[Federal Register Volume 91, Number 52 (Wednesday, March 18, 2026)]
[Notices]
[Pages 13078-13081]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-05255]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-413; NRC-2026-1321]


Duke Energy Carolinas, LLC; Catawba 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 August 18, 2025, from Duke 
Energy Carolinas, LLC, to allow the use of AXIOM[supreg] fuel cladding 
at Catawba Nuclear Station, Unit 1. Current NRC regulations limit 
applicability to the use

[[Page 13079]]

of fuel rod cladding with zircaloy or ZIRLOTM.

DATES: The exemption was issued on March 10, 2026.

ADDRESSES: Please refer to Docket ID NRC-2026-1321 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-2025-1321. 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 August 18, 2025, 
is available in ADAMS under Accession Nos. ML25230A072.
     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: March 16, 2026.

    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. 50-413; Duke Energy Carolinas, LLC; Catawba Nuclear Station, 
Unit 1; Exemption

I. Background

    Duke Energy Carolinas, LLC (Duke Energy, the licensee), is the 
holder of Renewed Facility Operating License (RFOL) No. NPF-35 for 
Catawba Nuclear Station, Unit 1 (Catawba). 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.
    Catawba, Unit 1, consists of a pressurized-water reactor located 
at the licensee's site in York County, South Carolina.

II. Request/Action

    By application dated August 18, 2025 Agencywide Documents Access 
and Management System (ADAMS), Accession No. ML25230A072, the 
licensee, pursuant to Title 10 of the Code of Federal Regulations 
(10 CFR), Section 50.12, ``Specific exemptions,'' requested an 
exemption from certain requirements of 10 CFR 50.46, ``Acceptance 
criteria for emergency core cooling systems for light-water nuclear 
power reactors,'' to allow the use of AXIOM[supreg] fuel cladding at 
Catawba.
    The regulations in 10 CFR 50.46 are currently limited in 
applicability to the use of fuel rods with zircaloy or 
ZIRLOTM cladding. The special circumstances associated 
with the exemption request are that application of the regulation in 
this circumstance is not necessary to achieve the underlying purpose 
of the rule.

III. Discussion

    The regulation in 10 CFR 50.46(a)(1)(i) states, in part, that:

each boiling or pressurized light-water nuclear power reactor fueled 
with uranium oxide pellets within cylindrical zircaloy or ZIRLO 
cladding must be provided with an emergency core cooling system 
(ECCS) that must be designed so that its calculated cooling 
performance following postulated loss-of-coolant accidents [LOCA] 
conforms to the criteria set forth in paragraph (b) of this section. 
ECCS cooling performance must be calculated in accordance with an 
acceptable evaluation model and must be calculated for a number of 
postulated loss-of-coolant accidents of different sizes, locations, 
and other properties sufficient to provide assurance that the most 
severe postulated loss-of-coolant, accidents are calculated.
    Since 10 CFR 50.46 specifically refers to fuel with zircaloy or 
ZIRLOTM cladding, its application to fuel clads with 
materials other than zircaloy or ZIRLOTM requires an 
exemption from this section of the regulations.
    The exemption request from the licensee relates solely to the 
types of fuel cladding materials specified in these regulations. As 
written, the regulations specify the use of zircaloy or 
ZIRLOTM cladding. Thus, an exemption to 10 CFR 50.46 is 
necessary to use cladding materials (i.e., AXIOM[supreg]), other 
than zircaloy or ZIRLOTM cladding. The licensee's request 
does not propose to exempt Catawba from any other requirements of 10 
CFR 50.46 regarding acceptance criteria, evaluation model features 
and documentation, reporting of changes or errors, etc.
    Pursuant to 10 CFR 50.12, the NRC may, upon application by any 
interested person or upon its own initiative, grant exemptions from 
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.
    The licensee's proposed exemption request which would permit 
application of the requirements of 10 CFR 50.46 to fuel rods clad 
with AXIOM[supreg] at Catawba identifies, in particular, that the 
special circumstance associated with this exemption request is that 
the application of the regulation in this circumstance is not 
necessary to achieve the underlying purpose of the rule.
    The technical basis for the use of fuel cladding with 
AXIOM[supreg] in Pressurized Water Reactors (PWRs) is documented in 
Topical Report (TR) WCAP-18546NP-A, Revision 0, ``Westinghouse 
AXIOM[supreg] Cladding for Use in Pressurized Water Reactor Fuel,'' 
March 2023 (ML23089A066). This TR describes Westinghouse's 
evaluation for the use of the AXIOM[supreg] alloy in PWR fuel 
assemblies as a replacement for ZIRLOTM and Optimized 
ZIRLOTM. This TR discusses material properties of 
AXIOM[supreg], as well as its behavior under normal operation, 
anticipated transients, and postulated accident conditions.

