Washington, DC 20555-
0001, telephone (301) 415-6674, e-mail [email protected]; or Lydia Chang,
Office of Nuclear Material Safety and Safeguards, U.S. Nuclear
Regulatory Commission, Washington, DC 20555-0001, telephone (301) 415-
6319, e-mail [email protected].
SUPPLEMENTARY INFORMATION:
I. Background
On November 2, 2001 (66 FR 55732), NRC published its final rule, 10
CFR part 63, governing disposal of high-level radioactive wastes in a
potential geologic repository at Yucca Mountain, Nevada. The U.S.
Department of Energy (DOE) must comply with these regulations for NRC
to authorize construction and license operation of a potential
repository at Yucca Mountain. As mandated by the Energy Policy Act of
1992, Public Law 102-486 (EnPA), NRC's final rule was consistent with
the radiation protection standards issued by EPA at 40 CFR Part 197 (66
FR 32074; June 13, 2001). EPA developed these standards under Congress'
direction, in Section 801 of EnPA, to issue public health and safety
standards for protection of the public from releases of radioactive
materials stored or disposed of in a potential repository at the Yucca
Mountain site. These standards were to be ``based upon and consistent
with'' the findings and recommendations of the National Academy of
Sciences (NAS). The NAS issued its findings and recommendations, on
August 1, 1995, in a report entitled Technical Bases for Yucca Mountain
Standards.
The State of Nevada and other petitioners challenged both the EPA
standards and the NRC regulations in court. On July 9, 2004, the United
States Court of Appeals for the District of Columbia Circuit upheld
both EPA's standards and NRC's regulations on all but one of the issues
raised by the petitioners. See Nuclear Energy Institute, Inc. v.
Environmental Protection Agency, 373 F.3d 1251 (D.C. Cir. 2004). The
court disagreed with EPA's decision to adopt a 10,000-year period for
compliance with the standards and NRC's adoption of that 10,000-year
compliance period in NRC's implementing regulations. The court found
that EPA's 10,000-year compliance period was not ``based upon and
consistent with'' NAS findings, as required by Section 801 of EnPA. See
the aforementioned 373 F.3d at 1270. The NAS recommended that a
standard be developed that would provide protection when radiation
doses reach their peak within the limits imposed by long-term stability
of the geologic environment. In addition, NAS found no scientific basis
for limiting application of the individual-risk standard to 10,000
years. Thus, the court vacated EPA's rule at 40 CFR part 197 to the
extent that it specified a 10,000-year compliance period and remanded
the matter to EPA. The court also vacated NRC's rule at 10 CFR Part 63
insofar as it incorporated EPA's 10,000-year compliance period.
In response to the remand, EPA issued its proposed revised
standards on August 22, 2005 (70 FR 49014). To comply with EnPA and the
court's remand, NRC must now revise 10 CFR Part 63 to be consistent
with EPA's revised standards. For that purpose, NRC is proposing
revisions to 10 CFR part 63 in this notice.
II. Discussion
To address the court's decision, EPA is retaining the standards
applicable to the first 10,000 years after disposal and proposes to add
separate requirements for the peak dose after 10,000 years and within
the period of geologic stability. EPA also proposes to revise the
approach for calculating doses, based on International Commission on
Radiological Protection (ICRP) recommendations, for the periods before
and after 10,000 years. Specifically, EPA's proposed revisions to its
standards: (1) Provide a limit for the peak dose after 10,000 years;
(2) specify criteria DOE must use in performance assessments for
estimating doses after 10,000 years; and (3) specify ``weighting
factors'' for DOE's use when calculating individual dose during the
operational or preclosure phase as well as after the disposal or
postclosure phase. Also, in its proposal, EPA states that NRC should
specify a value or values that DOE must use to represent climate change
after 10,000 years.
In this rulemaking, the NRC proposes to (1) adopt the limit EPA
sets for the peak dose after 10,000 years; (2) adopt the criteria EPA
has specified for performance assessments that estimate
[[Page 53315]]
doses after 10,000 years; (3) adopt the ``weighting factors'' EPA
specifies for calculating individual doses during the operational or
preclosure phase, as well as after the disposal or postclosure phase;
(4) require that calculations of radiation doses for workers use the
same weighting factors EPA is proposing for calculating individual
dose; and (5) specify a value that DOE must use to project the long-
term impact of climate variation after 10,000 years, as called for by
EPA. These proposals are more fully described below.
