[Federal Register Volume 88, Number 150 (Monday, August 7, 2023)]
[Notices]
[Pages 52216-52218]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-16755]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-425; NRC-2023-0092]


Southern Nuclear Operating Company; Vogtle Electric Generating 
Plant, Unit 2

AGENCY: Nuclear Regulatory Commission.

ACTION: Exemption; issuance.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) has issued an 
exemption in response to a request dated June 30, 2022, as supplemented 
by letters dated September 13, 2022, and January 20, and May 5, 2023, 
from Southern Nuclear Operating Company to allow the use of AXIOM fuel 
rod cladding material in lead test assemblies 7ST1, 7ST2, 7ST3, and 
7ST4, for up to two cycles of operation at Vogtle Electric Generating 
Plant, Unit 2.

DATES: The exemption was issued on August 1, 2023.

ADDRESSES: Please refer to Docket ID NRC-2023-0092 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-2023-0092. Address 
questions about Docket IDs in Regulations.gov to Stacy Schumann; 
telephone: 301-415-0624; email: [email protected]. For technical 
questions, contact the individual listed

[[Page 52217]]

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 Web-based ADAMS 
Search.'' For problems with ADAMS, please contact the NRC's Public 
Document Room (PDR) reference staff at 1-800-397-4209, 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 G. Lamb, Office of Nuclear 
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 
20555-0001; telephone: 301-415-3100; email: [email protected].

SUPPLEMENTARY INFORMATION: The text of the exemption is attached.

    Dated: August 2, 2023.
    For the Nuclear Regulatory Commission.
John G. Lamb,
Senior Project Manager, Licensing Plant Branch 2-1, Division of 
Operating Reactor Licensing, Office of Nuclear Reactor Regulation.

Attachment--Exemption from 10 CFR part 50, Appendix K, for Vogtle, Unit 
2, to Allow the Use of AXIOM Fuel Rod Cladding Material in Lead Test 
Assemblies.

NUCLEAR REGULATORY COMMISSION

Docket No. 50-425

Southern Nuclear Operating Company

Vogtle Electric Generating Plant, Unit 2

Exemption

I. Background

    Southern Nuclear Operating Company (SNC, the licensee) is the 
holder of Facility Operating License No. NPF-81, for the Vogtle 
Electric Generating Plant (Vogtle), Unit 2. The license provides, 
among other things, that the license is subject to all rules, 
regulations, and orders of the Commission now or hereafter in 
effect.
    The Vogtle, Unit 2, consists of a pressurized-water reactor 
located at the licensee's site in Burke County, Georgia.

II. Request/Action

    By letter dated June 30, 2022 (Agencywide Documents Access and 
Management System (ADAMS) Accession No. ML22181B156), as 
supplemented by letters dated September 13, 2022 (ML22256A198), 
January 20, 2023 (ML23020A148), and May 5, 2023 (ML23125A269), SNC 
requested an exemption to title 10 of the Code of Federal 
Regulations (10 CFR), part 50, appendix K, ``ECCS [Emergency Core 
Cooling Systems] Evaluation Models,'' for Vogtle, Unit 2.
    Specifically, SNC requested an exemption from 10 CFR part 50, 
appendix K to allow the use of AXIOM fuel rod cladding material in 
lead test assemblies (LTAs) 7ST1, 7ST2, 7ST3, and 7ST4 for up to two 
cycles of operation at Vogtle, Unit 2.
    The regulation at 10 CFR 50.46(a)(1)(ii) provides that, 
``[a]lternatively, an ECCS evaluation model may be developed in 
conformance with the required and acceptable features of Appendix K 
ECCS Evaluation Models.'' Appendix K of 10 CFR part 50 requires, in 
paragraph I.A.5, that ``[t]he rate of energy release, hydrogen 
generation, and cladding oxidation from the metal/water reaction 
shall be calculated using the Baker-Just equation (Baker, L., Just, 
L.C., `Studies of Metal Water Reactions at High Temperatures, III. 
Experimental and Theoretical Studies of the Zirconium Water 
Reaction,' ANL-6548, page 7, May 1962).'' The regulations make no 
provisions for use of fuel rods clad in a material other than 
zircaloy or ZIRLO. Since the Baker-Just equation presumes the use of 
zircaloy or ZIRLO clad fuel, strict application of this provision of 
the rule would not permit use of the equation for AXIOM cladding for 
determining acceptable fuel performance.

