Nuclear Power Plant License Renewal; Revisions
Federal RegisterMay 8, 1995
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NUCLEAR REGULATORY COMMISSION
10 CFR Parts 2, 51, and 54
RIN 3150-AF05
Nuclear Power Plant License Renewal; Revisions
AGENCY: Nuclear Regulatory Commission.
ACTION: Final rule.
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SUMMARY: The Nuclear Regulatory Commission (NRC) has amended its
regulations to revise the requirements that an applicant must meet for
obtaining the renewal of a nuclear power plant operating license. The
rule also clarifies the required information that must be submitted for
review so that the agency can determine whether those requirements have
been met and changes the administrative requirements that a holder of a
renewed license must meet. These amendments are intended to provide a
more stable and predictable regulatory process for license renewal.
EFFECTIVE DATE: June 7, 1995.
FOR FURTHER INFORMATION CONTACT: Thomas G. Hiltz, Office of Nuclear
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC
20555, telephone: (301) 415-1105.
SUPPLEMENTARY INFORMATION:
I. Background.
II. Final Action.
III. Principal Issues.
a. Continued validity of certain findings in previous
rulemaking.
b. Reaffirmation of the regulatory philosophy and approach and
clarification of the two principles of license renewal.
c. Systems, structures, and components within the scope of
license renewal.
d. The regulatory process and aging management.
e. Reaffirmation of conclusions concerning the current licensing
basis and maintaining the function of systems, structures, and
components.
f. Integrated plant assessment.
g. Time-limited aging analyses and exemptions.
h. Standards for issuance of a renewed license and the scope of
hearings.
i. Regulatory and administrative controls.
IV. General Comments and Responses.
V. Public Responses to Specific Questions.
VI. Availability of Documents.
VII. Finding of No Significant Environmental Impact: Availability.
VIII. Paperwork Reduction Act Statement.
IX. Regulatory Analysis.
X. Regulatory Flexibility Act Certification.
XI. Non-Applicability of the Backfit Rule.
I. Background
The previous license renewal rule (10 CFR Part 54) was adopted by
the Nuclear Regulatory Commission (NRC) on December 13, 1991 (56 FR
64943). This rule established the procedures, criteria, and standards
governing the renewal of nuclear power plant operating licenses.
Since publishing the previous license renewal rule, the NRC staff
has conducted various activities related to implementing this rule.
These activities included: developing a draft regulatory guide,
developing a draft standard review plan for license renewal,
interacting with lead plant licensees, and reviewing generic industry
technical reports sponsored by the Nuclear Management and Resources
Council (now part of the Nuclear Energy Institute (NEI)).
In November 1992, the law firm of Shaw, Pittman, Potts, and
Trowbridge submitted a paper to the NRC that presented the perspective
of Northern States Power Company on the license renewal process. The
paper included specific recommendations for making the license renewal
process more workable. In addition, industry representatives provided
the Commission with views on several key license renewal implementation
issues. In late 1992, the NRC staff conducted a senior management
review and discussed key license renewal issues with the Commission,
industry groups, [[Page 22462]] and individual licensees. The NRC staff
presented its recommendations regarding several of these key license
renewal issues in two Commission policy papers: SECY-93-049,
``Implementation of 10 CFR Part 54, `Requirements for Renewal of
Operating Licenses for Nuclear Power Plants,''' and SECY-93-113,
``Additional Implementation Information for 10 CFR Part 54,
`Requirements for Renewal of Operating Licenses for Nuclear Power
Plants.'''
In its staff requirements memorandum (SRM) of June 28, 1993, the
Commission stated that it is essential to have a predictable and stable
regulatory process clearly and unequivocally defining the Commission's
expectations for license renewal. This process would permit licensees
to make decisions about license renewal without being influenced by a
regulatory process that is perceived to be uncertain, unstable, or not
clearly defined. The Commission directed the NRC staff to convene a
public workshop to evaluate alternative approaches for license renewal
that best take advantage of existing licensee activities and programs
as a basis for concluding that aging will be addressed in an acceptable
manner during the period of extended operation. In particular, the
Commission directed the NRC staff to examine the extent to which
greater reliance can be placed on the maintenance rule (10 CFR 50.65,
``Requirements for Monitoring the Effectiveness of Maintenance at
Nuclear Power Plants'') as a basis for concluding that the effects of
aging will be effectively managed during the license renewal term.
On September 30, 1993, the NRC staff conducted a public workshop in
Bethesda, Maryland, that was attended by over 180 people. Attendees
included nuclear utilities, industry organizations, public interest
groups, architect and engineering firms, consultants and contractors,
and Federal and State governments. In December 1993, the NRC staff
forwarded SECY-93-331, ``License Renewal Workshop Results and Staff
Proposals for Revision to 10 CFR Part 54, `Requirements for Renewal of
Operating Licenses for Nuclear Power Plants,''' to the Commission. The
NRC staff recommended that the Commission amend 10 CFR Part 54.
In its SRM of February 3, 1994, the Commission agreed with the NRC
staff's conceptual approach (explained in SECY-93-331) for performing
license renewal reviews and directed the staff to proceed with
rulemaking to amend 10 CFR Part 54. The Commission believes that the
license renewal process should focus on the management of the effects
of aging on certain systems, structures, and components during the
period of extended operation. An objective for the amendment is to
establish a more stable and predictable license renewal process. The
amendment will identify certain systems, structures, and
components1 that require review in order to provide the necessary
assurance that they will continue to perform their intended function
for the period of extended operation.
\1\Throughout the Statement of Considerations, the phrases,
``systems, structures, and components'' and ``structures and
components'' are used. As a matter of clarification, the Commission
intends that the phrase, ``systems, structures, and components''
applies to the matters involving the discussions of the overall
renewal review, the specific license renewal scope (Sec. 54.4),
time-limited aging analyses (Sec. 54.21(c)), and the license renewal
finding (Sec. 54.29). The phrase, ``structures and components''
applies to matters involving the integrated plant assessment (IPA)
required by Sec. 54.21(a) because the aging management review
required within the IPA should be a component and structure level
review rather than a more general system level review. The phrase
systems, structures, and components applies to the evaluation of
time-limited aging analyses required by Sec. 54.21(c) because such
plant-specific analyses may have been carried out, for the initial
operating term, for either systems, structures, or components.
Reevaluation for the renewal term is intended to focus on the same
systems, structures, or components subject to the initial term time-
limited aging analyses. The finding required by Sec. 54.29 considers
both the results of the integrated plant assessment and the time-
limited aging analyses and, therefore, the phrase system,
structures, and components is applicable to this section.
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On May 23, 1994, the NRC staff provided the Commission with its
proposed amendment to the license renewal rule in SECY-94-140,
``Proposed Amendment to the Nuclear Power Plant License Renewal Rule
(10 CFR Part 54).'' In the SRM of June 24, 1994, the Commission
approved the publication of the proposed rule amendment for a 90-day
public comment period. In the SRM, the Commission directed the staff to
(1) ensure consistency in the use of the terms ``structures, systems,
and components'' and ``structures and components,'' (2) solicit
comments on the ability of existing programs to detect failures in
redundant structures and components before there is a loss of intended
system or structure function, (3) address the need for Sec. 54.4(a)(3)
in the statements of consideration for the proposed rule, and (4)
review the necessity of retaining Sec. 54.4(a)(4) and include the
rationale for its conclusions in the proposed rule.
On September 9, 1994, (59 FR 46574) the proposed revisions to the
license renewal rule were published in the Federal Register for a 90-
day public comment period. The public comment period ended on December
9, 1994. The Commission received 42 separate responses concerning the
proposed rulemaking for license renewal. In early April 1995, after
reviewing SECY-95-067, ``Final Amendment to the Nuclear Power Plant
License Renewal Rule (10 CFR Part 54),'' the Nuclear Energy Institute
and Yankee Atomic Electric Company provided additional comments. All
comments received have been considered in developing this final rule.
Comments on the proposed rule came from a variety of sources. These
included: a private citizen, 3 public interest groups (Sierra Club--
Atlantic Chapter, Public Citizen, and the Ohio Citizens for Responsible
Energy Inc.), 1 Federal organization (Department of Energy (DOE)), 4
State organizations (Illinois Department of Nuclear Safety (Illinois),
Connecticut Department of Public Utility Control (Connecticut), New
Jersey Department of Environmental Protection (New Jersey), and Nevada
Agency for Nuclear Projects, Nuclear Waste Project Office (Nevada)), 2
industry organizations (NEI and Nuclear Utility Group on Equipment
Qualification (NUGEQ)), 2 vendor owners groups (Babcock and Wilcox (B &
W) Owners Group and Westinghouse Owners Group), 2 vendors/consultants
(B & W Nuclear Technologies and Westinghouse Electric Corporation), and
27 separate nuclear power plant licensees. All 27 licensees endorsed
the comments provided by NEI, and some utilities also provided
additional comments.
The Commission specifically solicited responses to five questions
in the proposed rule. The questions and the responses to them can be
found in Section V of the Supplementary Information also known as the
Statement of Considerations (SOC).
Many of the letters contained similar comments, which were grouped
together and are addressed on an issue basis. The NRC has responded to
all of the significant points raised by the commenters. Those comments
that are applicable to a specific issue discussed in a specific section
of the Supplementary Information portion of this document are discussed
within that section. Comments received that are not responsive to a
particular issue are addressed in Section IV. Public comments received
on the proposed rule are available for inspection and copying for a fee
at the Commission's Public Document Room located at 2120 L Street NW.
(Lower Level), Washington, DC. [[Page 22463]]
II. Final Action
The final rule revises certain requirements contained in 10 CFR
Part 54 and establishes a regulatory process that is simpler, more
stable, and more predictable than the previous license renewal rule.
The final rule continues to ensure that continued operation beyond the
term of the original operating license will not be inimical to the
public health and safety. The more significant changes made to the
previous license renewal rule are as follows:
(1) The intent of the license renewal review has been clarified to
focus on the adverse effects of aging rather than identification of all
aging mechanisms. The final rule is intended to ensure that important
systems, structures, and components will continue to perform their
intended function in the period of extended operation. Identification
of individual aging mechanisms is not required as part of the license
renewal review. The definitions of age-related degradation, age-related
degradation unique to license renewal, aging mechanisms, renewal term,
and effective program have been deleted.
(2) The definitions of integrated plant assessment (IPA)
(Sec. 54.3) and the IPA process (Sec. 54.21(a)) have been clarified to
be consistent with the revised focus in item (1) on the detrimental
effects of aging.
(3) A new Sec. 54.4 has been added to replace the definition of
systems, structures, and components ``important to license renewal'' in
Sec. 54.3. Section 54.4 defines those systems, structures, and
components within the scope of the license renewal rule and identifies
the important functions (intended functions) that must be maintained.
The requirement to include systems, structures, and components that
have limiting conditions for operation in facility technical
specifications within the scope of license renewal has been deleted.
(4) In Sec. 54.21(a), the IPA process has been simplified. The
wording has been changed to resolve any ambiguity associated with the
use of the terms systems, structures, and components (SSCs) and
structures and components (SCs). A simplified methodology for
determining whether a structure or component requires an aging
management review for license renewal has been delineated. Only
passive, long-lived structures and components are subject to an aging
management review for license renewal. Sections 54.21 (b) and (d) have
been deleted, and a new Sec. 54.21(c) dealing with time-limited aging
analyses (TLAA) and Sec. 54.21(d) dealing with requirements for the
final safety analysis report (FSAR) supplement have been added. The
requirement in Sec. 54.21(c) of the previous rule to review any relief
from codes and standards has been deleted, and the requirement in
Sec. 54.21(c) of the previous rule to review exemptions from regulatory
requirements has been clarified and linked with the time-limited aging
analyses.
(5) In Sec. 54.22, the requirement to include detailed
justification for certain technical specification changes in the FSAR
supplement has been modified to require that the detailed justification
be included in the license renewal application.
(6) In Sec. 54.29, the standards for issuance of a renewed license
have been changed to reflect the revised focus on the detrimental
effects of aging concerning structures and components requiring an
aging management review for license renewal and any time-limited issues
(including exemptions) applicable for the renewal term. A new
Sec. 54.30 has been added to distinguish between those issues
identified during the license renewal process that require resolution
during the license renewal process and those issues that require
resolution during the current license term.
(7) In Sec. 54.33, requirements for continuation of the current
licensing basis (CLB) and conditions of renewed licenses have been
changed to delete all reference to age-related degradation unique to
license renewal (ARDUTLR). Section 54.33(d) of the previous rule, which
requires a specific change control process, has been deleted.
(8) In Sec. 54.37, additional records and recordkeeping
requirements have been changed to be less prescriptive. Section
54.37(c) has been deleted.
III. Principal Issues
a. Continued Validity of Certain Findings in Previous Rulemaking
The principal purpose of this final rule is to simplify and clarify
the previous license renewal rule. Unless otherwise clarified or
reevaluated, either directly or indirectly, in the discussion for this
final rule, the conclusions in the SOC for the previous license renewal
rule remain valid (56 FR 64943; December 13, 1991).
One commenter stated that the previous license renewal rule has
been substantially modified in the proposed rule so as to constitute a
``recision'' of the previous rule.
The Commission does not believe that this final rule represents a
recision of the previous license renewal rule, 10 CFR Part 54. As
stated in the SOC for the proposed rule, ``[u]nless otherwise clarified
or reevaluated, either directly or indirectly, in the discussion for
this proposed rule, the conclusions in the SOC for the current license
renewal rule remain valid * * *'' September 9, 1994 (59 FR 46576). Some
of the subjects resolved in the previous Part 54 rulemaking that remain
unaffected by this final rule include the concept of the CLB, the
nature of the current regulatory process, the regulatory process for
assuring compliance with the CLB, form of the renewed license, the term
of the renewed license, antitrust considerations, and the applicability
of the provisions of the Price-Anderson Act.
Furthermore, regardless of whether this final rule constitutes a
recision of the previous rule, the Commission agrees with the commenter
that the Administrative Procedure Act (APA) requires the Commission to
provide a ``reasoned analysis'' for the changes to Part 54 that are
being adopted in this final rule. The Commission takes issue with the
commenter with regard to whether the SOC for the proposed and for the
final rule adequately explain the bases for the changes. The Commission
believes that this SOC provides a detailed discussion setting forth the
perceived problems with the previous license renewal rule as well as a
discussion of the bases for this final rule. In sum, the Commission has
fulfilled its obligation under the APA to provide the bases for this
rule, regardless of whether the changes that are being adopted in this
final rule constitute a recision of the previous license renewal rule.
b. Reaffirmation of the Regulatory Philosophy and Approach and
Clarification of the Two Principles of License Renewal
(i) Regulatory Philosophy
In developing the previous license renewal rule, the Commission
concluded that issues material to the renewal of a nuclear power plant
operating license are to be confined to those issues that the
Commission determines are uniquely relevant to protecting the public
health and safety and preserving common defense and security during the
period of extended operation. Other issues would, by definition, have a
relevance to the safety and security of the public during current plant
operation. Given the Commission's ongoing obligation to oversee the
safety and security of operating reactors, issues that are relevant to
current plant operation will be addressed by the existing regulatory
[[Page 22464]] process within the present license term rather than
deferred until the time of license renewal. Consequently, the
Commission formulated two principles of license renewal.
