Exelon Generation Company, LLC; Byron Station, Unit No. 2; Exemption, 21418-21421 [E9-10619]
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Federal Register / Vol. 74, No. 87 / Thursday, May 7, 2009 / Notices
NUCLEAR REGULATORY
COMMISSION
[NRC–2009–0198; Docket No. 50–455]
Exelon Generation Company, LLC;
Byron Station, Unit No. 2; Exemption
1.0
Background
Exelon Generation Company, LLC
(Exelon, the licensee) is the holder of
Facility Operating License No. NPF–66
which authorizes operation of the Byron
Station, Unit No. 2 (Byron 2). The
license provides, among other things,
that the facility is subject to all rules,
regulations, and orders of the Nuclear
Regulatory Commission (NRC, the
Commission) now or hereafter in effect.
The facility is one unit of a two-unit
pressurized-water reactor station located
in Ogle County, Illinois.
2.0
Request/Action
Pursuant to Title 10 of the Code of
Federal Regulations (10 CFR), Section
50.12, ‘‘Specific exemptions,’’ the
licensee has, by letter dated March 24,
2008 (Agencywide Documents Access
and Management System (ADAMS)
Accession No. ML080850235),
requested an exemption from the
requirements of 10 CFR 50.46,
‘‘Acceptance criteria for emergency core
cooling systems for light-water nuclear
power reactors,’’ and 10 CFR Part 50,
Appendix K, ‘‘ECCS Evaluation
Models,’’ for one lead test assembly
(LTA) using Westinghouse AXIOMTM
cladding.
The regulation at 10 CFR 50.46(a)(1)(i)
requires that ‘‘[e]ach boiling or
pressurized light-water nuclear power
reactor fueled with uranium oxide
pellets within cylindrical zircaloy or
ZIRLOTM cladding must be provided
with an emergency core cooling system
(ECCS) that must be designed so that its
calculated cooling performance
following postulated loss-of-coolant
accidents conforms to the criteria set
forth in paragraph (b) of this section.’’
The regulation at 10 CFR 50.46(a)(1)(ii)
requires that, ‘‘[a]lternatively, an ECCS
evaluation model may be developed in
conformance with the required and
acceptable features of appendix K ECCS
Evaluation Models.’’ Appendix K of 10
CFR Part 50 requires, in paragraph I.A.5,
that ‘‘[t]he rate of energy release,
hydrogen generation, and cladding
oxidation from the metal/water reaction
shall be calculated using the Baker-Just
equation (Baker, L., Just, L.C., ‘‘Studies
of Metal Water Reactions at High
Temperatures, III. Experimental and
Theoretical Studies of the ZirconiumWater Reaction,’’ ANL–6548, page 7,
May 1962).’’ The regulations make no
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provisions for use of fuel rods clad in a
material other than zircaloy or
ZIRLOTM. The licensee plans to irradiate
one LTA using fuel rods clad with
AXIOMTM alloy in Byron 2. Because the
material specification of the AXIOMTM
alloy differs from the specification for
zircaloy or ZIRLOTM, the licensee
requested a plant-specific exemption
from the requirements of 10 CFR 50.46
and 10 CFR Part 50, Appendix K, to
support the use of the LTA for Byron 2.
However, as discussed subsequently in
Sections 3.0 and 4.0, the NRC staff
determined that a broad exemption from
all the requirements of 10 CFR 50.46
and 10 CFR Part 50, Appendix K, is not
required in this particular circumstance.
The licensee plans to use one LTA,
containing fresh and twice-burned
AXIOMTM clad fuel rods, in the Byron
2 Cycle 16 reactor core. The twiceburned AXIOMTM clad fuel rods would
continue to be irradiated up to a lead
rod average burnup of up to 75,000
megawatt days per metric ton uranium
(MWD/MTU).
Previously, by letter dated June 30,
2006 (ADAMS Accession No.
ML061380518), the NRC staff approved
the irradiation of four LTAs containing
AXIOMTM clad fuel rods in the Byron
Station, Unit No. 1 (Byron 1), Cycle 15
core. In the same letter, the NRC staff
also approved the re-insertion of two of
the four LTAs into the Byron 1 Cycle 16
core and the other two LTAs into the
Byron 2 Cycle 15 core. Byron 1 is
currently operating in Cycle 16; Byron
2 is currently operating in Cycle 15.
Prior to re-insertion of the LTAs into the
Cycle 16 and Cycle 15 cores,
respectively, for the second cycle of
irradiation, the licensee performed postirradiation examination (PIE) for the
LTAs. During the spring 2010, Byron 2
refueling outage, the licensee plans to
perform PIE for the two LTAs, then reinsert one LTA into the Byron 2 Cycle
16 core to gain high burnup data. The
LTA will consist of fresh fuel rods in
AXIOMTM cladding along with up to 16
twice-burned fuel rods in AXIOMTM
cladding selected from the irradiated
LTAs. During this third cycle, the twiceburned fuel rods will reach a peak rod
average burnup of 75,000 MWD/MTU,
which exceeds the NRC staff’s burnup
limit of 62,000 MWD/MTU (ADAMS
Accession No. ML061420458), based on
the capabilities of the fuel performance
and design models for Westinghouse
VANTAGE+ fuel, which is used in the
Byron 2 reactor core.
3.0 Discussion
Pursuant to 10 CFR 50.12, the
Commission may, upon application by
any interested person or upon its own
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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. The
Commission will not consider granting
an exemption unless special
circumstances are present.
Authorized by Law
This exemption would allow the
licensee to re-insert one LTA containing
AXIOMTM fuel rod cladding that is
neither Zircaloy nor ZIRLOTM, which
are the cladding materials contemplated
by 10 CFR 50.46(a)(1)(i) and by 10 CFR
Part 50, Appendix K, paragraph I.A.5.
