Federal Register, Volume 89 Issue 103 (Tuesday, May 28, 2024)

[Federal Register Volume 89, Number 103 (Tuesday, May 28, 2024)]
[Notices]
[Pages 46167-46170]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-11561]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-423; NRC-2024-0102]


Dominion Energy Nuclear Connecticut, Inc.; Millstone Power 
Station, Unit No. 3; Exemption

AGENCY: Nuclear Regulatory Commission.

ACTION: Notice; issuance.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) has issued an 
exemption in response to an exemption request from Dominion Energy 
Nuclear Connecticut, Inc. (DENC, the licensee) submitted by letter 
dated May 2, 2023.

DATES: The exemption was issued on May 21, 2024.

ADDRESSES: Please refer to Docket ID NRC-2024-0102 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-2024-0102. 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 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. The request for the 
exemption was submitted by letter dated May 2, 2023 (ADAMS Accession 
No. ML23123A279), as supplemented by letter dated April 1, 2024 (ADAMS 
Accession No. ML24093A216).
     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: Richard Guzman, Office of Nuclear 
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 
20555-0001, telephone: 301-415-1030; email: [email protected].

SUPPLEMENTARY INFORMATION: The licensee is the holder of Renewed 
Facility Operating License No. NPF-49, which authorizes operation of 
Millstone Power Station, Unit No. 3 (Millstone 3), a pressurized-water 
reactor. The license provides, among other things, that the facility is 
subject to all rules, regulations, and orders of the NRC now or 
hereafter in effect. By letter dated May 2, 2023, as supplemented by 
letter dated April 1, 2024, DENC requested an exemption to section 
50.46 of title 10 of the Code of Federal Regulations (10 CFR), 
``Acceptance criteria for emergency core cooling systems for light-
water nuclear power reactors,'' and 10 CFR part 50, appendix K, ``ECCS 
[Emergency Core Cooling Systems] Evaluation Models,'' for Millstone 3. 
The text of the exemption is attached.

    Dated: May 21, 2024.

    For the Nuclear Regulatory Commission.
Richard V. Guzman,
Senior Project Manager, Plant Licensing Branch 1, Division of Operating 
Reactor Licensing, Office of Nuclear Reactor Regulation.

Attachment--Exemption

Nuclear Regulatory Commission

Docket No. 50-423

Dominion Energy Nuclear Connecticut, Inc., Millstone Power Station, 
Unit No. 3; Exemption

I. Background

    Dominion Energy Nuclear Connecticut, Inc. (DENC, the licensee) is 
the holder of Renewed Facility Operating License No. NPF-49, which 
authorizes operation of Millstone Power

[[Page 46168]]

Station, Unit No. 3 (Millstone 3), a pressurized-water reactor (PWR). 
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.
    Millstone 3 shares the site with Millstone Power Station, Unit 1, a 
permanently defueled boiling water reactor nuclear unit, and Millstone 
Power Station, Unit 2, a PWR. The facility is located in Waterford, 
Connecticut, approximately 3.2 miles west southwest of New London, 
Connecticut. This exemption applies to Millstone 3 only. The other 
units, Units 1 and 2, are not covered by this exemption.