The first principle of license renewal was that, with the exception
of age-related degradation unique to license renewal and possibly a few
other issues related to safety only during the period of extended
operation of nuclear power plants, the regulatory process is adequate
to ensure that the licensing bases of all currently operating plants
provides and maintains an acceptable level of safety so that operation
will not be inimical to public health and safety or common defense and
security. Moreover, consideration of the range of issues relevant only
to extended operation led the Commission to conclude that the
detrimental effects of aging is probably the only issue generally
applicable to all plants. As a result, continuing this regulatory
process in the future will ensure that this principle remains valid
during any period of extended operation if the regulatory process is
modified to address age-related degradation that is of unique relevance
to license renewal. Consequently, the previous license renewal rule
focused the Commission's review on this one safety issue.
The second and equally important principle of license renewal holds
that the plant-specific licensing basis must be maintained during the
renewal term in the same manner and to the same extent as during the
original licensing term. This principle would be accomplished, in part,
through a program of age-related degradation management for systems,
structures, and components that are important to license renewal as
defined in the previous rule.
The Commission still believes that mitigation of the detrimental
effects of aging resulting from operation beyond the initial license
term should be the focus for license renewal. After further
consideration and experience in implementing the previous rule, the
Commission has, however, determined that the requirements for carrying
out the license renewal review can and should be simplified and
clarified. The Commission has concluded that, for certain plant
systems, structures, and components, the existing regulatory process
will continue to mitigate the effects of aging to provide an acceptable
level of safety in the period of extended operation.
The objective of a license renewal review is to determine whether
the detrimental effects of aging, which could adversely affect the
functionality of systems, structures, and components that the
Commission determines require review for the period of extended
operation, are adequately managed. The license renewal review is
intended to identify any additional actions that will be needed to
maintain the functionality of the systems, structures, and components
in the period of extended operation. The Commission has determined that
it can generically exclude from the IPA aging management review for
license renewal (1) those structures and components that perform active
functions and (2) structures and components that are replaced based on
qualified life or specified time period. However, all systems,
structures, and components evaluated based on time-limited aging
analyses would be subject to a license renewal evaluation. Structures
or components may have active functions, passive functions, or both.
Detailed discussions concerning determination of those systems,
structures, and components requiring a license renewal review are
contained in Section III.c of this SOC; detailed discussions of those
structures and components subject to an aging management review are in
Section III.f of this SOC; and detailed discussions of systems,
structures, and components requiring a license renewal evaluation are
contained in Section III.g of this SOC.
This final rule focuses the license renewal review on certain
systems, structures, and components that the Commission has determined
require evaluation to ensure that the effects of aging will be
adequately managed in the period of extended operation. This change is
viewed as a modification consistent with the first principle of license
renewal established in the previous rule. In view of this final rule,
the first principle can be revised to state that, with the possible
exception of the detrimental effects of aging on the functionality of
certain plant systems, structures, and components in the period of
extended operation and possibly a few other issues related to safety
only during extended operation, the regulatory process is adequate to
ensure that the licensing bases of all currently operating plants
provides and maintains an acceptable level of safety so that operation
will not be inimical to public health and safety or common defense and
security. As modified, the Commission affirms its support of the first
principle of license renewal, as well as the (unmodified) second
principle.
(ii) Deletion of the term ``Age-Related Degradation Unique to License
Renewal''
The use of the term ``age-related degradation unique to license
renewal'' in the previous license renewal rule caused significant
uncertainty and difficulty in implementing the rule. A key problem
involved how ``unique'' aging issues were to be identified and, in
particular, how existing licensee activities and Commission regulatory
activities would be considered in the identification of systems,
structures, and components as either subject to or not subject to
ARDUTLR. The difficulty in clearly establishing ``uniqueness'' in
connection with the effects of aging is underscored by the fact that
aging is a continuing process, the fact that many licensee programs and
regulatory activities are already focused on mitigating the effects of
aging to ensure safety in the current operating term of the plant, and
the fact that no new aging phenomena have been identified as
potentially occurring only during the period of extended operation.
The final rule eliminates both the definition of ARDUTLR and use of
the term in codified regulatory text. Thus, confusion regarding the
detailed definition of ARDUTLR in the rule and questions regarding
which structures and components could be subject to ARDUTLR have been
eliminated.
Public Citizen noted that deletion of the term ARDUTLR represents
alteration of the ``original premise'' of the rule and this change
``has not been precipitated by any realization about reactor aging and
safety.'' Under both the previous renewal rule as well as this final
rule, the objective was to supplement the regulatory process, if
warranted, to provide sufficient assurance that adequate safety will be
assured during the extended period of operation. The Commission has
concluded that the only issue where the regulatory process may not
adequately maintain a plant's current licensing basis concerns the
detrimental effects of aging on the functionality of certain systems,
structures, and components in the period of extended operation. While
the objective and conclusion has remained the same in the two
rulemakings, the first principle of license renewal has been revised
consistent with the deletion of ARDUTLR. The Commission recognizes that
the concept of ARDUTLR has been removed inasmuch as the term
``ARDUTLR'' has been deleted from the first principle and from the rule
language itself. However, consistent with the focus of the previous
rule, the final rule will ensure that the [[Page 22465]] effects of
aging in the period of extended operation are adequately managed.
The Commission disagrees with the commenter's statement that this
change was arrived at without regard to reactor aging and safety. As
discussed above, greater understanding that (1) aging is a continuous
process and (2) that the actual effects of aging are not explicitly
linked, from a technical perspective, to the term of an operating
license, led the Commission to consider deleting ARDUTLR. The
Commission's current determination that a narrower set of systems,
structures, and components than that of the previous license renewal
rule should require evaluation to ensure that the effects of aging will
be adequately managed in the period of extended operation recognizes
that many licensee programs and regulatory activities will continue to
adequately manage the adverse effects of aging during the period of
extended operation. Therefore, the Commission believes that this
alteration is firmly based on an appropriate consideration of reactor
safety and aging. The final rule reflects a greater understanding of
effective aging management (focus on effects rather than mechanisms)
and more realistic expectations of aging in the extended period of
operation.
c. Systems, Structures, and Components Within the Scope of License
Renewal
(i) Scope of the License Renewal Review and Elimination of the
Technical Specification Limiting Conditions for Operation Scoping
Category
In the final rule, the Commission has deleted the definition (in
Sec. 54.3) of systems, structures, and components important to license
renewal and replaced it with a new section entitled Sec. 54.4 Scope.
This new section continues to define the set of plant systems,
structures, and components that would be the initial focus of a license
renewal review. From this set of systems, structures, and components, a
license renewal applicant will determine those systems, structures, and
components that require review for license renewal. The intent of the
definition of systems, structures, and components important to license
renewal (i.e., to initially focus the review on important systems,
structures, and components) remains intact in the new Sec. 54.4.
In the SOC for the previous license renewal rule, the Commission
concluded that applicants for license renewal should focus on the
management of aging for those systems, structures, and components that
are of principal importance to the safety of the plant. The Commission
also believed that the focus of an aging evaluation for license renewal
cannot be limited to only those systems, structures, and components
that the Commission has traditionally defined as safety-related.
Therefore, the Commission determined that, in order to ensure the
continued safe operation of the plant during the renewal term, the
initial focus of license renewal should be (1) safety-related systems,
structures, and components, (2) nonsafety-related systems, structures,
and components that directly support the function of a safety-related
system, structure, or component or whose failure could prevent the
performance of a required function of a safety-related system,
structure, or component, (3) systems, structures, and components relied
upon to meet a specific set of Commission regulations, and (4) systems,
structures, and components subject to the operability requirements
contained in the facility technical specification limiting conditions
for operation.
Since publishing the previous rule, the Commission has gained
considerable preapplication rule implementation experience and gained a
better understanding of aging management, in part, through the
development of a regulatory guide to implement the maintenance rule, 10
CFR 50.65. The Commission now believes that (1) by appropriately
crediting existing licensee programs that manage the effects of aging
and (2) by appropriately crediting the continuing regulatory process,
it can more narrowly define those systems, structures, and components
within the scope of license renewal and more narrowly focus the license
renewal review.
The Commission continues to believe that the initial scope for the
license renewal review should not be limited to only those systems,
structures, or components that the Commission has traditionally defined
as safety-related. However, as discussed below (see Justification for
the Elimination of the Technical Specification Limiting Conditions for
Operation Scoping Category) the Commission determined that the
requirement to consider additional systems, structures, and components
subject to the operability requirements contained in the facility
technical specification limiting conditions for operation is
unnecessary and has been deleted.
The first two categories of systems, structures, and components
discussed in the new scope section (Sec. 54.4(a)(1) and (a)(2)) are the
same categories defined in the previous definition of systems,
structures, and components important to license renewal. These scoping
categories concern (1) all safety-related systems, structures, and
components and (2) all nonsafety-related systems, structures, and
components that support the function of a safety-related system,
structure, or component or whose failure could prevent a safety-related
system, structure, or component from satisfactorily fulfilling its
intended function(s). These two categories are meant to capture, as a
minimum, automatic reactor shutdown systems, engineered safety feature
systems, systems required for safe shutdown (achieve and maintain the
reactor in a safe shutdown condition), and nonsafety-related systems,
such as auxiliary systems, necessary for the function of safety-related
systems.
The third category of systems, structures, and components discussed
in the new scope section (Sec. 54.4(a)(3)) are those systems,
structures, and components whose functionality may be relied on in
safety analyses or plant evaluations to perform a function that
demonstrates compliance with the Commission's regulations for 10 CFR
50.48 (Fire Protection), 10 CFR 50.49 (Environmental Qualification), 10
CFR 50.61 (Pressurized Thermal Shock), 10 CFR 50.62 (Anticipated
Transients Without Scram), and 10 CFR 50.63 (Station Blackout). This
category is also specified in the previous definition of systems,
structures, and components important to license renewal and included
those systems, structures, and components relied upon to meet certain
regulations. This category was developed to ensure that important
systems, structures, and components that may be considered outside the
traditional definition of safety-related and outside of the first two
categories in Sec. 54.4, would be included within the initial focus of
license renewal. Through evaluation of industry operating experience
and through continuing regulatory analysis, the Commission has
reaffirmed that systems, structures, and components required to comply
with these regulations are important to safe plant operation because
they provide substantial additional protection to the public health and
safety or are an important element in providing adequate protection to
the public health and safety. The Commission, therefore, concludes that
these systems, structures, and components should be included as part of
the initial scope of the license renewal review.
In their comments on the proposed revision to the rule, NUGEQ noted
that there is substantial overlap between the [[Page 22466]] equipment
that would be identified in Sec. 54.4(a) and the electrical equipment
important to safety identified in Sec. 50.49(b). To provide clarity and
consistency and minimize the potential that a licensee will be required
to reassess the entire scope of Sec. 50.49 equipment, NUGEQ suggests
that Sec. 54.4(a)(3) be modified to include only the additional
electric equipment identified in Sec. 50.49(b)(3). The Commission
concludes that the rule modification proposed by NUGEQ is not
necessary. However, the Commission agrees that for purposes of
Sec. 54.4, the scope of Sec. 50.49 equipment to be included within
Sec. 54.4 is that equipment already identified by licensees under 10
CFR 50.49(b). Licensees may rely upon their listing of 10 CFR 50.49
equipment, as required by 10 CFR Part 50.49(d), for purposes of
satisfying Sec. 54.4 with respect to equipment within the scope of
Sec. 50.49.
Justification for the Elimination of the Technical Specification
Limiting Conditions for Operation Scoping Category
In the previous license renewal rule, the Commission established a
fourth category of systems, structures, and components to be the focus
of the initial license renewal review. In this category, the Commission
included all systems, structures, and components that have operability
requirements in the plant technical specifications limiting conditions
for operation. As defined in Standard Technical Specifications, ``a
system, subsystem, train, component, or device shall be operable when
it is capable of performing its specified safety function(s) and when
all necessary attendant instrumentation, controls, normal or emergency
electrical power, cooling and seal water, lubrication, and other
auxiliary equipment that are required for the system, subsystem, train,
component, or device to perform its specified safety function(s) are
also capable of performing their related support function(s).'' This
was intended to include (1) all systems, structures, and components
specifically identified in the technical specification limiting
conditions for operation, (2) any system, structure or component for
which a functional requirement is specifically identified in the
technical specification limiting conditions for operation, and (3) any
necessary supporting system, structure or component that must be
operable or have operability in order for a required system, structure,
or component to be operable.
The Commission previously considered the technical specification
limiting conditions for operation scoping category to be consistent
with the Commission's intent not to re-examine the entire plant for
license renewal but to ensure that all systems, structures, and
components of principal importance to safe plant operation were
identified and, if necessary, evaluated. However, existing technical
specifications for many plants have functional requirements on certain
systems, structures, and components with low or indirect safety
significance. Preapplication rule implementation experience has
indicated that this category of systems, structures, and components, as
defined in the previous rule, could lead to an unwarranted re-
examination of plant systems, structures, and components that are not
of principal importance for license renewal.
For example, limiting conditions for operation are frequently
included in technical specifications for plant meteorological and
seismic monitoring instrumentation, main turbine bypass systems, and
traversing incore probes. These requirements, while important for
certain aspects of power plant operation, have little or no direct
bearing on protection of public health and safety. Recognizing this,
the Commission concludes that current activities for such systems,
structures, and components, including licensee programs and the NRC
regulatory process, are sufficient and that no additional evaluation is
necessary for license renewal. The technical specification category
would only add (i.e., not captured by Sec. 54.4(a)(1)-(3)) nonsafety-
related systems, structures, and components that do not support safety-
related systems, structures, and components. As discussed in greater
detail below, the Commission concludes that these additional nonsafety-
related systems, structures, and components should not be the subject
of license renewal.
Relationship Between Improved Technical Specifications and License
Renewal Scoping
While it is not the Commission's intent to require applicants for
license renewal to ``improve'' their technical specifications, it
remains the Commission's intent to focus the license renewal review on
those systems, structures, and components that are of principal
importance to safety. Therefore, a license renewal scoping category
that requires wholesale consideration of systems, structures, and
components within the scope of technical specifications may not
appropriately focus licensee and NRC resources on those systems,
structures, and components that are of principal importance to safety.