Selection of a specific cladding material
in 10 CFR 50.46(a)(1)(i) and in 10 CFR
Part 50, Appendix K, paragraph I.A.5
was at the discretion of the Commission
consistent with its statutory authority.
No statute required the NRC to adopt
this specification. As stated above, 10
CFR 50.12 allows the Commission to
grant exemptions from the requirements
of 10 CFR Part 50. The NRC staff has
determined that granting of an
exemption from 10 CFR 50.46(a)(1)(i)
and from 10 CFR Part 50, Appendix K,
paragraph I.A.5 related to AXIOMTM
fuel rod cladding, which is neither
Zircaloy nor ZIRLOTM, will 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. Furthermore, the
NRC staff has determined that, because
the licensee plans to ensure that the
acceptance and analytical criteria of 10
CFR 50.46 and 10 CFR Part 50,
Appendix K are met following the
insertion of the subject LTA, exemption
from the remaining requirements of 10
CFR 50.46 and 10 CFR Part 50,
Appendix K is not required.
No Undue Risk to Public Health and
Safety
In its March 24, 2008 letter, the
licensee provided technical justification
to support its conclusion that irradiating
one LTA, containing fresh and twiceburned AXIOMTM clad fuel rods, in the
Byron 2 Cycle 16 reactor core, up to a
lead rod average burnup of up to 75,000
MWD/MTU would result in no undue
risk to public health and safety. The
licensee’s technical justification and the
NRC staff’s associated conclusions
follow.
Fuel Mechanical Design Considerations
Prior to Byron 2 Cycle 16,
characterization of the twice-burned
AXIOMTM fuel rods will be performed
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to include an overall visual examination
and measurements of cladding oxide,
fuel rod growth, and diameter profile.
Prior to irradiating the LTA during
Byron 2 Cycle 16, the twice-burned
AXIOMTM clad fuel rods will be
evaluated with current fuel performance
methods and codes to ensure that all
current design criteria are met for the
projected burnup. The licensee stated
that if some of the AXIOMTM clad twiceburned rods scheduled for
reconstitution exhibit anomalous
behavior, have measured characteristics
of oxide thickness or rod length that are
outside acceptable bounds, or are
determined incapable of meeting all
current design requirements, those
twice-burned rods will not be used for
reconstitution and will be replaced with
rods meeting the reload requirements.
The licensee also stated that, to ensure
that the acceptance criteria of 10 CFR
50.46 and 10 CFR Part 50, Appendix K,
are met, the LTA using AXIOMTM
cladding will be evaluated using NRCapproved analytical methods and will
address the changes in the cladding
material properties and that the reload
core containing AXIOMTM cladding will
continue to be operated in accordance
with the operating limits specified in
the Byron Station Technical
Specifications (TS). Based upon the
limited number of AXIOMTM clad fuel
rods, the PIE and characterization which
would detect anomalous behavior, the
use of NRC-approved models to ensure
that all design criteria remain satisfied,
and the requirement to operate the
Byron Cycle 16 core within TS limits,
the NRC staff finds the LTA mechanical
design acceptable for Byron 2 Cycle 16.
Traditionally, the NRC staff had two
criteria for LTA programs: (1) The
number of LTAs should be limited, and
(2) the core locations of LTAs should be
non-limiting (i.e., not in the highest
power regions). In 2003, the NRC staff
endorsed the concept of locating LTAs
next to the highest power or high-duty
regions for simulating typical reactor
operations. By letters dated January 8
and August 29, 2003 (ADAMS
Accession Nos. ML030070476 and
ML032410054, respectively), the NRC
staff approved Westinghouse Topical
Report WCAP–15604–NP, Revision 1,
‘‘Limited Scope High Burnup Lead Test
Assemblies,’’ which provides the basis
and guidelines for the operation of a
limited number of LTAs for a high
burnup irradiation program. Based on
the licensee’s planned LTA program, the
NRC staff considers that the burnup
extension is consistent with the
approved report. Based on the approved
report, acceptable PIEs for the Byron
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LTAs prior to the second cycle of
irradiation, and the licensee’s plans for
PIE and characterization of the twiceburned fuel rods prior to the third cycle
of irradiation, the NRC staff concludes
that it is acceptable to extend the LTA
burnup limit to a peak rod average of
75,000 MWD/MTU for Byron Unit 2.
The Byron 2 reactor core contains a
total of 193 fuel assemblies; each fuel
assembly contains 264 fuel rods. As
mentioned previously, the Byron 2
Cycle 16 LTA, which is the subject of
the licensee’s exemption request, will
consist of up to 16 twice-burned fuel
rods in AXIOMTM cladding with the
remainder (and the majority) being fresh
fuel rods in AXIOMTM cladding, and
will be placed in the Cycle 16 reactor
core in a non-limiting core location. The
licensee stated that setting the number
of AXIOMTM clad rods at this level
restricts the portion of such rods to a
value of 0.52 percent, which, even if
failed, is well within the postulated core
damage in the Byron Station’s current
licensing basis. The licensee also stated
that, even though there have been no
AXIOMTM clad fuel rod failures in the
industry to date, if a failure were to
occur, the effects would be well within
the TS limits for doses and core coolable
geometry would be maintained. Based
upon the limited number of AXIOMTM
clad fuel rods placed in non-limiting
core locations, the use of approved
models and methods, and the acceptable
performance to date of the AXIOMTM
cladding, the NRC staff finds that the
irradiation of the subject LTA in the
Byron 2 Cycle 16 core will not result in
unsafe operation nor violation of
specified acceptable fuel design limits.
