ML23096A198
| ML23096A198 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 08/02/2023 |
| From: | John Lamb Plant Licensing Branch II |
| To: | |
| Shared Package | |
| ML23096A206 | List: |
| References | |
| EPID L-2022-LLE-0021, NRC-2023-0092, 88 FR 552216; 8/7/2023 | |
| Download: ML23096A198 (10) | |
Text
[7590-01-P]
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.
SUMMARY
- The U.S. Nuclear Regulatory Commission (NRC) has issued an exem ption
in response to a request dated June 30, 2022, as supplemented b y letters dated
September 13, 2022, and January 20, and May 5, 2023, from South ern 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; ema il:
Stacy.Schumann@nrc.gov. For technical questions, contact the in dividual listed in the
For Further Information Contact section of this document.
- NRCs Agencywide Documents Access and Management System
(ADAMS): You may obtain publicly available documents online in the ADAM S Public
Documents collection at https://www.nrc.gov/reading-rm/adams.ht ml. To begin the search, select Begin Web-based ADAMS Search. For problems wit h ADAMS, please
contact the NRCs Public Document Room (PDR) reference staff at 1-800-397-4209,
301-415-4737, or by email to PDR.Resource@nrc.gov. The ADAMS ac cession number
for each document referenced (if it is available in ADAMS) is p rovided the first time that it
is mentioned in this document.
- NRCs PDR: The PDR, where you may examine and order copies of publicly
available documents, is open by appointment. To make an appoint ment to visit the PDR,
please send an email to PDR.Resource@nrc.gov or call 1-800-397-4209 or 301-415-
4737, between 8 a.m. and 4 p.m. eastern time (ET), Monday throu gh 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: John.Lamb@nrc.gov.
SUPPLEMENTARY INFORMATION: The text of the exemption is attached.
Dated: August 2, 2023.
For the Nuclear Regulatory Commission.
/RA/
John G. Lamb, Senior Project Manager, Licensing Plant Branch 2-1, Division of Operating Reactor Licensing, Office of Nuclear Reactor Regulation.
2 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 Assemb lies
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 h older of
Facility Operating License No. NPF-81, for the Vogtle Electric Generating Plant (Vogtle),
Unit 2. The license provides, among other things, that the lice nse is subject to all rules,
regulations, and orders of the Commission now or hereafter in e ffect.
The Vogtle, Unit 2, consists of a pressurized-water reactor loc ated at the
licensees 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 l etters dated
September 13, 2022 (ML22256A198), January 20, 2023 (ML23020A148 ), and May 5,
2023 (ML23125A269), SNC requested an exemption to title 10 of t he Code of Federal
Regulations (10 CFR), part 50, appendix K, ECCS [Emergency Core Cooling S ystems]
Evaluation Models, for Vogtle, Unit 2.
3 Specifically, SNC requested an exemption from 10 CFR part 50, a ppendix 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 Vogtl e, Unit 2.
The regulation at 10 CFR 50.46(a)(1)(ii) provides that, [a]lte rnatively, an ECCS
evaluation model may be developed in conformance with the requi red and acceptable
features of Appendix K ECCS Evaluation Models. Appendix K of 1 0 CFR part 50
requires, in paragraph I.A.5, that [t]he rate of energy releas e, hydrogen generation, and
cladding oxidation from the metal/water reaction shall be calcu lated using the Baker-Just
equation (Baker, L., Just, L.C., Studies of Metal Water Reacti ons at High Temperatures,
III. Experimental and Theoretical Studies of the Zirconium Wate r 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 equ ation presumes the use
of zircaloy or ZIRLO clad fuel, strict application of this prov ision of the rule would not
permit use of the equation for AXIOM cladding for determining a cceptable 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 re quirements of 10 CFR part
50, including 10 CFR part 50, appendix K when: (1) the exemptio ns are authorized by
law, will not present an undue risk to the public health or saf ety, and are consistent with
the common defense and security; and (2) when special circumsta nces are present.
Under 10 CFR 50.12(a)(2), special circumstances include, among other things, when
application of the specific regulation in the particular circum stances would not serve, or
4 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 b y law. The exemption
requested in this instance is authorized by law, because no oth er 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 con taining 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 c onsistent 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 f rom the requirements
of 10 CFR part 50. The NRC staff has determined that granting o f 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 vi olation of the Atomic Energy Act of 1954, as amended, or
the Commission's regulations. Therefore, the exemption is autho rized by law.