In its ``Final Policy Statement on Technical Specifications
Improvements for Nuclear Power Reactors'' (58 FR 39132; July 22, 1993),
the Commission identified four criteria for defining the scope of
improved technical specifications. The four criteria are as follows:
Criterion 1: Installed instrumentation that is used to detect, and
indicate in the control room, a significant abnormal degradation of the
reactor coolant pressure boundary.
Criterion 2: A process variable, design feature, or operating
restriction that is an initial condition of a Design Basis Accident or
Transient analysis that either assumes the failure of or presents a
challenge to the integrity of a fission product barrier.
Criterion 3: A structure, system, or component that is part of the
primary success path and which functions or actuates to mitigate a
Design Basis Accident or Transient that either assumes the failure of
or presents a challenge to the integrity of a fission product barrier.
Criterion 4: A structure, system, or component which operating
experience or probabilistic safety assessment has shown to be
significant to public health and safety.
Nuclear power plant licensees that voluntarily choose to
``improve'' their technical specifications based on this Commission
policy may submit changes to the Commission for review and approval
that will remove systems, structures, and components from their
technical specifications before conducting license renewal (experience
shows that approximately 40 percent of limiting conditions for
operation and surveillance requirements could be deleted).
After considering the substantial overlap between the four criteria
for defining the scope of technical specifications and the first three
scoping categories for license renewal, the Commission concluded that
the number of additional systems, structures, and components that would
be considered as a result of applying the technical specification
scoping category to improved technical specifications is small. These
additional systems, structures, and components most likely would result
from differences in each plant's current licensing basis and from the
application of these criteria and categories on a plant-specific bases.
The Commission cannot make conclusions in this rulemaking about the
appropriateness of whether these [[Page 22467]] additional systems,
structures, and components should be included in an individual plant's
technical specifications. However, the Commission can conclude that
these additional systems, structures, and components are of a
relatively lower safety significance because they are, by exclusion,
nonsafety-related systems, structures, and components whose failure
cannot prevent the performance or reduce the availability of a safety-
related system, structure, or component. Additionally, the Commission
believes that the existing regulatory process for these additional
nonsafety-related systems, structures, and components is adequate to
ensure that age degradation will not result in a loss of functionality
in accordance with the CLB.
The Commission believes that there is sufficient experience with
its policy on technical specifications to apply that policy generically
in revising the license renewal rule consistent with the Commission's
desire to credit existing regulatory programs. Therefore, the
Commission concludes that the technical specification limiting
conditions for operation scoping category is unwarranted and has
deleted the requirement that identifies systems, structures, and
components with operability requirements in technical specifications as
being within the scope of the license renewal review.
(ii) Intended Function
The previous license renewal rule required an applicant for license
renewal to identify, from systems, structures, and components important
to license renewal, those structures and components that contribute to
the performance of a ``required function'' or could, if they fail,
prevent systems, structures, and components from performing a
``required function.'' This requirement initially posed some difficulty
in conducting pre-application reviews of proposed scoping methodologies
because it was not clear what was meant by ``required function.'' Most
systems, structures, and components have more than one function and
each could be regarded as ``required.'' Although the Commission could
have required a licensee to ensure all functions of a system,
structure, or component as part of the aging management review, the
Commission concluded that this requirement would be unreasonable and
inconsistent with the Commission's original intent to focus only on
those systems, structures, and components of primary importance to
safety. Consideration of ancillary functions would expand the scope of
the license renewal review beyond the Commission's intent. Therefore,
the Commission determined that ``required function'' in the previous
license renewal rule refers to those functions that are responsible for
causing the systems, structures, and components to be considered
important to license renewal.
To avoid any confusion with the previous rule, the Commission has
changed the term ``required function'' to ``intended function'' and
explicitly stated in Sec. 54.4 that the intended functions for systems,
structures, and components are the same functions that define the
systems, structures, and components as being within the scope of the
final rule.
(iii) Bounding the Scope of Review
Pre-application rule implementation has indicated that the
description of systems, structures, and components subject to review
for license renewal could be broadly interpreted and result in an
unnecessary expansion of the review. To limit this possibility for the
scoping category relating to nonsafety-related systems, structures, and
components, the Commission intends this nonsafety-related category
(Sec. 54.4(a)(2)) to apply to systems, structures, and components whose
failure would prevent the accomplishment of an intended function of a
safety-related system, structure, and component. An applicant for
license renewal should rely on the plant's CLB, actual plant-specific
experience, industry-wide operating experience, as appropriate, and
existing engineering evaluations to determine those nonsafety-related
systems, structures, and components that are the initial focus of the
license renewal review. Consideration of hypothetical failures that
could result from system interdependencies that are not part of the CLB
and that have not been previously experienced is not required.
Likewise, to limit the potential for unnecessary expansion of the
review for the scoping category concerning those systems, structures,
and components whose function is relied upon in certain plant safety
analyses to demonstrate compliance with the Commission regulations
(i.e., environmental qualification, station blackout, anticipated
transient without scram, pressurized thermal shock, and fire
protection), the Commission intends that this scoping category include
all systems, structures, and components whose function is relied upon
to demonstrate compliance with these Commission's regulations. An
applicant for license renewal should rely on the plant's current
licensing bases, actual plant-specific experience, industry-wide
operating experience, as appropriate, and existing engineering
evaluations to determine those systems, structures, and components that
are the initial focus of the license renewal review. Consideration of
hypothetical failures that could result from system interdependencies,
that are not part of the current licensing bases and that have not been
previously experienced is not required.
Several commenters noted that the word ``directly'' did not precede
the phrase ``prevent satisfactory accomplishment of any of the
functions identified in paragraphs (a)(1)(i), (ii), or (iii) of this
section'' in Sec. 54.4(a)(2) and concluded that, in the absence of the
word ``directly,'' the license renewal review could cascade into a
review of second-, third-, or fourth-level support systems. The
Commission reaffirms its position that consideration of hypothetical
failures that could result from system interdependencies that are not
part of the CLB and that have not been previously experienced is not
required. However, for some license renewal applicants, the Commission
cannot exclude the possibility that hypothetical failures that are part
of the CLB may require consideration of second-, third-, or fourth-
level support systems. In these cases the word ``directly'' may cause
additional confusion, not clarity, regarding the systems, structures
and components required to be within the scope of license renewal. In
removing the word ``directly'' from this scoping criterion, the
Commission believes it has (1) achieved greater consistency between the
scope of the license renewal rule and the scope of the maintenance rule
(Sec. 50.65) regarding nonsafety-related systems whose failure could
prevent satisfactory accomplishment of safety-related functions and
thus (2) promoted greater efficiency and predictability in the license
renewal scoping process.
The inclusion of nonsafety-related systems, structures, and
components whose failure could prevent other systems, structures, and
components from accomplishing a safety function is intended to provide
protection against safety function failure in cases where the safety-
related structure or component is not itself impaired by age-related
degradation but is vulnerable to failure from the failure of another
structure or component that may be so impaired. Although it may be
considered outside the scope of the maintenance rule, the Commission
intends to include equipment that is not seismically qualified located
near seismically qualified equipment (i.e., [[Page 22468]] Seismic II/I
equipment already identified in a plant CLB) in this set of nonsafety-
related systems, structures and components.
In one of its comments, the Sierra Club indicated that all
nonsafety-related equipment and required functions should be considered
because failures could go unnoticed for a long period of time and start
a chain reaction that could lead to catastrophic events. Nevada also
proposed a fuel life-cycle approach to license renewal that would
consider the plant operations as an ``Integrated Operating System.''
The Commission disagrees with the Sierra Club comment and the
Commission concludes that the license renewal approach proposed by
Nevada would result in the consideration of issues outside the scope of
this rule and result in consideration of additional systems,
structures, and components that are not directly related to the safe
operation of the plant for the period of extended operation. The
Commission has reviewed its scoping criteria and determined that the
criteria (1) reflect an appropriate consideration of the existing
regulatory process, (2) properly focus the initial license renewal
review on those systems, structures, and components that are most
important to safety and (3) will not result in an unwarranted re-
examination of the entire plant.
One commenter indicated that the scope of systems, structures, and
components considered for license renewal could be further reduced by
identifying and addressing the very few issues in which a plant's
design must specifically consider 40 years of degradation. In one of
its comments, Illinois suggested that those systems, structures and
components required to mitigate a sequence leading to core damage, as
determined by plant-specific probabilistic analyses, and those systems,
structures, and components required to make protective action
recommendations for the protection of the public, should also be
included in the scope of this rulemaking.
As the commenter suggested, the Commission did consider further
limiting the scope of license renewal to certain issues in a plant's
design that were specifically based on a time period bounded by the
current license term (40 years). As a result, the Commission explicitly
identified the need to review time-limited aging analyses and
incorporated this requirement into the final rule. However, as
discussed in Section III.d and III.f of this SOC, the Commission
determined that, at this time, there was not an adequate basis to
generically exclude passive, long-lived structures and components from
an aging management review. Therefore, the Commission believes it is
inappropriate to further reduce the systems, structures, and components
within the scope of license renewal.
Regarding the use of probabilistic analyses in the license renewal
scoping process, a separate Section III.c(iv) has been added to the
SOC, to discuss the role of probabilistic risk assessment in license
renewal. Regarding systems, structures, and components required to make
protective action recommendations, the Commission thoroughly evaluated
emergency planning considerations in the previous license renewal
rulemaking. These evaluations and conclusions are still valid and can
be found in the SOC for the previous license renewal rule (56 FR 64943
at 64966). Therefore, the Commission concludes that systems,
structures, and components required for emergency planning, unless they
meet the scoping criteria in Sec. 54.4, should not be the focus of a
license renewal review.
(iv) Use of Probabilistic Risk Assessment in License Renewal
Several comments from Illinois concerned the use of probabilistic
analysis techniques in the license renewal process. Illinois indicated
that the NRC should require rigorous probabilistic analyses, require
these analyses to be used in appropriate regulatory applications, and
require these probabilistic analyses to be updated, as needed. In
addition, Illinois noted that the previous rule and the proposed rule
did not require consideration of individual plant examination (IPE)
results.
The Commission is finalizing a policy statement regarding the
increased use of probabilistic risk assessment (PRA) methods in nuclear
regulatory activities (59 FR 63389; December 8, 1994). However, there
is currently no additional guidance for licensees to conduct more
rigorous probabilistic analyses beyond the guidance for an IPE and an
IPE External Events (IPEEE) (Generic Letter 88-20). The Commission's
consideration of regulatory requirements associated with developing,
maintaining, or using probabilistic analyses is beyond the scope of
this rulemaking.
The CLB for currently operating plants is largely based on
deterministic engineering criteria. Consequently, there is considerable
logic in establishing license renewal scoping criteria that recognize
the deterministic nature of a plant's licensing basis. Without the
necessary regulatory requirements and appropriate controls for plant-
specific PRAs, the Commission concludes that it is inappropriate to
establish a license renewal scoping criterion, as suggested by
Illinois, that relies on plant-specific probabilistic analyses.
Therefore, within the construct of the final rule, PRA techniques are
of very limited use for license renewal scoping.
In license renewal, probabilistic methods may be most useful, on a
plant-specific basis, in helping to assess the relative importance of
structures and components that are subject to an aging management
review by helping to draw attention to specific vulnerabilities (e.g.,
results of an IPE or IPEEE). Probabilistic arguments may assist in
developing an approach for aging management adequacy. However,
probabilistic arguments alone will not be an acceptable basis for
concluding that, for those structures and components subject to an
aging management review, the effects of aging will be adequately
managed in the period of extended operation.
Illinois also indicated that as probabilistic insights are more
fully integrated with our traditional deterministic methods of
regulation, they may define a narrower safety focus. Thus, the use of
probabilistic insights could reduce the scope of the very programs that
the license renewal rule credits for monitoring and identifying the
effects of aging.
The Commission reaffirms its previous conclusion (see 56 FR 64943
at 64956) that PRA techniques are most valuable when they focus the
traditional, deterministic-based regulations and support the defense-
in-depth philosophy. In this regard, PRA methods and techniques would
focus regulations and programs on those items most important to safety
by eliminating unnecessary conservatism or by supporting additional
regulatory requirements. PRA insights would be used to more clearly
define a proper safety focus, which may be narrower or may be broader.
In any case, PRA will not be used to justify poor performance in aging
management or to reduce regulatory or programmatic requirements to the
extent that the implementation of the regulation or program is no
longer adequate to credit for monitoring or identifying the effects of
aging.
d. The Regulatory Process and Aging Management
(i) Aging Mechanisms and Effects of Aging
The license renewal review approach discussed in the SOC
accompanying the December 13, 1991, rule emphasized the
[[Page 22469]] identification and evaluation of aging mechanisms for
systems, structures, and components within the scope of the rule.
Primarily through pre-application implementation experience associated
with the previous license renewal rule and the evaluation of comments
resulting from the September 1993 license renewal workshop, the
Commission determined that an approach to license renewal that focuses
only on the identification and evaluation of aging mechanisms could
constitute an open-ended research project. Ultimately, this type of
approach may not provide reasonable assurance that certain systems,
structures, and components will continue to perform their intended
functions. The Commission believes that regardless of the specific
aging mechanism, only aging degradation that leads to degraded
performance or condition (i.e., detrimental effects) during the period
of extended operation is of principal concern for license renewal.
Because the detrimental effects of aging are manifested in degraded
performance or condition, an appropriate license renewal review would
ensure that licensee programs adequately monitor performance or
condition in a manner that allows for the timely identification and
correction of degraded conditions. The Commission concludes that a
shift in focus to managing the detrimental effects of aging for license
renewal reviews is appropriate and will provide reasonable assurance
that systems, structures, and components are capable of performing
their intended function during the period of extended operation.
This shift in focus of the license renewal review has resulted in
several proposed changes to the license renewal rule. These changes
include deleting the definitions of aging mechanism and age-related
degradation and replacing the requirement to manage ARDUTLR in the IPA
with a requirement to demonstrate that the effects of aging will be
adequately managed for the period of extended operation.
Illinois commented that additional research should be undertaken to
ensure all aging effects are understood. Mitigating the effects of
aging cannot be completely divorced from understanding the aging
mechanisms. Illinois indicated that the effects of aging on a system,
structure, and component cannot be managed without some consideration
of all the aging mechanisms causing the effects. As some aging
mechanisms are not well understood, research will still need to be
performed, and the regulatory process will still need to be adequate to
address aging uncertainties.
When the Commission concluded that the proper approach for a
license renewal review was one that focused on mitigating the
detrimental effects of aging regardless of the mechanisms causing the
effects, the intent was to concentrate efforts on identification of
functional degradation; that is, except for well-understood aging
mechanisms, the straightforward approach to detecting and mitigating
the effects of aging begins with a process that verifies that the
intended design functions of systems, structures, and components have
not been compromised or degraded. Once functional degradation is
identified through performance or condition monitoring, corrective
actions can be applied. The Commission agrees that adverse aging
effects cannot be completely divorced from an understanding of the
aging mechanisms. The corrective actions that should be taken following
identification of functional degradation logically include
determination of the cause of the degradation, which could involve
mechanisms other than aging (e.g., faulty manufacturing processes,
faulty maintenance, improper operation, or personnel errors). If one or
more aging mechanisms are the cause of functional degradation,
corrective actions should focus, as appropriate, on prevention,
elimination, or management of the effects caused by the mechanism(s) in
the future. Licensees are required by current regulations to develop
and implement programs that ensure that conditions adverse to quality,
including degraded system, structure, and component function, are
promptly identified and corrected.