II. Request/Action

    By letter dated May 2, 2023 (Agencywide Documents Access and 
Management System (ADAMS) Accession No. ML23123A279), as supplemented 
by letter dated April 1, 2024 (ML24093A216), DENC, requested an 
exemption to title 10 of the Code of Federal Regulations (10 CFR), part 
50, section 50.46, ``Acceptance criteria for emergency core cooling 
systems for light-water nuclear power reactors,'' and part 50, Appendix 
K, ``ECCS [Emergency Core Cooling Systems] Evaluation Models,'' for 
Millstone 3.
    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 ZIRLO^TM. 
Since these regulations specifically apply only to zircaloy and 
ZIRLO^TM, an exemption would be required to apply them to 
fuel clad with other materials, in this case Framatome M5\TM\. 
Therefore, the licensee has requested such an exemption to support the 
introduction of Framatome GAIA fuel with the M5\TM\ cladding. The 
proposed request would not exempt Millstone 3 from other requirements 
of 10 CFR 50.46 or 10 CFR part 50, appendix K, such as acceptance 
criteria, evaluation model features and documentation, and reporting of 
changes or errors.
    This exemption request is specific to the M5\TM\ cladding material 
exemption request only. The technical analysis necessary to support the 
use of M5\TM\ cladding in the Millstone 3 GAIA Small Break and Large 
Break Loss-of-Coolant Accident (SBLOCA and RLBLOCA) evaluations under 
Framatome methods is documented in a separate safety evaluation for the 
related license amendment request (ML24109A003).

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 assemblies 
containing fuel rods fabricated with M5\TM\ cladding material at 
Millstone 3.
    The technical basis for the use of fuel clad with M5\TM\ 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\TM\ 
alloy in PWR fuel assemblies as a replacement for Zircaloy-4. This TR 
discusses material properties of M5\TM\, as well as its behavior under 
normal operation, anticipated transients, and postulated accident 
conditions.
    The regulation in 10 CFR 50.46(a)(1)(i) requires, in part, that 
each boiling or pressurized light-water nuclear power reactor fueled 
with uranium oxide pellets within cylindrical zircaloy or ZIRLO\TM\ 
cladding must be provided with an ECCS that must be designed so that 
its calculated cooling performance following postulated loss-of-coolant 
accidents conforms to the criteria set forth in 10 CFR 50.46(b). Since 
10 CFR 50.46 specifically refers to fuel with zircaloy or 
ZIRLO^TM cladding, the use of fuel with M5^TM 
cladding 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 requires the Baker-Just equation be used in the ECCS 
evaluation model to determine the rate of energy release, hydrogen 
generation, and cladding oxidation. The requirement for using the 
Baker-Just equation in appendix K conformant loss-of-coolant accident 
(LOCA) evaluation models presume use of zircaloy- or 
ZIRLO^TM-clad fuel rods. Therefore, application of 10 CFR 
part 50, appendix K to cladding materials other than zircaloy or 
ZIRLO^TM also requires an exemption. 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 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)(ii), 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 use of M5\TM\ cladding at Millstone 
3 for GAIA SBLOCA and RLBLOCA analyses performed using Framatome (FRM) 
methods, instead of zircaloy or ZIRLO\TM\ cladding. 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 
M5\TM\ 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

    The 10 CFR 50.46 requirements establish acceptance criteria for 
ECCS performance for reactors fueled with zircaloy or ZIRLO cladding 
during a LOCA. The technical basis for the use of fuel clad with M5\TM\ 
in PWRs is documented in NRC-approved 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). In 
this TR, Framatome demonstrated that the effectiveness of the ECCS will 
not be affected by a change from zircaloy or ZIRLO fuel rod cladding to 
M5\TM\ fuel rod cladding. The analysis described in the TR demonstrated 
that the ECCS acceptance criteria applied to reactors fueled with 
zircaloy or ZIRLO clad fuel are also applicable to reactors fueled with 
M5\TM\ fuel rod cladding.
    Paragraph I.A.5 of appendix K to 10 CFR 50 requires that the Baker-
Just equation be used in the ECCS evaluation

