[Federal Register Volume 85, Number 46 (Monday, March 9, 2020)]
[Notices]
[Pages 13676-13678]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-04767]


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NUCLEAR REGULATORY COMMISSION

[Docket Nos. STN 50-528, STN 50-529, and STN 50-530; NRC-2020-0069]


Arizona Public Service Company; Palo Verde Nuclear Generating 
Station, Units 1, 2, and 3

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 July 6, 2018, request, as supplemented by 
letters dated October 18, 2018; March 1, 2019; May 17, 2019; October 4, 
2019; November 26, 2019; and December 19, 2019, from Arizona Public 
Service Company (the licensee) in order to use Framatome M5[supreg] 
alloy as a fuel rod cladding material at Palo Verde Nuclear Generating 
Station, Units 1, 2, and 3.

DATES: The exemption was issued on March 4, 2020.

ADDRESSES: Please refer to Docket ID NRC-2020-0069 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 http://www.regulations.gov and search for Docket ID NRC-2020-0069. Address 
questions about NRC docket IDs in Regulations.gov to Jennifer Borges; 
telephone: 301-287-9127; 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 ``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 in this

[[Page 13677]]

document (if that document 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: Siva P. Lingam, Office of Nuclear 
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 
20555-0001; telephone: 301-415-1564, email: [email protected].

SUPPLEMENTARY INFORMATION: The text of the exemption is attached.

    Dated at Rockville, Maryland, this 4th day of March, 2020.

    For the Nuclear Regulatory Commission.
Siva P. Lingam,
Project Manager, Plant Licensing Branch IV, Division of Operating 
Reactor Licensing, Office of Nuclear Reactor Regulation.
Attachment: Exemption

Nuclear Regulatory Commission

Docket Nos. STN 50-528, STN 50-529, and STN 50-530 Arizona Public 
Service Company Palo Verde Nuclear Generating Station, Units 1, 2, and 
3 Exemption

I. Background

    Arizona Public Service Company (APS, the licensee) is the holder of 
Renewed Facility Operating License Nos. NPF-41, NPF-51, and NPF-74, 
which authorizes operation of Palo Verde Nuclear Generating Station, 
Units 1, 2, and 3 (Palo Verde), respectively. 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 Maricopa County, Arizona.
    By application dated July 6, 2018, as supplemented by letters dated 
October 18, 2018; March 1, 2019; May 17, 2019; October 4, 2019; 
November 26, 2019; and December 19, 2019 (Agencywide Documents Access 
and Management System (ADAMS) Accession Nos. ML18187A417, ML18296A466, 
ML19060A298, ML19137A118, ML19277J457, ML19331A361, and ML19353C038, 
respectively), APS, pursuant to Title 10 of the Code of Federal 
Regulations (10 CFR) Section 50.12, ``Specific exemptions,'' requested 
an exemption from certain requirements of 10 CFR 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,'' for Palo Verde. Since these regulations 
specifically refer only to zircaloy and ZIRLOTM, an 
exemption would be required to apply them to fuel clad with other 
materials, such as Framatome M5[supreg] zirconium alloy.\1\ Therefore, 
APS has requested such an exemption to support transition to the 
Framatome M5[supreg] alloy cladding. The proposed request would not 
exempt Palo Verde from the 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.
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    \1\ HTP and M5[supreg]'' are trademarks or registered 
trademarks of Framatome, Inc. (formerly AREVA Inc.).
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    The submittal from APS described above also contains the fuel 
transition license amendment request that is necessary to support batch 
loading of Framatome Advanced Combustion Engineering (CE) 16x16 High 
Thermal Performance (HTPTM) fuel. This exemption is specific 
to the Framatome M5[supreg] cladding material exemption request only. 
The fuel transition and associated technical specification changes are 
subject to a concurrent review that is being documented in the safety 
evaluation (SE) with the license amendments (ADAMS Accession No. 
ML20031C947).
    Precedent exemptions have also been approved for other CE plants 
including St. Lucie Plant, Unit Nos. 1 and 2 (ADAMS Accession Nos. 
ML14064A125 and ML16015A286, respectively).

