[Federal Register Volume 81, Number 154 (Wednesday, August 10, 2016)]
[Notices]
[Pages 52910-52912]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-18979]
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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-482; NRC-2016-0162]
Wolf Creek Generating Station; Use of Optimized
ZIRLOTM 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 January 27, 2016, request, as supplemented
on May 19, 2016, from Wolf Creek Nuclear Operating Corporation (WCNOC
or the licensee) in order to use Optimized ZIRLOTM fuel rod
cladding material at Wolf Creek Generating Station (WCGS).
DATES: The exemption was issued on August 2, 2016.
ADDRESSES: Please refer to Docket ID NRC-2016-0162 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-2016-0162. 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 in this document
(if that document is 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: Carl F. Lyon, Office of Nuclear
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001; telephone: 301-415-2296, email: [email protected].
SUPPLEMENTARY INFORMATION:
I. Background
The licensee is the holder of Renewed Facility Operating License
No. NPF-42, which authorizes operation of WCGS. 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
facility consists of a pressurized-water reactor located in Coffey
County, Kansas.
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 January 27, 2016, as supplemented by letter dated May
19, 2016 (ADAMS Accession Nos. ML16033A470 and ML16161A509,
respectively), an exemption from specific 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,'' to allow the use of fuel rod cladding with
Optimized ZIRLOTM alloy for future reload applications. The
regulations in 10 CFR 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 Optimized ZIRLOTM.
The licensee requested the exemption because these regulations do not
have provisions for the use of fuel rod cladding material other than
zircaloy or ZIRLOTM. Because the material specifications of
Optimized ZIRLOTM differ from the specifications for
zircaloy or ZIRLOTM, a plant-specific exemption is required
to support the reload applications for WCGS.
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 provide for
the application of the acceptance criteria of 10 CFR 50.46 and 10 CFR
part 50, appendix K, to fuel assembly designs using Optimized
ZIRLOTM fuel rod cladding material. In its letter dated
January 27, 2016, as supplemented by letter dated May 19, 2016, the
licensee indicated that it was 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 Optimized ZIRLOTM fuel
rod cladding material.
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),
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 10 CFR part 50,
appendix K, is to establish acceptance criteria for ECCS performance.
The regulations in 10 CFR 50.46 and 10 CFR part 50, appendix K, are not
directly applicable to Optimized ZIRLOTM, 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 10 CFR 50.46 and 10 CFR part 50, appendix K,
[[Page 52911]]
are achieved through the use of Optimized ZIRLOTM fuel rod
cladding material, 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 Optimized ZIRLOTM
fuel rod cladding material for future reload applications at WCGS. 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
granting the licensee's proposed 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.
C. 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 postulated loss-of-coolant accidents (LOCAs)
conforms to the criteria set forth in 10 CFR 50.46(b). The underlying
purpose of 10 CFR 50.46 is to establish acceptance criteria for
adequate ECCS performance. As previously documented in the NRC staff's
safety evaluation dated June 10, 2005 (ADAMS Package Accession No.
ML051670395), of topical reports submitted by Westinghouse Electric
Company (Westinghouse), and subject to compliance with the specific
conditions of approval established in the safety evaluation, the NRC
staff found that Westinghouse demonstrated the applicability of these
ECCS acceptance criteria to Optimized ZIRLOTM. The NRC staff
found that the Westinghouse topical report demonstrates the
applicability of these ECCS acceptance criteria to Optimized ZIRLO\TM\,
subject to the compliance with the specific conditions of approval
established therein. The NRC staff reviewed the licensee's January 27,
2016, application, as supplemented by letter dated May 9, 2016, against
these specific conditions and found that the licensee was in compliance
with all of the applicable conditions. The NRC staff's review of these
specific conditions for WCGS can be found in ADAMS under Accession No.
ML16179A293. Ring compression tests performed by Westinghouse on
Optimized ZIRLOTM (see WCAP-14342-A & CENPD-404-NP-A, dated
July 2006 (ADAMS Accession No. ML062080569), demonstrate an acceptable
retention of post-quench ductility up to 10 CFR 50.46 limits of 2200
degrees Fahrenheit and 17 percent equivalent clad reacted. Furthermore,
the NRC staff concluded that oxidation measurements provided by the
licensee by letter LTR-NRC-07-58 from Westinghouse to the NRC, ``SER
Compliance with WCAP-12610-P-A & CENPD-404-P-A, Addendum 1-A,
`Optimized ZIRLOTM,' '' dated November 6, 2007 (public
version in ADAMS under Accession No. ML073130560), illustrate that
oxide thickness and associated hydrogen pickup for Optimized
ZIRLOTM at any given burnup would be less than both
zircaloy-4 and ZIRLOTM. Hence, the NRC staff concludes that
Optimized ZIRLOTM would be expected to maintain better post-
quench ductility than ZIRLOTM. This finding is further
supported by an ongoing LOCA research program at Argonne National
Laboratory, which has identified a strong correlation between cladding
hydrogen content (caused by in-service corrosion) and post-quench
ductility.
