[Federal Register Volume 88, Number 198 (Monday, October 16, 2023)]
[Notices]
[Pages 71381-71383]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-22783]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-483; NRC-2023-0158]


Union Electric Company, dba Ameren Missouri; Callaway Plant; Unit 
No. 1

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 an exemption request from Union Electric 
Company doing business as Ameren Missouri (the licensee) submitted by 
letter dated October 12, 2022, as supplemented by letters dated 
December 1, 2022, May 9, 2023, June 21, 2023, and August 3, 2023.

DATES: The exemption was issued on October 5, 2023.

ADDRESSES: Please refer to Docket ID NRC-2023-0158 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-2023-0158. 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 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, at 301-415-4737, 
or by email to [email protected]. The request for

[[Page 71382]]

the exemption was submitted by letter dated October 12, 2022 (ADAMS 
Package Accession No. ML22285A115), as supplemented by letters dated 
December 1, 2022 (ADAMS Package Accession No. ML22335A497); May 9, 2023 
(ADAMS Package Accession No. ML23129A793); June 21, 2023 (ADAMS 
Accession No. ML23172A145); and August 3, 2023 (ADAMS Package Accession 
No. ML23215A196).
     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: Mahesh Chawla, Office of Nuclear 
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 
20555-0001, telephone: 301-415-8371; email: [email protected].

SUPPLEMENTARY INFORMATION: The text of the exemption is attached.

    Dated: October 11, 2023.

    For the Nuclear Regulatory Commission.
Mahesh L. Chawla,
Project Manager, Plant Licensing Branch 4, Division of Operating 
Reactor Licensing, Office of Nuclear Reactor Regulation.

Attachment--Exemption

Nuclear Regulatory Commission

Docket No. 50-483

Union Electric Company Callaway Plant, Unit No. 1

Exemption

I. Background

    Union Electric Company, doing business as (dba) as Ameren Missouri 
(the licensee), is the holder of Renewed Facility Operating License No. 
NPF-30, which authorizes operation of the Callaway Plant, Unit No. 1 
(Callaway). The license provides, 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. The facility 
consists of a pressurized-water reactor (PWR) located in Callaway 
County, Missouri.

II. Request/Action

    By letter dated October 12, 2022 (Agencywide Documents Access and 
Management System (ADAMS) Accession No. ML22285A115), as supplemented 
by letters dated December 1, 2022; May 9, 2023; June 21, 2023; and 
August 3, 2023 (ML22335A497, ML23129A793, ML23172A145, and ML23215A196, 
respectively), Ameren Missouri, submitted a license amendment request 
(LAR) for Callaway, proposing to load a limited number of Framatome 
GAIA fuel assemblies starting in operating cycle 27 to obtain incore 
performance data and acquire operational experience associated with the 
GAIA fuel design. Pursuant to title 10 of the Code of Federal 
Regulations (10 CFR) section 50.12, ``Specific exemptions,'' the 
licensee also requested an exemption from certain requirements of 10 
CFR 50.46, ``Acceptance criteria for emergency core cooling systems,'' 
and 10 CFR part 50, appendix K, ``ECCS [Emergency Core Cooling Systems] 
Evaluation Models,'' for Callaway in enclosure 2 to the LAR dated 
October 12, 2022.
    This exemption request relates solely to the specific types of 
cladding materials for which 10 CFR 50.46 and 10 CFR part 50, appendix 
K, are expressly applicable, namely zircaloy and ZIRLOTM. 
Since these regulations specifically apply only to zircaloy and 
ZIRLOTM, an exemption would be required to apply them to 
fuel clad with other materials, in this case Framatome M5[supreg]. 
Therefore, the licensee has requested such an exemption to support the 
introduction of Framatome GAIA fuel with the M5[supreg] cladding. The 
proposed request would not exempt Callaway from requirements of 10 CFR 
50.46 or 10 CFR part 50, appendix K, regarding acceptance criteria, 
evaluation model features and documentation, reporting of changes or 
errors, etc.
    This exemption request is specific to the M5[supreg] cladding 
material exemption request only. The technical analysis necessary to 
support proposed loading of a limited number of Framatome GAIA fuel 
assemblies starting in operating cycle 27 is documented in the safety 
evaluation (SE) for the related LAR (ML23240A369).

III. Discussion

    Pursuant to 10 CFR 50.12, the licensee requested an exemption from 
the requirements of 10 CFR 50.46, and appendix K to 10 CFR part 50. The 
proposed exemption request would permit application of the requirements 
of 10 CFR 50.46 and appendix K to 10 CFR part 50 to fuel rods clad with 
M5[supreg] at Callaway.
    The technical basis for the use of fuel clad with M5[supreg] in 
PWRs is documented in Topical Report (TR) BAW-10227P-A, Revision 1, 
``Evaluation of Advanced Cladding and Structural Material (M5) in PWR 
Reactor Fuel,'' dated June 2003 (ADAMS Package No. ML15162B043). This 
TR describes Framatome's evaluation for the use of the M5[supreg] alloy 
in PWR fuel assemblies as a replacement for Zircaloy-4. This TR 
discusses material properties of M5, as well as its behavior under 
normal operation, anticipated transients, and postulated accident 
conditions.
    The regulation in 10 CFR 50.46(a)(1)(i) states, in part:

    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 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 clad with 
materials other than zircaloy or ZIRLOTM requires an 
exemption from this section of the regulations.
    Paragraph I.A.5, ``Metal--Water Reaction Rate,'' of appendix K to 
10 CFR part 50 states, in part:

    The 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,'' [Argonne 
National Laboratory] ANL-6548, page 7, May 1962).

