80 FR 29102 - Dominion Nuclear Connecticut, Inc., Millstone Power Station, Unit 2

NUCLEAR REGULATORY COMMISSION

Federal Register Volume 80, Issue 97 (May 20, 2015)

The U.S. Nuclear Regulatory Commission (NRC) is issuing an exemption in response to an April 11, 2014, request from Dominion Nuclear Connecticut, Inc., requesting an exemption to use a different fuel rod cladding material (M5<SUP>TM</SUP>, hereafter referred as M5).

[Federal Register Volume 80, Number 97 (Wednesday, May 20, 2015)]
[Notices]
[Pages 29102-29105]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2015-12264]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-336; NRC-2015-0125]


Dominion Nuclear Connecticut, Inc., Millstone Power Station, Unit 
2

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 an April 11, 2014, request from Dominion 
Nuclear Connecticut, Inc., requesting an exemption to use a different 
fuel rod cladding material (M5TM, hereafter referred as M5).

DATES: May 20, 2015.

ADDRESSES: Please refer to Docket ID NRC-2015-0125 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-2015-0125. 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

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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 available in ADAMS) is provided the first 
time that a document is referenced.
     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].

I. Background

    Dominion Nuclear Connecticut, Inc. (the licensee) is the holder of 
Renewed Facility Operating License No. DPR-65, which authorizes 
operation of Millstone Power Station, Unit 2 (MPS2), 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.
    The MPS2 shares the site with Millstone Power Station, Unit 1, a 
permanently defueled boiling water reactor nuclear unit, and Millstone 
Power Station, Unit 3, a pressurized water reactor. The facility is 
located in Waterford, Connecticut, approximately 3.2 miles west 
southwest of New London, Connecticut. This exemption applies to MPS2 
only. The other units, Units 1 and 3, are not covered by this 
exemption.

II. Request/Action

    Pursuant to section 50.12 of Title 10 of the Code of Federal 
Regulations (10 CFR), ``Specific exemptions,'' the licensee has, by 
letter dated April 11, 2014 (ADAMS Accession No. ML14112A072), 
requested an exemption from 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,'' 
to allow the use of fuel rod cladding with M5 alloy for future 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 appendix K to 10 CFR part 50 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 M5. Thus, the strict application of these regulations 
does not permit the use of fuel rod cladding material other than 
Zircaloy or ZIRLO[supreg]. Because the material specifications of M5 
differ from the specifications for Zircaloy or ZIRLO[supreg], and the 
regulations specify a cladding material other than M5, a plant-specific 
exemption is required to allow the use of, and application of these 
regulations to, M5 at MPS2.
    The exemption request relates solely to the cladding material 
specified in these regulations (i.e., fuel rods with Zircaloy or 
ZIRLO[supreg] cladding material). This exemption would allow 
application of the acceptance criteria of 10 CFR 50.46 and appendix K 
to 10 CFR part 50, to fuel assembly designs using M5 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 
the use of M5 fuel rod cladding material at MPS2. The detailed 
technical basis of the licensee's proposed use of M5 cladding is being 
addressed by the Nuclear Regulatory Commission staff under a proposed 
amendment to the MPS2 operating license; the amendment is issued 
concurrently with the issuance of this exemption.

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)(ii), 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. Special Circumstances

    Special circumstances, in accordance with 10 CFR 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 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 loss-of-
coolant accident (LOCA). Although the regulations in 10 CFR 50.46 and 
appendix K to 10 CFR part 50 are not expressly applicable to M5 alloy 
cladding, the evaluations described in the following sections of this 
exemption show that the purpose of the regulations are met by this 
exemption, in that the effectiveness of the ECCS will not be affected 
by a change from Zircaloy or ZIRLO[supreg] clad fuel rod to M5 clad 
fuel rod. Normal reload safety analyses will confirm that there is no 
adverse impact on ECCS performance. Thus, a strict application of the 
rule (which would preclude the applicability of ECCS performance 
acceptance criteria to, and the use of, M5 fuel cladding material) is 
not necessary to achieve the underlying purposes of 10 CFR 50.46 and 
appendix K to 10 CFR part 50. The purpose of these regulations is 
achieved through application of the requirements to the use of M5 fuel 
rod clad material. Therefore, the special circumstances required by 10 
CFR 50.12(a)(2)(ii) for the granting of an exemption exist.

B. Authorized by Law

    This exemption would allow the use of M5 fuel rod cladding material 
for future reload operations at MPS2. As stated above, 10 CFR 50.12 
allows the NRC to grant exemptions from the requirements of 10 CFR part 
50 provided that special circumstances are present. As described above, 
the NRC staff has determined that special circumstances exist to grant 
the requested exemption. In addition, granting the exemption will not 
result in a violation any part of the Atomic Energy Act of 1954, as 
amended, or the Commission's regulations. Therefore, the exemption is 
authorized by law.