(ii) Regulatory Requirements and Reliance on the Regulatory Process for
Managing the Effects of Aging
Commercial nuclear power plants have been performing a variety of
maintenance activities that function effectively as aging management
programs since plants were initially constructed. The Commission also
recognizes that both the industry and the NRC have acquired extensive
experience and knowledge in the area of nuclear power plant
maintenance. Regarding the need for a maintenance rule, the results of
the Commission's maintenance team inspections (MTIs) indicated that
licensees generally have adequate maintenance programs in place and
have exhibited an improving trend in implementing them (56 FR 31307;
July 10, 1991). However, the Commission determined that a maintenance
rule was needed, in part because the MTIs identified some common
maintenance-related weaknesses, such as inadequate root-cause analysis
leading to repetitive failures, lack of equipment performance trending,
and lack of appropriate consideration of plant risk in the
prioritization, planning, and scheduling of maintenance.
The Commission amended its regulations, at 10 CFR 50.65, on July
10, 1991 (56 FR 31306), to require commercial nuclear power plant
licensees to monitor the effectiveness of maintenance activities for
safety-significant plant equipment to minimize the likelihood of
failures and events caused by the lack of effective maintenance. The
maintenance rule and its implementation guidance (1) Provide for
continued emphasis on the defense-in-depth principle by including
selected balance-of-plant (BOP) systems, structures, and components,
(2) integrate risk consideration into the maintenance process, (3)
provide an enhanced regulatory basis for inspection and enforcement of
BOP maintenance-related issues, and (4) provide a strengthened
regulatory basis for ensuring that the progress achieved to date is
sustained in the future. The requirements of the maintenance rule must
be implemented by each licensee by July 10, 1996.
In June 1993, the NRC issued Regulatory Guide 1.160, ``Monitoring
the Effectiveness of Maintenance at Nuclear Power Plants.'' The
regulatory guide provides an acceptable method for complying with the
requirements of the maintenance rule and states that a licensee can use
alternative methods if the licensee can demonstrate that these
alternative methods satisfy the requirements of the rule. Because aging
is a continuing process, the Commission has concluded that existing
programs and regulatory requirements that continue to be applicable in
the period of extended operation and provide adequate aging management
for systems, structures, and components should be credited for license
renewal. Accordingly, the amendment to the license renewal rule focuses
the renewal review on plant systems, structures, and components for
which current activities and requirements may not be sufficient to
manage the effects of aging in the period of extended operation.
Since publishing the license renewal rule on December 13, 1991, the
regulatory process (e.g., regulatory requirements, aging research,
inspection requirements, and inspection philosophy) for managing the
detrimental effects of aging for important systems, structures, and
[[Page 22470]] components has continued to evolve. The changes in the
regulatory process and initial experience with the license renewal rule
have had a direct bearing on the Commission's conclusions regarding the
appropriate focus of aging management review for systems, structures,
and components that are within the scope of the license renewal rule,
and how these systems, structures, and components are treated in the
IPA process.
(iii) Maintenance Rule Requirements and Implementation
As discussed in the regulatory analysis for the maintenance rule
and in Regulatory Guide 1.160, the Commission's determination that a
maintenance rule was needed arose from the conclusion that proper
maintenance was essential to plant safety. A clear link exists between
effective maintenance and safety as it relates to factors such as the
number of transients and challenges to safety-related systems and the
associated need for operability, availability, and reliability of
safety-related systems, structures, and components. In addition, good
maintenance is important to providing assurance that failures of other
than safety-related systems, structures, and components that could
initiate or adversely affect a transient or accident are minimized.
Minimizing challenges to safety-related systems is consistent with the
Commission's defense-in-depth philosophy. Therefore, nuclear power
plant maintenance is clearly important to protecting the public health
and safety.
The maintenance rule requires that power reactor licensees monitor
the performance or condition of systems, structures, and components
against licensee-established goals in a manner sufficient to provide
reasonable assurance that these systems, structures, and components are
capable of fulfilling their intended functions. Performance and
condition monitoring against licensee-established goals is not
required, where it can be demonstrated that the performance or
condition of systems, structures, and components is being effectively
controlled through the performance of appropriate preventive
maintenance. Performance and condition-monitoring activities and
associated goals and preventive maintenance activities must be
evaluated once every refueling cycle, provided the interval between
evaluations does not exceed 24 months.
As discussed in Regulatory Guide 1.160, the extent of monitoring
may vary from system to system, depending on the system's importance to
risk. Some monitoring at the component level may be necessary,
although, most of the monitoring could be done at the plant, system, or
system train level. For systems, structures, and components that fall
within the requirements of Sec. 50.65(a)(1), licensees must establish
goals and monitor performance against these goals. These goals should
be derived from information in the CLB and should be established
commensurate with safety significance of the systems, structures, or
components. These goals may be performance-oriented (reliability,
unavailability) or condition-oriented (pump flow, pressure, vibration,
valve stroke time, current, electrical resistance). An effective
preventive maintenance program is required under Sec. 50.65(a)(2) if
monitoring under Sec. 50.65(a)(1) is not performed.
The SOC for the maintenance rule (56 FR 31308; July 10, 1991)
states that the scope of Sec. 50.65(a)(2) includes those systems,
structures, and components that have ``inherently high reliability''
without maintenance. It is expected that many long-lived, passive
structures and components could be considered inherently reliable by
licensees and not be monitored under 10 CFR 50.65(a)(1). There may be
few, if any, actual maintenance activities (e.g., inspection or
condition monitoring) that a licensee conducts for such structures and
components. Further, experience gained under the previous license
renewal rule, staff review of industry reports, NRC aging research, and
operating experience indicate that such structures and components
should be reviewed for license renewal if they are passive and long-
lived. Therefore, the Commission believes that such structures and
components that are technically within the scope of the maintenance
rule should not be generically excluded from review for license renewal
on the basis of their inherent reliability.
Although the maintenance rule does not become effective and
enforceable until July 10, 1996, the Commission believes that crediting
the rule (along with the entire regulatory program) is acceptable to
support managing the effects of aging for certain systems, structures,
and components. As discussed in Regulatory Guide 1.160, implementation
of the maintenance rule relies extensively on existing maintenance
programs and activities. The industry has developed guidance for
complying with the maintenance rule and the NRC staff has reviewed this
guidance and found it acceptable. Many utilities are expected to follow
the industry guidance in implementing the maintenance rule.
Furthermore, the failure of any licensee to comply with the maintenance
rule is enforceable by the Commission after July 10, 1996.
One commenter stated that reliance on the maintenance rule is
inappropriate because the NRC does not plan to scrutinize every system,
structure, and component and how it is monitored in assuring compliance
with the maintenance rule. According to the commenter, if there are
uncertainties in the maintenance rule or its implementation, then there
is uncertainty in the license renewal rule. The commenter also stated
that the aging management analyses and measurements required by the
license renewal rule for the period of extended operation should
commence for all operating reactors when the maintenance rule goes into
effect. The NRC disagrees with the commenter that the 100-percent
inspection of all systems, structures, and components is necessary to
verify compliance with NRC requirements, including the maintenance
rule. The Commission disagrees with the commenter that the licensees
should be required to commence aging management reviews required for
license renewal when the maintenance rule becomes effective.
As discussed in the SOC for the previous rule (56 FR at 64951), the
NRC inspection methodology utilizes a sampling technique. When problems
are identified, the inspection sample size is broadened to determine
the extent of the problem. Additionally, while the maintenance rule
does not require licensees to submit their maintenance programs to the
NRC for review and approval, compliance with the requirements of the
maintenance rule will be verified through the NRC inspection process.
The NRC will be conducting inspections on a routine basis onsite to
verify licensee compliance with the maintenance rule. Furthermore, as
discussed in Section III(d)(iv) of this SOC, the maintenance rule
allows for monitoring at a train, system, or plant level, and that
goals should be commensurate with safety. If performance problems
arise, corrective action requirements of 10 CFR 50, Appendix B, and the
maintenance rule require effective corrective actions to preclude
repetition of the failure.
Passive, long-lived structures and components that are the focus of
the license renewal rule are also within the requirements of the
maintenance rule, as discussed in the SOC Section III(d)(iv). Treatment
of these structures and components, however, under the maintenance rule
is likely to involve minimal preventive maintenance or monitoring to
maintain functionality of [[Page 22471]] such structures and components
in the original operating period. Consequently, under the license
renewal rule, the Commission did not allow for a generic exclusion of
passive, long-lived structures and components based solely on
maintenance activities associated with implementing the requirements of
the maintenance rule. It also would be inappropriate to require that
all licensees perform an aging management review required for license
renewal when some licensees may not seek license renewal and do not
intend to operate beyond the end of their current operating license.
Furthermore, if aging issues are identified during the license renewal
review that apply to the current operating term, licensees are required
to take measures under their current license to ensure that the
intended function of systems, structures, and components will be
maintained in accordance with the CLB throughout the term of the
current license. In addition, if aging issues are identified during the
license renewal review that apply to the current operating term, the
NRC will evaluate these issues for generic applicability as part of the
regulatory process.
Therefore, the Commission believes that with the additional
experience it has gained with age-related degradation reviews and with
the implementation of the maintenance rule, there is a sufficient basis
for concluding that current licensee programs and activities, along
with the regulatory process, will be adequate to manage the effects of
aging on the active functions of all systems, structures, and
components within the scope of license renewal during the period of
extended operation so that the CLB will be maintained. The bases for
this conclusion are discussed further in the following sections.
(iv) Integration of the Regulatory Process and the Maintenance Rule
With the License Renewal Rule
Because of the resultant insight and understanding that the NRC
gained in developing the implementation guidance for the maintenance
rule, the Commission is now in a position to more fully integrate the
maintenance rule and the license renewal rule. Because the intent of
the license renewal rule and the maintenance rule is similar (ensuring
that the detrimental effects of aging on the functionality of important
systems, structures, and components are effectively managed), the
Commission has determined that the license renewal rule should credit
existing maintenance activities and maintenance rule requirements for
most structures and components. Recognition that licensee activities
associated with the implementation of the maintenance rule will
continue throughout the renewal period and are consistent with the
first principle of license renewal is fundamental to establishing
credit for the existing programs and the requirements of the
maintenance rule. As a result, the requirements in this rule reflect a
greater reliance on existing licensee programs that manage the
detrimental effects of aging on functionality, including those
activities implemented to meet the requirements of the maintenance
rule.
Two commenters stated that it is inappropriate for the license
renewal rule to rely on the maintenance rule implementation because 10
CFR 50.65 will not be in effect until July 10, 1996. The Commission
disagrees with the commenters. As discussed in Section III.d. (ii) and
(iii) of this SOC, the results of the Commission's MTIs indicate that
licensees have adequate maintenance programs in place and have
exhibited an improving trend in implementing them. Nuclear power plants
have been performing a variety of maintenance activities since plants
were initially constructed. The need for a maintenance rule arose
primarily because the MTIs identified three common maintenance-related
weaknesses (inadequate root-cause analysis, lack of equipment
performance trending, and lack of appropriate consideration of plant
risk in the prioritization, planning, and scheduling of maintenance).
Additionally, the SOC for the maintenance rule (56 FR 31310) states
that ``[T]he focus of the rule is on the results achieved through
maintenance, and, in this regard, it is not the intent of the rule that
existing licensees necessarily develop new maintenance programs.''
Furthermore, as stated in Regulatory Guide 1.160, it is intended that
activities currently being conducted by licensees, such as technical
specification surveillance testing, can satisfy monitoring
requirements. Such activities could be integrated with, and provide the
basis for, the requisite level of monitoring. Finally, at the time of
this rulemaking, nine licensees volunteered to participate in an NRC
pilot inspection effort to review implementation of the maintenance
rule. Five pilot inspections had been completed at nuclear power
plants. The pilot inspections involved a step-by-step review of the
implementation of the maintenance rule. In general, the pilot
inspections found that licensees were able to utilize existing
maintenance activities in complying with requirements of the
maintenance rule. Therefore, for these reasons and as discussed in
Section III.(d) of this SOC, the Commission continues to believe that
there is a sufficient basis for concluding that current licensee
programs and activities, along with the regulatory process, will be
adequate to manage the effects of aging on the active functions of all
systems, structures, and components within the scope of license renewal
during the period of extended operation so that the CLB will be
maintained.
In addition to the maintenance rule, the Commission has many
individual requirements relative to maintenance throughout its
regulations. These include 10 CFR 50.34(a)(3)(i); 50.34(a)(7);
50.34(b)(6) (i), (ii), (iii), and (iv); 50.34(b)(9); 50.34(f)(1) (i),
(ii), (iii); 50.34(g); 50.34a(c); 50.36(a); 50.36(c) (2), (3), (5), and
(7); 50.36a(a)(1); 50.49(b); 50.55a(g); Part 50, Appendix A, Criteria
1, 13, 18, 21, 32, 36, 37, 40, 43, 45, 46, 52, 53; and Part 50,
Appendix B.
(v) Excluding Structures and Components With Active Functions
Performance and condition monitoring for systems, structures, and
components typically involves functional verification, either directly
or indirectly. Direct verification is practical for active functions
such as pump flow, valve stroke time, or relay actuation where the
parameter of concern (required function), including any design margins,
can be directly measured or observed. For passive functions, the
relationship between the measurable parameters and the required
function is less directly verified. Passive functions, such as pressure
boundary and structural integrity are generally verified indirectly, by
confirmation of physical dimensions or component physical condition
(e.g., piping structural integrity can be predicted based on measured
wall thickness and condition of structural supports, but its seismic
resistance capability cannot be verified by inspection alone). Although
the requirements of the maintenance rule apply to systems, structures,
and components that perform both active and passive functions, the
Commission has determined that performance and condition-monitoring
programs for structures and components that perform passive functions
present limitations that should be considered in determining that
structures and components can be generically excluded from an aging
management review for license renewal.
