[Federal Register Volume 90, Number 247 (Wednesday, December 31, 2025)]
[Notices]
[Pages 61424-61427]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-24117]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-369; NRC-2025-1798]
Duke Energy Carolinas, LLC; McGuire Nuclear Station, Unit 1;
Exemption
AGENCY: Nuclear Regulatory Commission.
ACTION: Notice; issuance.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing an
exemption in response to a request dated May 8, 2025, as supplemented
by letter dated August 21, 2025, from Duke Energy Carolinas, LLC, to
allow the implementation of the American Society of Mechanical
Engineers Code Case N-921 after the start dates of the fifth Inservice
Inspection (ISI) interval at McGuire Nuclear Station, Unit 1.
DATES: The exemption was issued on December 23, 2025.
ADDRESSES: Please refer to Docket ID NRC-2025-1798 when contacting the
NRC about the availability of information regarding this document. You
may obtain publicly available information related to this document
using any of the following methods:
Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2025-1798. Address
questions about Docket IDs in Regulations.gov to Bridget Curran;
telephone: 301-415-1003; email: [email protected]. For technical
questions, contact the individual listed in the For Further Information
Contact section of this document.
NRC's Agencywide Documents Access and Management System
(ADAMS): You may obtain publicly available documents online in the
ADAMS Public Documents collection at https://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``Begin ADAMS Public Search.''
For problems with ADAMS, please contact the NRC's Public Document Room
(PDR) reference staff at 1-800-397-4209, at 301-415-4737, or by email
to [email protected]. The exemption request dated May 8, 2025, as
supplemented by letter dated August 21, 2025, is available in ADAMS
under Accession Nos. ML25128A041, and ML25233A035, respectively.
NRC's PDR: The PDR, where you may examine and order copies
of publicly available documents, is open by appointment. To make an
appointment to visit the PDR, please send an email to
[email protected] or call 1-800-397-4209 or 301-415-4737, between 8
a.m. and 4 p.m. eastern time (ET), Monday through Friday, except
Federal holidays.
FOR FURTHER INFORMATION CONTACT: John Klos, Office of Nuclear Reactor
Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555-
0001; telephone: 301-415-5136; email: [email protected].
SUPPLEMENTARY INFORMATION: The text of the exemption is attached.
Dated: December 29, 2025.
For the Nuclear Regulatory Commission.
Lee Klos,
Project Manager, Plant Licensing Branch II-1, Division of Operating
Reactor Licensing, Office of Nuclear Reactor Regulation.
Attachment--Exemption
NUCLEAR REGULATORY COMMISSION
Docket No. 50-369; Duke Energy Carolinas, LLC; McGuire Nuclear Station,
Unit 1; Exemption
I. Background
Duke Energy Carolinas, LLC (Duke Energy, the licensee) is the
holder of the Renewed Facility Operating License (RFOL) No. NPF-9
for McGuire Nuclear Station, Unit 1 (McGuire Unit 1), which is a
pressurized water reactor (PWR) located in Huntersville,
[[Page 61425]]
North Carolina. The RFOL provides, among other things, that the
facility is subject to all rules, regulations, and orders of the
U.S. Nuclear Regulatory Commission (NRC, the Commission) now or
hereafter in effect.
On July 17, 2024, NRC issued a final rule incorporating by
reference Regulatory Guide (RG) 1.147, Revision 21 (Agencywide
Documents Access and Management System (ADAMS), Accession No.
ML23291A003), into Title 10 of the Code of Federal Regulations (10
CFR) 50.55a(3)(ii) (89 FR 58039). This RG determined American
Society of Mechanical Engineers Boiler and Pressure Vessel Code,
Section XI (ASME BPV XI) Code Case N-921, ``Alternative 12-yr
Inspection Interval Duration, Section XI, Division 1,'' to be
conditionally acceptable. This code case allows NRC licensees to
implement an inservice inspection (ISI) program based upon a 12-year
ISI interval, as opposed to the traditional 10-year ISI interval
required by ASME BPV XI, Article IWA-2431. RG 1.147, Revision 21,
specifies four conditions on Code Case N-921. Condition 2 states,
``This code case can only be implemented at the beginning of an ISI
interval as part of a routine update of the ISI program.'' The July
17, 2024, final rule also added 10 CFR 50.55a(y), which includes a
definition for the term ``inservice inspection interval.'' This
definition, in part, specifies that the length of the ISI interval
is described in ASME BPV XI, Article IWA-2431.
