[Federal Register Volume 91, Number 81 (Tuesday, April 28, 2026)]
[Notices]
[Pages 22870-22874]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-08219]
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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 72-1031, 50-413, and 50-414; NRC-2026-1486]
Duke Energy Carolinas, LLC; Catawba Nuclear Station, Units 1 and
2; Independent Spent Fuel Storage Installation; Exemption
AGENCY: Nuclear Regulatory Commission.
ACTION: Notice; issuance.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) issued an
exemption to Duke Energy Carolinas, LLC (Duke), permitting Catawba
Nuclear Station (CNS) to maintain one loaded transportable storage
canister (TSC) and to load nine new TSCs in the MAGNASTOR[supreg]
storage system at the CNS Units 1 and 2 independent spent fuel storage
installation, beginning July 6, 2026, in a storage condition where the
terms, conditions, and specifications in the Certificate of Compliance
No. 1031, Amendment No. 15, are not met.
DATES: The exemption was issued on April 21, 2026.
ADDRESSES: Please refer to Docket ID NRC-2026-1486 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-2026-1486. 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 ADAMS accession number for each document
referenced (if it is available in ADAMS) is provided the first time
that it is mentioned in this document.
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-Chau Nguyen, Office of Nuclear
Material Safety and Safeguards, U.S. Nuclear Regulatory Commission,
Washington, DC 20555; telephone: 301-415-0262; email: [email protected].
SUPPLEMENTARY INFORMATION: The text of the exemption is attached.
Authority: 42 U.S.C. 2011 et seq.
Dated: April 24, 2026.
For the Nuclear Regulatory Commission.
Yoira Diaz-Sanabria,
Chief, Storage and Transportation Licensing Branch, Division of Fuel
Management, Office of Nuclear Material Safety, and Safeguards.
Attachment--Exemption
NUCLEAR REGULATORY COMMISSION
Docket Nos. 72-1031, 50-413, and 50-414
Duke Energy Carolinas, LLC Catawba Nuclear Station, Units 1 and 2
Independent Spent Fuel Storage Installation
I. Background
Duke Energy Carolinas, LLC (Duke) is the holder of Facility
Operating
[[Page 22871]]
Licenses Nos. NPF-035 and NPF-052, which authorize operation of the
Catawba Nuclear Station (CNS) in South Carolina, pursuant to part 50 of
title 10 of the Code of Federal Regulations (10 CFR), ``Domestic
Licensing of Production and Utilization Facilities.'' The licenses
provide, among other things, that the facility is subject to all rules,
regulations, and orders of the U.S. Nuclear Regulatory Commission (NRC)
now or hereafter in effect.
Consistent with 10 CFR part 72, subpart K, ``General License for
Storage of Spent Fuel at Power Reactor Sites,'' a general license is
issued for the storage of spent fuel in an independent spent fuel
storage installation (ISFSI) at power reactor sites to persons
authorized to possess or operate nuclear power reactors under 10 CFR
part 50. Duke is authorized to operate nuclear power reactors under 10
CFR part 50 and holds a 10 CFR part 72 general license for storage of
spent fuel at the CNS ISFSI. Under the terms of the general license,
Duke stores spent fuel at its CNS ISFSI using the MAGNASTOR[supreg]
storage system in accordance with Certificate of Compliance (CoC) No.
1031, Amendment No. 15.
II. Request/Action
By letter dated March 19, 2026 (Agencywide Documents Access and
Management System [ADAMS] Accession Nos ML26078A371), Duke requested an
exemption from the requirements of 10 CFR 72.212(a)(2), 72.212(b)(3),
72.212(b)(5)(i), 72.212(b)(11), 72.214, 72.154(b), and 72.174 that
require CNS to comply with the terms, conditions, and specifications of
CoC No. 1031, Amendment No. 15 (ML25112A096). If approved, Duke's
exemption request would accordingly allow CNS to maintain one loaded
and to load nine transportable storage canisters (TSCs) in the
MAGNASTOR[supreg] storage system, beginning July 6, 2026, and thus, to
load the systems in a storage condition where the terms, conditions,
and specifications in CoC No. 1031, Amendment No. 15, are not met.
Duke currently uses the MAGNASTOR[supreg] storage system under CoC
No. 1031, Amendment No. 15, for dry storage of spent nuclear fuel in
TSC at the CNS ISFSI. The MAGNASTOR[supreg] storage system CoC provides
the requirements, conditions, and operating limits necessary for use of
the system to store spent fuel. In regard to neutron absorber
materials, compliance with specifications such as minimum effective
areal density (75% for Boral and 90% for borated aluminum/MMC) and a
minimum \10\B loading of 0.040 g/cm\2\, as outlined in the
MAGNASTOR[supreg] technical specifications and final safety analysis
report (FSAR), is verified through neutron transmission testing and
acceptance inspections to ensure compliance with the CoC.
