[Federal Register Volume 82, Number 95 (Thursday, May 18, 2017)]
[Notices]
[Pages 22862-22865]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-10073]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-423; NRC-2017-0118]
Dominion Nuclear Connecticut, Inc.; Millstone Power Station, Unit
No. 3; Use of AXIOM Fuel Rod Cladding Material
AGENCY: Nuclear Regulatory Commission.
ACTION: Exemption; issuance.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing an
exemption in response to a June 30, 2016, request, as supplemented by
letter dated March 27, 2017, from Dominion Nuclear Connecticut, Inc.
(DNC or the licensee) in order to use AXIOM fuel rod cladding material
at Millstone Power Station, Unit No. 3 (MPS-3).
DATES: The exemption was issued on May 10, 2017.
ADDRESSES: Please refer to Docket ID NRC-2017-0118 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 Web site: Go to http://www.regulations.gov and search for Docket ID NRC-2017-0118. Address
questions about NRC dockets to Carol Gallagher; telephone: 301-415-
3463; 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 http://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``ADAMS Public Documents'' and
then 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: You may examine and purchase copies of public
documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555
Rockville Pike, Rockville, Maryland 20852.
FOR FURTHER INFORMATION CONTACT: Richard V. Guzman, Office of Nuclear
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington DC
20555-0001; telephone: 301-415-1030, email: [email protected].
SUPPLEMENTARY INFORMATION:
I. Background
Dominion Nuclear Connecticut, Inc. is the holder of Renewed
Facility Operating License No. NPF-49, which authorizes operation of
MPS-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. Millstone Power Station,
Unit No. 3, shares the site with Millstone Power Station, Unit No. 1, a
permanently defueled boiling water reactor nuclear unit, and Millstone
Power Station, Unit No. 2, a pressurized-water reactor. The facility is
located in Waterford, Connecticut, approximately 2.3 miles southwest of
New London, Connecticut. This exemption applies to MSP-3 only. The
other Millstone Power Station units, No. 1 and No. 2, are not covered
by this exemption.
II. Request/Action
Pursuant to Sec. 50.12 of title 10 of the Code of Federal
Regulations (10 CFR), ``Specific exemptions,'' the licensee requested,
by letter dated June 30, 2016 (ADAMS Accession No. ML16189A104), as
supplemented by letter dated March 27, 2017 (ADAMS Accession No.
ML17090A428), an exemption from Sec. 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 fuel rod cladding with AXIOM alloy for future
reload applications. The regulations in Sec. 50.46 contain acceptance
criteria for the ECCS for reactors fueled with Zircaloy or
ZIRLOTM fuel rod cladding material. In addition, 10 CFR part
50, 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 assumes the use of a zirconium alloy, which is a material
different from AXIOM. Therefore, the strict application
[[Page 22863]]
of these regulations does not permit the use of fuel rod cladding
material other than Zircaloy or ZIRLOTM. Because the
material specifications of AXIOM differ from the specificaitons for
Zircaloy or ZIRLOTM, and the regulations specify a cladding
material other than AXIOM, a plant-specific exemption is required to
allow the use of, and application of these regulations to, AXIOM at
MPS-3.
The exemption request relates solely to the cladding material
specified in these regulations (i.e., fuel rods with Zircaloy or
ZIRLOTM cladding material). This exemption would allow
application of the acceptance criteria of Sec. 50.46 and appendix K to
10 CFR part 50, for fuel assembly designs using AXIOM fuel rod cladding
material. The licensee is not seeking an exemption from the acceptance
and analytical criteria of these regulations. The intent of the request
is to allow the use of the criteria set forth in these regulations for
application of the AXIOM fuel road cladding material at MPS-3.
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 Sec. 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.
A. Authorized by Law
This exemption would allow the use of AXIOM fuel rod cladding
material for future reload applications at MPS-3. As stated above, 10
CFR 50.12 allows the NRC to grant exemptions from the requirements of
10 CFR part 50. The NRC staff has determined that special circumstances
exist to grant the requested exemption and that granting the licensee's
requested 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. No Undue Risk to Public Health and Safety
Section 50.46 requires that each boiling or pressurized light-water
nuclear power reactor fueled with uranium oxide pellets within
cylindrical Zircaloy or ZIRLOTM cladding must be provided
with an ECCS that must be designed so that its calculated cooling
performance following a postulated loss-of-coolant accident (LOCA)
conforms to the criteria set forth in Sec. 50.46(b). The underlying
purpose of Sec. 50.46 is to establish acceptance criteria for adequate
ECCS performance in response to LOCAs.
The licensee states that there will be up to eight lead test
assemblies (LTAs) containing fuel rods fabricated with AXIOM cladding
inserted into the core for MPS-3, Cycle 19. These LTAs will be placed
in non-limiting locations. Westinghouse performed preliminary high
temperature steam oxidation tests on AXIOM cladding and confirmed that
AXIOM cladding exhibits a ductile response to ring compression tests
for peak cladding temperature and equivalent cladding reacted values up
to and beyond the Sec. Sec. 50.46(b)(1) and (b)(2) acceptance
criteria, therefore satisfying the underlying cladding performance
metric used to judge ECCS performance. This evidence supports the use
of the existing acceptance criteria for fuel rods fabricated with AXIOM
cladding.