Furthermore, in the event of a designbasis accident, these LTAs will not
promote consequences beyond those
currently analyzed, as discussed next.
Dose Analyses Considerations for
Extended Burnup
The licensee stated in its March 24,
2008 letter, that the assessment
contained in Westinghouse Topical
Report WCAP–12610–P–A, ‘‘VANTAGE
+ Fuel Assembly Reference Core
Report,’’ April 1995, concluded that the
fuel-handling accident (FHA) total
effective dose equivalent doses are not
adversely affected by extended burnup
up to 75,000 MWD/MTU. However, the
licensee recognized that there is
uncertainty in fission product gap
inventory, due to the limited fission gas
release measurements on high burnup
fuel, and provided a discussion of the
conservatisms in the Byron FHA dose
calculation. These included use of the
alternative source term (AST)
methodology, the relative power for this
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21419
particular LTA in Cycle 16, offloading
time, containment isolation, and
mechanical fuel damage due to impact.
AST Methodology
The NRC approved the use of an AST
methodology for Byron Station in
License Amendment No. 147, dated
September 8, 2006 (ADAMS Accession
No. ML062340420). The analyses
provided by the licensee in support of
the amendment and approved by the
NRC staff used gap release fractions for
accidents other than the loss-of-coolant
accident (LOCA), which are two times
the values in Table 3 of Regulatory
Guide (RG) 1.183, ‘‘Alternative
Radiological Source Terms for
Evaluating Design Basis Accidents at
Nuclear Power Reactors,’’ July 2000.
The factor of two was used to offset the
fact that some fuel assemblies would
exceed the rod power/burnup criteria in
RG 1.183. For the FHA, all of the fuel
rods in the limiting assembly were
assumed to fail, releasing their fuel/clad
gap fission product inventory. The NRC
staff has previously found this approach
acceptable in the safety evaluation
accompanying the above-cited
amendment.
LTA Relative Power
The licensee stated that, due to its
high burnup, the LTA’s relative power
will not approach the 1.7 peaking limit
assumed in the Updated Final Safety
Analysis Report (UFSAR). The Byron 2
Cycle 16 reactor core will be designed
such that the LTA will remain in a nonlimiting location. Therefore, with more
appropriate relative assembly powers
credited for both the LTA and other
potentially-impacted assemblies, the
calculated dose would decrease.
Although relative assembly powers are
not generally credited in design-basis
accident (DBA) radiological
consequences analyses, the NRC staff
finds that the specific situation
described above does show that
conservatism exists in the current
licensing basis FHA analysis when
compared to the expected impact of
dropping the extended burnup LTA.
Offloading Time
The licensee stated that, although the
FHA calculation assumes that core
offload begins no sooner than 48 hours
after shutdown, in practice, core offload
typically commences much later than 48
hours after entry into Mode 3. However,
because the licensee did not provide
supporting documentation on how it
would assure the expected >48 hours to
start core offload (i.e., TS, physical
constraints, procedures, etc.), the NRC
staff finds that this conservatism cannot
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be credited as a conservatism related to
this exemption request for the subject
LTA. However, the NRC staff notes that
other conservatisms in the FHA,
discussed previously and below, more
than offset this non-credited core
offload time.
Containment Isolation
In accordance with Byron Station TS
3.9.4, the movement of recently
irradiated fuel (i.e., fuel that has
occupied part of a critical reactor core
within the previous 48 hours) requires
that containment integrity be in effect.
Fuel with additional decay can be
moved without containment integrity or
exhaust filtration. Compensatory
measures to close any openings and
ensure exhaust is in the proper direction
within 1 hour after a FHA are required
procedurally as defense-in-depth
measures; however, they are not
credited in the analysis in accordance
with RG 1.183. The NRC staff, in its
review of the licensee’s AST
methodology, has previously found this
approach acceptable and would,
therefore, apply to movement of the
LTA.
Mechanical Fuel Damage Due to Impact
The Byron Station UFSAR analysis
assumes all rods of the dropped
assembly fail. The licensee stated that
this is a very conservative assumption
given the broad spectrum of loads
considered and the resulting high
structural strength of the fuel assembly
and other core components. The
licensee also stated that irradiated fuel
assembly drop events (e.g., Fort Calhoun
in 2003, North Anna in 2001, and
Haddam Neck in 1986) have also
yielded no increase in local area dose
rates. The NRC staff concludes that the
amount of assumed fuel damage in the
current licensing basis is conservative
based on fuel mechanical design and
actual industry experience, even if the
FHA were to involve the subject LTA.
The NRC staff finds that the
conservatisms associated with the AST
analysis, LTA relative power,
compensatory measures during
irradiated fuel movement, and FHA fuel
damage assumptions compensate for the
uncertainties in the gap fractions.
Therefore, the fission product gap
inventory assumed in the current
licensing basis FHA radiological
assessment remains bounding for the
extended burnup LTA.
For other DBAs, even though
extended burnup to 75,000 MWD/MTU
for the one LTA would cause a variation
in the core inventory compared to the
current fuel, there are no significant
increases to isotopes that are major
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contributors to accident doses.
Therefore, the NRC staff finds that
current licensing basis DBA results
remain bounding for estimated offsite
and control room operator doses and the
radiation dose limitations of 10 CFR
50.67, ‘‘Accident Source term,’’ and 10
CFR Part 50, Appendix A, GDC–19,
‘‘Control Room,’’ will not be exceeded.
The NRC staff finds that the licensee
used assumptions, inputs, and methods
that are consistent with the conservative
regulatory requirements and guidance
identified above. Based on the Byron
Station current licensing bases and the
acceptable conservatisms discussed
above, the NRC staff finds with
reasonable assurance that the licensee’s
estimates of the exclusion area
boundary, low-population zone, and
control room doses will continue to
comply with the applicable regulatory
criteria. Therefore, the proposed
extension of the fuel rod average burnup
limit for one LTA is acceptable with
regard to the radiological consequences
of postulated DBAs.
