[Federal Register Volume 86, Number 209 (Tuesday, November 2, 2021)]
[Notices]
[Pages 60479-60481]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-23843]
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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-327 and 50-328; NRC-2021-0178]
Tennessee Valley Authority; Sequoyah Nuclear Plant, Units 1 and 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 September 23, 2020, request from the
Tennessee Valley Authority to allow for the use of Optimized
ZIRLOTM fuel rod cladding at Sequoyah Nuclear Plant, Units 1
and 2.
DATES: The exemption was issued on October 26, 2021.
ADDRESSES: Please refer to Docket ID NRC-2021-0178 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-2021-0178. 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, contact the NRC's Public Document
Room (PDR) reference staff at 1-800-397-4209, 301-415-4737, or by email
to [email protected]. For the convenience of the reader,
instructions about obtaining materials referenced in this document are
provided in the ``Availability of Documents'' section.
Attention: The PDR, where you may examine and order copies
of public documents, is currently closed. You may submit your request
to the PDR via email at [email protected] or call 1-800-397-4209 or
301-415-4737, between 8:00 a.m. and 4:00 p.m. (ET), Monday through
Friday, except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Perry Buckberg, Office of Nuclear
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001; telephone: 301-415-1383, email: [email protected].
SUPPLEMENTARY INFORMATION: The text of the exemption is attached.
Dated: October 28, 2021.
For the Nuclear Regulatory Commission.
Perry H. Buckberg,
Senior Project Manager, Plant Licensing Branch II-2, Division of
Operating Reactor Licensing, Office of Nuclear Reactor Regulation.
Attachment--Exemption
NUCLEAR REGULATORY COMMISSION
Docket Nos. 50-327 and 50-328
Tennessee Valley Authority, Sequoyah Nuclear Plant, Units 1 and 2
Exemption
I. Background
The Tennessee Valley Authority (TVA) is the holder of Renewed
Facility Operating License Nos. DPR-77 and DPR-79, which authorize
operation of Sequoyah Nuclear Plant, Units 1 and 2 (Sequoyah). The
licenses provide, among other things, that the facilities are subject
to all rules, regulations, and orders of the NRC now, or hereafter, in
effect. The Sequoyah units are pressurized-water reactors located in
Hamilton County, Tennessee, approximately 9.5 miles northeast of
Chattanooga. TVA plans to use fuel rods with Optimized ZIRLO\TM\
cladding. Optimized ZIRLO cladding was developed to provide enhanced
corrosion resistance in more adverse in-reactor primary chemistry
environments and at higher fuel duties with higher burnups.
II. Request/Action
By letter dated September 23, 2020, TVA requested an exemption from
title 10 of the Code of Federal Regulations (10 CFR) section 50.46,
``Acceptance criteria for emergency core cooling systems [ECCS] for
light-water nuclear power reactors,'' and 10 CFR part 50, appendix K,
``ECCS Evaluation Models,'' to allow the use of Optimized ZIRLO fuel
rod cladding for future core reload applications. The regulations in 10
CFR 50.46 contain acceptance criteria for the ECCS for reactors fueled
with zircaloy or ZIRLO[supreg] fuel rod cladding material. In addition,
paragraph I.A.5 of 10 CFR part 50,
[[Page 60480]]
appendix K, requires that the Baker-Just equation be used to predict
the rates of energy release, hydrogen concentration, and cladding
oxidation from the metal/water reaction. The Baker-Just equation
presumes the use of zircaloy or ZIRLO cladding material. Therefore, an
exemption to 10 CFR 50.46 and 10 CFR part 50, appendix K, was requested
to support the use of Optimized ZIRLO fuel rod cladding at Sequoyah.
The exemption request relates solely to the specific types of
cladding material specified in these regulations for use in light-water
reactors (i.e., fuel rods with zircaloy or ZIRLO cladding). This
request will provide for the application of the acceptance criteria of
10 CFR 50.46 and 10 CFR part 50, appendix K, to fuel assembly designs
using Optimized ZIRLO fuel rod cladding.
III. Discussion
Pursuant to 10 CFR 50.12, the Commission 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 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 circumstance would not serve,
or is not necessary to achieve, the underlying purpose of the rule.