B. The Exemption Presents no Undue Risk to Public Health and Sa fety.
SNC stated the following in its letter dated June 30, 2022:
The Vogtle reactors each contain 193 fuel assemblies. Each asse mbly consists of a matrix of 264 Zircaloy, ZIRLO TM[], or Optimized ZIRLO[TM]
clad fuel rods with an initial composition of natural or slight ly enriched uranium dioxide (UO2) as fuel material, not to exceed 5 wt% [we ight-percent] enrichment. The proposed change is to load four LTAs w ith advanced ATF [accident tolerant fuel] features, including ADOPT fuel [2],
AXIOM cladding [3], chromium coating, and four rods per LTA wit h up to 6 wt% enrichment, in limiting core locations for up to two cycl es of operation.
5 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 Opti mized ZIRLO and standard ZIRLO alloys, fuel assemblies using AXIOM fu el rod cladding are evaluated using plant-specific models to address t he 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 Specificati ons (TS).
Reload cores are required to be operated in accordance with the operating limits specified in the TS. Thus, the granting of thi s exemption request will not pose an undue risk to public health and safety.
Based upon the limited number of AXIOM clad fuel rods, the safe guards 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 accept able for Vogtle, Unit 2. In
conclusion, the NRC staff finds t hat 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 acceptabl e 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 NRC staff has determined that SNCs evaluation
of coated cladding emissivity and its effect on loss-of-coolant accident peak clad
temperature (PCT) is acceptable, because data was provided demo nstrating no
significant difference in PCT, (3) the NRC staff has determined that SNCs evaluation of
ADOPT fuel pellets in the LTAs is acceptable, because there wil l be no reduction in fuel
performance and the applicable limitations and conditions have been implicitly
addressed, and (4) the number of rods with enrichments exceedin g five weight-percent
Uranium 235 is small compared to the total number of fuel rods. See the NRC safety
evaluation (ML23093A028) for further details.
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.
6 C. The Exemption is Consistent with the Common Defense and Secu rity.
The proposed exemption would allow the use of four LTAs with a variant cladding
material. This change to the plant core configuration has no im pact on security issues.
Special nuclear material in the LTAs will continue to be handle d and controlled in
accordance with applicable regulations. Therefore, the common d efense 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 circum stances would not serve
the underlying purpose of the rule or is not necessary to achie ve 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 safe ty evaluation (SE)
contained in ML23093A028 for the license amendment request, the NRC staff evaluated
for Vogtle, Unit 2, four LTAs that demonstrated the acceptabili ty of the AXIOM cladding
under LOCA conditions. The unique features of the LTAs were eva luated for effects on
the LOCA analyses. The results showed that the LTAs would not a dversely 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 no t permit use of the equation for
AXIOM cladding for determining acceptable fuel performance. The refore, the NRC staff
concludes that application of the cladding material applicabili ty requirements of the
Baker-Just equation of 10 CFR part 50, Appendix K in this parti cular circumstance is not
necessary for the licensee to achieve the underlying purpose of the rule.
E. Environmental Considerations
7 With respect to its impact on the quality of the human environm ent, 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 staffs
determination that all of the criteria for this categorical exc lusion 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 u nder part 50 or part 52 of this chapter that changes a requirement or iss uance of an exemption from a requirement, with respect to installation or u se of a facility component located within the restricted area, as defin ed 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) Th e amendment or exemption involves no significant hazards consider ation; (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 occupati onal radiation exposure.
Staff Analysis: The exemption is from requirements with respect to the
installation or use of facility components located within the r estricted 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 a ction involves
installed four LTAs. As stated in the evaluation in ML23093A028, the Commission has
previously issued a proposed finding that the amendments involv e 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 N RC staff
evaluated under the SE contained in ML23093A028, this action do es not involve any
significant changes in the types o r significant increase in the amounts of any effluents
that may be released offsite.
The proposed action involves installing four LTAs, and as the N RC staff
8 evaluated under the SE contained in ML23093A028, this action do es not involve any
significant increase in individual or cumulative occupational e xposure.
Based on the above, the NRC staff concludes that the proposed e xemption
meets the eligibility criteria for the categorical exclusion se t 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 th e NRCs 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 7S T1, 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.
9 10