[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]
 BILLING CODE 7590-01-P