III. Discussion

    Pursuant to 10 CFR 50.12, the NRC may, upon application by any 
interested person or upon its own initiative, grant exemptions from 
the requirements of 10 CFR part 50, including 10 CFR part 50, 
appendix K when: (1) the exemptions are authorized by law, will not 
present an undue risk to the public health or safety, and are 
consistent with the common defense and security; and (2) when 
special circumstances are present. Under 10 CFR 50.12(a)(2), special 
circumstances include, among other things, when application of the 
specific regulation in the particular circumstances would not serve, 
or is not necessary to achieve, the underlying purpose of the rule.

A. The Exemption is Authorized by Law

    In accordance with 10 CFR 50.12, the NRC may grant an exemption 
from the requirements of 10 CFR part 50 if the exemption is 
authorized by law. The exemption requested in this instance is 
authorized by law, because no other prohibition of law exists to 
preclude the activities which would be authorized by the exemption.
    This exemption would allow the licensee to insert four LTAs 
containing AXIOM fuel rod cladding that is neither Zircaloy nor 
ZIRLO, which are the cladding materials contemplated by 10 CFR 
50.46(a)(1)(i). Selection of a specific cladding material in 10 CFR 
50, appendix K was at the discretion of the Commission consistent 
with its statutory authority. No statute required the NRC to adopt 
this specification. As stated above, 10 CFR 50.12 allows the 
Commission to grant exemptions from the requirements of 10 CFR part 
50. The NRC staff has determined that granting of an exemption from 
10 CFR part 50, appendix K related to AXIOM fuel rod cladding, which 
is neither Zircaloy nor ZIRLO, will not result in a violation of the 
Atomic Energy Act of 1954, as amended, or the Commission's 
regulations. Therefore, the exemption is authorized by law.

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

    SNC stated the following in its letter dated June 30, 2022:
    The Vogtle reactors each contain 193 fuel assemblies. Each 
assembly consists of a matrix of 264 Zircaloy, ZIRLO[supreg]\[TM]\, 
or Optimized ZIRLO[supreg]\[TM]\ clad fuel rods with an initial 
composition of natural or slightly enriched uranium dioxide (UO2) as 
fuel material, not to exceed 5 wt% [weight-percent] enrichment. The 
proposed change is to load four LTAs with advanced ATF [accident 
tolerant fuel] features, including ADOPT fuel [2], AXIOM cladding 
[3], chromium coating, and four rods per LTA with up to 6 wt% 
enrichment, in limiting core locations for up to two cycles of 
operation.
    This exemption will not present an undue risk to public health 
and safety. Reload evaluations ensure that acceptance criteria are 
met for the insertion of LTAs with fuel rods clad with AXIOM 
material. Due to similarities in the composition of the AXIOM alloy 
and the Optimized ZIRLO and standard ZIRLO alloys, fuel assemblies 
using AXIOM fuel rod cladding are evaluated using plant-specific 
models to address the changes in the cladding material properties. 
The LOCA [loss-of-coolant accident] safety analyses for VEGP [Vogtle 
Electric Generating Plant] are supported by the applicable site-
specific Technical Specifications (TS). Reload cores are required to 
be operated in accordance with the operating limits specified in the 
TS. Thus, the granting of this exemption request will not pose an 
undue risk to public health and safety.
    Based upon the limited number of AXIOM clad fuel rods, the 
safeguards in place which would detect anomalous behavior, the use 
of NRC-approved models to ensure that all design criteria remain 
satisfied, and the requirement to operate the Vogtle, Unit 2, core 
within TS limits, the NRC staff finds the four LTAs acceptable for 
Vogtle, Unit 2. In conclusion, the NRC staff finds that the 
requested exemption does not result in any undue risk to the public 
health and safety, because (1) the NRC staff has determined that the 
use of AXIOM cladding in this application is acceptable because 
there is no expected loss of safety margin associated with the use 
of AXIOM cladding in the pertinent limiting core locations,\1\ (2) 
the

[[Page 52218]]