II. Request/Action
By application dated May 8, 2025 (ML25128A041), as supplemented
by letter dated August 21, 2025, (ML25233A035), the licensee,
pursuant to 10 CFR 50.12, ``Specific exemptions,'' requested an
exemption from certain requirements of 10 CFR 50.55a(a)(3)(ii) and
10 CFR 50.55a(y) to allow the use of Code Case N-921 after the start
dates of the fifth ISI interval at McGuire Unit 1, which is not in
accordance with Condition 2 on Code Case N-921, as specified in RG
1.147, Revision 21. The fifth ISI interval at McGuire 1 began on
December 1, 2021. The licensee stated that the proposed exemption
does not impact the Inservice Testing (IST) program or snubber
program, which are implemented under the requirements of the ASME
Operation and Maintenance Code.
III. Discussion
Pursuant to 10 CFR 50.12(a), the Commission may, upon
application by any interested person or upon its own initiative,
grant exemptions from the requirements of 10 CFR part 50 when (1)
the exemptions are authorized by law, will not present an undue risk
to the public health and safety, and are consistent with the common
defense and security and (2) special circumstances are present.
Under 10 CFR 50.12(a)(2), special circumstances are present when at
least one of the following six conditions are met:
(i) Application of the regulation in the particular
circumstances conflicts with other rules or requirements of the
Commission; or
(ii) Application of the regulation in the particular
circumstances would not serve the underlying purpose of the rule or
is not necessary to achieve the underlying purpose of the rule; or
(iii) Compliance would result in undue hardship or other costs
that are significantly in excess of those contemplated when the
regulation was adopted, or that are significantly in excess of those
incurred by others similarly situated; or
(iv) The exemption would result in benefit to the public health
and safety that compensates for any decrease in safety that may
result from the grant of the exemption; or
(v) The exemption would provide only temporary relief from the
applicable regulation and the licensee or applicant has made good
faith efforts to comply with the regulation; or
(vi) There is present any other material circumstance not
considered when the regulation was adopted for which it would be in
the public interest to grant an exemption.
A. The Exemption is Authorized by Law
The exemption would authorize exemption from certain
requirements of 10 CFR 50.55a(a)(3)(ii) and 10 CFR 50.55a(y) to
allow the use of Code Case N-921, after the start dates of the fifth
ISI interval at McGuire Unit 1. As stated, 10 CFR 50.12(a) allows
the NRC to grant an exemption from the requirements of 10 CFR part
50, including 10 CFR 50.55a(a)(3)(ii) and 10 CFR 50.55a(y), when the
exemption is authorized by law. An exemption is authorized by law
where it is not expressly prohibited by statute or regulation. A
proposed exemption is implicitly authorized by law if it will not
present an undue risk to the public health and safety, is consistent
with the common defense and security, and special circumstances are
present, and no other provisions in law prohibit, or otherwise
restrict, its application. The NRC staff has determined that no
provisions in law expressly prohibit or otherwise restrict the
application of the requested exemption. The NRC staff has also
determined, as explained below, that the requested exemption will
not present an undue risk to the public health and safety, is
consistent with the common defense and security, and special
circumstances are present. Therefore, the NRC staff concludes that
the exemption is authorized by law.
B. The Exemption Presents no Undue Risk to Public Health and Safety
This exemption would allow the licensee to implement Code Case
N-921 after the start dates of the fifth ISI interval at McGuire
Unit 1. The action does not change the manner in which the plant
operates and maintains public health and safety because the
exemption does not result in a change to the facility or the current
operating license. The licensee stated that extending the ISI
interval by two years does not impact the technical basis supporting
any of the currently authorized 10 CFR 50.55a alternatives and does
not create any particular challenge in reconciling the ISI
inspection schedules to conform with the three four-year periods
specified in Code Case N-921. Accordingly, the NRC staff reviewed
the alternatives listed in Attachment 2 of the licensee's exemption
request for ISI interval-related impacts and identified several
common themes in these alternatives and evaluated the alternatives
as described below.
Alternatives With No ISI Interval Relationship
The NRC staff noted that the authorized alternative identified
by RA-20-0031 is associated with the delay in updating the inservice
inspection program code of record during the first inspection period
of the fifth 10-year ISI interval. The NRC staff confirmed that this
authorized alternative granted by letter dated August 21, 2020
(ML20230A205) was only applicable through the first inspection
period of the fifth 10-year ISI interval (i.e., November 30, 2024),
which had already occurred at the time of the licensee's current
submittal for an exemption. Therefore, the NRC staff's basis for
approving this alternative is not impacted by extending the length
of the ISI interval to 12 years.