[[Page 13080]]

    As identified in TR WCAP-18546NP-A, Revision 0, the 
AXIOM[supreg] alloy is a proprietary niobium-bearing variant of 
zirconium. This material also has tin, vanadium, and copper as 
alloying elements. Westinghouse stated that the AXIOM[supreg] alloy 
was developed to provide enhanced performance with respect to 
corrosion, hydrogen pickup, growth, and creep. While demonstrating 
relevant differences in certain material properties and physical 
behavior, TR WCAP-18546NP-A, Revision 0, identifies that the basic 
physical properties of AXIOM[supreg] are similar to 
ZIRLOTM.
    In TR WCAP-18546NP-A, Revision 0, Section C, ``Submittal of 
Topical Report,'' Sections 3.11, ``Post Quench Ductility,'' 3.12, 
``Breakaway Oxidation,'' and 6.2.1.4, ``Fuel Clad Wear,'' 
Westinghouse states the rationale for concluding that each of the 
acceptance criteria in 10 CFR 50.46 is applicable to fuel clad with 
AXIOM[supreg].
    As documented in its safety evaluation on TR WCAP-18546NP-A, 
Revision 0, Section A, the NRC staff concluded that the criteria of 
10 CFR 50.46 are acceptable for the application of AXIOM[supreg] 
cladding. The TR's Section A also states the technical basis for the 
NRC staff's conclusions in support of the AXIOM[supreg] alloy is the 
testing and analysis that Westinghouse had performed. Despite 
finding application of 10 CFR 50.46 to AXIOM[supreg] acceptable from 
a technical perspective, current regulations in 10 CFR 50.46 are 
limited in applicability to the use of fuel rods with zircaloy or 
ZIRLOTM cladding; therefore, an exemption for use of a 
new cladding material (such as AXIOM[supreg]), is required.

A. The Exemption Is Authorized by Law

    The NRC has the authority under 10 CFR 50.12 to grant exemptions 
from the requirements of 10 CFR part 50 if the justification 
demonstrates it is authorized by law. The AXIOM[supreg] fuel that 
will be irradiated at Catawba is clad with a zirconium-based alloy 
that is not expressly within the scope of 10 CFR 50.46. However, the 
NRC staff considers all other aspects of these regulations (e.g., 
acceptance criteria, prescribed methods, reporting requirements) 
applicable to the AXIOM[supreg] cladding material, and the licensee 
states that it will ensure that these regulations are satisfied for 
operation with fuel clad with AXIOM[supreg]. The NRC staff has 
determined that granting the exemption from 10 CFR 50.46 related to 
AXIOM[supreg], which is neither zircaloy nor ZIRLOTM, 
will not result in a violation of the Atomic Energy Act of 1954, as 
amended, or the NRC's regulations. Therefore, the exemption is 
authorized by law.

B. The Exemption Presents No Undue Risk to Public Health and Safety

    In its submittal dated August 18, 2025, the licensee stated,
    The reload evaluations will ensure that acceptance criteria are 
met for future reload cores after the transition to fuel rods clad 
with AXIOM material. Fuel assemblies using AXIOM fuel rod cladding 
will be evaluated using NRC-approved analytical methods and plant-
specific models to address the changes in the cladding material 
properties. The safety analyses for CNS U1 and MNS are supported by 
the applicable site-specific TSs [Technical Specifications]. Reload 
cores are required to be operated in accordance with the operating 
limits specified in the TSs. Thus, the granting of this exemption 
request will not pose an undue risk to public health and safety.
    The NRC staff's previous review of TR WCAP-18546NP-A, Revision 
0, which concerns the properties of the AXIOM[supreg] alloy, 
provides assurance that predicted chemical, thermal, and mechanical 
characteristics of AXIOM[supreg]-alloy cladding are acceptable under 
normal operation, anticipated transients, and postulated accidents. 
The NRC staff finds that by utilizing the methods and properties 
stated in TR WCAP-18546NP-A, Revision 0, Section A, the licensee 
meets the acceptance criteria and analytical methods in 10 CFR 
50.46, and thus, ensures acceptable safety margins for fuel clad 
with AXIOM[supreg] that are consistent with those the Commission has 
established for zircaloy and ZIRLOTM. Catawba's cores 
involving AXIOM[supreg] cladding will continue to be subject to the 
operating limits specified in the technical specifications and core 
operating limits report. The licensee will manage core reloads of 
fuel with AXIOM[supreg] cladding using NRC-approved analytical 
methods and plant TS. Thus, granting this exemption request will not 
pose undue risk to public health and safety.