Paragraph I.A.5 of appendix K to 10 CFR part 50 states that the
rates of energy, hydrogen concentration, and cladding oxidation from
the metal-water reaction shall be calculated using the Baker-Just
equation. Since the Baker-Just equation presumes the use of Zircaloy
clad fuel, strict application of the rule would not permit use of the
equation for AXIOM cladding. The Baker-Just equation predicts
conservatively high oxidation rates compared with modern correlations
(i.e., Cathcart-Pawell) and has been shown to remain conservative and
applicable for many modern zirconium alloys. The licensee provided the
nominal alloying composition for ZIRLOTM, Optimized
ZIRLOTM, and AXIOM cladding material. The licensee provided
evidence that the Baker-Just equation conservatively predicts the rate
of energy release, hydrogen generation, and cladding oxidation for the
AXIOM material. Based upon similar material composition, the high
temperature metal-water reaction rates are expected to be similar, and
the continued use of the Baker-Just equation is judged by the NRC staff
to be acceptable. Additionally, the licensee performs cycle-specific
reload evaluations to assure that Sec. 50.46 acceptance criteria are
satisfied and will include the LTAs in such analysis. Therefore, the
NRC staff determined that the application of paragraph I.A.5 of 10 CFR
part 50, appendix K, related to cladding material is not necessary to
achieve the underlying purpose of the rule in these circumstances.
Since these evaluations demonstrate that the underlying purpose of the
rule will be met, there will be no undue risk to the public health and
safety. Based on the regulatory review of the exemption request, the
NRC staff concludes that the intent of Sec. 50.46 and 10 CFR part 50,
appendix K, will continue to be satisfied for the planned operation of
MPS-3 with Westinghouse AXIOM fuel cladding and fuel assembly material
used for non-limiting LTAs.
C. Consistent With the Common Defense and Security
The licensee's exemption request is to allow the application of the
aforementioned regulations to an improved fuel rod cladding material.
In its letter dated June 30, 2016, the licensee stated that all the
requirements and acceptance criteria will be maintained. The licensee
is required to handle and control special nuclear material in these
assemblies in accordance with its approved procedures. The use of LTAs
with AXIOM fuel rod cladding in the MPS-3 core is not related to and
does not raise security issues. Therefore, the NRC staff has determined
that this exemption does not 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 purpose of Sec. 50.46 and 10 CFR part 50,
appendix K, is to establish acceptance criteria for ECCS performance to
provide reasonable assurance of safety in the event of a LOCA. The
regulations in Sec. 50.46 and 10 CFR part 50, appendix K, are not
directly applicable to AXIOM, even though the evaluations described in
the following sections of this exemption show that the intent of the
regulation is met. Therefore, since the underlying purposes of Sec.
50.46 and 10 CFR part 50, appendix K, are achieved through the use of
AXIOM fuel rod cladding material, the special circumstances required by
Sec. 50.12(a)(2)(ii) for the granting of an exemption exist.
E. Environmental Considerations
The NRC staff determined that the exemption discussed herein meets
the eligibility criteria for the categorical exclusion set forth in
Sec. 51.22(c)(9) because it is related to a requirement concerning the
installation or use of a facility component located within the
[[Page 22864]]
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 Sec. 51.22(b), no
environmental impact statement or environmental assessment need to 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 Sec.
51.22(c)(9).
Requirements in Sec. 51.22(c)(9)(i)
The NRC staff evaluated the issue of no significant hazards
consideration, using the standards described in Sec. 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 DNC to insert up to eight LTAs
with AXIOM fuel rod cladding at MPS-3. The proposed exemption from the
requirements of Sec. 50.46 and 10 CFR part 50, appendix K, to permit
the use of the AXIOM cladding material in the MPS-3 core does not
adversely affect any fission product barrier, nor does it alter the
safety function of safety systems, structures, or components, or their
roles in accident prevention or mitigation. AXIOM cladding material is
not an accident initiator. The response of the fuel to an accident is
analyzed using conservative techniques, and the results are compared to
NRC-approved acceptance criteria. Reload specific analyses conducted by
DNC and the fuel vendor demonstrate that the design limits of the fuel
cladding are met. Station operation and analysis will continue to be in
compliance with NRC regulations. Westinghouse will perform a cycle-
specific analysis of the MPS-3 core using LOCA methods approved for the
site to ensure that assemblies with AXIOM fuel rod cladding material
meet the LOCA safety criteria. Therefore, the plant will continue to
meet applicable design criteria and safety analysis acceptance
criteria.
Consequently, permitting the insertion of up to eight LTAs with
AXIOM fuel rod cladding in the MPS-3 core does not affect the
probability of an accident or the consequences thereof.