NAC International (NAC), the vendor of the MAGNASTOR[supreg]
system, reported a fabrication deficiency on September 10, 2025
(ML25253A488) and provided an update on December 30, 2025
(ML25364A119), regarding certain neutron absorber panels supplied to
NAC by 3M. These neutron absorber panels, installed by NAC in the
MAGNASTOR[supreg] storage casks for use at the CNS ISFSI, did not meet
requirements of the MAGNASTOR[supreg] technical specifications and
FSAR. The deficiency occurred because test coupons were cut from non-
approved areas of master sheets, violating established process
controls. This error resulted in some coupons failing to meet the
required \10\B areal density, impacting 39 panels (three per sheet
across 13 sheet). These panels are associated with several TSCs at
Duke's Catawba site, including one loaded and nine unloaded TSCs.
The impacted TSCs include one already loaded, MAG-TSC-418-158, and
nine that Duke plans to load: MAG-TSC-418-155; MAG-TSC-418-156; MAG-
TSC-418-157; MAG-TSC-418-159; MAG-TSC-418-160; MAG-TSC-418-161; MAG-
TSC-418-162; MAG-TSC-418-166; and MAG-TSC-418-167. Duke plans to load
two of these TSCs in July 2026: MAG-TSC-418-155 and MAG-TSC-418-156. As
explained by Duke, the remaining seven impacted TSCs for upcoming
campaigns, already purchased and scheduled for loading beyond 2026, are
included in the scope of the request.
Duke submitted this exemption request to allow for the continued
storage of one already loaded TSC, and future loading of nine TSC
beginning on July 6, 2026, in the MAGNASTOR[supreg] storage system at
the CNS ISFSI, even though, because of the neutron absorber panels'
fabrication deficiency, the terms, conditions and specifications of the
CoC will not be met.
III. Discussion
Pursuant to 10 CFR 72.7, ``Specific exemptions,'' the Commission
may, upon application by any interested person or upon its own
initiative, grant such exemptions from the requirements of the
regulations of 10 CFR part 72 as it determines are authorized by law
and will not endanger life or property or the common defense and
security and are otherwise in the public interest.
A. The Exemption Is Authorized by Law
This exemption would allow Duke to maintain loaded and to load TSC
in the MAGNASTOR[supreg] storage system at its CNS ISFSI, beginning
July 6, 2026, in a storage condition where the terms, conditions, and
specifications in CoC No. 1031, Amendment No. 15, are not met. Duke is
requesting an exemption from the provisions in 10 CFR part 72 that
require the licensee to comply with the terms, conditions, and
specifications of the CoC for the approved cask model it uses. Section
72.7 allows the NRC to grant exemptions from the requirements of 10 CFR
part 72. This authority to grant exemptions is consistent with the
Atomic Energy Act of 1954, as amended, and is not otherwise
inconsistent with NRC's regulations or other applicable laws.
Additionally, no other law prohibits the activities that would be
authorized by the exemption. Therefore, the NRC concludes that there is
no statutory prohibition on the issuance of the requested exemption,
and the NRC is authorized to grant the exemption by law.
B. The Exemption Will Not Endanger Life or Property or the Common
Defense and Security
This exemption would allow Duke to maintain one loaded and to load
nine TSCs in the MAGNASTOR[supreg] storage system at its CNS ISFSI,
beginning July 6, 2026, in a storage condition where the terms,
conditions, and specifications in CoC No. 1031, Amendment No. 15, are
not met. Minor manufacturing variations in neutron absorber panels,
caused by misalignment during coupon cutting, affected ten TSCs, with
three master sheets slightly below the minimum \10\B areal density
requirement of 0.040 g/cm\2\. NAC performed a safety assessment to
evaluate the reduced \10\B conditions. In support of this exemption
request, Duke asserts that issuance of the exemption would not endanger
life or property or the common defense and security because NAC's
safety assessment demonstrates that the reduced \10\B areal density
results in a change in reactivity of less than 2 [Delta]k/[sigma],
which is not statistically significant, and the neutron absorber
continues to perform within the licensing basis safety margins. TSC
incorporates a welded closure to prevent the loss of contents and
ensure public health and safety during long-term storage. When
installed in a storage cask, the TSC benefits from structural
protection, radiation shielding, and natural convection cooling, while
the cask also provides environmental protection under adverse
conditions. NAC's
[[Page 22872]]
calculation further demonstrates using the licensing basis method of
evaluation and the lowest measured \10\B areal densities from the
coupons cut in the wrong area of the master sheet, the ``reduced
absorber sheet'' \10\B has a less than 2 [Delta]k/[sigma], effect on
system reactivity which is not statistically significant. NAC's
calculation shows the lower neutron absorber result produces similar
system reactivities for each fuel assembly and will therefore have the
same relative effect.