[[Page 46169]]

models to determine the rate of energy release, cladding oxidation, and 
hydrogen generation. In the NRC-approved TR BAW-10227-P-A, Revision 1, 
Framatome demonstrated that the Baker-Just model is conservative in the 
postulated LOCA scenarios with respect to the use of the M5\TM\ alloy 
as a fuel rod cladding material. The Baker-Just equation is used to 
calculate cladding oxidation for the SBLOCA methodologies in the NRC-
approved TR EMF-2328-P-A, Revision 0 (ML011410383) for fuel with M5\TM\ 
cladding. The SBLOCA analysis (Attachments 3 and 4 in the licensee's 
May 2, 2023, letter) using the methodologies in TR EMF-2328-P-A, 
Revision 0 for Millstone 3 demonstrated that the amount of hydrogen 
generated in an M5-clad core meets the 10 CFR 50.46 criteria.
    The NRC staff has reviewed the SBLOCA and RLBLOCA analyses in 
Attachments 3 through 6 in the licensee's May 2, 2023, letter, and 
concluded in a safety evaluation (ML24109A003) that the LOCA analyses 
meet the applicable acceptance criteria, confirming that the use of 
M5\TM\ fuel cladding at Millstone 3 would not result in an increase in 
the consequences of postulated LOCAs beyond the required limits. Based 
on these reviews, the NRC staff concludes that the exemption presents 
no 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 M5\TM\ fuel 
rod cladding material, an improved 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 its letter 
dated May 2, 2023, the licensee stated that the M5\TM\ fuel rod 
cladding material is similar in design to the current cladding material 
used in Millstone 3. The change in cladding material will not result in 
any changes to the security aspects associated with control of special 
nuclear material and is unrelated to other security issues. In addition 
to its review of the exemption request, the NRC staff's technical 
analysis necessary to support the use of M5\TM\ cladding in the 
Millstone 3 GAIA SBLOCA and RLBLOCA evaluations under Framatome methods 
is documented in a separate safety evaluation for the related license 
amendment request (ML24109A003). Based on these reviews, the NRC staff 
concludes that the use of M5\TM\ fuel rod cladding at Millstone 3 will 
not significantly affect plant operations and is therefore 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 circumstances 
would not serve the purpose of the rule or is not necessary to achieve 
the purpose of the rule.
    The underlying purpose of 10 CFR 50.46 and appendix K to 10 CFR 
part 50 is to establish acceptance criteria for ECCS performance to 
provide reasonable assurance of safety in the event of a LOCA. Although 
the regulations in 10 CFR 50.46 and appendix K to 10 CFR part 50 are 
not expressly applicable to M5\TM\ fuel rod cladding, the evaluations 
described in the above section show that the purpose of the regulations 
are met by this exemption; specifically, the NRC-approved topical 
report (TR) BAW-10227-A, Revision 1 demonstrated that the effectiveness 
of the ECCS will not be affected by a change from zircaloy or ZIRLO 
fuel rod cladding to M5\TM\ fuel rod cladding and that that the ECCS 
acceptance criteria applied to reactors fueled with zircaloy or ZIRLO 
clad fuel are also applicable to reactors fueled with M5\TM\ fuel rod 
cladding.
    Paragraph I.A.5 of appendix K to 10 CFR 50 requires that the Baker-
Just equation be used in the ECCS EMs to determine the rate of energy 
release, cladding oxidation, and hydrogen generation. The NRC-approved 
TR BAW-10227-P-A, Revision 1 demonstrated that the Baker-Just model is 
conservative in the postulated LOCA scenarios with respect to the use 
of the M5\TM\ alloy as a fuel rod cladding material.
    Neither 10 CFR 50.46 acceptance criteria nor the 10 CFR 50 appendix 
K requirements for use of the Baker-Just equation in the ECCS EMs 
allows the use of M5\TM\ fuel rod cladding material, even though the 
analysis demonstrated that applying the zircaloy or ZIRLO criteria to 
M5\TM\ fuel produces acceptable results. Application of the regulatory 
requirements of 10 CFR 50.46 and 10 CFR 50 appendix K in this 
circumstance is not necessary to achieve the purpose of the rule. The 
purpose of these regulations is achieved through the application of the 
requirements to the use M5\TM\ fuel rod cladding material. Therefore, 
the NRC staff determines that special circumstances for granting of an 
exemption, defined in 10 CFR 50.12(a)(2)(ii), exist.