On the basis of consideration of the effectiveness of existing
programs which monitor the performance and condition of systems,
structures, and components [[Page 22472]] that perform active
functions, the Commission concludes that structures and components
associated only with active functions can be generically excluded from
a license renewal aging management review. Functional degradation
resulting from the effects of aging on active functions is more readily
determinable, and existing programs and requirements are expected to
directly detect the effects of aging. Considerable experience has
demonstrated the effectiveness of these programs and the performance-
based requirements of the maintenance rule delineated in Sec. 50.65 are
expected to further enhance existing maintenance programs. For example,
many licensee programs that ensure compliance with technical
specifications are based on surveillance activities that monitor
performance of systems, structures, and components that perform active
functions. As a result of the continued applicability of existing
programs and regulatory requirements, the Commission believes that
active functions of systems, structures, and components will be
reasonably assured in any period of extended operation. Further
discussion and justification for excluding structures and components
that perform active functions and are within the scope of the license
renewal rule, but outside the scope of the maintenance rule, are
presented in Section (vi).
One commenter argued that the Commission should not exclude active
components because aging can be discontinuous, leading to catastrophic
failures. Examples of catastrophic failures provided by the commenter
included overstretching of metal, bending of beams, and embrittlement.
In their supplemental comments, NEI and Yankee Atomic Electric Company
indicated that the use of the term ``portions of'' could be
misinterpreted and lead to an unnecessary evaluation of all passive
subcomponents of active structures and components.
The commenters appear to have misunderstood the Commission's intent
with regard to ``active'' and ``passive'' functions. Passive parts of
structures and components that only perform active functions do not
require an aging management review. Structures and components that
perform both passive and active functions require an aging management
review for their intended passive function only. The exclusion
regarding active components is focused on active functions rather than
on an exclusion of the entire component. For example, diesel generators
and air compressors (excluding structural supports) perform active
functions and can be excluded from an aging management review. The
examples given by the commenter for catastrophic failures are those
related to ``passive'' intended functions (e.g., structural integrity,
pressure boundary). It is the Commission's intent to include these
``passive'' functions in the license renewal review, irrespective of
the components ``active'' function. For example, a safety system pump
casing (i.e., pressure boundary function) would be required to be
reviewed, while the pump (i.e., the active pumping function) would not.
The Commission believes that considerable experience has demonstrated
that its regulatory process, including the performance-based
requirements of the maintenance rule, provide adequate assurance that
degradation due to aging of structures and components that perform
active functions will be appropriately managed to ensure their
continued functionality during the period of extended operation. In
addition, to address the NEI and Yankee Atomic Electric Company
comments, the Commission has removed the words ``portions of'' and
similar wording from the Statement of Considerations when it could be
misinterpreted to mean a subcomponent piece-part demonstration.
A commenter argued that the Commission should not exclude from
review manual valves that are rarely operated during the life of the
plant, some of which are relied on as part of contingency actions in
plant emergency operating procedures. The commenter argued that because
these valves are rarely ``officially'' exercised, there is insufficient
evidence that the active functions will be maintained in the renewal
period. The Commission disagrees with the commenter's assertion that
there is insufficient evidence that the active functions will be
maintained in the renewal period. Such valves are within the scope of
various regulatory programs, including the maintenance rule.
Consequently, the ability of the valves to perform their intended
function must be assured through either (1) effective preventive
maintenance or (2) performance or condition monitoring.
(vi) Excluding Fire Protection Components With Active Functions
The scope of the maintenance rule does not generally include
installed fire protection systems, structures, and components because
performance and condition monitoring is required by Sec. 50.48.
Therefore, for the purposes of license renewal, installed structures
and components that perform active functions can be generically
excluded from an aging management review because they are either within
the scope of Sec. 50.65 or Sec. 50.48. Compliance with Sec. 50.48 is
verified through the NRC inspection program.
The fire protection rule (Sec. 50.48) requires each nuclear power
plant licensee to have in place a fire protection plan (FPP) that
satisfies 10 CFR Part 50, Appendix A, Criterion 3. Licensees are
required by Sec. 50.48 to retain the FPP and each change to the plan
until the Commission terminates the reactor license. The NRC reviews
each licensee's total FPP as described in the licensee's safety
analysis report (SAR), using basic review guidance described in
Sec. 50.48, as applicable to each plant.
The FPP establishes the fire protection policy for the protection
of systems, structures, and components important to safety at each
plant and the procedures, equipment, and personnel requirements
necessary to implement the program at the plant site. The FPP is the
integrated effort that involves systems, structures, and components,
procedures, and personnel to carry out all activities of fire
protection. The FPP includes system and facility design, fire
prevention, fire detection, annunciation, confinement, suppression,
administrative controls, fire brigade organization, inspection and
maintenance, training, quality assurance, and testing.
The FPP is part of the CLB and contains maintenance and testing
criteria that provide reasonable assurance that fire protection
systems, structures, and components are capable of performing their
intended function. The Commission concludes that it is appropriate to
allow license renewal applicants to take credit for the FPP as an
existing program that manages the detrimental effects of aging. The
Commission concludes that installed fire protection components that
perform active functions can be generically excluded from an aging
management review on the basis of performance or condition-monitoring
programs afforded by the FPP that are capable of detecting and
subsequently mitigating the detrimental effects of aging.
(vii) Future Exclusion of Structures and Components on the Basis of NRC
Requirements
As part of the ongoing regulatory process, the NRC evaluates
emerging technical issues and, when warranted, establishes new or
revised regulatory requirements as part of the resolution of a new
technical issue, subject to the provisions of the backfit rule
(Sec. 50.109). Increasing experience with aging [[Page 22473]] nuclear
power plants has led to the imposition or consideration of additional
requirements. For example, at this time the Commission is considering
rulemaking activities associated with steam generator performance and
containment inspections. For steam generators, the Commission is
considering the need for a performance-based rule to address steam
generator tube integrity. To address concerns regarding containments
and liners, the Commission is considering amending Sec. 50.55(a) to
incorporate the most recent version of Subsections IWE and IWL in the
American Society of Mechanical Engineers (ASME) Code, Section XI.
These new requirements, if implemented, would be relevant to both
aging management and the structures and components subject to an aging
management review for license renewal (i.e., passive, long-lived
structures and components). As a result, as part of relevant future
rulemakings, the Commission intends to evaluate whether these new
requirements can be considered effective in continuing to manage the
effects of aging through any renewal term. A positive conclusion could
establish the bases for further limiting the license renewal review.
e. Reaffirmation of Conclusions Concerning the Current Licensing Basis
and Maintaining the Function of Systems, Structures, and Components
(i) Current Licensing Basis
As defined in Sec. 54.3 of the rule, the CLB is the set of NRC
requirements applicable to a specific plant and a licensee's written
commitments for ensuring compliance with and operation within
applicable NRC requirements and the plant-specific design basis
(including all modifications and additions to such commitments over the
life of the license) that are docketed and are in effect. A detailed
explanation of the CLB, the regulatory processes underlying the CLB,
compliance with the CLB, and consideration of the CLB is contained in
the SOC for the previous license renewal rule (56 FR 64949: December
13, 1991). In summary, the conclusions made in the SOC for the previous
rule remain valid. The CLB represents the evolving set of requirements
and commitments for a specific plant that are modified as necessary
over the life of a plant to ensure continuation of an adequate level of
safety. The regulatory process is the means by which the Commission
continually assesses the adequacy of and compliance with the CLB.
Compilation of the CLB is unnecessary to perform a license renewal
review.
One commenter argued that the definition of CLB in Sec. 54.3 should
be clarified. Specifically, the commenter interprets that licensee
written commitments made in docketed licensing correspondence such as
responses to bulletins, generic letters, and enforcement actions and
commitments in safety evaluations and licensee event reports (items in
the third sentence of the definition) should be considered as part of
the CLB only to the extent that these commitments reflect compliance
with more formal requirements and regulations. These would include
those elements of NRC requirements and regulations identified in the
first two sentences of the definition. All other licensee commitments
identified in those document types listed in the third sentence should
not be considered CLB commitments if they are not otherwise necessary
to demonstrate compliance with NRC requirements and regulations.
The Commission is aware of public concerns associated with the
definition of CLB in Sec. 54.3. Some of these concerns can be
explicitly linked to what is meant by the term ``written commitments''
as it relates to the CLB. These concerns relate to ongoing
consideration of the regulatory and licensee processes for defining,
identifying, tracking, and validating licensee commitments. Although
identified in the license renewal rulemaking process, many of these
concerns are not directly associated with license renewal, but are
relevant to current commitment management methods and practices.
Therefore, the Commission is evaluating concerns associated with the
definition of CLB in the context of currently operating reactors and
may, in the future, determine that the definition of CLB needs to be
clarified. Thus, the Commission concludes that, at this time, a
revision to the definition of CLB is premature and will not be
considered as part of this rulemaking.
In addition, the Commission concludes that, for the licensee
renewal review, consideration of written commitments only need
encompass those commitments that concern the capability of systems,
structures, and components, identified in Sec. 54.21(a), integrated
plant assessment and Sec. 54.21(c) time-limited aging analyses, to
perform their intended functions, as delineated in Sec. 54.4(b).
For the previous rule as well as for this rulemaking, commenters
argued that the CLB of a number of plants is inadequate. Multiple
examples of operational concerns and issues at specific plants were
identified to demonstrate the inadequacy of the CLBs. One commenter
stated that the Yankee Rowe reactor pressure vessel problem (the plant
was removed from service rather than show compliance with its CLB for
its reactor pressure vessel) demonstrates the inadequacy of CLBs. The
commenter stated that ``the Rowe experience demonstrated that
examination of the licensing basis for extended operation could
jeopardize the remaining years on the current license.''
The Commission did not agree with the comments on the previous rule
in this area and comments received for this rulemaking did not provide
compelling reasons to alter the previous Commission determinations. The
examples cited were all identified by the NRC through the inspection
and oversight processes. The identification of these issues through the
regulatory process demonstrates that the Commission's programs are
effective in identifying and resolving new technical and safety issues
and areas of noncompliance in a timely fashion. In each example
provided by the commenters, appropriate corrective action was taken or
is being taken on a plant-specific or on an industry-wide basis to
either modify the CLB to resolve the concern or to ensure the continued
compliance with the present CLB. The Commission agrees that the Yankee
Rowe case demonstrated that the regulatory process can jeopardize
current operation during license renewal activities. The decision to
retire the Yankee Rowe plant was a utility economic decision when faced
with the prospect of demonstrating continued compliance with its CLB.
Non-compliance with the CLB, while not shown in the Rowe example, is
one of the reasons that justifies the existence of the regulatory
process.
Public Citizen stated that the Commission's contention that all
reactors are in compliance with their CLBs is both arbitrary and
capricious and neither stands the test of logic nor reality. The
commenter continued by stating that the ``NRC's assumption is based
upon the specious argument that having operated without a meltdown for
a finite period of time means that safety is adequate.''
The Commission does not contend that all reactors are in full
compliance with their respective CLBs on a continuous basis. Rather, as
discussed in the SOC for the previous rule, the regulatory process
provides reasonable assurance that there is compliance with the CLB.
The NRC conducts its inspection and enforcement activities
[[Page 22474]] under the presumption that non-compliances will occur.
The Commission does not believe that an absence of accidents over a
given period of time equates to adequate safety. Neither does the
Commission believe that all risk can be eliminated. Adequate safety is
a subjective term that cannot be directly measured. The Commission's
performance indicators demonstrate that, while not quantifiable,
relative safety levels are increasing. An absence of accidents over a
finite period of time can be considered as just one safety performance
indicator. Despite improving performance indicators, the Commission
intends to continue the meticulous process of insuring and maintaining
an adequate level of protection.
Commenters for both the previous rule and for this rulemaking
argued that the plant-specific CLB should be compiled and the NRC
should verify compliance with the CLB as part of the license renewal
process. Public Citizen stated that ``The NRC must review the documents
which make up the current licensing basis and examine the plant itself
in order to determine whether the licensee has complied with the
current licensing basis,'' and further, submission of the documents,
and NRC verification of the licensee's compliance with its CLB is
necessary to avoid ``fraud and abuse.'' Public Citizen also contends
that ``[a]bsent the submission of the documents the public and the
Commission are left to examine the reactor's license renewal
application and the IPA in a vacuum.''
The Commission disagrees with the commenter, and points out that
the proposed rule did not explicitly require the renewal applicant to
compile the CLB for its plant. The Commission rejected a compilation
requirement for the previous license renewal rule for the reasons set
forth in the accompanying SOC (56 FR at 64952). The Commission
continues to believe that a prescriptive requirement to compile the CLB
is not necessary. Furthermore, submission of documents for the entire
CLB is not necessary for the Commission's review of the renewal
application. As stated in section III.b(i) of this SOC, the Commission
has determined that the single issue generic to all plants with regard
to license renewal is the effects of age-related degradation during the
period of extended operation. As explained in the SOC for the previous
rule, section IV.c(i) (56 FR at 64948), the CLB of any plant is
comprised of numerous regulations, license conditions, the design
basis, etc. As discussed in III(e)(ii), ``Maintaining the function of
systems, structures, and components,'' the portion of the CLB that can
be impacted by the detrimental effects of aging is the design basis.
Thus, there is no compelling reason to consider, for license renewal,
any portion of the CLB other than that which is associated with the
structures and components of the plant (i.e., that part of the CLB that
can suffer detrimental effects of aging). All other aspects of the CLB
have continuing relevance in the license renewal period as they do in
the original operating term, but without any association with an aging
process that may cause invalidation. From a practical standpoint, an
applicant must consult the CLB for a structure or component in order to
perform an aging management review. The CLB for the structure or
component of interest contains the information describing the
functional requirements necessary to determine the presence of any
aging degradation.
The definition of CLB in Sec. 54.3(a) states that a plant's CLB
consists, in part, of ``a licensee's written commitments * * * that are
docketed * * *'' Because these documents have already been submitted to
the NRC and are in the docket files for the plant, they are not only
available to the NRC for use in the renewal review, they are also
available for public inspection and copying in the Commission's public
document rooms. Furthermore, the NRC may review any supporting
documentation that it may wish to inspect or audit in connection with
its renewal review. If the renewed license is granted, those documents
continue to remain subject to NRC inspection and audit throughout the
term of the renewed license. The Commission continues to believe that
resubmission of the documents constituting the CLB is unnecessary. With
respect to the commenter's argument that the CLB needs to be verified,
the Commission had concluded when it adopted the previous license
renewal rule that a reverification of CLB compliance as part of the
renewal review was unnecessary (56 FR at 64951-52). Public Citizen
presented no information questioning the continuing soundness of the
Commission's rationale, and the Commission reaffirms its earlier
conclusion that a special verification of CLB compliance in connection
with the review of a license renewal application is unnecessary. The
Commission intends, as stated by the commenter, to examine the plant-
specific CLB as necessary to make a licensing decision on the continued
functionality of systems, structures, and components subject to an
aging management review and a license renewal evaluation. This activity
will likely include examination of the plant itself to understand and
verify licensee activities associated with aging management reviews and
actions being taken to mitigate detrimental effects of aging.
After consideration of all comments concerning the compilation of
the CLB, the Commission has reconfirmed its conclusion made for the
previous rule that it is not necessary to compile, review, and submit a
list of documents that comprise the CLB in order to perform a license
renewal review.