Additionally, technical specifications require surface dose rate
measurements before storage operations to ensure compliance with
regulatory limits and detect potential misloads, providing an extra
layer of safety assurance. NAC's analysis confirmed that even with
reduced neutron absorber levels, the system remains subcritical under
all analyzed conditions. NAC determined there are no impacts to thermal
performance, structural integrity, shielding effectiveness, or
confinement boundaries, and site boundary doses remain within
regulatory limits. In addition, the combined radiation dose from all
storage systems located at the CNS ISFSI will remain within the annual
dose limits established in 10 CFR 72.104(a) for normal operations and
anticipated operational occurrences and will also remain below the
limits of 10 CFR 72.106 for design-basis accident conditions. Duke
notes that the requested exemption does not affect any physical
security requirements, nor does it impact the protection or defensive
capabilities of the CNS ISFSI.
The NRC staff reviewed Duke's exemption request and concluded, as
discussed below, that the proposed exemption from certain requirements
of 10 CFR part 72 will not cause CoC No. 1031 to encounter conditions
beyond those for which it has already been evaluated and demonstrated
to meet the applicable safety requirements in 10 CFR part 72. The
request does not change the fundamental design, components, or safety
features of the storage system.
The staff's evaluation focused on the application and those
calculations and analyses submitted with the application. The staff
followed the guidance in NUREG-2215 to complete its safety evaluation.
The NRC's staff evaluation includes criticality, materials, and
operations safety areas, which the staff determined are the relevant
technical disciplines affected by this exemption.
Criticality Evaluation
In support of its exemption request, Duke asserts that issuance of
the exemption would not endanger life or property, or the common
defense or security. Duke based this conclusion on NAC's safety
assessment provided in Calculation 12418-6002, ``MAGNASTOR Criticality
Evaluation for Duke Catawba Reduced Absorber Sheet B-10 Content,''
which evaluated the effect of reduced \10\B areal density in certain
neutron absorber sheets. NAC's analysis demonstrates that, when
applying the licensing-basis method of evaluation and using the lowest
measured \10\B areal densities obtained from coupons cut from an
incorrect portion of the master sheet, the resulting change in
reactivity is less than 2[Delta]k/[sigma]. NAC concluded, and NRC staff
confirmed in its own safety evaluation, that this change is not
statistically significant. NAC's calculation further shows that the
reduced absorber sheet \10\B values produce system reactivities
comparable to those obtained using fully compliant absorber material,
and therefore the reduced boron content yields no meaningful change in
relative reactivity.
NRC staff notes that the MAGNASTOR[supreg] system design basis
requires a minimum neutron absorber content of 0.040 g/cm\2\ \10\B. The
reduced \10\B content values used in the analysis were derived from
destructive testing of three coupons taken from the affected master
sheets. For coupon C89842, two absorber panels installed in MAG-TSC-
418-167 had a minimum measured \10\B areal density of 0.03910 g/cm\2\.
Coupons C89789-1 and C89810-1 showed minimum measured values of 0.03994
g/cm\2\ and were used in the remaining affected TSCs. Although these
values are slightly below the nominal \10\B requirement, staff noted
that the measurements trend toward the design basis 0.040 g/cm\2\
specification. Due to limitations arising from the cutting pattern of
the master sheet, insufficient material remained to definitively
confirm compliance. Accordingly, NAC performed a criticality analysis
using the measured reduced boron values for each affected TSC.
For the two absorber sheets affected in MAG-TSC-418-167, NAC
modified the licensing-basis MCNP input files to explicitly model the
reduced \10\B areal density of 0.03910 g/cm\2\, as described in Figure
4-1 of the calculation package, after applying the MAGNASTOR[supreg]
design assumption that credits only 90 percent of the nominal boron
content as illustrated in Figure 6-1. For the remaining nine TSCs, NAC
modeled all absorber sheets using the reduced 10B value of 0.03994 g/
cm\2\, adjusting only the absorber material density and composition.