The Optimized ZIRLO fuel cladding is different from standard ZIRLO
in two respects: (1) The tin content is lower and (2) the
microstructure is different. This difference in tin content and
microstructure can lead to differences in some material properties.
Westinghouse Electric Company (Westinghouse), the manufacturer of
Optimized ZIRLO fuel rod cladding, has provided irradiated data and
validate fuel performance models ahead of burnups achieved in batch
application (i.e., a group of fuel assemblies).
The NRC staff's safety evaluation dated June 10, 2005, related to
Optimized ZIRLO, which is included as Addendum 1 of Westinghouse
topical report WCAP-12610-P-A & CENPD-404-P-A, included ten conditions
and limitations. The NRC staff reviewed TVA's exemption request found
in enclosure 5 of TVA's letter dated September 23, 2020, and enclosure
1, attachment 8 of the same letter, which addresses the licensee's
compliance with each of the ten conditions and limitations. Based on
its review, the NRC staff determined that the licensee satisfied all
applicable conditions and limitations. The NRC staff evaluation of how
the licensee addressed each of the ten conditions and limitations may
be found in Section 3.8.10 of the staff Safety Evaluation related to
Amendment Nos. 356 and 349 to Renewed Facility Operating License Nos.
DPR-77 and DPR-79 for Sequoyah, dated October 26, 2021, which
authorizes the transition to Westinghouse RFA-2 fuel.
A. The Exemption Is Authorized by Law
This exemption would allow the use of Optimized ZIRLO fuel rod
cladding material at Sequoyah. As stated above, 10 CFR 50.12 allows the
NRC to grant exemptions from the requirements of 10 CFR part 50,
provided, among other things, it finds that special circumstances are
present. As described here and in the sections below, the NRC staff
makes the requisite exemption findings. The fuel that will be
irradiated at Sequoyah contains cladding material that differs from the
cladding material that is explicitly defined in 10 CFR 50.46 and
implicitly defined in 10 CFR part 50, appendix K. However, the criteria
of these regulations will continue to be satisfied for the operation of
the Sequoyah cores containing Optimized ZIRLO fuel cladding. The NRC
staff has determined that granting the licensee's proposed exemption
would not result in a violation of the Atomic Energy Act of 1954, as
amended, other laws, 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 NRC-approved Optimized ZIRLO topical report, WCAP-12610-P-A &
CENPD-404-P-A, Addendum 1-A, has demonstrated that predicted chemical,
thermal, and mechanical characteristics of the Optimized ZIRLO-alloy
cladding are bounded by those approved for ZIRLO under anticipated
operational occurrences and postulated accidents. The report
demonstrates an acceptable retention of post-quench ductility up to
2200 degrees Fahrenheit and oxidation of not more than 17 percent
cladding thickness within 10 CFR 50.46 limits. Reload cores are
required to be operated in accordance with the operating limits
specified in the TSs and core operating limits report. Thus, the
granting of this exemption request will not pose an undue risk to
public health and safety.
C. The Exemption Is Consistent With the Common Defense and Security
The exemption request would allow the licensee to use an improved
fuel rod cladding material. In its letter dated September 23, 2020, the
licensee stated that all the requirements and acceptance criteria will
be maintained. Therefore, the use of Optimized ZIRLO-clad fuel rods
will not adversely affect plant operations. Further, the licensee is
required to handle and control special nuclear material in these
assemblies in accordance with its approved procedures. Therefore, the
NRC staff determined that this exemption does not adversely impact
common defense and security.
D. Special Circumstances
Special circumstances, in accordance with Sec. 50.12(a)(2)(ii),
are present whenever application of the regulation in the particular
circumstances is not necessary to achieve the underlying purpose of the
rule. The underlying purposes of 10 CFR 50.46 and 10 CFR part 50,
appendix K, are to establish acceptance criteria for ECCS performance.
The underlying purpose of the rule to maintain post-quench ductility in
the fuel cladding material through ECCS performance criteria, and to
ensure that analyses of fuel response are conservatively calculated,
will continue to be achieved through the application of 10 CFR 50.46
and 10 part 50, appendix K, to the new cladding. The regulations ensure
that nuclear power reactors fueled with uranium oxide pellets within
zircaloy or ZIRLO cladding must be provided with an ECCS designed to
provide core cooling following postulated loss-of-coolant accidents.