Additionally, the NRC staff noted that the authorized
alternative identified by RA-19-0352 is based on a technical report
that considers the primary degradation mechanisms applicable to
reactor pressure vessel studs, assesses typical design basis loads
and transients, evaluates the stresses using a finite element
analysis of the reactor vessel head closure, identifies and
evaluates flaw stability limits, and evaluates fatigue crack growth
of a postulated flaw in the reactor pressure vessel studs. The NRC
staff confirmed that while this authorized alternative granted by
letter dated November 18, 2022 (ML22096A003), incorporates a time-
related assumption (i.e., transient occurrences per year), it is
independent from and unrelated to the length of the ISI interval.
Therefore, the NRC staff's basis for approving this alternative is
not impacted by extending the length of the ISI interval to 12
years.
Alternatives Based on Technical Reports With 10-Year ISI Intervals
The NRC staff noted that the authorized alternatives identified
by RA-22-0256 and RA-22-0257 are based on technical reports, as
identified below, which were originally developed based on the
assumption of 10-year ISI intervals:
EPRI Technical Report 3002015906, ``Technical Bases for
Inspection Requirements for PWR Steam Generator Class 1 Nozzle-to-
Vessel Welds and Class 1 and Class 2 Vessel Head, Shell, Tubesheet-
to-Head, and Tubesheet-to-Shell Welds,'' 2019 (ML20225A141).
EPRI Technical Report 3002014590, ``Technical Bases for
Inspection Requirements for PWR Steam Generator Feedwater and Main
Steam Nozzle-to-Shell Welds and Nozzle Inside Radius Sections,''
2019 (ML19347B107).
EPRI Technical Report 3002015905, ``Technical Bases for
Inspection Requirements for PWR Pressurizer Head, Shell-to-Head, and
Nozzle-to-Vessel Welds,'' 2019 (ML21021A271).
These assessments include flaw tolerance evaluations using
probabilistic fracture mechanics and deterministic fracture
mechanics, and a survey of inspection results from 74 domestic and
international nuclear units. Based on the conclusions of the three
reports, the licensee requested an alternative to the ASME Section
XI examination
[[Page 61426]]
requirements for the subject steam generator and pressurizer welds
in RA-22-0256 and RA-22-0257, respectively.
While the analyses in these technical reports were developed
based on the assumption of 10-year ISI intervals in calculating
failure probability, the staff noted that there are offsetting
factors that account for potential impacts of a 12-year ISI
interval. First, these technical reports and the licensee's
submittal for the authorized alternatives (see ML23256A088 and
ML23264A853) contain generic and plant-specific sensitivity studies
that considered a pre-service inspection followed by various
scenarios for subsequent inservice inspections as well as a plant-
specific limiting scenario, which was not specifically considered in
these EPRI technical reports. The NRC staff finds that these
sensitivity studies bound the impacts of a 12-year ISI interval,
where the examinations may be more spread out in time but not
eliminated. In addition, the analyses in these technical reports
assume the existence of flaws in the subject welds. This is a
conservative assumption, since the examination history of these
locations does not indicate that significant cracking is occurring.
Additionally, specific inspections to be completed by the licensee
at pre-determined years as part of its performance monitoring plan
are outlined in the respective approval letters for RA-22-0256 and
RA-22-0257. The NRC staff noted that these scheduled inspections at
the Duke Energy fleet addressed within RA-22-0256 and RA-22-0257
ensure that no more than 20 years elapses between the performance of
an ASME Code, Section XI, examination for the respective weld/
component and is scheduled to occur regardless of the length of the
ISI interval. Therefore, the NRC staff's basis for this performance
monitoring plan in those alternatives is not impacted by extending
the length of the ISI interval to 12 years. Finally, the licensee
stated that alternatives RA-22-0256 and RA-22-0257, which addressed
the steam generator welds and pressurizer welds, respectively, are
authorized only through the end of the current license. Therefore,
the licensee must reassess this examination requirement at the end
of the license, regardless of the length of the ISI interval.
Accounting for these factors, as discussed above, the NRC staff
finds that the NRC staff's basis for approving the alternatives in
RA-22-0256 and RA-22-0257 is not impacted by extending the length of
the ISI interval to 12 years.
Based on its review of the licensee's analysis of alternatives
in Attachment 2 of the exemption request, the NRC staff concludes
that the exemption would not result in any significant reduction in
the effectiveness of the ISI programs implemented by the licensee at
McGuire Unit 1. Further, based on the above, the NRC staff concludes
that the exemption would not present an undue risk to the public
health and safety.