The NRC's proposal of these changes to part 63 coincides with EPA's
publication of its proposal to provide important and timely information
to the public on how NRC plans to incorporate and implement EPA's
standards in NRC's regulations. In general, the changes to part 63
adopt the same or approximately the same wording as used by EPA in its
proposed revisions to 40 CFR part 197. Comments on EPA's proposal
(e.g., the dose limit) should be directed to EPA and refer to EPA's
proposal published on August 22, 2005. NRC's existing regulations,
which are applicable for the first 10,000 years after disposal, remain
in place [e.g., the 0.15 millisieverts/year (15 millirem/year)
individual protection standard] consistent with the existing EPA
standards, and are not affected by this rulemaking except insofar as
NRC's rule adopts more up-to-date dosimetry for dose calculations.
The Commission welcomes comments on NRC's proposed implementation
of EPA's proposed revisions to its standards as well as on NRC's
revisions for use of specific weighting factors for calculating worker
doses, and on NRC's specification of a value for climate change. NRC
requests and will respond to comments only on those provisions of part
63 that we are now proposing to change. A description of these changes
follows.
1. Dose Limit
EPA's proposed standards would require DOE to estimate peak dose
after 10,000 years as part of the evaluations for both individual
protection and human intrusion. DOE must then compare the results of
these estimates to an annual dose limit of 3.5 mSv/yr (350 mrem/yr).
For this comparison, EPA proposes that DOE use the median value of the
projected doses after 10,000 years and through the period of geologic
stability. NRC proposes to incorporate the new EPA dose limit and
statistical measure for compliance directly into NRC's regulations at
Sec. 63.311 for individual protection and at Sec. 63.321 for human
intrusion.
2. Criteria for Performance Assessments Used to Estimate Peak Dose
After 10,000 Years
EPA proposes using the performance assessment for the first 10,000
years as the basis for projecting repository performance after 10,000
years. EPA asserts that its requirements for the performance assessment
for the first 10,000 years (e.g., consideration for features, events,
and processes with a probability of occurrence greater than
10-\8\ per year) provide a suitable basis for projecting
performance after 10,000 years. NRC's existing regulations at 10 CFR
Part 63 already include additional requirements, governing the
preparation of the performance assessment, that ensure that features,
events, and processes considered for inclusion in the performance
assessment over the 10,000-year compliance period represent a wide
range of both favorable and detrimental effects on performance.
Because of the uncertainties associated with estimating performance
over very long times (e.g., hundreds of thousands of years) and to
limit speculation, EPA proposes specific constraints on the
consideration of features, events, and processes after 10,000 years.
First, EPA asserts that data and models used to prepare the performance
assessment for the first 10,000 years provide adequate support for
projections used in the performance assessment after 10,000 years. For
example, DOE may apply the seismic hazard curves used in the 10,000-
year assessment to project seismic activity after 10,000 years. Second,
EPA proposes to (1) limit the analysis of seismic activity to the
effects caused by damage to the drifts and the waste package; (2) limit
analysis of igneous activity to effects on the waste package that
result in release of radionuclides to the atmosphere or ground water;
(3) limit the effect of climate variation to those resulting from
increased water flowing to the repository; and (4) require DOE to
include general corrosion in its analysis of engineered barrier
performance. NRC proposes to incorporate these criteria into NRC
regulations at Sec. 63.342. NRC also proposes revising requirements
for the performance assessment, specified at Sec. 63.114, to be
consistent with EPA's proposal that the performance assessment for the
first 10,000 years serve as the basis for projecting repository
performance assessment after 10,000 years.
3. Individual Dose Calculations
EPA proposes that DOE use specific weighting factors provided in
proposed Appendix A of its standards at 40 CFR 197. These weighting
factors reflect current methods of dosimetry and updated models for
calculating individual exposures from radiation. EPA cites, as a basis
for this proposal, recommendations and guidance from ICRP Publications
60 through 72. NRC supports the use of current dosimetry and proposes
to adopt this specification.
4. Worker Dose Calculations
Consistent with EPA's specification of dosimetry for calculating
individual doses to members of the public (public doses), NRC proposes
to revise its part 63 regulations to allow DOE to use the same methods
for calculating doses to workers during the operational period as those
required for calculating public doses. NRC believes that calculations
of doses to workers and the public should rely on a single set of
weighting factors, based on current dosimetry. This approach would
avoid the unnecessary complication and potential confusion for
stakeholders that could result from the use of two sets of weighting
factors. NRC proposes to add a definition for ``weighting factor'' to
Sec. 63.2 that specifies the weighting factors provided in the EPA
proposal, and to amend Sec. 63.111(a)(1) to provide that calculation
of doses to meet the requirements of 10 CFR part 20 shall use the
definition for ``weighting factor'' in Sec. 63.2. Calculation of both
worker and public doses would use the weighting factor as defined.