The NRC staff reviewed the exemption request, including NAC's
criticality evaluation for the MAGNASTOR[supreg] TSCs containing
absorber sheets with reduced \10\B content. Based on the information
provided, the staff finds that NAC appropriately modified the
licensing-basis analyses to account for the reduced boron areal density
in the affected absorber panels. NAC demonstrates, and the staff
confirms, that all ten affected TSCs remain adequately subcritical. The
changes in reactivity resulting from the reduced boron content are less
than 2[Delta]k/[sigma] for all evaluated configurations, which the
staff concludes is not statistically significant. Considering the
limited number of TSCs affected, the conservatism inherent in the
MAGNASTOR[supreg] Amendment No. 15 design-basis analyses, and the
results of NAC's revised evaluations, the staff finds, with reasonable
assurance, that the affected MAGNASTOR[supreg] TSCs meet the
criticality safety requirements of 10 CFR part 72.
Materials Evaluation
In support of its exemption request, Duke cited NAC's analysis
which showed that even when the material properties criteria for the
borated metal matrix composite neutron absorbing panels at issue is
altered to accommodate the fabrication deficiency, materials safety is
maintained. NAC identified 13 master sheets (39 panels in total) that
were not fabricated in accordance with their prescribed processes,
resulting in ten TSCs being fabricated with certain panels that may not
meet the 0.04 g/cm\2\ required \10\B minimum actual areal density, as
described in Table 8.8-1 of the FSAR. NAC performed additional neutron
attenuation testing of affected neutron panels, as documented in NAC
Surveillance Report 25-S-21. As a result of the findings of this
additional testing, NAC proposed using the following \10\B areal
density values for demonstrating the acceptability of the fabricated
neutron absorbing panels in their criticality evaluation of these ten
TSCs:
Two sheets in the basket at 0.03910 g/cm\2\ boron 10.
All sheets in the basket at 0.03994 g/cm\2\ boron 10.
The NRC staff reviewed the testing methodology and results in NAC
Surveillance Report 25-S-21 and determined that these values of \10\B
areal density are bounding of the results and are appropriate for the
evaluation of the affected TSCs. Additionally, the staff reviewed the
exemption request and
[[Page 22873]]
determined that granting the request would not impact the material
properties or critical design characteristics of the borated metal
matrix composite neutron absorbing panels. Per the above discussion,
the NRC staff finds, with reasonable assurance, the material properties
of the neutron absorbing materials in the exemption request acceptable
and that the affected MAGNASTOR[supreg] TSCs meet the materials safety
requirements of 10 CFR part 72.
Operations
The NRC staff evaluated whether the identified condition affects
operating procedures associated with fuel loading and storage
operations. The exemption request does not propose changes to loading
procedures, fuel selection criteria, loading configurations, or
administrative controls credited in the FSAR. In addition, the
exemption does not change the configuration or function of the neutron
absorber panels within the fuel basket.
Based on the information provided by Duke in the exemption request
and supporting correspondence, certain neutron absorber panel material
verification activities did not fully demonstrate conformance with the
specified boron content requirements. Specifically, NAC indicated that
some test coupons used for boron content verification were obtained
from non-representative locations within absorber panel sheets and that
certain supplier oversight activities associated with the testing
laboratory did not fully meet established quality assurance program
requirements. The staff notes that this condition represents a
fabrication and procurement control issue rather than a loss of safety
function.
Based on its review, the NRC staff concludes that the identified
condition does not necessitate changes to the procedures used for
loading or storing spent fuel in the affected TSCs. Considering the
maintained margin to subcriticality demonstrated in the supporting
analyses, along with the corrective actions described by NAC, the staff
finds that there is reasonable assurance that granting the exemption
will continue to support safe operation of the facility and compliance
with applicable regulatory requirements.
C. The Exemption Is Otherwise in the Public Interest
The proposed exemption would allow the already loaded TSC in the
MAGNASTOR[supreg] storage system to remain in storage at the Catawba
ISFSI and would authorize future use of the nine affected TSCs in
planned loading campaigns, beginning July 6, 2026, in storage
conditions where the terms, conditions, and specifications in CoC No.
1031, Amendment No. 15, are not met. According to Duke, the exemption
is in the public interest because it would maintain the safe, passive
dry-storage configuration, and avoid unnecessary fuel handling.