(ii) Maintaining the Function of Systems, Structures, and Components
As discussed in the SOC for the previous license renewal rule, the
Commission stated that continued safe operation of a nuclear power
plant requires that systems, structures, and components that perform or
support safety functions continue to perform in accordance with the
applicable requirements in the licensing basis. In addition, the
Commission stated that the effects of ARDUTLR must be mitigated to
ensure that the aged systems, structures, and components will
adequately perform their designed safety or intended function.
In developing this final rule, a key issue that the Commission
considered was whether or not a focus on ensuring a system's,
structure's or component's function through performance or condition
monitoring is a sufficient basis for concluding that the CLB will be
maintained throughout the period of extended operation. The Commission
considered whether the regulatory process and a focus on functionality
during the license renewal review for the period of extended operation
are sufficient to provide reasonable assurance that an acceptable level
of safety (i.e., the CLB) will be maintained.
Continued safe operation of a commercial nuclear power plant
requires that systems, structures, and components that perform or
support safety functions continue to function in accordance with the
applicable requirements in the licensing basis of the plant and that
others do not substantially increase the frequency of challenges to
those required for safety. As a plant ages, a variety of aging
mechanisms are operative, including erosion, corrosion, wear, thermal
and radiation embrittlement, microbiologically induced aging effects,
creep, shrinkage, and possibly others yet to be identified or fully
understood. However, the detrimental effects of aging mechanisms can be
observed by detrimental changes in the performance
[[Page 22475]] characteristics or condition of systems, structures, and
components if they are properly monitored.
Aging can affect all systems, structures, and components to some
degree. Generally, the changes resulting from detrimental aging effects
are gradual. Licensees have ample opportunity to detect these
degradations through performance and condition monitoring programs,
technical specification surveillances required by Sec. 50.36, and other
licensee maintenance activities. Except for some well-understood aging
mechanisms such as neutron embrittlement and intergranular stress
corrosion cracking, the straightforward approach to detecting and
mitigating the effects of aging begins with a process that verifies
that the intended design functions of systems, structures, and
components have not been compromised or degraded. Licensees are
required by current regulations to develop and implement programs that
ensure that conditions adverse to quality, including degraded system,
structure, or component function, are promptly identified and
corrected. The licensees' programs include self-inspection,
maintenance, and technical specification surveillance programs that
monitor and test the physical condition of plant systems, structures,
and components.
For example, technical specifications include limiting conditions
for operation (LCOs), which are the lowest functional capability or
performance levels of equipment required for safe operation of the
facility. Technical specifications also require surveillance
requirements relating to test, calibration, or inspection to verify
that the necessary quality of systems, structures, and components is
maintained, that facility operation is within safety limits, and that
LCOs continue to be met. Furthermore, Sec. 50.55a requires, in part,
that systems, structures, and components be tested and inspected
against quality standards commensurate with the importance of the
safety function to be performed, such as inservice testing (IST) and
inservice inspections (ISIs) of pumps and valves.
Elements for timely mitigation of the effects of age-related
degradation include activities that provide reasonable assurance that
systems, structures, and components will perform their intended
functions when called on. Through these programs, licensees identify
the degradation of components resulting from a number of different
environmental stressors as well as degradation from inadequate
maintenance or errors caused by personnel. Once a detrimental
performance or condition caused by aging or other factors is revealed,
mitigating actions are taken to fully restore the condition to its
original design basis. As a result of these programs, degradation due
to aging mechanisms (detrimental aging effects) is currently being
adequately managed, either directly or indirectly, for most systems,
structures, and components.
Consequently, there is considerable logic in ensuring that the
design basis (as defined in Sec. 50.2) of systems, structures, and
components is maintained through activities that ensure continued
functionality. This process, including surveillance, is relied on in
the current term to ensure continued operability, (i.e., to the
greatest extent practicable, the intended design functions will be
properly performed). The focus on maintaining functionality results in
the continuing capability of systems, structures, and components,
including supporting systems, structures, and components, to perform
their intended functions as designed.
A key element of the 10 CFR 54 definition of the CLB is the plant-
specific design-basis information defined in 10 CFR 50.2. According to
this definition, ``[d]esign bases means that information which
identifies the specific functions to be performed by a structure,
system, or component of a facility, and the specific values or ranges
of values chosen for controlling parameters as reference bounds for
design.'' In addition, design bases identify specific functions to be
performed by a system, structure, and component, and design-basis
values may be derived for achieving functional goals. For plant
systems, structures, and components that are not subject to performance
or condition-monitoring programs or for those on which the detrimental
effects of aging may not be as readily apparent, verification of
specific design values (e.g., piping wall thickness) or demonstration
by analysis can be a basis for concluding that the required function(s)
will be maintained in the period of extended operation.
When the design bases of systems, structures, and components can be
confirmed either indirectly by inspection or directly by verification
of functionality through test or operation, a reasonable conclusion can
be drawn that the CLB is or will be maintained. This conclusion
recognizes that the portion of the CLB that can be impacted by the
detrimental effects of aging is limited to the design-bases aspects of
the CLB. All other aspects of the CLB, e.g., quality assurance,
physical protection (security), and radiation protection requirements,
are not subject to physical aging processes that may cause
noncompliance with those aspects of the CLB.
Although the definition of CLB in Part 54 is broad and encompasses
various aspects of the NRC regulatory process (e.g., operation and
design requirements), the Commission concludes that a specific focus on
functionality is appropriate for performing the license renewal review.
Reasonable assurance that the function of important systems,
structures, and components will be maintained throughout the renewal
period, combined with the rule's stipulation that all aspects of a
plant's CLB (e.g., technical specifications) and the NRC's regulatory
process carry forward into the renewal period, are viewed as sufficient
to conclude that the CLB (which represents an acceptable level of
safety) will be maintained. Functional capability is the principal
emphasis for much of the CLB and is the focus of the maintenance rule
and other regulatory requirements to ensure that aging issues are
appropriately managed in the current license term.
An example of performance verification activities that must be
performed by licensees is the loss of coolant accident (LOCA)/loss of
offsite power (LOOP) integrated tests. This technical specification
surveillance is typically required to be performed at least once every
18 months. This test simulates a coincident LOCA/LOOP (design-basis
accident) for each train or division of emergency alternating current
(ac) power source (e.g., emergency diesel generators), the associated
emergency core cooling systems (e.g., safety injection subsystems), and
other electrically driven safety components (e.g., containment
isolation valves, emergency ventilation/filtration components, and
auxiliary feedwater components). All engineered safety features
required to actuate for an actual LOCA/LOOP are required to actuate for
the test and either duplicate the LOCA/LOOP function completely (e.g.,
electric loads are sequenced onto emergency busses, containment
isolation valves actually shut from fully open positions) or
approximate the actual function to the greatest extent practicable
(e.g., safety injection pumps start and run in recirculation mode
instead of actually injecting water into the reactor coolant system).
Design-basis values that can only be measured during this testing, such
as load sequence times and emergency bus voltage response to the
sequenced loads, are directly verified. [[Page 22476]] Between
integrated tests, monthly and quarterly surveillances verify specific
component performance criteria such as emergency diesel generator start
times or pump flow values. The acceptance criteria stated in the
surveillance requirements are derived from design-basis values with
appropriate conservatisms built in to account for any uncertainties or
measurement tolerances. Satisfactory accomplishment and periodic
repetition of these types of surveillance provide reasonable assurance
that system, structure, and component functions will be performed as
designed.
f. Integrated Plant Assessment
The previous license renewal rule required license renewal
applicants to perform a systematic screening of plant systems,
structures, and components to ultimately determine if aging would be
adequately managed in the period of extended operation. This IPA
process would begin broadly and consider all plant systems, structures,
and components. The IPA would then focus on only those that are
important to license renewal and finally on only those structures and
components that could be subject to ARDUTLR. For those structures and
components subject to ARDUTLR, the IPA process required an evaluation
and demonstration that either (1) new programs or licensee actions
would be implemented to prevent or mitigate any ARDUTLR during the
period of extended operation or (2) justifies that no actions are
necessary.
On the basis of experience gained from implementation of the
previous license renewal rule, the Commission determined that the
previous rule required the evaluation of an unnecessarily large number
of plant systems, structures, and components to establish appropriate
aging management in the period of extended operation. This experience,
further consideration of existing activities, and the recent adoption
of the maintenance rule have led the Commission to conclude that many
of these systems, structures, and components are already subject to
activities that ensure their function through any period of extended
operation. Therefore, the Commission is amending the IPA process in
this rulemaking to more efficiently focus the license renewal review on
certain structures and components for which the regulatory process and
existing licensee programs and activities may not adequately manage the
detrimental effects of aging in the period of extended operation.
The approach reflected in this rule maintains the requirement for
each renewal applicant to address possible detrimental effects of aging
for certain systems, structures and components during the period of
extended operation through the IPA process. The rule will simplify the
IPA process consistent with (1) the Commission's determination that the
aging management review should focus on ensuring that structures and
components perform their intended function(s) and (2) the additional
experience the Commission has gained related to aging management review
since publishing the current license renewal rule.
The IPA process continues to require an initial review of all plant
systems, structures, and components to identify the scope of structures
and components requiring aging management review for license renewal.
The principal differences between the IPA process in the previous
license renewal rule and the IPA process in this rule is--
(1) The determination of the reduced set of structures and
components that must undergo an aging management review;
(2) The form of the aging management review (managing the effects
of aging on functionality versus managing aging mechanisms); and
(3) The elimination of the term, `` ARDUTLR''.
(i) Determination of Structures and Components Requiring Aging
Management Review for License Renewal
In the SOC for the previous license renewal rule, the Commission
stated that, as it gains more experience with age-related degradation
reviews, it may revisit the need for such a disciplined review process
and may narrow the scope of the safety review. The Commission now
believes that after reviewing its recent implementation experience, a
narrower scope of review is warranted. The Commission concludes that a
generic exclusion from aging management review is appropriate for those
categories of structures and components subject to existing programs
and activities that the Commission believes are sufficient to provide
reasonable assurance of continued function in the period of extended
operation.
As discussed in Section III.d of this SOC, the Commission has
determined that the existing regulatory process, existing licensee
programs and activities, and the maintenance rule provide the basis for
generically excluding structures and components that perform active
functions from an aging management review. However, the Commission does
not believe that it can generically exclude structures and components
that--
(1) Do not have performance and condition characteristics that are
as readily monitorable as active components; and
(2) Are not subject to periodic, planned replacement.
Unlike the extensive experience associated with the performance and
condition monitoring of the active functions of structures and
components, little experience has been gained from the evaluation of
long-term effects of aging on the passive functions of structures and
components. The Commission considers that the detrimental effects of
aging affecting passive functions of structures and components are less
apparent than the detrimental effects of aging affecting the active
functions of structures and components. Therefore, the Commission
concludes that a generic exclusion for passive structures and
components is inappropriate at this time. The Commission also concludes
that an aging management review of the passive functions of structures
and components is warranted to provide the reasonable assurance that
their intended functions are adequately maintained during the period of
extended operation. Additional experience with managing the effects of
aging on the function of these structures and components may narrow the
selection of structures and components requiring an aging management
review for license renewal in the future.
New Jersey commented that since so much of original plant design
assumed 40 years of service, utilities should be required to determine
the actual conditions of systems, structures, and components at the 40-
year point ``license renewal milestone.''
The focus of the license renewal rule on passive, long-lived
structures and components conforms to the commenter's concern. For a
licensee to perform an effective aging management review of long-lived,
passive structures and components identified in the IPA, a logical
starting point for a given structure or component may be to assess its
current condition against the CLB via a ``one time'' inspection.
Although this assessment is not specifically required by the rule, the
licensee must demonstrate that the effects of aging will be managed so
that the intended function(s) will be maintained for the period of
extended operation. If a licensee chooses not to perform a ``one time''
inspection or similar assessment for a particular structure or
component, [[Page 22477]] the aging management review must still
adequately demonstrate that detrimental effects of aging will be
managed during the period of extended operation.
(a) ``Passive'' Structures and Components
In Section III.d of this SOC, the Commission concluded that
structures and components that perform active functions can be
generically excluded from an aging management review on the basis of
performance or condition-monitoring programs. The Commission recognizes
that structures and components that have passive functions generally do
not have performance and condition characteristics that are as readily
monitorable as those that perform active functions. Therefore, the
Commission concludes that an aging management review is required for
structures and components within the scope of the license renewal rule
that perform passive intended functions.
The Commission has reviewed several industry concepts of
``passive'' structures and components and has determined that they do
not accurately describe the structures and components that should be
subject to an aging management review for license renewal. Accordingly,
the Commission has developed a description of ``passive''
characteristics of structures and components. Furthermore, the
Commission has directly incorporated these characteristics into the IPA
process to avoid the creation of a new term, ``passive.'' This SOC uses
the term ``passive'' for convenience. Furthermore, the description of
``passive'' structures and components incorporated into Sec. 54.21(a)
should be used only in connection with the IPA review in the license
renewal process.
The Commission has determined that passive structures and
components for which aging degradation is not readily monitored are
those that perform an intended function without moving parts or without
a change in configuration or properties. For example, a pump or valve
has moving parts, an electrical relay can change its configuration, and
a battery changes its electrolyte properties when discharging.
Therefore, the performance or condition of these components is readily
monitored and would not be captured by this description. Further, the
Commission has concluded that ``a change in configuration or
properties'' should be interpreted to include ``a change in state,''
which is a term sometimes found in the literature relating to
``passive.'' For example, a transistor can ``change its state'' and
therefore would not be screened in under this description.
Structures or components may have active functions, passive
functions, or both. For example, although a pump or a valve has some
moving parts, a pump casing or valve body performs a pressure-retaining
function without moving parts. A pump casing or a valve body meets the
Commission's description and would therefore be considered for an aging
management review. However, the moving parts of the pump, such as the
pump impeller, would not be subject to aging management review.
Additionally, the maintenance rule implementation guidance (Regulatory
Guide 1.160) contains a provision by which licensees may classify
certain systems, structures, and components (e.g., raceways, tanks, and
structures) as, ``inherently reliable.'' Inherently reliable systems,
structures, and components by definition generally do not require any
continuing maintenance actions and should be considered as ``passive.''
As examples of the implementation of this screening requirement,
the Commission considers structures and components meeting the passive
description as including, but not limited to, the reactor vessel, the
reactor coolant system pressure boundary, steam generators, the
pressurizer, piping, pump casings, valve bodies, the core shroud,
component supports, pressure retaining boundaries, heat exchangers,
ventilation ducts, the containment, the containment liner, electrical
and mechanical penetrations, equipment hatches, seismic Category I
structures, electrical cables and connections, cable trays, and
electrical cabinets.