5. Values Used To Project Climate Variation After 10,000 Years
EPA proposes that DOE should assume that the effect of climate
variation, after 10,000 years, is limited to the results of increased
water flowing through the repository. EPA also proposes that NRC
specify, in regulation, steady-state (constant-in-time) values that DOE
should use to project the long-term impact of climate variation after
10,000 years. This approach focuses on ``average'' climate conditions
over the long term rather than on time-varying aspects of climate
(e.g., timing, size, and duration of short-term variations) that can be
both uncertain and speculative. The NRC has considered what parameter
or parameters would represent the average climate conditions.
Precipitation and temperature are the most readily identified
parameters, associated with climate, that directly influence the amount
of water, or deep percolation, flowing to the repository horizon. It is
the rate of deep percolation, however, that directly influences
repository performance. Therefore, the NRC proposes to specify use of
the deep
[[Page 53316]]
percolation rate to represent the effect of future climate in
performance assessments after 10,000 years.
Southern Nevada has experienced significant variation in mean
annual precipitation and temperature over the past 1 to 3 million years
(Forester, R. M. ``Pliocene-Climate History of the Western United
States Derived from Lacustrine Ostracodes,'' Quaternary Science
Reviews, Volume 10, pages 133-146, 1991). Estimates of future climate
over the next 1 million years involve many assumptions and are
uncertain. One approach, discussed when NRC issued its regulations for
Yucca Mountain at 10 CFR part 63 (page 66 FR 55757; November 2, 2001),
is to assume that fundamental mechanisms that will change the future
climate will be the same as those that changed it in the past.
Paleoclimate data suggest that, in general, over the past 1 million
years, Southern Nevada has been cooler and wetter than it is today
(Thompson, R. S., K. H. Anderson, and P. J. Bartlein, ``Quantitative
Paleoclimatic Reconstructions from Late Pleistocene Plant Macrofossils
of the Yucca Mountain Region,'' U.S. Geological Survey Open-File Report
99-338, U.S. Geological Survey, Denver, CO, 1999; and Reheis, M.,
``Highest Pluvial Lake Shorelines and Pleistocene Climate in the
Western Great Basin,'' Quaternary Research, Volume 52, pages 196-205,
1999). Thus, NRC expects ``average'' conditions 10,000 years in the
future, and later, to be cooler and wetter. Those conditions will allow
more water to percolate to the repository horizon than expected during
the first 10,000 years.
According to climatologists, the so-called intermediate and monsoon
climate states, which occur between the warmer ``interglacial'' and the
cooler ``full glacial'' climate states, are both wetter than the
present climate state. Climatologists estimate a mean annual
precipitation, during these climate states, at about twice that of
present mean annual precipitation at Yucca Mountain. Over the past
million years, these two wetter climate states were the predominate
climate states (Civilian Radioactive Waste Management System,
Management and Operating Contractor, ``Future Climate Analysis--10,000
years to 1,000,000 Years After Present,'' MOD-01-001 Rev. 00, 2002). To
the extent that climate is controlled by changes in solar radiation
arising from variations in the Earth's orbit [op. cit.], it is
reasonable to assume that climate patterns during the next 1 million
years would follow a similar cycle. Deep percolation rates depend on
both precipitation and temperature and their associated effects on
evaporation and plant transpiration. Today, the mean precipitation,
measured at Yucca Mountain, is 125 millimeters/year (mm/year) (4.9
inches/year) (Thompson, R. S., K. H. Anderson, and P. J. Bartlein,
``Quantitative Paleoclimatic Reconstructions from Late Pleistocene
Plant Macrofossils of the Yucca Mountain Region,'' U.S. Geological
Survey Open-File Report 99-338, U.S. Geological Survey, Denver, CO,
1999). About 4 percent of that water reaches the repository horizon.
This corresponds to an estimated deep percolation rate of 5 mm/year
(0.20 inches/year) when averaged over the repository footprint (Zhu,
C., J. R. Winterle, and E. I. Love, ``Late Pleistocene and Holocene
Groundwater Recharge from the Chloride Mass Balance Method and
Chlorine-36 Data,'' Water Resources Research, Vol 39, No. 7, page 1182,
2003). Examination of locations in the United States, analogous to
Yucca Mountain in some future intermediate and monsoon climates,
suggests potential precipitation rates of between 266 and 321 mm/year
[10.5 and 12.6 inches/year] (Thompson, R. S., K. H. Anderson, and P. J.