C. The Exemption Is Consistent With the Common Defense and Security
The requested exemption would allow the licensee to implement
Code Case N-921 after the start dates of the fifth ISI interval at
McGuire Unit 1. The change is administrative in nature, adequately
controlled by the ISI Program criteria and ASME Code requirements
and is not related to security issues. The length of the ISI
interval is also not related to security issues. Thus, NRC staff
determined that the common defense and security is not impacted by
this exemption, and, therefore, the exemption is consistent with the
common defense and security.
D. Special Circumstances
The regulation under 10 CFR 50.12(a)(2) states, in part, that
``[t]he Commission will not consider granting an exemption unless
special circumstances are present,'' and describes, in 10 CFR
50.12(a)(2)(i)-(vi), the conditions under which special
circumstances exist. In the licensee's exemption request submittal
Section III, ``Basis for Approval of Exemption Request,'' item (d),
the licensee stated that three of the six special circumstances
listed in 10 CFR 50.12(a)(2) are present:
(ii) Application of the regulation in the particular
circumstances would not serve the underlying purpose of the rule or
is not necessary to achieve the underlying purpose of the rule.
(iii) Compliance would result in undue hardship or other costs
that are significantly in excess of those contemplated when the
regulation was adopted, or that are significantly in excess of those
incurred by others similarly situated.
(vi) There is present any other material circumstance not
considered when the regulation was adopted for which it would be in
the public interest to grant an exemption.
The NRC staff performed an independent review of the special
circumstances claimed by the licensee.
For the special circumstances in 10 CFR 50.12(a)(2)(ii), the
licensee stated that the purpose of the July 2024 final rule (89 FR
58039) was to identify ASME Code cases that the NRC determined to be
acceptable for use. The licensee noted that NRC's approval of Code
Case N-921 includes a condition that ``This code case can only be
implemented at the beginning of an ISI interval as part of a routine
update of the ISI program.'' The licensee provided the following
support to the claim that application of the regulation would not
serve the underlying purpose of the rule:
The licensee stated that the exemption would not
inhibit the ability of the licensee to comply with the ASME BPV XI
examination distribution requirements.
Table 3 for McGuire Unit 1 of the licensee's submittal
described the new inspection period dates and corresponding
refueling outages.
The licensee evaluated all NRC-authorized alternative
requests in Attachment 2 of the licensee's submittal, consistent
with NRC concerns expressed in the 89 FR 58039 final rule preamble
(see NRC staff's independent review in Section III.B above).
The licensee stated that the site ISI program owners
routinely modify the ISI examination schedule during the ISI
interval due to various reasons, such as evolving availability of
qualified personnel and equipment.
In the 89 FR 58039 final rule preamble, the NRC communicated
that order and predictability of licensee ISI programs is a
paramount consideration. The careful advance planning required by
ASME BPV XI and 10 CFR 50.55a maximizes licensee effectiveness in
successfully executing all ISI requirements. The successful
execution of ISI requirements, in turn, contributes to nuclear
safety by providing a data stream used to continuously evaluate the
structural integrity of safety-related components. The NRC staff
determined that the licensee provided adequate evidence that, if the
NRC staff approves the proposed exemption, the ISI programs at
McGuire Unit 1 will be managed in a manner that promotes order and
predictability.
In the 89 FR 58039 final rule, the NRC added a new condition
requiring that Code Case N-921 be implemented at the start of a new
ISI interval. The basis for the condition is that implementation of
Code Case N-921 in the middle of an ISI interval creates
complications related to existing examination schedules and
alternatives that were approved assuming a 10-year ISI interval. As
discussed above, the licensee demonstrated that no currently
approved alternatives are impacted by extending the length of the
ISI interval to 12 years. Another concern identified by the NRC
staff with allowing mid-cycle implementation of Code Case N-921
involves potential complications of reconciling ISI inspection
schedules to conform with the three 4-year periods specified in Code
Case N-921. As discussed above, the licensee stated that in
anticipation of implementing Code Case N-921, it proactively
adjusted examination schedules accordingly to maintain compliance
with Code Case N-921 periodic distribution requirements. Therefore,
the NRC staff concludes that application of the regulation would not
serve the underlying purpose of the rule because the licensee
demonstrated that mid-cycle implementation of Code Case N-921 will
have no impact on the ISI programs at McGuire Unit 1. Based on the
above, the NRC staff determined that the special circumstances
described in 10 CFR 50.12(a)(2)(ii) are present for the requested
exemption. Since the regulations require that one of the special
circumstances in 10 CFR 50.12(a)(2) be satisfied before NRC may
grant an exemption, the NRC staff did not evaluate the licensee's
additional claims that the special circumstances in 10 CFR
50.12(a)(2)(iii) and (vi) are also applicable.
