[Federal Register Volume 80, Number 97 (Wednesday, May 20, 2015)]
[Notices]
[Pages 29102-29105]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[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
[[Page 29103]]
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
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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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