C. The Exemption Is Consistent With the Common Defense and Security

    The exemption will allow the licensee to use an enhanced fuel 
rod cladding material relative to the zircaloy material for which 
the requirements of 10 CFR 50.46 were originally established. The 
NRC staff concluded in TR WCAP-18546NP-A, Revision 0, Section A, 
that the use of AXIOM[supreg] fuel rod cladding at Catawba will not 
significantly affect plant operations and is, therefore, consistent 
with the common defense and security. Special nuclear material in 
these fuel assemblies will be controlled using NRC-approved 
analytical methods, plant-specific models, and approved station 
procedures. Therefore, the exemption does not involve security 
requirements and does not create a security risk. Therefore, the 
exemption is consistent with the common defense and security.

D. Special Circumstances

    Special circumstances, in accordance with 10 CFR 
50.12(a)(2)(ii), are present whenever 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. The underlying purpose of 10 CFR 50.46 is to 
establish acceptance criteria for ECCS performance.
    The regulations in 10 CFR 50.46 do not explicitly apply to fuel 
clad with AXIOM[supreg]. However, the underlying purpose of 10 CFR 
50.46 is to provide requirements capable of ensuring adequate core 
cooling during and after the most limiting postulated LOCA. As 
discussed above, Westinghouse has demonstrated in an NRC-approved TR 
(i.e. TR WCAP-18546NP-A) that application of the acceptance criteria 
and analytical methods required in 10 CFR 50.46 to fuel cladding 
with AXIOM[supreg] is acceptable. For the maximum local oxidation 
limit in 10 CFR 50.46(b)(2), Westinghouse meets the 17 percent limit 
in the rule for cladding without any hydrogen but further justified 
the use of an alternative limit that the NRC finds acceptable for 
maintaining post quench ductility during a postulated LOCA. The 
licensee stated that the Catawba LOCA analysis for the fuel 
assemblies with AXIOM[supreg] cladding was performed using the Full 
Spectrum LOCA evaluation model and adheres to the limitations of the 
associated topical reports. Therefore, strict application of the 
material-specific requirements for fuel cladding in 10 CFR 50.46 is 
not necessary to achieve the underlying purpose of ensuring adequate 
core cooling in this instance. Furthermore, granting an exemption to 
allow application of the balance of these regulations for fuel 
cladding with AXIOM[supreg] at Catawba, Unit 1, would be consistent 
with the underlying regulatory purpose.

E. Environmental Considerations

    The exemption requested by the licensee includes changes to 
requirements with respect to installation or use of a facility 
component located within the restricted area. The NRC staff 
determined that the exemption meets the eligibility criteria for the 
categorical exclusion set forth in 10 CFR 51.22(c)(9) because the 
granting of this exemption involves: (i) no significant hazards 
consideration, (ii) no significant change in the types or a 
significant increase in the amounts of any effluents that may be 
released offsite, and (iii) no significant increase in individual or 
cumulative occupational radiation exposure. Therefore, in accordance 
with 10 CFR 51.22(b), no environmental impact statement or 
environmental assessment need be prepared in connection with the 
NRC's consideration of this exemption request. The basis for the NRC 
staff's determination of each of the requirements in 10 CFR 
51.22(c)(9) is discussed below.

Requirements in 10 CFR 51.22(c)(9)(i)--There Is No Significant Hazards 
Consideration

    The NRC staff evaluated the issue of no significant hazards 
consideration using the standards described in 10 CFR 50.92(c), as 
presented below:
    1. Does the proposed exemption involve a significant increase in 
the probability or consequences of an accident previously evaluated?
    Response: No.
    The proposed exemption to allow the use of AXIOM[supreg] fuel 
rod cladding does not involve a significant increase in the 
probability or consequences of an accident previously evaluated.
    For the set of previously evaluated accidents, their probability 
is governed by the failure or malfunction of equipment or components 
other than the fuel rod cladding. The fuel rod cladding itself is 
not an accident initiator and does not affect the accident 
probability. Therefore, the change in fuel rod cladding material 
does not affect the probability of previously evaluated accidents. 
The proposed exemption does not involve a significant increase in 
the consequences of