In addition, the provisions of 10 CFR 50.46 require the licensee to
periodically evaluate the performance of the ECCS, using currently
approved LOCA models and methods, to ensure that the fuel rods will
continue to satisfy the 10 CFR 50.46 acceptance criteria. In its letter
dated January 27, 2016, the licensee stated that for LOCA scenarios,
where the slight difference in Optimized ZIRLOTM material
properties relative to standard ZIRLOTM could have some
impact on the overall accident scenario, plant-specific LOCA analyses
using Optimized ZIRLOTM properties will demonstrate that the
acceptance criteria of 10 CFR 50.46 have been satisfied. Granting the
exemption to allow the licensee to use Optimized ZIRLOTM
fuel rod cladding material in addition to the current mix of fuel rods
does not diminish this requirement of periodic evaluation of ECCS
performance. Therefore, the underlying purpose of the rule will
continue to be achieved for WCGS.
Paragraph I.A.5 of 10 CFR part 50, appendix K, states that the
rates of energy release, 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 this provision of the rule would not
permit use of the equation for the Optimized ZIRLOTM fuel
rod cladding material for determining acceptable fuel performance.
However, the NRC staff previously found that metal-water reaction tests
performed by Westinghouse on Optimized ZIRLOTM (see Appendix
B of WCAP-12610-P-A & CENPD-404-P-A Addendum 1-A) demonstrate
conservative reaction rates relative to the Baker-Just equation.
Therefore, the NRC staff determined that the application of Paragraph
I.A.5 of 10 CFR part 50, appendix K, 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.
D. Consistent With the Common Defense and Security
The licensee's exemption request is only to allow the application
of the aforementioned regulations to an improved fuel rod cladding
material. In its letter dated January 27, 2016, as supplemented by
letter dated May 19, 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. This change to
the plant configuration is not related to security issues. Therefore,
the NRC staff determined that this exemption does not impact 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 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. 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).
Requirements in 10 CFR 51.22(c)(9)(i)
The NRC staff evaluated the issue of no significant hazards
consideration,
[[Page 52912]]
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 change would allow the use of
Optimized ZIRLOTM fuel rod cladding material in the
reactors. The NRC approved topical report WCAP-12610-P-A & CENPD-
404-P-A Addendum 1-A, ``Optimized ZIRLOTM,'' prepared by
Westinghouse, addresses Optimized ZIRLOTM and
demonstrates that Optimized ZIRLOTM has essentially the
same properties as the currently licensed ZIRLOTM. The
fuel cladding itself is not an accident initiator and does not
affect accident probability. Use of Optimized ZIRLOTM
fuel rod cladding material will continue to meet all 10 CFR 50.46
acceptance criteria and, therefore, will not increase the
consequences of an accident.
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 use of Optimized ZIRLOTM fuel rod
cladding material will not result in changes in the operation or
configuration of the facility. Topical Report WCAP-12610-P-A &
CENPD-404-P-A demonstrated that the material properties of Optimized
ZIRLOTM are similar to those of standard
ZIRLOTM. Therefore, the Optimized ZIRLOTM fuel
rod cladding material will perform similarly to those fabricated
from standard ZIRLOTM, therefore precluding the
possibility of the fuel cladding becoming an accident initiator and
causing a new or different type 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 change will not involve a significant
reduction in the margin of safety, because it has been demonstrated
that the material properties of the Optimized ZIRLOTM are
not significantly different from those of standard
ZIRLOTM. Optimized ZIRLOTM is expected to
perform similarly to standard ZIRLOTM for all normal
operating and accident scenarios, including both LOCA and non-LOCA
scenarios. For LOCA scenarios, where the slight difference in the
Optimized ZIRLOTM material properties, relative to
standard ZIRLOTM could have some impact on the overall
accident scenario, plant-specific LOCA analyses using the Optimized
ZIRLOTM properties demonstrate that the acceptance
criteria of 10 CFR 50.46 have been satisfied.
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 10 CFR 50.92(c), and, accordingly, a finding
of no significant hazards consideration is justified (i.e.,
satisfies the provision of 10 CFR 51.22(c)(9)(i)).
Requirements in 10 CFR 51.22(c)(9)(ii)
The proposed exemption would allow the use of Optimized
ZIRLOTM fuel rod cladding material in the reactors.
Optimized ZIRLOTM has essentially the same properties as the
currently licensed ZIRLOTM. The use of the Optimized
ZIRLOTM 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 provision of 10 CFR 51.22(c)(9)(ii) is
satisfied.
Requirements in 10 CFR 51.22(c)(9)(iii)
The proposed exemption would allow the use of the Optimized
ZIRLOTM fuel rod cladding material in the reactors.
Optimized ZIRLOTM has essentially the same properties as the
currently licensed ZIRLOTM. The use of the Optimized
ZIRLOTM fuel rod cladding material will not significantly
increase individual occupational radiation exposure, or significantly
increase cumulative occupational radiation exposure. Therefore, the
provision of 10 CFR 51.22(c)(9)(iii) is satisfied.
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 are present.
Therefore, the Commission hereby grants WCNOC an exemption from the
requirements of 10 CFR 50.46 and 10 CFR part 50, appendix K, to allow
the use of Optimized ZIRLOTM fuel rod cladding material at
WCGS. As stated above, this exemption relates solely to the cladding
material specified in these regulations.
Dated at Rockville, Maryland, this 2nd day of August 2016.
For the Nuclear Regulatory Commission.
Anne T. Boland,
Director, Division of Operating Reactor Licensing, Office of Nuclear
Reactor Regulation.
[FR Doc. 2016-18979 Filed 8-9-16; 8:45 am]
BILLING CODE 7590-01-P