C. No Undue Risk to Public Health and Safety

    Section 10 CFR 50.46 requires that each boiling or pressurized 
light-water nuclear power reactor fueled with uranium dioxide pellets 
within cylindrical Zircaloy or ZIRLO[supreg] cladding must be provided 
with an ECCS that must be designed so that its calculated cooling 
performance following a postulated LOCA conforms to the criteria set 
forth in paragraph (B) of this section. The underlying purpose of 10 
CFR 50.46 is to establish acceptance criteria for adequate ECCS 
performance.
    The NRC-approved topical report BAW-10227(P)-A, ``Evaluation of 
Advanced Cladding and Structural Material (M5) in PWR Reactor Fuel'' 
(ADAMS Accession No. ML003686365) has demonstrated that predicted 
chemical, mechanical, and material performance characteristics of the 
M5

[[Page 29104]]

alloy cladding are bound for those approved for Zircaloy under 
anticipated operational occurrences and postulated accidents. The NRC 
staff's Safety Evaluation (ADAMS Accession No. ML003671021) evaluating 
this topical report concluded that the M5 properties and mechanical 
design methodology are acceptable for fuel reload licensing 
applications. Topical report BAW-10227(P)-A also confirms that no new 
or different type of accident will be initiated that could pose a risk 
to public health and safety.
    The NRC-approved topical Report BAW-10240(P)-A, Revision 0, 
``Incorporation of M5 Properties in Framatome-ANP Approved Methods'' 
(ADAMS Accession No. ML042800314) describes the incorporation of the 
NRC-approved M5 material properties in a set of mechanical analyses, 
small-break loss-of-coolant accident (SBLOCA) and non-LOCA 
methodologies. This topical report demonstrates that the effectiveness 
of the ECCS will not be affected by changing the cladding from Zircaloy 
to M5 alloy.
    The objective of 10 CFR 50.46(b)(2) and (b)(3), and appendix K to 
10 CFR part 50, paragraph I.A.5 is to ensure that cladding oxidation 
and hydrogen generation are appropriately limited during a LOCA and 
conservatively accounted for in a plant's ECCS evaluation model. 
Paragraph I.A.5 of appendix K requires that the Baker-Just equation be 
used in the ECCS evaluation model to determine the rate of energy 
release, cladding oxidation, and hydrogen generation. Based on the 
above, the NRC staff concludes that the intent of 10 CFR 50.46 and 
appendix K to 10 CFR part 50 will continue to be satisfied for the 
planned operation of MPS2 with M5 alloy fuel cladding and fuel assembly 
material.

D. Consistent With the Common Defense and Security

    The M5 cladding material is similar in design to Zircaloy, the 
current cladding material used at MPS2. Thus, the change in cladding 
material from Zircaloy to M5 will not require any change to the 
security and control of special nuclear material. The licensee will 
continue to be required to handle and control special nuclear material 
in these assemblies in accordance with its approved procedures. This 
change to reactor core internals is adequately controlled by NRC 
requirements and is not related to security issues. Therefore, the NRC 
staff determined that this exemption does not impact, and thus is 
consistent with, the common defense and security.

E. 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 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 staff 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 fuel rod cladding 
material in the MPS2 reactor. The NRC approved topical reports cited 
above demonstrate that M5 alloy 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, 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?
    Response: No.
    The use of M5 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 are 
similar to those of standard Zircaloy. Therefore, M5 fuel rod 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 alloy are not significantly different from those 
of standard Zircaloy. M5 alloy is expected to perform similarly to 
standard Zircaloy for all normal operating and accident scenarios. Use 
of M5 alloy 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 fuel rod cladding 
material in the MPS2 reactor. M5 alloy has similar material properties 
and performance characteristics as the currently licensed Zircaloy 
cladding. Thus, the use of M5 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 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 fuel rod cladding 
material in the reactors. M5 alloy has similar material properties and 
performance characteristics as the currently licensed Zircaloy 
cladding. Thus, the use of M5 fuel rod cladding material will not 
significantly increase individual occupational radiation exposure, or

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significantly increase cumulative occupational radiation exposure. 
Therefore, the requirements of 10 CFR 51.22(c)(9)(iii) are met.
Conclusion
    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 proposed 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 pursuant to 10 CFR 
50.12(a)(2)(ii) are present. Therefore, the Commission hereby grants 
Dominion Nuclear Connecticut, Inc., an exemption from the requirements 
of 10 CFR 50.46 and Appendix K to 10 CFR part 50, to allow the 
application of those criteria to, and the use of, M5 fuel rod cladding 
material at MPS2.
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 12th Day of May, 2015.

For the Nuclear Regulatory Commission
Louise Lund,
Acting Director, Division of Operating Reactor Licensing, Office of 
Nuclear Reactor Regulation.
[FR Doc. 2015-12264 Filed 5-19-15; 8:45 am]
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