Conclusion
Based upon the limited number and
anticipated performance of the
AXIOMTM clad fuel rods, the use of PIE
and characterization to detect
anomalous behavior to preclude further
irradiation damage, and the use of NRCapproved models to ensure that all
design criteria remain satisfied, the NRC
staff finds the use of the subject LTA up
to 75,000 MWD/MTU in the Byron 2
Cycle 16 reactor core to be acceptable.
Consistent With Common Defense and
Security
The proposed exemption would allow
the use of one LTA with a variant
cladding material. This change to the
plant core configuration has no impact
on security issues. Special nuclear
material in the LTA will continue to be
handled and controlled in accordance
with applicable regulations. Therefore,
the common defense and security is not
impacted by this exemption.
Special Circumstances
In accordance with 10 CFR
50.12(a)(2)(ii), special circumstances are
present whenever application of the
regulation in the particular
circumstances would not serve the
underlying purpose of the rule or is not
necessary to achieve the underlying
purpose of the rule.
The underlying purpose of 10 CFR
50.46(a)(1)(i) is to establish acceptance
criteria for ECCS performance.
Previously, on June 30, 2006, the NRC
staff approved an exemption for four
Byron LTAs that demonstrated the
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acceptability of the AXIOMTM cladding
under LOCA conditions (ADAMS
Accession No. ML061380518). The
unique features of the LTAs were
evaluated for effects on the LOCA
analyses. The results showed that the
LTAs would not adversely affect ECCS
performance. Because the current LTA
will be located in a non-limiting core
location, the licensee concluded and the
NRC staff agrees that the LOCA safety
analyses will remain bounding for the
Cycle 16 LTA for Byron 2. Therefore,
the NRC staff concludes that application
of 10 CFR 50.46(a)(1)(i) in this particular
circumstance is not necessary for the
licensee to achieve the underlying
purpose of the rule.
10 CFR Part 50, Appendix K
Paragraph I.A.5 of Appendix K to 10
CFR Part 50 states that ‘‘[t]he rate of
energy release, hydrogen generation,
and cladding oxidation from the metal/
water reaction shall be calculated using
the Baker-Just equation.’’ The Baker-Just
equation, developed in 1962, presumed
the use of zircaloy clad fuel, and thus
did not address AXIOMTM clad fuel for
determining acceptable fuel
performance. The underlying intent of
this portion of Appendix K is to ensure
that analysis of fuel response to LOCAs
is conservatively calculated. Previously,
in its June 30, 2006, exemption for four
Byron LTAs with AXIOMTM clad fuel
rods (ADAMS Accession No.
ML061380518), the NRC staff concluded
that, based on the material composition
of the AXIOMTM alloy, which is similar
to other licensed zirconium alloys, the
high temperature metal-water reaction
rates are expected to be similar. The
NRC staff also concluded that, because
of the limited number of AXIOMTM clad
fuel rods and the similarity in material
composition to other advanced cladding
materials, the application of the BakerJust equation in the analysis of the four
Byron LTAs with AXIOMTM clad fuel
rods was acceptable. Based on the NRC
staff’s previous conclusions for four
LTAs with AXIOMTM clad fuel rods, the
NRC staff concludes that an exemption
from 10 CFR Part 50, Appendix K, as
requested by the licensee, is not
necessary for the licensee’s request to
apply the Baker-Just equation to the one
LTA with AXIOMTM clad fuel rods
planned for insertion in the Byron 2
Cycle 16 reactor core, because
application of the Baker-Just equation in
this circumstance will achieve the
underlying purpose of the rule.
4.0 Conclusion
Accordingly, the Commission has
determined that, pursuant to 10 CFR
50.12(a), an exemption from the
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requirements of 10 CFR 50.46(a)(1)(i) 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 the licensee an exemption from
the requirement of 10 CFR 46(a)(1)(i)
related to fuel cladding material to
allow one LTA containing AXIOMTM
clad fuel rods to be irradiated in Byron
2 during Cycle 16 up to a lead rod
average burnup of up to 75,000 MWD/
MTU. The remaining requirements of 10
CFR 50.46 remain in effect for the Byron
2 Cycle 16 reactor core.
Furthermore, for the reasons stated in
the previous section, the Commission
has determined that an exemption from
the requirements of 10 CFR Part 50,
Appendix K, is not required. Therefore,
the Commission is not issuing an
exemption from 10 CFR Part 50,
Appendix K for the Byron 2 Cycle 16
reactor core.
Pursuant to 10 CFR 51.32, the
Commission has determined that the
granting of the exemption from 10 CFR
46(a)(1)(i) will not have a significant
effect on the quality of the human
environment (74 FR 20000; April 30,
2009).
This exemption is effective upon
issuance.
Dated at Rockville, Maryland, this 30th day
of April 2009.
For the Nuclear Regulatory Commission.
Joseph Giitter,
Director, Division of Operating Reactor
Licensing, Office of Nuclear Reactor
Regulation.
[FR Doc. E9–10619 Filed 5–6–09; 8:45 am]
BILLING CODE 7590–01–P
NUCLEAR REGULATORY
COMMISSION
Request To Amend a License for the
Export of Radioactive Waste
Pursuant to 10 CFR 110.70(b) ‘‘Public
Notice of Receipt of an Application,’’
please take notice that the Nuclear
Regulatory Commission (NRC) has
received the following request to amend
an export license. Copies of the request
are available electronically through
ADAMS and can be accessed through
the Public Electronic Reading Room
(PERR) link https://www.nrc.gov/readingrm.html at the NRC Homepage.