Westinghouse demonstrated in its NRC-approved topical report WCAP-
12610-P-A & CENPD-404-P-A Addendum 1-A that ECCS effectiveness will not
be adversely affected by a change from zircaloy or ZIRLO clad fuel to
Optimized ZIRLO clad fuel. The Westinghouse analysis also demonstrated
that the ECCS acceptance criteria applied to reactors with fuel in
zircaloy or ZIRLO fuel rod cladding are also applicable to reactors
fueled with Optimized ZIRLO clad fuel. Normal safety analyses performed
prior to core reload will confirm that there is no adverse impact on
ECCS performance. Therefore, because the underlying purposes of 10 CFR
50.46 and 10 CFR part 50, appendix K, are achieved through the use of
Optimized ZIRLO fuel rod cladding material, the special circumstances
required by 10 CFR 50.12(a)(2)(ii) for the granting of an exemption
exist.
E. Environmental Considerations
In 10 CFR 51.22, the Commission determined that certain NRC actions
are eligible for categorical exclusion from the requirement to prepare
an
[[Page 60481]]
environmental assessment or an environmental impact statement because
each action category does not individually or cumulatively have a
significant effect on the human environment.
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 a facility component located within the
restricted area, as defined in 10 CFR part 20, and the granting of this
exemption involves: (1) No significant hazards consideration [NSHC],
(2) no significant change in the types or a significant increase in the
amounts of any effluents that may be released offsite, and (3) no
significant increase in individual or cumulative occupational radiation
exposure. Therefore, in accordance with Sec. 51.22(b), no
environmental impact statement or environmental assessment need be
prepared in connection with the NRC staff's consideration of this
exemption request. The basis for the NRC staff's determination is in
the licensee's discussion of the 10 CFR 51.22(c)(9) criteria in the
associated LAR noticed in the Federal Register on December 1, 2020 (85
FR 77265). In addition, because Optimized ZIRLO cladding has
essentially the same material properties and performance
characteristics, and is adequately controlled by 10 CFR 50.46 and 10
CFR part 50, appendix K.I.A.5, the use of Optimized ZIRLO will not
significantly increase the types or amounts of effluents that may be
released offsite, significantly increase individual occupational
radiation exposure, or significantly increase cumulative occupational
radiation exposure. Therefore, pursuant to 10 CFR 51.22(b), no
environmental impact statement or environmental assessment need be
prepared in connection with the NRC staff's consideration of this
exemption request.
IV. Availability of Documents
The documents identified in the following table are available to
interested persons through one or more of the following methods, as
indicated.
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Document ADAMS accession No.
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TVA, ``Application to Modify the ML20267A617
Sequoyah Nuclear Plant Units 1 and 2
Technical Specification to Allow for
Transition to Westinghouse RFA-2 Fuel
(SQN-TS-20-09)'' (September 23, 2020).
Westinghouse, ``Final Safety Evaluation ML051670395
for Addendum 1 to Topical Report WCAP-
12610-P-A & CENPD-404-P-A Addendum 1-A,
`Optimized ZIRLO' '' (June 10, 2005).
NRC Safety Evaluation related to ML21245A267
Amendment Nos. 356 and 349 to Renewed
Facility Operating License Nos. DPR-77
and DPR-79 for Tennessee Valley
Authority Sequoyah Nuclear Plant, Units
1 and 2, Docket Nos. 50 327 And 50 328
(October 26, 2021).
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V. 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 TVA an exemption from 10 CFR
50.46 and 10 CFR part 50, appendix K paragraph I.A.5, to allow for the
use of Optimized ZIRLO fuel rod cladding material at Sequoyah.
Dated this 26 day of October, 2021.
For the Nuclear Regulatory Commission.
Bo M. Pham,
Director, Division of Operating Reactor Licensing, Office of Nuclear
Reactor Regulation.
[FR Doc. 2021-23843 Filed 11-1-21; 8:45 am]
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