Bartlein, ``Quantitative Paleoclimatic Reconstructions from Late
Pleistocene Plant Macrofossils of the Yucca Mountain Region,'' U.S.
Geological Survey Open-File Report 99-338, U.S. Geological Survey,
Denver, CO, 1999).
Estimates of deep percolation rate as a fraction of precipitation
have been calculated for various climate conditions. Between 5 to 20
percent of precipitation could reach the repository depth under
intermediate/monsoon to ``full glacial'' climate conditions. The larger
percentage reflects ``full glacial'' conditions (Mohanty, S., R.
Codell, J. M. Menchaca, et al., System-Level Performance Assessment of
the Proposed Repository at Yucca Mountain Using the TPA Version 4.1
Code, CNWRA 2002-05 Revision 2, Center for Nuclear Waste Regulatory
Analyses, San Antonio, TX, 2004). Given that average deep percolation
at Yucca Mountain is about 4 percent of precipitation, under current
conditions, and assuming between 5 to 20 percent for the fraction of
precipitation that remains as deep percolation under intermediate/
monsoon climates, one may estimate higher average water flow to the
repository than observed today. On this basis, the NRC proposes that
DOE represent the effects of climate change after 10,000 years by
assuming that deep percolation rates vary between 13 to 64 mm/year (0.5
to 2.5 inches/year) \1\. DOE would implement this assumption in its
performance assessment by sampling values of deep percolation rates
within this range, and, for a given calculation, by assuming the deep
percolation rate remained constant, at the sampled rate, after 10,000
years.
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\1\ The low value of the range is derived using the lower
estimated fraction of precipitation that results in deep percolation
and the lower precipitation rate (i.e., 5 percent of 266 is
approximately 13) and the high value of the range from using the
higher estimated fraction of precipitation that results in deep
percolation and the higher value for precipitation rate (i.e., 20
percent of 321 is approximately 64).
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Thus, NRC proposes that DOE use a time-independent deep percolation
rate, after 10,000 years, based on a log uniformly distributed range of
deep percolation rates from 13 to 64 mm/year (0.5 to 2.5 inches/year).
This ``average'' deep percolation rate represents the average amount of
water flowing to the repository horizon. Specifying a rate that is
constant over time, however, does not imply that this same rate should
necessarily be held constant spatially over the entire repository
horizon. To the contrary, current understanding of site behavior (e.g.,
NRC staff and DOE staff representations of infiltration and percolation
processes at Yucca Mountain) shows significant variation in current
deep percolation rates across the repository horizon. This would be
expected to continue to occur into the far future. NRC expects DOE to
continue such calculations of spatial variation, subject to the
constraint that, across the repository footprint, the ``average''
overall percolation rate would remain within the range and distribution
specified by NRC.
The Commission considers it appropriate to specify these
constraints on how DOE must account for the effects of climate change
during the period after 10,000 years because this approach: (1) Is
consistent with EPA's proposal for treatment of climate change after
10,000 years; (2) specifies, in a straightforward way, how DOE shall
represent climate change in its performance assessment; (3) results in
a mean deep percolation rate of approximately 32 mm/year \2\ (1.3
inches/year), a rate that is approximately six times greater than the
current rate, representing wetter and cooler conditions (e.g.,
interglacial and monsoon climate states); and (4) provides information
on the relative significance of the deep percolation rate
[[Page 53317]]
(e.g., results of the performance assessment when the deep percolation
rate is assumed to be at the low value of the range versus the high
value of the range).
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\2\ The mean value of a log-uniform distribution of deep
percolation that ranges from 13 mm/year to 64 mm/yr is equal to (64
mm/year -13 mm/year)/[loge(64 mm/year) -
loge(13 mm/year)] = 32 mm/year.
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III. Discussion of Proposed Amendments by Section
Section 63.2s Definitions
This section would be modified to revise the definition of
``performance assessment'' to exclude the limitation of ``10,000 years
after disposal,'' consistent with EPA's modified definition of
``performance assessment.'' This section also would be modified to
include a definition for ``weighting factor'' that conforms the
weighting factors to be used in dose calculations to the values EPA
proposes.