Additionally, the Commission determined that structures and
components that perform active functions are not subject to an aging
management review (e.g., pumps (except casing), valves (except body),
motors, diesel generators, air compressors, snubbers, the control rod
drive, ventilation dampers, pressure transmitters, pressure indicators,
water level indicators, switchgears, cooling fans, transistors,
batteries, breakers, relays, switches, power inverters, circuit boards,
battery chargers, and power supplies). However, pressure-retaining
boundaries (e.g., pump casings, valve bodies, fluid system piping) and
structural supports (e.g., diesel generator structural supports) that
are necessary for the structure or component to perform its intended
function meet the description of passive, and will be subject to an
aging management review.
A commenter requested clarification as to whether the Commission
intended pressure boundaries, other than the reactor coolant pressure
boundary, to be included in an aging management review (e.g.,
pressurized water reactor main steam lines). The Commission does not
limit the consideration of pressure boundaries for an aging management
review to only the reactor coolant pressure boundary. All pressure
retaining boundaries necessary for the performance of the intended
functions delineated in Sec. 54.4 would be subject to an aging
management review. For example, those portions of a plant's main steam
lines that meet the intended function criteria of Sec. 54.4 would be
included in an aging management review.
One commenter expressed a belief that cables were prematurely
included as ``passive'' and should not be subject to an aging
management review. The commenter stated that the only aging effects of
cables are shorting and loss of continuity, and for cables not in a
harsh environment, these effects would be immediately detected during
normal operation or functional testing. The Commission considers the
examples of electrical components (e.g., electrical cables,
connections, and electrical penetrations) listed in 10 CFR
54.21(a)(1)(i) and Section III.f(i)(a) of the SOC to be properly
categorized as ``passive'' because they perform their intended function
without moving parts or without a change in configuration or properties
and the effects of aging degradation for these components are not
readily monitorable. The Commission also believes that this
categorization is not premature as stated by the commenter.
The Commission disagrees with the commenter's assertion that the
aging effects of cable make it easy to monitor functional degradation.
Although there have been significant advances in this area, there is no
single method or combination of methods that can provide the necessary
information about the condition of electrical cable currently in
service regarding the extent of aging degradation or remaining
qualified life. Degradation due to aging of electrical cables caused by
elevated temperature and radiation can cause embrittlement in the form
of cracking of insulation and jacket materials. The cracks degrade the
electrical properties of the insulation materials. The major concern is
that failures of deteriorated cable systems (cables, connections, and
penetrations) might be induced during accident conditions. Because
these components are relied on to remain functional during and
following design-basis events (including conditions of normal
operation) and there are currently no known effective methods
[[Page 22478]] for continuous monitoring of cable systems, these
examples of passive electrical components subject to an aging
management review will remain in 10 CFR 54.21(a)(1)(i) and Section III
f(i)(a) of the SOC.
(b) ``Long-Lived'' Structures and Components
The Commission recognizes that, as a general matter, the effects of
aging on a structure or component are cumulative throughout its service
life. One way to effectively mitigate these effects is to replace that
structure or component, either (i) on a specified interval based upon
the qualified life of the structure or component or (ii) periodically
in accordance with a specified time period to prevent performance
degradations leading to loss of intended function during the period of
operation.
Where a structure or component is replaced based upon a qualified
life (appropriately determined), it follows that the replaced structure
or component will not experience detrimental effects of aging
sufficient to preclude its intended function. This is because the
purpose of qualification of the life of a structure or component is to
determine the time period for which the intended function of that
structure or component can be reasonably assured.
Where a structure or component is replaced periodically in
accordance with a specified time period, the regulatory process will
ensure that degraded performance of the structure or component
experienced during the replacement interval will be adequately
addressed and the established replacing interval will be appropriate.
Thus, there is a high likelihood that the detrimental effects of aging
will not accumulate during the subsequent period such that there is a
loss of intended function.
In sum, a structure or component that is not replaced either (i) on
a specified interval based upon the qualified life of the structure or
component or (ii) periodically in accordance with a specified time
period, is deemed by Sec. 54.21(a)(1)(ii) of this rule to be ``long-
lived,'' and therefore subject to the Sec. 54.21(a)(3) aging management
review.
It is important to note, however, that the Commission has decided
not to generically exclude passive structures and components that are
replaced based on performance or condition from an aging management
review. Absent the specific nature of the performance or condition
replacement criteria and the fact that the Commission has determined
that components with ``passive'' functions are not as readily
monitorable as components with active functions, such generic exclusion
is not appropriate. However, the Commission does not intend to preclude
a license renewal applicant from providing site-specific justification
in a license renewal application that a replacement program on the
basis of performance or condition for a passive structure or component
provides reasonable assurance that the intended function of the passive
structure or component will be maintained in the period of extended
operation.
A commenter recommended that the Commission exclude specific
components from an aging management review if they have been replaced
in the later years of the original license or if they are subject to
routine testing. The Commission believes that one-time component
replacements and replacements based on routine testing are essentially
replacements based on performance or condition. Absent the specific
nature of the performance or condition replacement criteria (e.g.,
routine testing program) it is not appropriate for the Commission to
generically exclude all such replacement programs of passive structures
and components. However, the Commission does not preclude a license
renewal applicant from providing a plant-specific justification in a
license renewal application that a one-time replacement program or
replacement program on the basis of routine testing of passive
structures and components provides reasonable assurance that
functionality will be maintained in the period of extended operation.
A commenter requested that the Commission provide an example of a
performance- or condition-based replacement program that could be used
to justify that aging effects will be adequately managed during the
period of extended operation. While an exact application of a
performance or condition replacement is necessarily dependent on plant-
specific situations and their respective aging effects of concern, the
Commission would generally expect that such a replacement program would
have defined performance or condition measuring methods (e.g., wall
thickness of heat exchanger tubes), an established monitoring frequency
that supports timely discovery of degraded conditions (e.g., every
refueling outage), and an appropriate replacement criterion (e.g., upon
reaching a specified number of tubes plugged).
One commenter stated that the Commission should consider dividing
long-lived passive structures and components into two categories: those
that have a less rigorous approach to oversight and maintenance and
those that have a sufficiently high level of licensee programs and
regulatory oversight. The commenter then suggests that the rule should
recognize the quality and effectiveness of the programs in the second
category and appropriately credit them relative to an aging management
review. Specifically, the commenter provided the reactor coolant
pressure boundary as an example of a passive, long-lived component for
which rigorous programs and regulatory oversight currently exist to
adequately manage the effects of aging. Currently, the Commission
believes it would be too difficult to further divide the structures and
components required for an aging management review into those passive,
long-lived structures and components ``rigorously'' managed and those
``not as rigorously'' managed. The variations among plant specific
designs and programs make such a determination unmanageable at present.
However, as the Commission gains more experience with industry
activities for management of passive, long-lived structures and
components, it may consider further narrowing the scope of those
structures and components requiring an aging management review. With
regard to the commenter's specific example of the reactor coolant
pressure boundary, because of its high-risk significance, the
differences in plant-specific design and operational histories, and the
lack of operating experience beyond the original operating terms, the
Commission does not believe it appropriate to generically exclude the
reactor coolant pressure boundary from an aging management review.
(ii) The IPA Process
The Commission revised and simplified the IPA requirements
(Sec. 54.21(a)) as follows:
First, instead of listing those systems, structures, and components
that are important to license renewal, only a list is required (from
those systems, structures, and components within the scope of license
renewal) of structures and components that a licensee determines to be
subject to an aging management review for the period of extended
operation. A licensee has the flexibility to determine the set of
structures and components for which an aging management review is
performed, provided that this set encompasses the structures and
components for which the Commission has determined an aging management
review is required for the period of extended operation.
[[Page 22479]]
Therefore, a licensee's aging management review must include
structures and components--
(1) That were not subject to replacement based on a qualified life
or a specified time period; and
(2) That perform an intended function (Sec. 54.4) without moving
parts or without a change in configuration or properties.
In establishing this flexibility, the Commission recognizes that
licensees may find it preferable to not take maximum advantage of the
Commission's generic conclusion regarding structures and components
that do not require an aging management review, and may undertake a
broader scope of review than is minimally required. For example, a
licensee may desire to review all ``passive'' structures and
components. This set of structures and components would be acceptable
because it includes ``long-lived'' as well as periodically replaced
structures and components and, therefore, encompasses all structures
and components that would be identified through criteria (1) and (2)
above.
Second, the IPA must contain a description of the methodology used
to determine those systems, structures, and components within the scope
of license renewal and those structures and components subject to an
aging management review.
Third, the IPA must contain a demonstration, for each structure and
component subject to an aging management review, that the effects of
aging will be managed so that the intended function(s) will be
maintained for the period of extended operation. This demonstration
must include a description of activities, as well as any changes to the
CLB and plant modifications that are relied on to demonstrate that the
intended function(s) will be adequately maintained despite the effects
of aging in the period of extended operation.
A commenter suggested that the regulatory text include a more
comprehensive list of components subject to an aging management review
in order to clarify its intent. The Commission decided that not to
include a more detailed list of components subject to an aging
management review. Components subject to an aging management review are
highly plant specific and the Commission does not intend to establish
plant-specific lists by regulation. However, the Commission will
include additional clarification and examples of components requiring
an aging management review in its implementation guidance for the rule.
DOE commented that the wording in Sec. 54.21(a)(3), requiring a
demonstration that the effects of aging will be managed so that the
intended function(s) will be maintained, could be interpreted too
restrictively. Specifically, DOE asserts that the IPA process serves to
demonstrate that a structure or component will perform in a manner
consistent with the CLB rather than to provide ``absolute'' assurance
that the structure or component will not fail. Therefore, DOE
recommends revising Sec. 54.21(a)(3) to include requiring a
demonstration that the effects of aging are ``adequately managed'' and
that the intended functions are maintained, ``to the extent required by
the CLB.''
The Commission agrees with DOE that the IPA process is not intended
to demonstrate absolute assurance that structures or components will
not fail, but rather that there is reasonable assurance that they will
perform such that the intended functions, as delineated in Sec. 54.4,
are maintained consistent with the CLB. The Commission has clarified
the wording in Sec. 54.21(a)(3) to require a demonstration that the
effects of aging be adequately managed so that the intended function(s)
will be maintained consistent with the CLB.
One commenter suggested that the amendment provides more
uncertainty as to which structures and components should be considered
for an aging management review. Specifically, the commenter cited
fasteners as an example of what is important but appears not to be
considered in the proposed rule. The commenter states that the NRC
should provide more detailed guidance.
The Commission does not agree that the rule provides more
uncertainty with regard to what structures and components should be
considered. In fact, the rule provides clear criteria for what types of
structures and components must be subject to an aging management
review--namely passive, long-lived structures and components from those
determined to be within the scope of license renewal. With regard to
the specific example of fasteners cited by the commenter, the rule
would require an aging management review for fasteners because
fasteners are considered to be passive and if the fasteners (1) were
determined to be within the scope of license renewal as defined in
Sec. 54.4 and (2) were determined not to be subject to periodic
replacement or replacement based on a qualified fastener life. As in
the previous rule, this rule does not delineate a comprehensive list of
the specific structures and components that must be considered for an
aging management review.
g. Time-Limited Aging Analyses and Exemptions
(i) Time-Limited Aging Analyses
The definition of ARDUTLR in the previous license renewal rule
requires a licensee evaluation and NRC approval of previous time-
limited aging analyses for systems, structures, and components within
the scope of license renewal that either were based on an assumed
service life or a period of operation defined by the original license
term. For example, certain plant-specific safety analyses may have been
based on an explicitly assumed 40-year plant life (e.g., aspects of the
reactor vessel design). As a result, an evaluation for license renewal
would be required. Those time-limited aging analyses that need to be
evaluated for renewal are limited to those analyses with (i) time-
related assumptions, (ii) utilized in determining the acceptability of
systems, structures, and components within the scope of license renewal
(as defined in Section 54.4), (iii) which are based upon a period of
plant operation equal to or greater than the current license term, but
less than the cumulative period of plant operation (viz., the existing
license term plus the period of extended operation requested in the
renewal application). Time-limited aging analyses based on an assumed
period of plant operation short of the current operating term should be
addressed within the original license and need not be reviewed for
license renewal.
Because the Commission deleted the term of ARDUTLR, this license
renewal rule identifies these explicit time-limited analyses as issues
that must be clearly addressed within the license renewal process. This
rule explicitly requires that--
(1) Applicants perform an evaluation of time-limited aging issues
relevant to systems, structures, and components within the scope of
license renewal in the license renewal application; and
(2) The adequate resolution of time-limited aging analysis issues
as part of the standards for issuance of a renewed license.
The time-limited provisions or analyses of concern are those that--
(1) Involve the effects of aging;
(2) Involve time-limited assumptions defined by the current
operating term, for example, 40 years;
(3) Involve systems, structures, and components within the scope of
license renewal;
(4) Involve conclusions or provide the basis for conclusions
related to the [[Page 22480]] capability of the system, structure, and
component to perform its intended functions;
(5) Were determined to be relevant by the licensee in making a
safety determination; and
(6) Are contained or incorporated by reference in the CLB.
The applicant for license renewal will be required in the renewal
application to--
(1) Justify that these analyses are valid for the period of
extended operation;
(2) Extend the period of evaluation of the analyses such that they
are valid for the period of extended operation, for example, 60 years;
or
(3) Justify that the effects of aging will be adequately managed
for the period of extended operation if an applicant cannot or chooses
not to justify or extend an existing time-limited aging analysis.
The Commission considers analyses to be ``relevant'' if the
analyses provided the basis for the licensee's safety determination
and, in the absence of the analyses, the licensee may have reached a
different safety conclusion. Time-limited aging analyses that need to
be addressed in a license renewal evaluation are not necessarily those
analyses that have been previously reviewed or approved by the
Commission. The following examples illustrate time-limited aging
analyses that need to be addressed and were not previously reviewed and
approved by the Commission.
(1) The FSAR states that the design complies with a certain ASME
Code requirement. A review of the ASME Code requirement reveals that a
time-limited aging analysis is required. The actual calculation was
performed by the licensee to meet code requirements. The specific
calculation was not referenced in the FSAR and the NRC had not reviewed
the calculation.
(2) In response to a generic letter, a licensee submitted a letter
to the NRC committing to perform a time-limited aging analysis that
would address the concern in the generic letter. The NRC had not
documented a review of the licensee's response and had not reviewed the
actual analysis.
The Commission expects that the number of time-limited aging
analyses that need to be addressed in a license renewal evaluation is
relatively small. Although the number and type will vary depending on
the plant-specific CLB, these analyses could include reactor vessel
neutron embrittlement (pressurized thermal shock, upper-shelf energy,
surveillance program), concrete containment tendon prestress, metal
fatigue, environmental qualification (EQ) of electrical equipment,
metal corrosion allowance, inservice flaw growth analyses that
demonstrate structural stability for 40 years, inservice local metal
containment corrosion analyses, and high-energy line-break postulation
based on fatigue cumulative usage factor.