A request for a hearing or petition for
leave to intervene may be filed within
thirty days after publication of this
notice in the Federal Register. Any
request for hearing or petition for leave
to intervene shall be served by the
requestor or petitioner upon the
applicant, the Office of the General
Counsel, U.S. Nuclear Regulatory
21421
Commission, Washington, DC 20555;
the Secretary, U.S. Nuclear Regulatory
Commission, Washington, DC 20555;
and the Executive Secretary, U.S.
Department of State, Washington, DC
20520.
A request for a hearing or petition for
leave to intervene may be filed with the
NRC electronically in accordance with
NRC’s E–Filing rule promulgated in
August 2007, 72 FR 49139 (Aug. 28,
2007). Information about filing
electronically is available on the NRC’s
public Web site at https://www.nrc.gov/
site-help/e-submittals.html. To ensure
timely electronic filing, at least 5 (five)
days prior to the filing deadline, the
petitioner/requestor should contact the
Office of the Secretary by e-mail at
HEARINGDOCKET@NRC.GOV, or by
calling (301) 415–1677, to request a
digital ID certificate and allow for the
creation of an electronic docket.
In addition to a request for hearing or
petition for leave to intervene, written
comments, in accordance with 10 CFR
110.81, should be submitted within
thirty (30) days after publication of this
notice in the Federal Register to the
Office of the Secretary, U.S. Nuclear
Regulatory Commission, Washington,
DC 20555, Attention: Rulemaking and
Adjudications.
The information concerning the
application follows.
NRC APPLICATION TO AMEND LICENSE FOR THE EXPORT OF RADIOACTIVE WASTE
Name of
Applicant, date
of Application,
date received,
application No., docket No.
Diversified Scientific Services,
Inc. (DSSI), February 26,
2009, February 27, 2009,
XW008/03, 11005323.
Description of material
End use
Material type
Total quantity
Class A radioactive mixed
waste.
For the Nuclear Regulatory Commission.
Dated this 30th day of April 2009 at
Rockville, Maryland.
Scott W. Moore,
Deputy Director, Office of International
Programs.
[FR Doc. E9–10610 Filed 5–6–09; 8:45 am]
BILLING CODE 7590–01–P
License to be amended to:
(1) Extend the expiration
date from 03/31/09 to 12/
31/13; and (2) add authorization to export any waste
generated as a result of
processing materials imported from Atomic Energy
of Canada, Limited (AECL)
under IW012, as amended.
OFFICE OF THE UNITED STATES
TRADE REPRESENTATIVE
[Docket No. WTO/DS392/1]
WTO Dispute Settlement Proceeding
Regarding United States—Certain
Measures Affecting Imports of Poultry
From China
AGENCY: Office of the United States
Trade Representative.
ACTION: Notice; request for comments.
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17:03 May 06, 2009
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Return of non-conforming
waste and/or waste resulting from processing materials imported to AECL for
appropriate disposition.
Recipient
country
Canada.
SUMMARY: The Office of the United
States Trade Representative (‘‘USTR’’) is
providing notice that on April 17, 2009,
the People’s Republic of China
(‘‘China’’) requested consultations with
the United States under the Marrakesh
Agreement Establishing the World Trade
Organization (‘‘WTO Agreement’’) with
respect to certain measures affecting the
import of poultry products from China
into the United States. That request may
be found at www.wto.org contained in a
document designated as WT/DS392/1.
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]]>Agencies
[Federal Register Volume 74, Number 87 (Thursday, May 7, 2009)]
[Notices]
[Pages 21418-21421]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-10619]
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NUCLEAR REGULATORY COMMISSION
[NRC-2009-0198; Docket No. 50-455]
Exelon Generation Company, LLC; Byron Station, Unit No. 2;
Exemption
1.0 Background
Exelon Generation Company, LLC (Exelon, the licensee) is the holder
of Facility Operating License No. NPF-66 which authorizes operation of
the Byron Station, Unit No. 2 (Byron 2). The license provides, among
other things, that the facility is subject to all rules, regulations,
and orders of the Nuclear Regulatory Commission (NRC, the Commission)
now or hereafter in effect.
The facility is one unit of a two-unit pressurized-water reactor
station located in Ogle County, Illinois.
2.0 Request/Action
Pursuant to Title 10 of the Code of Federal Regulations (10 CFR),
Section 50.12, ``Specific exemptions,'' the licensee has, by letter
dated March 24, 2008 (Agencywide Documents Access and Management System
(ADAMS) Accession No. ML080850235), requested an exemption from the
requirements of 10 CFR 50.46, ``Acceptance criteria for emergency core
cooling systems for light-water nuclear power reactors,'' and 10 CFR
Part 50, Appendix K, ``ECCS Evaluation Models,'' for one lead test
assembly (LTA) using Westinghouse AXIOMTM cladding.