Section 63.111 Performance Objectives for the Geologic Repository
Operations Area Through Permanent Closure
This section specifies requirements for radiation exposures for the
geologic repository operations area. This section would be modified to
require use of the definition for ``weighting factor'' in Sec. 63.2
when calculating doses to meet the requirements of part 20 of this
chapter.
Section 63.114 Requirements for Performance Assessment
This section specifies the requirements for the performance
assessment used to demonstrate compliance with the requirements
specified at Sec. 63.113(b), (c), and (d). This section would be
revised to conform to EPA's proposed standards that specify what DOE
must consider in the performance assessment for the period after 10,000
years.
Section 63.302 Definitions for Subpart L
The definition for the ``period of geologic stability'' would be
modified to clarify that this period ends at 1 million years after
disposal.
Section 63.303 Implementation of Subpart L
This section provides a functional overview of this subpart. This
section would be revised to conform to EPA's proposed standard that
specifies the arithmetic mean of the projected doses to be used for
determining compliance for the period within 10,000 years after
disposal and the median value of the projected doses to be used for
determining compliance for the period after 10,000 years and through
the period of geologic stability.
Section 63.305 Required Characteristics of the Reference Biosphere
This section specifies characteristics of the reference biosphere
to be used by DOE in its performance assessments to demonstrate
compliance with the requirements specified at Sec. 63.113. This
section would be modified to conform to EPA's proposed standards, which
specify the types of changes DOE shall account for in the performance
assessment for the period after 10,000 years and through the period of
geologic stability.
Section 63.311 Individual Protection Standard After Permanent Closure
This section specifies the dose limit for individual protection
after permanent closure for any geologic repository at the Yucca
Mountain site. This section would be modified to conform with the
public health and environmental radiation standards EPA proposes for
the peak dose after 10,000 years and through the period of geologic
stability.
Section 63.321 Individual Protection Standard for Human Intrusion
This section directs DOE to estimate the dose resulting from a
stylized human intrusion drilling scenario and specifies the dose limit
that any geologic repository at the Yucca Mountain site must meet as
the result of a hypothetical human intrusion. This section would be
modified to conform with the public health and environmental radiation
standards EPA proposes for the peak dose after 10,000 years and through
the period of geologic stability.
Section 63.341 Projections of Peak Dose
This section has been removed.
Section 63.342 Limits on Performance Assessments
This section specifies how DOE will identify and consider features,
events, and processes in the dose assessments described in subpart L to
part 63. This section would be modified to conform to EPA's proposed
standards, which specify the types of changes DOE shall account for in
the performance assessment for the period after 10,000 years and
through the period of geologic stability. A range of values has been
specified that DOE shall use to represent the effects of climate change
after 10,000 years and through the period of geologic stability.
IV. Agreement State Compatibility
Under the ``Policy Statement on Adequacy and Compatibility of
Agreement State Programs'' approved by the Commission on June 30, 1997,
and published in the Federal Register on September 3, 1997 (62 FR
46517), this rule is classified as Compatibility Category ``NRC.''
Compatibility is not required for Category ``NRC'' regulations. The NRC
program elements in this category are those that relate directly to
areas of regulation reserved to the NRC by the Atomic Energy Act of
1954, as amended (AEA), or the provisions of Title 10 of the Code of
Federal Regulations. An Agreement State may not adopt program elements
reserved to NRC.
V. Plain Language
The Presidential memorandum, dated June 1, 1998, entitled, ``Plain
Language in Government Writing,'' directed that the Government's
writing be in plain language. This memorandum was published on June 10,
1998 (63 FR 31883). NRC requests comments on this proposed rule
specifically with respect to the clarity and effectiveness of the
language used. Comments should be sent to the address listed under the
heading of ADDRESSES, above.
VI. Voluntary Consensus Standards
The National Technology Transfer and Advancement Act of 1995 (Pub.
L. 104-113) requires that Federal agencies use technical standards that
are developed or adopted by voluntary consensus standards bodies unless
the use of such a standard is inconsistent with applicable law or
otherwise impractical. In this proposed rule, NRC would implement site-
specific standards proposed by EPA and developed solely for application
to a proposed geologic repository for high-level radioactive waste at
Yucca Mountain, Nevada. This action does not constitute the
establishment of a standard that establishes generally applicable
requirements.
VII. Finding of No Significant Environmental Impact: Availability
Pursuant to Section 121(c) of the Nuclear Waste Policy Act, this
proposed rule does not require the preparation of an environmental
impact statement under Section 102(2)(c) of the National Environmental
Policy Act of 1969 or any environmental review under subparagraph (E)
or (F) of Section 102(2) of such act.
