Wolf Creek Generating Station; Use of Optimized ZIRLOTM, 52910-52912 [2016-18979]
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Federal Register / Vol. 81, No. 154 / Wednesday, August 10, 2016 / Notices
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SUPPLEMENTARY INFORMATION:
I. Background
Wolf Creek Generating Station; Use of
Optimized ZIRLOTM Fuel Rod Cladding
Material
Nuclear Regulatory
Commission.
ACTION: Exemption; issuance.
AGENCY:
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
https://www.regulations.gov and search
for Docket ID NRC–2016–0162. Address
questions about NRC dockets to Carol
Gallagher; telephone: 301–415–3463;
email: Carol.Gallagher@nrc.gov. 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 publiclyavailable documents online in the
mstockstill on DSK3G9T082PROD with NOTICES
SUMMARY:
VerDate Sep<11>2014
17:34 Aug 09, 2016
Jkt 238001
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 § 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
PO 00000
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Fmt 4703
Sfmt 4703
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,
E:\FR\FM\10AUN1.SGM
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Federal Register / Vol. 81, No. 154 / Wednesday, August 10, 2016 / Notices
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.
mstockstill on DSK3G9T082PROD with NOTICES
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
ZIRLOTM, 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
VerDate Sep<11>2014
17:34 Aug 09, 2016
Jkt 238001
(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 metalwater 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
PO 00000
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Fmt 4703
Sfmt 4703
52911
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,
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52912
Federal Register / Vol. 81, No. 154 / Wednesday, August 10, 2016 / Notices
mstockstill on DSK3G9T082PROD with NOTICES
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.
VerDate Sep<11>2014
17:34 Aug 09, 2016
Jkt 238001
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
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Frm 00103
Fmt 4703
Sfmt 4703
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]
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Agencies
[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.
-----------------------------------------------------------------------
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 https://www.regulations.gov and search for Docket ID NRC-2016-0162. Address
questions about NRC dockets to Carol Gallagher; telephone: 301-415-
3463; email: Carol.Gallagher@nrc.gov. 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 https://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 pdr.resource@nrc.gov. 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: Fred.Lyon@nrc.gov.
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