The regulation at 10 CFR 50.46(a)(1)(i) requires that ``[e]ach
boiling or pressurized light-water nuclear power reactor fueled with
uranium oxide pellets within cylindrical zircaloy or ZIRLOTM
cladding must be provided with an emergency core cooling system (ECCS)
that must be designed so that its calculated cooling performance
following postulated loss-of-coolant accidents conforms to the criteria
set forth in paragraph (b) of this section.'' The regulation at 10 CFR
50.46(a)(1)(ii) requires that, ``[a]lternatively, an ECCS evaluation
model may be developed in conformance with the required and acceptable
features of appendix K ECCS Evaluation Models.'' Appendix K of 10 CFR
Part 50 requires, in paragraph I.A.5, that ``[t]he rate of energy
release, hydrogen generation, and cladding oxidation from the metal/
water reaction shall be calculated using the Baker-Just equation
(Baker, L., Just, L.C., ``Studies of Metal Water Reactions at High
Temperatures, III. Experimental and Theoretical Studies of the
Zirconium-Water Reaction,'' ANL-6548, page 7, May 1962).'' The
regulations make no provisions for use of fuel rods clad in a material
other than zircaloy or ZIRLOTM. The licensee plans to
irradiate one LTA using fuel rods clad with AXIOMTM alloy in
Byron 2. Because the material specification of the AXIOMTM
alloy differs from the specification for zircaloy or
ZIRLOTM, the licensee requested a plant-specific exemption
from the requirements of 10 CFR 50.46 and 10 CFR Part 50, Appendix K,
to support the use of the LTA for Byron 2. However, as discussed
subsequently in Sections 3.0 and 4.0, the NRC staff determined that a
broad exemption from all the requirements of 10 CFR 50.46 and 10 CFR
Part 50, Appendix K, is not required in this particular circumstance.
The licensee plans to use one LTA, containing fresh and twice-
burned AXIOMTM clad fuel rods, in the Byron 2 Cycle 16
reactor core. The twice-burned AXIOMTM clad fuel rods would
continue to be irradiated up to a lead rod average burnup of up to
75,000 megawatt days per metric ton uranium (MWD/MTU).
Previously, by letter dated June 30, 2006 (ADAMS Accession No.
ML061380518), the NRC staff approved the irradiation of four LTAs
containing AXIOMTM clad fuel rods in the Byron Station, Unit
No. 1 (Byron 1), Cycle 15 core. In the same letter, the NRC staff also
approved the re-insertion of two of the four LTAs into the Byron 1
Cycle 16 core and the other two LTAs into the Byron 2 Cycle 15 core.
Byron 1 is currently operating in Cycle 16; Byron 2 is currently
operating in Cycle 15. Prior to re-insertion of the LTAs into the Cycle
16 and Cycle 15 cores, respectively, for the second cycle of
irradiation, the licensee performed post-irradiation examination (PIE)
for the LTAs. During the spring 2010, Byron 2 refueling outage, the
licensee plans to perform PIE for the two LTAs, then re-insert one LTA
into the Byron 2 Cycle 16 core to gain high burnup data. The LTA will
consist of fresh fuel rods in AXIOMTM cladding along with up
to 16 twice-burned fuel rods in AXIOMTM cladding selected
from the irradiated LTAs. During this third cycle, the twice-burned
fuel rods will reach a peak rod average burnup of 75,000 MWD/MTU, which
exceeds the NRC staff's burnup limit of 62,000 MWD/MTU (ADAMS Accession
No. ML061420458), based on the capabilities of the fuel performance and
design models for Westinghouse VANTAGE+ fuel, which is used in the
Byron 2 reactor core.
3.0 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. The Commission will not
consider granting an exemption unless special circumstances are
present.
Authorized by Law
This exemption would allow the licensee to re-insert one LTA
containing AXIOMTM fuel rod cladding that is neither
Zircaloy nor ZIRLOTM, which are the cladding materials
contemplated by 10 CFR 50.46(a)(1)(i) and by 10 CFR Part 50, Appendix
K, paragraph I.A.5. Selection of a specific cladding material in 10 CFR
50.46(a)(1)(i) and in 10 CFR Part 50, Appendix K, paragraph I.A.5 was
at the discretion of the Commission consistent with its statutory
authority. No statute required the NRC to adopt this specification. As
stated above, 10 CFR 50.12 allows the Commission to grant exemptions
from the requirements of 10 CFR Part 50. The NRC staff has determined
that granting of an exemption from 10 CFR 50.46(a)(1)(i) and from 10
CFR Part 50, Appendix K, paragraph I.A.5 related to AXIOMTM
fuel rod cladding, which is neither Zircaloy nor ZIRLOTM,
will 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. Furthermore, the NRC staff has determined that,
because the licensee plans to ensure that the acceptance and analytical
criteria of 10 CFR 50.46 and 10 CFR Part 50, Appendix K are met
following the insertion of the subject LTA, exemption from the
remaining requirements of 10 CFR 50.46 and 10 CFR Part 50, Appendix K
is not required.
No Undue Risk to Public Health and Safety
In its March 24, 2008 letter, the licensee provided technical
justification to support its conclusion that irradiating one LTA,
containing fresh and twice-burned AXIOMTM clad fuel rods, in
the Byron 2 Cycle 16 reactor core, up to a lead rod average burnup of
up to 75,000 MWD/MTU would result in no undue risk to public health and
safety. The licensee's technical justification and the NRC staff's
associated conclusions follow.
Fuel Mechanical Design Considerations
Prior to Byron 2 Cycle 16, characterization of the twice-burned
AXIOMTM fuel rods will be performed
[[Page 21419]]
to include an overall visual examination and measurements of cladding
oxide, fuel rod growth, and diameter profile. Prior to irradiating the
LTA during Byron 2 Cycle 16, the twice-burned AXIOMTM clad
fuel rods will be evaluated with current fuel performance methods and
codes to ensure that all current design criteria are met for the
projected burnup. The licensee stated that if some of the
AXIOMTM clad twice-burned rods scheduled for reconstitution
exhibit anomalous behavior, have measured characteristics of oxide
thickness or rod length that are outside acceptable bounds, or are
determined incapable of meeting all current design requirements, those
twice-burned rods will not be used for reconstitution and will be
replaced with rods meeting the reload requirements. The licensee also
stated that, to ensure that the acceptance criteria of 10 CFR 50.46 and
10 CFR Part 50, Appendix K, are met, the LTA using AXIOMTM
cladding will be evaluated using NRC-approved analytical methods and
will address the changes in the cladding material properties and that
the reload core containing AXIOMTM cladding will continue to
be operated in accordance with the operating limits specified in the
Byron Station Technical Specifications (TS). Based upon the limited
number of AXIOMTM clad fuel rods, the PIE and
characterization which would detect anomalous behavior, the use of NRC-
approved models to ensure that all design criteria remain satisfied,
and the requirement to operate the Byron Cycle 16 core within TS
limits, the NRC staff finds the LTA mechanical design acceptable for
Byron 2 Cycle 16.