VIII. Paperwork Reduction Act Statement
This proposed rule does not contain new or amended information
collection requirements subject to the Paperwork Reduction Act of 1995
(44 U.S.C. 3501
[[Page 53318]]
et seq.). Existing requirements were approved by the Office of
Management and Budget (OMB), approval number 3150-0199.
Public Protection Notification
NRC may not conduct nor sponsor, and a person is not required to
respond to, a request for information nor an information collection
requirement, unless the requesting document displays a currently valid
OMB control number.
IX. Regulatory Analysis
The Commission has prepared a draft regulatory analysis on this
proposed regulation. The analysis examines the costs and benefits of
the alternatives considered by the Commission, consistent with the
options that are open to NRC in carrying out the statutory directive of
EnPA. The Commission requests public comment on the draft regulatory
analysis. Comments on the draft analysis may be submitted to NRC, as
indicated under the ADDRESSES, heading. The analysis is available for
inspection in the NRC PDR, 11555 Rockville Pike, Rockville, MD 20852.
Single copies of the regulatory analysis may be obtained from Lydia
Chang, Office of Nuclear Material Safety and Safeguards, U.S. Nuclear
Regulatory Commission, Washington, DC 20555-0001, telephone (301) 415-
6319, e-mail [email protected].
X. Regulatory Flexibility Certification
In accordance with the Regulatory Flexibility Act of 1980 [5 U.S.C.
605(b)], NRC certifies that this proposed rule will not, if issued,
have a significant economic impact on a substantial number of small
entities. This proposed rule affects only the licensing of one entity,
DOE, which does not fall within the scope of the definition of ``small
entities'' set forth in the Regulatory Flexibility Act nor the Small
Business Size Standards set out in regulations issued by the Small
Business Administration at 13 CFR part 121.
XI. Backfit Analysis
NRC has determined that the backfit rule (Sec. Sec. 50.109, 70.76,
72.62, or 76.76) does not apply to this proposed rule because this
amendment would not involve any provisions that would impose backfits,
as defined in the backfit rule. Therefore, a backfit analysis is not
required.
List of Subjects in 10 CFR Part 63
Criminal penalties, High-level waste, Nuclear power plants and
reactors, Reporting and recordkeeping requirements, Waste treatment and
disposal.
For the reasons set out in the preamble and under the authority of
the Atomic Energy Act of 1954, as amended; the Energy Reorganization
Act of 1974, as amended; the Nuclear Waste Policy Act of 1982, as
amended; and 5 U.S.C. 553, the NRC is proposing to adopt the following
amendments to 10 CFR part 63.
PART 63--DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC
REPOSITORY AT YUCCA MOUNTAIN, NEVADA
1. The authority citation for part 63 continues to read as follows:
Authority: Secs. 51, 53, 62, 63, 65, 81, 161, 182, 183, 68 Stat.
929, 930, 932, 933, 935, 948, 953, 954, as amended (42 U.S.C. 2071,
2073, 2092, 2093, 2095, 2111, 2201, 2232, 2233); secs. 202, 206, 88
Stat.1244, 1246 (42 U.S.C. 5842, 5846); secs. 10 and 14, Pub. L. 95-
601, 92 Stat. 2951 (42 U.S.C. 2021a and 5851); sec. 102, Pub. L. 91-
190, 83 Stat. 853 (42 U.S.C. 4332); secs. 114, 121, Pub. L. 97-425,
96 Stat. 2213g, 2238, as amended (42 U.S.C. 10134, 10141); and Pub.
L. 102-486, sec. 2902, 106 Stat. 3123 (42 U.S.C. 5851); sec. 1704,
112 stat. 2750 (44 U.S.C. 3504 note).
2. Section 63.2 is amended by revising paragraph (1) of the
definition of ``performance assessment'' and by adding a new definition
for ``weighting factor,'' in alphabetical order, to read as follows:
Sec. 63.2 Definitions.
* * * * *
Performance assessment means an analysis that:
(1) Identifies the features, events, processes (except human
intrusion), and sequences of events and processes (except human
intrusion) that might affect the Yucca Mountain disposal system and
their probabilities of occurring;
* * * * *
Weighting factor for an organ or tissue is the proportion of the
risk of stochastic effects resulting from irradiation of that organ or
tissue to the total risk of stochastic effects when the whole body is
irradiated uniformly. For calculating the effective dose equivalent,
the values in Appendix A of 40 CFR part 197 are to be used.