NRC staff has determined that SNC's evaluation of coated cladding 
emissivity and its effect on loss-of-coolant accident peak clad 
temperature (PCT) is acceptable, because data was provided 
demonstrating no significant difference in PCT, (3) the NRC staff 
has determined that SNC's evaluation of ADOPT fuel pellets in the 
LTAs is acceptable, because there will be no reduction in fuel 
performance and the applicable limitations and conditions have been 
implicitly addressed, and (4) the number of rods with enrichments 
exceeding five weight-percent Uranium 235 is small compared to the 
total number of fuel rods. See the NRC safety evaluation 
(ML23093A028) for further details.
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    \1\ As stated in the May 5, 2023, supplement, the LTAs will not 
be placed in core regions that have been shown to be limiting with 
respect to the control rod ejection analysis.
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C. The Exemption Is Consistent With the Common Defense and Security

    The proposed exemption would allow the use of four LTAs with a 
variant cladding material. This change to the plant core 
configuration has no impact on security issues. Special nuclear 
material in the LTAs will continue to be handled and controlled in 
accordance with applicable regulations. Therefore, the common 
defense and security is not impacted by this exemption.

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 part 50, 
Appendix K, Section I.A.5 is to establish acceptance criteria for 
ECCS performance. In the safety evaluation (SE) contained in 
ML23093A028 for the license amendment request, the NRC staff 
evaluated for Vogtle, Unit 2, four LTAs that demonstrated the 
acceptability of the AXIOM cladding under LOCA conditions. The 
unique features of the LTAs were evaluated for effects on the LOCA 
analyses. The results showed that the LTAs would not adversely 
affect ECCS performance. Since the Baker-Just equation presumes the 
use of zircaloy or ZIRLO clad fuel, strict application of this 
provision of the rule would not permit use of the equation for AXIOM 
cladding for determining acceptable fuel performance. Therefore, the 
NRC staff concludes that application of the cladding material 
applicability requirements of the Baker-Just equation of 10 CFR part 
50, Appendix K in this particular circumstance is not necessary for 
the licensee to achieve the underlying purpose of the rule.

E. Environmental Considerations

    With respect to its impact on the quality of the human 
environment, the NRC has determined that the issuance of the 
exemption discussed herein meets the eligibility criteria for 
categorical exclusion set forth in 10 CFR 51.22(c)(9). The NRC 
staff's determination that all of the criteria for this categorical 
exclusion are met is as follows:
    The regulation 10 CFR 51.22(c)(9) states:
    Issuance of an amendment to a permit or license for a reactor 
under part 50 or part 52 of this chapter that changes a requirement 
or issuance of an exemption from a requirement, with respect to 
installation or use of a facility component located within the 
restricted area, as defined in part 20 of this chapter; or the 
issuance of an amendment to a permit or license for a reactor under 
part 50 or part 52 of this chapter that changes an inspection or a 
surveillance requirement; provided that: (i) The amendment or 
exemption involves 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; and (iii). 
There is no significant increase in individual or cumulative 
occupational radiation exposure.
    Staff Analysis: The exemption is from requirements with respect 
to the installation or use of facility components located within the 
restricted area as defined in 10 CFR part 20. The criteria for 
determining whether an action involves a significant hazards 
consideration are found in 10 CFR 50.92. The proposed action 
involves installed four LTAs. As stated in the evaluation in 
ML23093A028, the Commission has previously issued a proposed finding 
that the amendments involve no significant hazards consideration, 
published in the Federal Register on November 8, 2022 (87 FR 67508), 
and there has been no public comment on such finding.
    The proposed action involves installing four LTAs, and as the 
NRC staff evaluated under the SE contained in ML23093A028, this 
action does not involve any significant changes in the types or 
significant increase in the amounts of any effluents that may be 
released offsite.
    The proposed action involves installing four LTAs, and as the 
NRC staff evaluated under the SE contained in ML23093A028, this 
action does not involve any significant increase in individual or 
cumulative occupational exposure.
    Based on the above, 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 issuance of this exemption.

IV. Conclusions

    Accordingly, the NRC 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, pursuant 
to 10 CFR 50.12(a)(2)(ii), are present. Therefore, the NRC hereby 
grants SNC an exemption from the requirements of 10 CFR part 50, 
appendix K to allow the use of AXIOM fuel rod cladding material in 
LTAs 7ST1, 7ST2, 7ST3, and 7ST4 for up to two cycles of operation at 
Vogtle, Unit 2.
    Dated at Rockville, Maryland, this 1st day of August, 2023.

    For the Nuclear Regulatory Commission.

/RA/

Bo M. Pham,

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

[FR Doc. 2023-16755 Filed 8-4-23; 8:45 am]
BILLING CODE 7590-01-P