Traditionally, the NRC staff had two criteria for LTA programs: (1)
The number of LTAs should be limited, and (2) the core locations of
LTAs should be non-limiting (i.e., not in the highest power regions).
In 2003, the NRC staff endorsed the concept of locating LTAs next to
the highest power or high-duty regions for simulating typical reactor
operations. By letters dated January 8 and August 29, 2003 (ADAMS
Accession Nos. ML030070476 and ML032410054, respectively), the NRC
staff approved Westinghouse Topical Report WCAP-15604-NP, Revision 1,
``Limited Scope High Burnup Lead Test Assemblies,'' which provides the
basis and guidelines for the operation of a limited number of LTAs for
a high burnup irradiation program. Based on the licensee's planned LTA
program, the NRC staff considers that the burnup extension is
consistent with the approved report. Based on the approved report,
acceptable PIEs for the Byron LTAs prior to the second cycle of
irradiation, and the licensee's plans for PIE and characterization of
the twice-burned fuel rods prior to the third cycle of irradiation, the
NRC staff concludes that it is acceptable to extend the LTA burnup
limit to a peak rod average of 75,000 MWD/MTU for Byron Unit 2.
The Byron 2 reactor core contains a total of 193 fuel assemblies;
each fuel assembly contains 264 fuel rods. As mentioned previously, the
Byron 2 Cycle 16 LTA, which is the subject of the licensee's exemption
request, will consist of up to 16 twice-burned fuel rods in
AXIOMTM cladding with the remainder (and the majority) being
fresh fuel rods in AXIOMTM cladding, and will be placed in
the Cycle 16 reactor core in a non-limiting core location. The licensee
stated that setting the number of AXIOMTM clad rods at this
level restricts the portion of such rods to a value of 0.52 percent,
which, even if failed, is well within the postulated core damage in the
Byron Station's current licensing basis. The licensee also stated that,
even though there have been no AXIOMTM clad fuel rod
failures in the industry to date, if a failure were to occur, the
effects would be well within the TS limits for doses and core coolable
geometry would be maintained. Based upon the limited number of
AXIOMTM clad fuel rods placed in non-limiting core
locations, the use of approved models and methods, and the acceptable
performance to date of the AXIOMTM cladding, the NRC staff
finds that the irradiation of the subject LTA in the Byron 2 Cycle 16
core will not result in unsafe operation nor violation of specified
acceptable fuel design limits. Furthermore, in the event of a design-
basis accident, these LTAs will not promote consequences beyond those
currently analyzed, as discussed next.
Dose Analyses Considerations for Extended Burnup
The licensee stated in its March 24, 2008 letter, that the
assessment contained in Westinghouse Topical Report WCAP-12610-P-A,
``VANTAGE + Fuel Assembly Reference Core Report,'' April 1995,
concluded that the fuel-handling accident (FHA) total effective dose
equivalent doses are not adversely affected by extended burnup up to
75,000 MWD/MTU. However, the licensee recognized that there is
uncertainty in fission product gap inventory, due to the limited
fission gas release measurements on high burnup fuel, and provided a
discussion of the conservatisms in the Byron FHA dose calculation.
These included use of the alternative source term (AST) methodology,
the relative power for this particular LTA in Cycle 16, offloading
time, containment isolation, and mechanical fuel damage due to impact.
AST Methodology
The NRC approved the use of an AST methodology for Byron Station in
License Amendment No. 147, dated September 8, 2006 (ADAMS Accession No.
ML062340420). The analyses provided by the licensee in support of the
amendment and approved by the NRC staff used gap release fractions for
accidents other than the loss-of-coolant accident (LOCA), which are two
times the values in Table 3 of Regulatory Guide (RG) 1.183,
``Alternative Radiological Source Terms for Evaluating Design Basis
Accidents at Nuclear Power Reactors,'' July 2000. The factor of two was
used to offset the fact that some fuel assemblies would exceed the rod
power/burnup criteria in RG 1.183. For the FHA, all of the fuel rods in
the limiting assembly were assumed to fail, releasing their fuel/clad
gap fission product inventory. The NRC staff has previously found this
approach acceptable in the safety evaluation accompanying the above-
cited amendment.
LTA Relative Power
The licensee stated that, due to its high burnup, the LTA's
relative power will not approach the 1.7 peaking limit assumed in the
Updated Final Safety Analysis Report (UFSAR). The Byron 2 Cycle 16
reactor core will be designed such that the LTA will remain in a non-
limiting location. Therefore, with more appropriate relative assembly
powers credited for both the LTA and other potentially-impacted
assemblies, the calculated dose would decrease. Although relative
assembly powers are not generally credited in design-basis accident
(DBA) radiological consequences analyses, the NRC staff finds that the
specific situation described above does show that conservatism exists
in the current licensing basis FHA analysis when compared to the
expected impact of dropping the extended burnup LTA.