Three issues were raised by five commenters relating to time-
limited aging analyses in the proposed rule.
(1) The proposed rule contains a definition of time-limited aging
analyses in Sec. 54.3 which is further discussed in the proposed SOC.
However, the proposed rule definition appeared to contain two criteria
in defining time-limited aging analyses while the discussion in the
proposed SOC appeared to contain six criteria. Three commenters
indicated that there may be potential inconsistencies between the
proposed rule definition and the proposed SOC. The commenters
recommended various methods for incorporating the SOC language in the
rule.
The proposed SOC discussion was intended to further clarify the
criteria contained in the proposed rule definition. After reviewing the
comments, the Commission has decided to replace the proposed definition
of time-limited aging analyses in Sec. 54.3 with the six criteria in
the proposed SOC as recommended.
(2) One commenter recommended reconsideration of all proposed plant
modifications which were not imposed by the Commission due to a cost-
benefit analysis that had time-dependent factors. The commenter
suggested that this should include any backfits which the Commission
declined to impose, as well as potential plant modifications to reduce
risk identified in programs such as the individual plant examination
(IPE) and the individual plant examination of external events (IPEEE)
for severe accident vulnerabilities.
The Commission does not regard such reconsideration to be necessary
to provide reasonable assurance that there is no undue risk to the
public health and safety for the period of extended operation of
nuclear power plants.
As discussed in the SOC for the previous license renewal rule (56
FR 64943 at 64948), in NUREG-0933, A Prioritization of Generic Safety
Issues, the NRC examined 249 generic safety issues (GSIs) that had been
resolved through October 1990, in order to identify possible cases
where consideration of the additional period of operation during the
renewal term might have altered the NRC's regulatory decision not to
undertake additional action. Of the 139 GSIs resolved through October
1990 that did not result in backfits, the Commission found that only 3
issues for which a reexamination of the backfit determination appeared
to be prudent. In two instances, the reexamination confirmed the
appropriateness of the no backfit conclusion for an additional 20 years
of operation beyond the original 40-year license term. The third issue
(GSI Item III.A.1.3 ``Maintain Supply of Thyroid Blocking Agent'') had
been placed in the resolution process for reasons apart from license
renewal. Thus, cost-benefit analyses of the resolved GSIs were
relatively insensitive to consideration of the period of extended
operation. The cost-benefit methodologies utilized in resolution of
GSIs are the same as those used by the NRC in conjunction with the full
gamut of regulatory actions involving nuclear power plants, including
rulemaking and enforcement. Since the methodologies are the same, the
Commission believes that the results of NUREG-0933 can be reasonably
extrapolated to other regulatory assessments where backfits were not
imposed on the basis of cost-benefit analyses limited to 40 years of
operation. Furthermore, cost-benefit considerations simply do not come
into play in backfit determinations involving adequate protection--
except in selecting among different ways of achieving adequate
protection, as is acknowledged in 10 CFR 50.109(a)(7). The IPE and
IPEEE are licensees' studies to search for plant vulnerabilities to
internal and external events. As such, the IPE and IPEEE are not
intended to identify or address matters involving adequate protection
and, to date, no such issues have been identified.
(3) Two commenters recommended clarifying that the requirement of
time-limited aging analyses does not apply to a component that is
replaced based on a qualified life less than the full original license
term. The commenters cited the EQ of electrical equipment pursuant to
Sec. 50.49 as a specific example. This type of equipment is replaced
during the current license term and will continue to be replaced during
the renewal term based on its qualified life.
The Commission's intent for the requirement of time-limited aging
analyses is to capture, for renewal review, certain plant-specific
aging analyses that are explicitly based on the duration of the current
operating license of the plant. The Commission's concern is that these
aging analyses do not cover the period of extended operation. Unless
these analyses are evaluated, the Commission does not have assurance
that the systems, structures, and components addressed by these
[[Page 22481]] analyses can perform their intended function(s) during
the period of extended operation. The periodic replacement program
discussed in the previous paragraph would ensure that the subject
component can perform its intended function(s) during the period of
extended operation. Thus, the Commission agrees with the commenters
that components replaced based on qualified lives less than the
duration of the current license term need not be addressed under time-
limited aging analyses for renewal if the scheduled replacement
continues to be performed in the period of extended operation. This is
consistent with the definition of time-limited aging analyses in
Sec. 54.3.
(ii) Exemptions
The previous license renewal rule required that an applicant for
license renewal provide a list of all plant-specific exemptions granted
under 10 CFR 50.12. An evaluation that justifies the continuation of
the exemptions for the renewal term must be provided for exemptions
that were either granted on the basis of an assumed service life or a
period of operation bounded by the original license term of the
facility or otherwise related to systems, structures, or components
subject to ARDUTLR.
With the deletion of the definition of ARDUTLR and the
corresponding addition of a separate time-limited aging analysis
requirement, the Commission has included this exemption review with the
separate time-limited aging analysis requirement in Sec. 54.21(c). This
change is consistent with the Commission's intent to review exemptions
based on time-limited aging analyses under the current rule.
Two commenters questioned the proposed requirement to list and
evaluate all granted exemptions, including those that are no longer in
effect. One commenter recommended that only exemptions in effect at the
time of renewal application and continuing into the period of extended
operation should be considered for renewal. Further, the other
commenter indicated that requiring a listing of all exemptions is
inconsistent with the removal of other lists currently required in 10
CFR 54, such as the list of systems, structures, and components
important to license renewal, to provide applicants flexibility in
developing suitable methodologies to implement the requirements of
Sec. 54.21. The Commission agrees with the commenters. Exemptions that
have expired are no longer part of the CLB for that plant. Further, a
requirement to list all exemptions in effect is unnecessary because the
only exemptions of concern for license renewal are those that have
time-limited aging analyses.
Thus, the Commission has revised Sec. 54.21(c)(2) to require a
listing of only those exemptions in effect at the time of renewal
application that are based on time-limited aging analyses as defined in
Sec. 54.3.
The Commission will rely on explicit wordings in the granted
exemptions to determine if an exemption is in effect at the time of
renewal application. The Commission will not require an exemption to be
considered for license renewal if the exemption was granted with an
explicit expiration date that has passed prior to the renewal
application. However, the Commission will require exemptions granted
without explicit expiration dates to be considered for renewal. If an
applicant believes that a certain exemption has expired and yet the
supporting documentation does not have a clearly stated expiration
date, the applicant should update its CLB prior to submitting its
renewal application to clearly indicate that the exemption has expired.
h. Standards for Issuance of a Renewed License and the Scope of
Hearings
Section 54.29 of the previous license renewal rule provided that
the Commission may issue a renewed license if--
(a) Actions have been identified and have been or will be taken
with respect to age-related degradation unique to license renewal of
systems, structures, and components important to license renewal, such
that there is reasonable assurance that the activities authorized by
the renewed license will be conducted in accordance with the current
licensing basis, and that any changes made to the plant's current
licensing basis in order to comply with this paragraph are otherwise in
accord with the Act and the Commission's regulations.
(b) Any applicable requirements of subpart A of 10 CFR Part 51 have
been satisfied.
(c) Any matters raised under 10 CFR 2.758 have been addressed as
required by that (section).
Issues that were material to the findings in Sec. 54.29 of the
previous rule, as well as matters approved by the Commission for
hearing under Sec. 2.758, were within the scope of a hearing on a
renewed license. The previous license renewal rule modified Sec. 2.758
to clarify that challenges to the license renewal rule in an
adjudicatory hearing on a renewal application would be considered by
the Commission only in the following limited circumstances:
(1) That there are special circumstances with respect to age-
related degradation unique to license renewal or environmental
protection so that application of either 10 CFR Part 54 or 10 CFR Part
51 would not serve the purpose for which these rules were intended; or
(2) Because of circumstances unique to the period of extended
operation, there would be noncompliance with the plant's CLB or
operation that is inimical to the public health and safety during the
period of extended operation.
The intent of those provisions in the previous rule was to clarify
that safety and environmental matters not unique to the period of
extended operation would not be the subject of the renewal application
or the subject of a hearing in a renewal proceeding absent specific
Commission direction. Rather, issues that represent a current problem
for operation would have been addressed in accordance with the
Commission's regulatory process and procedures. Thus, under the
previous rule, a member of the public who believed that a current
problem exists with a license or a matter exists that is not adequately
addressed by current NRC regulations would have either petitioned the
NRC to take appropriate action under Sec. 2.206, or petitioned the NRC
to institute rulemaking to address the issue under Sec. 2.802.
The Commission continues to believe that aging management of
certain important systems, structures, and components during this
period of extended operation should be the focus of a renewal
proceeding and that issues concerning operation during the currently
authorized term of operation should be addressed as part of the current
license rather than deferred until a renewal review (which would not
occur if the licensee chooses not to renew its operating license).
However, in this final rule, the Commission has narrowed the scope of
structures and components that will require an aging management review
for the period of extended operation and identification and evaluation
of time-limited aging analyses by the applicant. Accordingly,
conforming changes in Sec. 54.29 have been made to reflect the
refocused renewal review. Specifically, Sec. 54.29 has been revised to
delete the term ``age-related degradation unique to license renewal,''
and substitute the findings (required for consistency with the revised
Sec. 54.21 (a)(3) and (c)) with respect to aging management review and
time-limited aging analyses evaluation for the period of extended
operation. Furthermore, Sec. 2.758 has similarly been revised to delete
the terms ``age-related [[Page 22482]] degradation unique to license
renewal'' and ``unique to the requested term.'' The elimination of
ARDUTLR requires elimination of the concept that the renewal review or
hearing must be confined to aging issues that are ``unique'' to license
renewal. Instead, limits on the scope of renewal review and hearing are
based on careful review of the sufficiency of the NRC regulatory
process to resolve issues not considered in renewal.
Section 54.29 of the proposed rule (59 FR 46579) was intended to
accomplish several things. Proposed Sec. 54.29(a) was intended to
define the findings that the Commission must make in order to issue a
renewed operating license to a nuclear power plant and the scope of any
hearing on the renewal application.\2\ By contrast, proposed Sec. 54.29
(b) and (c) were intended to identify the issues that were NOT to be
part of the renewal review and to re-emphasize the renewal applicant's
obligation under its current operating license to address, in the
context of that license, those aging matters identified in the course
of its renewal review that may reasonably be expected to cause a loss
of function for systems, structures, or components during the current
term of operation. Both DOE and NEI commented that by combining these
purposes into a single section, the proposed rule could be erroneously
interpreted as requiring a general demonstration of compliance with the
CLB as a prerequisite for issuing a renewed license. While the
Commission believes that the proposed rule was sufficiently clear in
distinguishing between the issues that must be addressed as part of the
renewal review versus those which must be addressed in the context of
the current license, the Commission has considered the comments of DOE
and NEI as evidence that the language of the proposed rule could be
further improved. Upon review of NEI's and DOE's proposals, the
Commission has decided to adopt an approach similar to the DOE
proposal, which narrows Sec. 54.29 to the findings to be made for
issuance of a renewed license, and describes in a new section, 54.30,
the licensee's responsibilities for addressing safety matters under its
current license, that are not within the scope of the renewal review.
Separating the subjects into two different sections should minimize any
possibility of misinterpreting the scope of the renewal review and
finding.
\2\The scope of Commission review determines the scope of
admissible contentions in a renewal hearing absent a Commission
finding under 10 CFR 2.758.
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Section 54.29(a) of the proposed rule set forth the three findings,
in paragraphs (a)(1), (a)(2) and (a)(3), which the NRC must make in
order to issue a renewed license. The first finding in paragraph (a)(1)
was divided into two numbered paragraphs (1)(i) and (1)(ii). DOE
commented that numbering the clauses could lead to an erroneous
interpretation that two separate, parallel conditions must be met in
order to make the first finding. To avoid the potential
misinterpretation, DOE recommended a revised numbering scheme. The
Commission agrees that separately numbering clauses (i) and (ii) in
paragraph (a)(1) could lead to an erroneous interpretation that two
parallel conditions must be met in order to make the finding in
paragraph (a)(1). Therefore, the Commission has adopted an approach
similar to the DOE proposal.
i. Regulatory and Administrative Controls
Certain regulatory and administrative controls in the previous
license renewal rule were imposed to specify the circumstances and
requirements necessary to make changes relating to the determination
and management of ARDUTLR and the recordkeeping and reporting
requirements relating to the renewal application. In view of the
greater reliance on existing programs in the license renewal process,
as discussed in Section III.d of this SOC, the Commission has
determined that many of these requirements are no longer necessary.
Therefore, the Commission has decreased the recordkeeping and reporting
burden on the applicant for license renewal in the level of detail in
the application, requirements for supplementing the FSAR, and in
recordkeeping requirements.
The Commission seeks to ensure that, in general, only the
information needed to make its safety determination is submitted to the
NRC for license renewal review and that regulatory controls imposed by
the license renewal rule are consistent with existing regulatory
controls on similar information that may be developed by a licensee
during the current operating term.
(i) Controls on Technical Information in an Application
In Sec. 54.21, the previous license renewal rule requires that an
application include a supplement to the FSAR that presents the
information required by this section. This information included the IPA
lists of systems, structures, and components, justification for
assessment methods, and descriptions of programs to manage ARDUTLR.
The simplification of the IPA process (Section III.f of this SOC)
and the clarification of the concept of ARDUTLR (Section III.b of this
SOC) have resulted in a potential inconsistency regarding the treatment
of information associated with the IPA. The Commission has determined
that there is no need to include the entire IPA in an FSAR supplement
because only the information associated with the IPA regarding the
basis for determining that aging effects are managed during the period
of extended operation requires the additional regulatory oversight
afforded by placing the information in the FSAR. Therefore, only a
summary description of the programs and activities for managing the
effects of aging during the period of extended operation for those
structures and components requiring an aging management review needs to
be included in the FSAR supplement. The IPA methodology and the list of
structures and components need not appear in an FSAR supplement,
although this information will still be required in the application for
license renewal.
The Commission has also eliminated Sec. 54.21 (b) and (d) of the
previous rule. These sections concern CLB changes associated with
ARDUTLR and plant modifications necessary to ensure that ARDUTLR is
adequately managed during the period of extended operation. This
information is now required as part of Sec. 54.21 (a)(3) and (c).
Relevant information concerning changes to the CLB and plant
modifications required to demonstrate that aging effects for systems,
structures, and components requiring an aging management review for
license renewal must be described in the application for license
renewal (Sec. 54.21 (a)(3) and (c)). If a license renewal applicant or
the Commission determines that CLB changes or plant modifications form
the basis for an IPA conclusion regarding structures and components
requiring an aging management review, then an appropriate description
of the CLB change or plant modification must be included in the FSAR
supplement. Subsequent changes are c
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