Therefore, the proposed change 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?
Response: No.
The proposed exemption from the requirements of Sec. 50.46 and 10
CFR part 50, appendix K, does not impact the plant configuration or
system performance. The proposed exemption does not modify any
interfaces with existing equipment, change the equipment's function, or
change the method of operating the equipment. Use of the AXIOM fuel rod
cladding material in the MPS-3 core does not adversely affect any
fission product barrier, nor does it alter the safety function of
safety systems, structures, or components, or their roles in accident
prevention or mitigation. Westinghouse will perform a cycle-specific
analysis of the MPS-3 core using LOCA methods approved for the site to
ensure that assemblies with AXIOM fuel rod cladding material meet the
LOCA safety criteria. Prior to each cycle, the AXIOM LTAs will be
evaluated to ensure that current design criteria are met for the
projected burnup. Current NRC-approved models will be conservatively
applied to bound AXIOM cladding material properties and expected
behavior. If any current design criteria are not met, the LTAs with
AXIOM fuel rod cladding will not be inserted into the core. The
proposed exemption assures there is adequate margin available to meet
safety analysis criteria and does not introduce any failure modes,
accident initiators, or equipment malfunctions that would cause a new
or different kind of accident.
Therefore, the proposed change 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 from the requirements of Sec. 50.46 and 10
CFR part 50, appendix K, does not impact the plant configuration or
system performance, and use of the AXIOM cladding material in the MPS-3
core does not adversely affect any fission product barrier. Current
NRC-approved models will be conservatively applied to bound AXIOM
cladding material properties and expected behavior to ensure the plant
continues to meet applicable design criteria and safety analysis
acceptance criteria. The proposed exemption does not alter the manner
in which safety limits, limiting safety system settings, or limiting
conditions for operation are determined, and the dose analysis
acceptance criteria are not affected. The proposed exemption does not
result in plant operation in a configuration outside the analysis or
design basis and does not adversely affect systems that respond to
safely shut down the plant and maintain the plant in a safe shutdown
condition. Westinghouse will perform a cycle-specific analysis of the
MPS-3 core using LOCA methods approved for the site to ensure that
assemblies with AXIOM fuel rod cladding material meet the LOCA safety
criteria. Prior to each cycle, the AXIOM LTAs will be evaluated to
ensure that current design criteria are met for the projected burnup.
Current NRC-approved models will be conservatively applied to bound
AXIOM cladding material properties and expected behavior. If any
current design criteria are not met, the AXIOM cladding LTAs will not
be inserted into the core.
Therefore, the proposed change does not involve a significant
reduction in a margin of safety.
Based on the above, the NRC staff concludes that the proposed
exemption presents no significant hazards consideration under the
standards set forth in Sec. 50.92(c), and, accordingly, a finding of
no significant hazards consideration is justified (i.e., satisfies the
provisions of Sec. 51.22(c)(9)(i)).
Requirements in Sec. 51.22(c)(9)(ii)
The proposed exemption would allow the use of AXIOM fuel rod
cladding material in the MPS-3 reactor. AXIOM material has essentially
the same properties as the currently licensed Optimized
ZIRLOTM cladding and standard ZIRLOTM alloys. The
use of the AXIOM fuel rod cladding material will not significantly
change the types of effluents that may be released offsite or
significantly increase the amount of effluents that may be released
offsite. Therefore, the provisions of Sec. 51.22(c)(9)(ii) are
satisfied.
Requirements in Sec. 51.22(c)(9)(iii)
The proposed exemption would allow the use of AXIOM fuel rod
cladding material in the reactors. AXIOM material has essentially the
same properties as the currently licensed Optimized ZIRLOTM
cladding and standard ZIRLOTM alloys. The use of the AXIOM
fuel rod cladding material will not significantly increase individual
occupational radiation exposure or significantly increase cumulative
occupational radiation exposure. Therefore, the provisions of Sec.
51.22(c)(9)(iii) are satisfied.
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Conclusion
Based on the above, the NRC staff concludes that the proposed
exemption meets the eligibility criteria for the categorical exclusion
set forth in Sec. 51.22(c)(9). Therefore, in accordance with Sec.
51.22(b), no environmental impact statement or environmental assessment
need to be prepared in connection with the NRC's proposed issuance of
this exemption.
IV. Conclusion
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 DNC an exemption from the
requirements of 10 CFR 50.46 and appendix K of 10 CFR part 50, to allow
the use of AXIOM fuel rod cladding material at MPS-3. As stated above,
this exemption relates solely to the cladding material specified in
these regulations.
Dated at Rockville, Maryland, this 10th day of May 2017.
For the Nuclear Regulatory Commission.
MaryJane Ross-Lee,
Acting Director, Division of Operating Reactor Licensing, Office of
Nuclear Reactor Regulation.
[FR Doc. 2017-10073 Filed 5-17-17; 8:45 am]
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