E. Environmental Considerations
The NRC staff determined that the exemption discussed herein
meets the eligibility criteria for categorical exclusion set forth
in 10 CFR 51.22(c)(25) because (i) there is no significant hazards
consideration; (ii) there is no significant change in the types or
significant increase in the amounts of any effluents that may be
released offsite; (iii) there is no significant increase in
individual or cumulative public or occupational radiation exposure;
(iv) there is no significant construction impact; (v) there is no
significant increase in the potential for or
[[Page 61427]]
consequences from radiological accidents; and (vi) the requirements
from which an exemption is sought are among those identified in 10
CFR 51.22(c)(25)(vi), including requirements of an administrative,
managerial, or organizational nature. Therefore, in accordance with
10 CFR 51.22(b), no environmental impact statement or environmental
assessment need to be prepared in connection with the issuance of
the exemption. The basis for this NRC staff determination is
discussed as follows with an evaluation against each of the
requirements in 10 CFR 51.22(c)(25).
Requirements in 10 CFR 51.22(c)(25)(i)--There is no significant
hazards consideration.
The criteria for determining whether an action involves a
significant hazards consideration are found in 10 CFR 50.92(c). The
exemption only involves an ISI program implementation change, which
is administrative in nature. The exemption does not adversely affect
plant equipment, operation, or procedures. Therefore, there are no
significant hazard considerations, because granting the exemption
would not: (1) involve a significant increase in the probability or
consequences of an accident previously evaluated; or (2) create the
possibility of a new or different kind of accident from any accident
previously evaluated; or (3) involve a significant reduction in a
margin of safety.
Requirements in 10 CFR 51.22(c)(25)(ii)--There is no significant
change in the types or significant increase in the amounts of any
effluents that may be released offsite.
The exemption involves only an ISI program implementation
change, which is administrative in nature, and does not involve any
changes in the types or significant increase in the amounts of any
effluents that may be released offsite.
Requirements in 10 CFR 51.22(c)(25)(iii)--There is no
significant increase in individual or cumulative public or
occupational radiation exposure.
Since the exemption involves only an ISI program implementation
change, which is administrative in nature, it does not contribute to
any significant increase in occupational or public radiation
exposure.
Requirements in 10 CFR 51.22(c)(25)(iv)--There is no significant
construction impact.
Since the exemption involves only an ISI program implementation
change, which is administrative in nature, it does not involve any
construction impact.
Requirements in 10 CFR 51.22(c)(25)(v)--There is no significant
increase in the potential for or consequences from radiological
accidents.
The exemption involves only an ISI program implementation
change, which is administrative in nature and does not impact the
potential for or consequences from accidents.
Requirements in 10 CFR 51.22(c)(25)(vi)(I)--The requirements
from which the exemption is sought involve requirements that are of
an administrative, managerial, or organizational nature.
The exemption involves only an ISI program implementation change
regarding examination scheduling requirements and other requirements
of an administrative, managerial, or organizational nature, because
it is associated with the marginal extension from a 10-year to 12-
year ISI interval.
Based on the above, NRC staff determined that the exemption meet
the eligibility criteria for the categorical exclusion set forth in
10 CFR 51.22(c)(25). Therefore, in accordance with 10 CFR 51.22(b),
no environmental impact statement or environmental assessment need
be prepared in connection with these exemption requests.
IV. Conclusions
Accordingly, the Commission has determined that, pursuant to 10
CFR 50.12, the exemption is authorized by law, will not present an
undue risk to the public health and safety, and is consistent with
the common defense and security. Also, special circumstances are
present. Therefore, the Commission hereby grants Duke Energy
Carolinas, LLC's request for exemption from certain requirements of
10 CFR 50.55a(a)(3)(ii) and 10 CFR 50.55a(y) to allow the
implementation of ASME Code Case N-921 after the start date of the
fifth ISI interval at McGuire Unit 1.
This exemption is effective upon issuance.
Dated: December 23, 2025.
For the Nuclear Regulatory Commission.
/RA/
Aida Rivera-Varona,
Acting Director, Division of Operating Reactor Licensing, Office of
Nuclear Reactor Regulation.
[FR Doc. 2025-24117 Filed 12-30-25; 8:45 am]
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