[[Page 13081]]

previously evaluated accidents. This conclusion is demonstrated by 
the analysis submitted by the licensee in support of the proposed 
use of AXIOM[supreg] cladding that the NRC staff has reviewed in 
support of the proposed license amendment. The licensee's analysis 
shows that fuel clad with AXIOM[supreg] material performs comparably 
to fuel cladding materials that have been used previously. This 
satisfies the acceptance criteria in 10 CFR 50.46(b) for the LOCA 
event.
    Therefore, the proposed exemption does not involve a significant 
increase in the probability or consequences of an accident 
previously evaluated.
    2. Does the proposed exemption create the possibility of a new 
or different kind of accident from any accident previously 
evaluated?
    Response: No.
    The use of AXIOM[supreg] fuel rod cladding does not create the 
possibility of a new or different kind of accident from any 
previously evaluated. The fuel rod cladding is not an accident 
initiator. The use of AXIOM[supreg] cladding has been assessed by 
the licensee and vendor, and it has been found to exhibit comparable 
or enhanced behavior relative to the zircaloy and ZIRLOTM 
cladding material specifically identified in 10 CFR 50.46. The NRC 
staff has previously reviewed this information in its safety 
evaluation approving TR WCAP-18546NP-A. Use of Westinghouse fuel 
with AXIOM[supreg] cladding in the Catawba, Unit 1, reactor cores is 
compatible with the plant design and does not introduce any new 
safety functions for plant structures, systems, or components. 
Furthermore, the introduction of AXIOM[supreg] cladding does not 
affect any accident mitigation systems and does not introduce any 
new accident initiation methods.
    Therefore, the proposed exemption do not create the possibility 
of a new or different kind of accident from any previously 
evaluated.
    3. Does the proposed exemption involve a significant reduction 
in a margin of safety?
    Response: No.
    The proposed exemption does not involve a significant reduction 
in the margin of safety. The licensee's analysis of the spectrum of 
postulated LOCA events for fuel rods clad with AXIOM[supreg] 
exhibits results comparable to those for the fuel currently in use 
at Catawba for the small-break and the large-break LOCA events. 
Furthermore, the fuel vendor has generically evaluated the 
performance of AXIOM[supreg] cladding relative to the zircaloy 
cladding specifically identified in 10 CFR 50.46. The vendor 
concluded that the performance of the AXIOM[supreg] cladding 
material is quite similar to or enhanced relative to the 
ZIRLOTM cladding material. The NRC staff has performed a 
review of these conclusions and documented in its safety evaluation 
on TR WCAP-18546NP-A that the AXIOM[supreg] material properties and 
mechanical design methodology are in accordance with applicable 
regulations and regulatory guidance.
    Therefore, the proposed exemption does not involve a significant 
reduction in a margin of safety.
    The NRC staff concludes that the proposed exemption presents no 
significant hazards consideration under the standards set forth in 
10 CFR 50.92(c), and, accordingly, a finding of no significant 
hazards consideration is justified (i.e., satisfies the provision of 
10 CFR 51.22(c)(9)(i)).

Requirements in 10 CFR 51.22(c)(9)(ii)--There Is No Significant Change 
in the Types or Significant Increase in the Amounts of Any Effluents 
That May Be Released Offsite

    The proposed exemption would allow the use of AXIOM[supreg] fuel 
rod cladding material in the reactors. AXIOM[supreg] cladding has 
similar properties and performance characteristics as the currently 
licensed optimized ZIRLOTM cladding. Therefore, the use 
of the AXIOM[supreg] fuel rod cladding material will not 
significantly change the types of effluents, or significantly 
increase the amount of effluents that may be released offsite. 
Therefore, the provision of 10 CFR 51.22(c)(9)(ii) is satisfied.

Requirements in 10 CFR 51.22(c)(9)(iii)--There Is No Significant 
Increase in Individual or Cumulative Occupational Radiation Exposure

    The proposed exemption would allow the use of the AXIOM[supreg] 
fuel rod cladding material in the reactors. AXIOM cladding has 
similar properties and performance characteristics as the currently 
licensed optimized ZIRLO cladding. Therefore, the use of the 
AXIOM[supreg] fuel rod cladding material will not significantly 
increase individual occupational radiation exposure or significantly 
increase cumulative occupational radiation exposure. Therefore, the 
provision of 10 CFR 51.22(c)(9)(iii) is satisfied.
    The NRC staff concludes that the proposed exemption meets the 
eligibility criteria for the categorical exclusion set forth in 10 
CFR 51.22(c)(9). Therefore, in accordance with 10 CFR 51.22(b), no 
environmental impact statement or environmental assessment need be 
prepared in connection with the NRC's proposed granting of this 
exemption.

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 an exemption from the specific 
requirements of 10 CFR 50.46 for use of AXIOM[supreg] fuel rod 
cladding.
    This exemption is effective upon issuance.

    Dated: March 10, 2026.

    For the Nuclear Regulatory Commission.

    /RA/

Aida Rivera-Varona,

Acting Director Division of Operating Reactor Licensing, Office of 
Nuclear Reactor Regulation.

[FR Doc. 2026-05255 Filed 3-17-26; 8:45 am]
BILLING CODE 7590-01-P