3. In Sec. 63.111, paragraph (a)(1) is revised to read as follows:
Sec. 63.111 Performance objectives for the geologic repository
operations area through permanent closure.
(a) * * *
(1) The geologic repository operations area must meet the
requirements of part 20 of this chapter. Calculation of doses to meet
the requirements of part 20 of this chapter shall use the definition
for ``weighting factor'' in Sec. 63.2.
* * * * *
4. Section 63.114 is revised to read as follows:
Sec. 63.114 Requirements for performance assessment.
(a) Any performance assessment used to demonstrate compliance with
Sec. 63.113 for 10,000 years after disposal must:
(1) Include data related to the geology, hydrology, and
geochemistry (including disruptive processes and events) of the Yucca
Mountain site, and the surrounding region to the extent necessary, and
information on the design of the engineered barrier system used to
define, for 10,000 years after disposal, parameters and conceptual
models used in the assessment.
(2) Account for uncertainties and variabilities in parameter
values, for 10,000 years after disposal, and provide for the technical
basis for parameter ranges, probability distributions, or bounding
values used in the performance assessment.
(3) Consider alternative conceptual models of features and
processes, for 10,000 years after disposal, that are consistent with
available data and current scientific understanding and evaluate the
effects that alternative conceptual models have on the performance of
the geologic repository.
(4) Consider only features, events, and processes consistent with
the limits on performance assessment specified at Sec. 63.342.
(5) Provide the technical basis for either inclusion or exclusion
of specific features, events, and processes in the performance
assessment. Specific features, events, and processes must be evaluated
in detail if the magnitude and time of the resulting radiological
exposures to the reasonably maximally exposed individual, or
radionuclide releases to the accessible environment, for 10,000 years
after disposal, would be significantly changed by their omission.
(6) Provide the technical basis for either inclusion or exclusion
of degradation, deterioration, or alteration processes of engineered
barriers in the performance assessment, including those processes that
would adversely affect the performance of natural barriers.
Degradation, deterioration, or alteration processes of engineered
barriers must be evaluated in detail if the magnitude and time of the
resulting radiological exposures to the reasonably maximally exposed
individual, or radionuclide releases to the accessible
[[Page 53319]]
environment, for 10,000 years after disposal, would be significantly
changed by their omission.
(7) Provide the technical basis for models used to represent the
10,000 years after disposal in the performance assessment, such as
comparisons made with outputs of detailed process-level models and/or
empirical observations (e.g., laboratory testing, field investigations,
and natural analogs).
(b) Any performance assessment used to demonstrate compliance with
Sec. 63.113 for the period of time after 10,000 years through the
period of geologic stability must be based on the performance
assessment specified in paragraph (a) of this section.
5. In Section 63.302, the definition of ``period of geologic
stability'' is revised to read as follows:
Sec. 63.302 Definitions for Subpart L.
* * * * *
Period of geologic stability means the time during which the
variability of geologic characteristics and their future behavior in
and around the Yucca Mountain site can be bounded, that is, they can be
projected within a reasonable range of possibilities. This period is
defined to end at 1 million years after disposal.
* * * * *
6. Section 63.303 is revised to read as follows:
Sec. 63.303 Implementation of Subpart L.
(a) Compliance is based upon the arithmetic mean of the projected
doses from DOE's performance assessments for the period within 10,000
years after disposal for:
(1) Sec. 63.311(a)(1); and
(2) Sec. Sec. 63.321(b)(1) and 63.331, if performance assessment
is used to demonstrate compliance with either or both of these
sections.
(b) Compliance is based upon the median of the projected doses from
DOE's performance assessments for the period after 10,000 years of
disposal and through the period of geologic stability for:
(1) Sec. 63.311(a)(2); and
(2) Sec. 63.321(b)(2), if performance assessment is used to
demonstrate compliance.
7. Section 63.305, paragraph (c) is revised to read as follows:
Sec. 63.305 Required characteristics of the reference biosphere.
* * * * *
(c) DOE must vary factors related to the geology, hydrology, and
climate based upon cautious, but reasonable assumptions consistent with
present knowledge of factors that could affect the Yucca Mountain
disposal system during the period of geologic stability and consistent
with the requirements for performance assessments specified at Sec.
63.342.
* * * * *
8. Section 63.311 is revised to read as follows:
Sec. 63.311 Individual protection standard after permanent closure.