    The requirement for using the Baker-Just equation in appendix K-
conformant loss-of-coolant accident (LOCA) evaluation models presume 
use of zircaloy- or ZIRLOTM-clad fuel rods. Therefore, 
application of 10 CFR part 50, appendix K to cladding materials other 
than zircaloy or ZIRLOTM also requires an exemption.
    Pursuant to 10 CFR 50.12, the Commission may grant exemption from 
requirements of the regulations in 10 CFR part 50 provided that (1) the 
exemption is authorized by law, (2) the exemption will not present an 
undue risk to the public health and safety, (3) the exemption is 
consistent with the common defense and security, and (4) special 
circumstances, as defined in 10 CFR 50.12(a)(2), are present. The 
licensee's submittal identifies that the special circumstance 
associated with its exemption request is that restricting application 
of 10 CFR 50.46 and appendix K to 10 CFR part 50 to fuels

[[Page 71383]]

clad with only zircaloy or ZIRLOTM is not necessary to 
achieve the purpose of these regulations.

A. The Exemption Is Authorized by Law

    The NRC has authority under 10 CFR 50.12 to grant exemptions from 
the requirements of 10 CFR part 50 upon demonstration of proper 
justification. The fuel that will be irradiated at Callaway is clad 
with a zirconium-based alloy that is not expressly within the scope of 
10 CFR 50.46 and 10 CFR part 50, appendix K. However, the NRC staff 
considers all other aspects of these regulations (e.g., acceptance 
criteria, prescribed methods, reporting requirements) applicable to the 
M5[supreg] cladding material, and the licensee states that it will 
ensure that these regulations are satisfied for operation with fuel 
clad with M5[supreg]. As discussed below, the NRC staff determined that 
special circumstances exist, which support granting the proposed 
exemption. Furthermore, granting the exemption would 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

    As summarized in the staff's safety evaluation supporting this 
exemption request (ML23234A152 (Enclosure 2)), the NRC-approved Topical 
Report BAW-10227P-A, Revision 1, which concerns the properties of the 
M5[supreg] alloy, provides assurance that predicted chemical, thermal, 
and mechanical characteristics of M5[supreg]-alloy cladding are 
acceptable under normal operation, anticipated transients, and 
postulated accidents. The NRC staff finds that by utilizing the methods 
and properties in NRC-approved TR (i.e., BAW-10227P-A), the licensee 
meets the acceptance criteria and analytical methods in 10 CFR 50.46 
and appendix K to 10 CFR part 50, and thus, ensures acceptable safety 
margins for fuel clad with M5[supreg] that are consistent with those 
the NRC has established for zircaloy and ZIRLOTM. Callaway 
cores involving M5[supreg] cladding will continue to be subject to the 
operating limits specified in the technical specifications (TSs) and 
core operating limits report. Thus, granting this exemption request 
does not pose undue risk to public health and safety.

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

    The proposed 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 and 10 CFR part 50, appendix K were 
originally established. In addition to its review of the exemption 
request, the NRC staff has evaluated all licensing-basis changes 
necessary to support loading fuel clad with M5[supreg] in a separate SE 
for the related license amendment request for fuel transition. Based on 
these reviews, the NRC staff concludes that the use of M5[supreg] fuel 
rod cladding at Callaway will not significantly affect plant operations 
and is therefore consistent with the common defense and security.

D. Special Circumstances

    Neither 10 CFR 50.46 nor 10 CFR part 50, appendix K explicitly 
applies to fuel clad with M5[supreg]. However, the underlying purpose 
of 10 CFR 50.46 and 10 CFR part 50, appendix K is to provide 
requirements capable of ensuring adequate core cooling following the 
most limiting postulated loss-of-coolant accident. As discussed above, 
Framatome has demonstrated in an NRC-approved TR (i.e., BAW-10227P-A) 
that application of the acceptance criteria and analytical methods 
required in 10 CFR 50.46 and 10 CFR part 50, appendix K to fuel clad 
with M5[supreg] is acceptable. The licensee stated in the exemption 
request that the core reload safety analyses will be used to confirm on 
a cycle-specific basis that there is no adverse impact on ECCS 
performance for Callaway. Therefore, strict application of the 
material-specific requirements for fuel cladding in 10 CFR 50.46 and 10 
CFR part 50, appendix K 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 to fuel clad with M5[supreg] at Callaway would be 
consistent with the underlying regulatory purpose.

E. Supplemental Information

    For more technical details, refer to the SE associated with this 
exemption under ML23234A152 (Enclosure 2).

F. Environmental Considerations

    As discussed in the SE associated with this exemption, the NRC 
staff determined that the exemption discussed herein meets the 
eligibility criteria for the categorical exclusion set forth in 10 CFR 
51.22(c)(9) because it is related to a requirement concerning the 
installation or use of facility components located within the 
restricted area, as defined in 10 CFR part 20, and 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.

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 Union Electric Company dba 
Ameren Missouri a one-time exemption from the requirements of 10 CFR 
50.46 and 10 CFR part 50, appendix K. The proposed exemption request 
would permit application of the requirements of 10 CFR 50.46 and 
appendix K to fuel rods clad with M5[supreg] at Callaway. As stated 
above, this exemption relates solely to the cladding material specified 
in these regulations.

    Dated at Rockville, Maryland, this 5th day of October, 2023

    For the Nuclear Regulatory Commission.

Bo M. Pham,

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

[FR Doc. 2023-22783 Filed 10-13-23; 8:45 am]
BILLING CODE 7590-01-P