Duke states that dry storage provides a passive, stable inherently
safe configuration, and leaving the already loaded canister undisturbed
eliminates any additional fuel-handling risks, aligning with the public
interest in minimizing operational dose and fuel handling events. Duke
explains that approval of this exemption prevents unnecessary unloading
and reloading of spent fuel, which would increase radiation exposure
and operational risk without a corresponding safety benefit. It also
supports timely fuel offload from the reactor, ensuring continued safe
operation.
Duke states that timely transfers of spent fuel to dry storage
supports timely transfers of spent fuel from the spent fuel pool (SFP),
which maintains adequate SFP capacity, supports heat-load management on
the cooling system, and limits additional fuel-handling operations that
could increase worker dose or the potential for handling events.
Maintaining SFP margin ensures Duke can offload the reactor when needed
and conduct refueling activities efficiently, allowing the reactor's
continued safe operation.
Duke further explains that without the ability to use the
identified canisters, upcoming loading campaigns could be delayed or
disrupted and the margin to SFP margin in the CNS SFP would be
significantly reduced, creating operational challenges in managing SFP
inventory and conducting safe fuel-handling operations during outages.
Loading campaigns rely on limited specialized personnel and equipment
scheduled years in advance. As Duke explains, these specialty resources
support multiple competing activities and priorities. The available
windows to complete cask loading campaigns are limited and delays have
a cascading impact on other scheduled activities. Delays could have
broader operational impacts and thus impair future reactor safety to
the detriment of the public interest.
Duke states that if the exemption is not approved, the loading
campaign would need to be rescoped as designed, because this would
constitute a substantial change in planned loading sequence affecting
the overall campaign, the SFP configuration, and associated analyses.
This would interfere with the safe operation of the reactor.
For the reasons described by Duke in the exemption request, the NRC
staff agree that it is in the public interest to grant the exemption.
If the exemption is not granted, for the already loaded TSC, Duke would
be required to unload and reload the spent fuel into a new TSC to bring
it in compliance with the CoC, creating safety risks. For the nine TSCs
scheduled for future loading, in order to comply with the CoC, Duke
would have to keep spent fuel in the spent fuel pool if it is not
permitted to use the MAGNASTOR[supreg] storage system during loading
and transport operations, thus impacting Duke's ability to effectively
manage the SFP margin, pool capacity and reactor fuel offloading.
Moreover, should spent fuel pool capacity be reached, the ability to
refuel the operating reactor unit is challenged. The inability to load
the TSCs could also challenge spent fuel heat removal and impact the
availability of the specialized resources and equipment which is
planned years in advance and needed to support competing fuel loading
and operational activities at CNS, including spent fuel pool clean-up
and refueling outages. Thus, if the nine impacted TSCs could not load,
there may be consequences impacting safe, continued reactor operations
to the detriment of the public interest.
Therefore, for these reasons, the staff concludes that granting the
exemption is in the public interest.
Environmental Consideration
The NRC staff also considered whether there would be any
significant environmental impacts associated with the exemption. For
this proposed action, the NRC staff performed an environmental
assessment pursuant to 10 CFR 51.30, ``Environmental Assessment.'' The
environmental assessment concluded that the proposed action would not
significantly impact the quality of the human environment. The NRC
staff concluded that the proposed action would not result in any
changes in the types or amounts of any radiological or non-radiological
effluents that may be released offsite, and there would be no
significant increase in occupational or public radiation exposure
because of the proposed action. The environmental assessment and the
finding of no significant impact was published on April 21, 2026 (91 FR
21330).
IV. Conclusion
Based on these considerations, the NRC has determined that,
pursuant to 10 CFR 72.7, the exemption is
[[Page 22874]]
authorized by law, will not endanger life or property or the common
defense and security, and is otherwise in the public interest.
Therefore, the NRC grants Duke an exemption from the requirements of
Sec. Sec. 72.212(a)(2), 72.212(b)(3), 72.212(b)(5)(i), 72.212(b)(11),
and 72.214, 72.154(b), and 72.174 with respect to the continued storage
of MAG-TSC-418-158 and future loading of MAG-TSC-418-155, 156, 157,
159, 160, 161, 162, 166, and 167 in the MAGNASTOR[supreg] storage
system beginning in July 6, 2026.
This exemption is effective upon issuance.
Dated: April 21, 2026.
For the Nuclear Regulatory Commission.
/RA/
Yoira Diaz Sanabria,
Chief, Storage and Transportation Licensing Branch, Division of Fuel
Management, Office of Nuclear Material Safety, and Safeguards.
[FR Doc. 2026-08219 Filed 4-27-26; 8:45 am]
BILLING CODE 7590-01-P