II. Request/Action

    By application dated July 6, 2018, as supplemented by letters dated 
October 18, 2018, and March 1, 2019; May 17, 2019; October 4, 2019; 
November 26, 2019; and December 19, 2019, APS, pursuant to 10 CFR 
50.12, 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 the application of 10 CFR 50.46 and Appendix K to 10 CFR part 50 
to fuel rods cladded with Framatome M5[supreg] alloy at Palo Verde. 
Since the requirements in 10 CFR 50.46 and Appendix K to 10 CFR part 50 
are predicated upon the use of fuel clad with zircaloy or 
ZIRLOTM alloy, an exemption is necessary to apply these 
requirements to fuel rods clad with Framatome M5[supreg] alloy.
    The technical basis supporting the use of fuel clad with M5[supreg] 
in PWRs is documented primarily in Topical Report BAW-10227-P-A, 
Revision 1, ``Evaluation of Advanced Cladding and Structural Material 
(M5[supreg]) in PWR Reactor Fuel,'' dated June 2003 (ADAMS Accession 
No. ML15162B043). This topical report describes Framatome's evaluation 
supporting the use of the M5[supreg] alloy in PWR fuel assemblies as a 
replacement for Zircaloy-4. This topical report discusses fundamental 
material properties of M5[supreg], as well as its behavior under normal 
operation, anticipated transients, and postulated accident conditions.

III. Discussion

    The regulation in Section 50.46(a)(1)(i) of 10 CFR 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.
    The regulation in paragraph I.A.5, ``Metal--Water Reaction Rate,'' 
of 10 CFR part 50, Appendix K, 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,'' ANL-6548, 
page 7, May 1962).

    The requirement for using the Baker-Just equation in Appendix K-
conformant loss-of-coolant accident evaluation models presumes 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.
    The exemption request from APS relates solely to the particular 
types of fuel cladding materials specified in these regulations. As 
written, the regulations presume use of zircaloy or ZIRLOTM 
cladding. Thus, an exemption is necessary to apply 10 CFR 50.46 and 10 
CFR part 50, Appendix K to other cladding materials such as M5[supreg]. 
The proposed request would not exempt Palo Verde from any other 
requirements of 10 CFR 50.46 or 10 CFR part 50,

[[Page 13678]]

Appendix K regarding acceptance criteria, evaluation model features and 
documentation, reporting of changes or errors, etc.
    Section 50.12 of 10 CFR states that the Commission may grant 
exemptions from requirements of the regulations in 10 CFR part 50 for 
reasons, which are (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 in 
particular that the special circumstance associated with this exemption 
request is that restricting application of 10 CFR 50.46 and 10 CFR part 
50, Appendix K to fuels clad with only zircaloy or ZIRLOTM 
is not necessary to achieve the underlying purpose of these 
regulations.

A. The Exemption is Authorized by Law

    The NRC has the authority under 10 CFR 50.12 to grant exemptions 
from the requirements of Part 50 upon demonstration of proper 
justification. The fuel that will be irradiated at Palo Verde 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 the acceptance criteria and methods of these regulations 
applicable to M5[supreg], and the licensee will ensure that these 
regulations are satisfied for operation with fuel clad with M5[supreg]. 
Therefore, the exemption is authorized by law.

B. The Exemption Presents No Undue Risk to Public Health and Safety

    The NRC-approved Topical Report BAW-10227-P-A, 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 further found that the 
acceptance criteria and analytical methods from 10 CFR 50.46 and 10 CFR 
part 50, Appendix K provide acceptable safety margins for fuel clad 
with M5[supreg] that are consistent with those the NRC has established 
for zircaloy and ZIRLO\TM\. Reload cores involving M5[supreg] cladding 
will continue to be subject to the operating limits specified in the 
technical specifications and core operating limits report. Thus, 
granting this exemption request will 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 described in this SE, the NRC staff has further evaluated all 
licensing-basis changes necessary to support loading fuel clad with 
M5[supreg] in a separate SE and documented the basis for their 
acceptability. Based on these reviews, the NRC staff concludes that the 
use of M5[supreg] fuel rod cladding at Palo Verde 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 topical report (i.e., 
BAW-10227-P-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. Normal core 
reload safety analyses will further confirm on a cycle-specific basis 
that there is no adverse impact on ECCS performance for Palo Verde. 
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 Palo Verde would be consistent with the underlying 
regulatory purpose.

E. Supplemental Information

    For more technical details, refer to the SE associated with this 
exemption under ADAMS Accession No. ML20022A109 (Enclosure 2).

F. Environmental Considerations

    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 APS an exemption from the 
requirements of 10 CFR 50.46 and 10 CFR part 50, Appendix K, to allow 
the use of Framatome M5[supreg] alloy fuel rod cladding material at 
Palo Verde, Units 1, 2, and 3. As stated above, this exemption relates 
solely to the cladding material specified in these regulations.

    Dated at Rockville, Maryland, this 4th day of March 2020.

    For the Nuclear Regulatory Commission.
Craig G. Erlanger,
Director, Division of Operating Reactor Licensing, Office of Nuclear 
Reactor Regulation.
[FR Doc. 2020-04767 Filed 3-6-20; 8:45 am]
BILLING CODE 7590-01-P