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) because it is related to a requirement 
concerning the installation or use of a facility component located 
within the restricted area, as defined in 10 CFR part 20, and issuance 
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 is discussed as 
follows with an evaluation against each of the requirements in 10 CFR 
51.22(c)(9)(i)-(iii).
Requirements in 10 CFR 51.22(c)(9)(i)
    The NRC evaluated whether the exemption involves 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 would allow the use of M5\TM\ cladding at 
Millstone 3 for GAIA SBLOCA and RLBLOCA analyses performed using FRM 
methods. The NRC approved topical reports cited above demonstrate that 
M5\TM\ cladding has similar properties as the currently licensed 
Zircaloy. The fuel cladding itself is not a postulated initiator of 
previously evaluated accidents; thus, fuel cladding material does not 
affect the probability of occurrence of any accident. The consequences 
of none of the previously evaluated accidents were affected by fuel 
cladding material, and M5\TM\ fuel cladding, likewise, is not expected 
to have any effect on the consequences of any previously evaluated 
accidents.
    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?

[[Page 46170]]

    Response: No.
    The use of M5\TM\ fuel rod cladding material will not result in 
changes in the operation or configuration of the facility. The above 
cited topical reports demonstrated that the material properties of 
M5\TM\ cladding are similar to those of standard Zircaloy. Therefore, 
M5\TM\ fuel cladding material will perform similarly to those 
fabricated from standard Zircaloy. The fuel cladding itself is not a 
postulated initiator of previously evaluated accidents and does not 
create the possibility of a new or different kind of accident.
    Therefore, the proposed exemption does 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 will not involve a significant reduction in 
the margin of safety because it has been demonstrated that the material 
properties of the M5\TM\ cladding is not significantly different from 
those of the standard Zircaloy. M5\TM\ fuel cladding material is 
expected to perform similarly to standard Zircaloy for all normal 
operating and accident scenarios. Use of M5\TM\ cladding does not 
require changing any of the current regulatory acceptance criteria, or 
relaxation of the methods of analysis.
    Therefore, the proposed exemption does not involve a significant 
reduction in a margin of safety.
    Based on the above evaluation of the standards set forth in 10 CFR 
50.92(c), the NRC staff concludes that the proposed exemption involves 
no significant hazards consideration. Accordingly, the requirements of 
10 CFR 51.22(c)(9)(i) are met.
Requirements in 10 CFR 51.22(c)(9)(ii)
    The proposed exemption would allow the use of M5\TM\ cladding at 
Millstone 3 for GAIA SBLOCA and RLBLOCA analyses performed using FRM 
methods. M5\TM\ cladding has similar properties and performance 
characteristics as the currently licensed Zircaloy cladding. Thus, the 
use of M5\TM\ fuel cladding material will not significantly increase 
the amount of effluents that may be released offsite. Therefore, the 
requirements of 10 CFR 51.22(c)(9)(ii) are met.
Requirements in 10 CFR 51.22(c)(9)(iii)
    The proposed exemption would allow the use of M5\TM\ cladding at 
Millstone 3 for GAIA SBLOCA and RLBLOCA analyses performed using FRM 
methods. M5\TM\ cladding has similar properties and performance 
characteristics as the currently licensed Zircaloy cladding. Thus, the 
use of M5\TM\ fuel cladding material will not significantly increase 
individual occupational radiation exposure, or significantly increase 
cumulative occupational radiation exposure. Therefore, the requirements 
of 10 CFR 51.22(c)(9)(iii) are met.
    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 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 DENC an 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 rod cladding with M5\TM\ at 
Millstone 3. As stated above, this exemption relates solely to the 
cladding material specified in these regulations.

    Dated at Rockville, Maryland, this 21st day of May, 2024.

    For the Nuclear Regulatory Commission.

Jamie Pelton,
Deputy Director, Division of Operating Reactor Licensing, Office of 
Nuclear Reactor Regulation.

[FR Doc. 2024-11561 Filed 5-24-24; 8:45 am]
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