(a) DOE must demonstrate, using performance assessment, that there
is a reasonable expectation that the reasonably maximally exposed
individual receives no more than the following annual dose from
releases from the undisturbed Yucca Mountain disposal system:
(1) 0.15 mSv (15 mrem) for 10,000 years following disposal; and
(2) 3.5 mSv (350 mrem) after 10,000 years, but within the period of
geologic stability.
(b) DOE's performance assessment must include all potential
environmental pathways of radionuclide transport and exposure.
9. Section 63.321 is revised to read as follows:
Sec. 63.321 Individual protection standard for human intrusion.
(a) DOE must determine the earliest time after disposal that the
waste package would degrade sufficiently that a human intrusion (see
Sec. 63.322) could occur without recognition by the drillers.
(b) DOE must demonstrate that there is a reasonable expectation
that the reasonably maximally exposed individual receives, as a result
of human intrusion, no more than the following annual dose:
(1) 0.15 mSv (15 mrem) for 10,000 years following disposal; and
(2) 3.5 mSv (350 mrem) after 10,000 years, but within the period of
geologic stability.
(c) DOE's analysis must include all potential environmental
pathways of radionuclide transport and exposure, subject to the
requirements at Sec. 63.322.
Sec. 63.341 [Removed]
10. Section 63.341 is removed.
11. Section 63.342 is revised to read as follows:
Sec. 63.342 Limits on performance assessments.
(a) DOE's performance assessments conducted to show compliance with
Sec. Sec. 63.311(a)(1), 63.321(b)(1), and 63.331 shall not include
consideration of very unlikely features, events, or processes, i.e.,
those that are estimated to have less than one chance in 10,000 of
occurring within 10,000 years of disposal (less than one chance in
100,000,000 per year). In addition, DOE's performance assessments need
not evaluate the impacts resulting from any features, events, and
processes or sequences of events and processes with a higher chance of
occurrence if the results of the performance assessments would not be
changed significantly in the initial 10,000 year period after disposal.
(b) For performance assessments conducted to show compliance with
Sec. Sec. 63.321(b) and 63.331, DOE's performance assessments shall
exclude the unlikely features, events, and processes, or sequences of
events and processes, i.e., those that are estimated to have less than
one chance in 10 and at least one chance in 10,000 of occurring within
10,000 years of disposal (less than one chance in 100,000 per year and
at least one chance in 100,000,000 per year).
(c) For performance assessments conducted to show compliance with
Sec. Sec. 63.311(a)(2) and 63.321(b)(2), DOE's performance assessments
shall project the continued effects of the features, events, and
processes included in paragraph (a) of this section beyond the 10,000
year post-disposal period through the period of geologic stability. DOE
must evaluate all of the features, events, or processes included in
paragraph (a) of this section, and also:
(1) DOE must assess the effects of seismic and igneous scenarios
subject to the probability limits in paragraph (a) of this section for
very unlikely features, events, and processes. Performance assessments
conducted to show compliance with Sec. 63.321(b)(2) are also subject
to the probability limits in paragraph (b) of this section for unlikely
features, events, and processes.
(i) The seismic analysis may be limited to the effects caused by
damage to the drifts in the repository and failure of the waste
package.
(ii) The igneous analysis may be limited to the effects of a
volcanic event directly intersecting the repository. The igneous event
may be limited to that causing damage to the waste packages directly,
causing releases of radionuclides to the biosphere, atmosphere, or
ground water.
(2) DOE must assess the effects of climate change. The climate
change analysis may be limited to the effects of increased water flow
through the repository as a result of climate change, and the resulting
transport and release of radionuclides to the accessible environment.
The nature and degree of climate change may be represented by constant
climate conditions. The analysis may commence at 10,000 years after
disposal and shall extend to the
[[Page 53320]]
period of geologic stability. The constant value to be used to
represent climate change is to be based on a log-uniform probability
distribution for deep percolation rates from 13 to 64 mm/year (0.5 to
2.5 inches/year).
(3) DOE must assess the effects of general corrosion on the
engineered barriers. DOE may use a constant representative corrosion
rate throughout the period of geologic stability or a distribution of
corrosion rates correlated to other repository parameters.
Dated at Rockville, Maryland, this 1st day of September, 2005.
For the Nuclear Regulatory Commission.
Annette Vietti-Cook,
Secretary of the Commission.
[FR Doc. 05-17778 Filed 9-7-05; 8:45 am]
BILLING CODE 7590-01-P