Offloading Time
The licensee stated that, although the FHA calculation assumes that
core offload begins no sooner than 48 hours after shutdown, in
practice, core offload typically commences much later than 48 hours
after entry into Mode 3. However, because the licensee did not provide
supporting documentation on how it would assure the expected >48 hours
to start core offload (i.e., TS, physical constraints, procedures,
etc.), the NRC staff finds that this conservatism cannot
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be credited as a conservatism related to this exemption request for the
subject LTA. However, the NRC staff notes that other conservatisms in
the FHA, discussed previously and below, more than offset this non-
credited core offload time.
Containment Isolation
In accordance with Byron Station TS 3.9.4, the movement of recently
irradiated fuel (i.e., fuel that has occupied part of a critical
reactor core within the previous 48 hours) requires that containment
integrity be in effect. Fuel with additional decay can be moved without
containment integrity or exhaust filtration. Compensatory measures to
close any openings and ensure exhaust is in the proper direction within
1 hour after a FHA are required procedurally as defense-in-depth
measures; however, they are not credited in the analysis in accordance
with RG 1.183. The NRC staff, in its review of the licensee's AST
methodology, has previously found this approach acceptable and would,
therefore, apply to movement of the LTA.
Mechanical Fuel Damage Due to Impact
The Byron Station UFSAR analysis assumes all rods of the dropped
assembly fail. The licensee stated that this is a very conservative
assumption given the broad spectrum of loads considered and the
resulting high structural strength of the fuel assembly and other core
components. The licensee also stated that irradiated fuel assembly drop
events (e.g., Fort Calhoun in 2003, North Anna in 2001, and Haddam Neck
in 1986) have also yielded no increase in local area dose rates. The
NRC staff concludes that the amount of assumed fuel damage in the
current licensing basis is conservative based on fuel mechanical design
and actual industry experience, even if the FHA were to involve the
subject LTA.
The NRC staff finds that the conservatisms associated with the AST
analysis, LTA relative power, compensatory measures during irradiated
fuel movement, and FHA fuel damage assumptions compensate for the
uncertainties in the gap fractions. Therefore, the fission product gap
inventory assumed in the current licensing basis FHA radiological
assessment remains bounding for the extended burnup LTA.
For other DBAs, even though extended burnup to 75,000 MWD/MTU for
the one LTA would cause a variation in the core inventory compared to
the current fuel, there are no significant increases to isotopes that
are major contributors to accident doses. Therefore, the NRC staff
finds that current licensing basis DBA results remain bounding for
estimated offsite and control room operator doses and the radiation
dose limitations of 10 CFR 50.67, ``Accident Source term,'' and 10 CFR
Part 50, Appendix A, GDC-19, ``Control Room,'' will not be exceeded.
The NRC staff finds that the licensee used assumptions, inputs, and
methods that are consistent with the conservative regulatory
requirements and guidance identified above. Based on the Byron Station
current licensing bases and the acceptable conservatisms discussed
above, the NRC staff finds with reasonable assurance that the
licensee's estimates of the exclusion area boundary, low-population
zone, and control room doses will continue to comply with the
applicable regulatory criteria. Therefore, the proposed extension of
the fuel rod average burnup limit for one LTA is acceptable with regard
to the radiological consequences of postulated DBAs.
Conclusion
Based upon the limited number and anticipated performance of the
AXIOMTM clad fuel rods, the use of PIE and characterization
to detect anomalous behavior to preclude further irradiation damage,
and the use of NRC-approved models to ensure that all design criteria
remain satisfied, the NRC staff finds the use of the subject LTA up to
75,000 MWD/MTU in the Byron 2 Cycle 16 reactor core to be acceptable.
Consistent With Common Defense and Security
The proposed exemption would allow the use of one LTA with a
variant cladding material. This change to the plant core configuration
has no impact on security issues. Special nuclear material in the LTA
will continue to be handled and controlled in accordance with
applicable regulations. Therefore, the common defense and security is
not impacted by this exemption.
Special Circumstances
In accordance with 10 CFR 50.12(a)(2)(ii), special circumstances
are present whenever application of the regulation in the particular
circumstances would not serve the underlying purpose of the rule or is
not necessary to achieve the underlying purpose of the rule.
The underlying purpose of 10 CFR 50.46(a)(1)(i) is to establish
acceptance criteria for ECCS performance. Previously, on June 30, 2006,
the NRC staff approved an exemption for four Byron LTAs that
demonstrated the acceptability of the AXIOMTM cladding under
LOCA conditions (ADAMS Accession No. ML061380518). The unique features
of the LTAs were evaluated for effects on the LOCA analyses. The
results showed that the LTAs would not adversely affect ECCS
performance. Because the current LTA will be located in a non-limiting
core location, the licensee concluded and the NRC staff agrees that the
LOCA safety analyses will remain bounding for the Cycle 16 LTA for
Byron 2. Therefore, the NRC staff concludes that application of 10 CFR
50.46(a)(1)(i) in this particular circumstance is not necessary for the
licensee to achieve the underlying purpose of the rule.
10 CFR Part 50, Appendix K
Paragraph I.A.5 of Appendix K to 10 CFR Part 50 states that ``[t]he
rate of energy release, hydrogen generation, and cladding oxidation
from the metal/water reaction shall be calculated using the Baker-Just
equation.'' The Baker-Just equation, developed in 1962, presumed the
use of zircaloy clad fuel, and thus did not address AXIOMTM
clad fuel for determining acceptable fuel performance. The underlying
intent of this portion of Appendix K is to ensure that analysis of fuel
response to LOCAs is conservatively calculated. Previously, in its June
30, 2006, exemption for four Byron LTAs with AXIOMTM clad
fuel rods (ADAMS Accession No. ML061380518), the NRC staff concluded
that, based on the material composition of the AXIOMTM
alloy, which is similar to other licensed zirconium alloys, the high
temperature metal-water reaction rates are expected to be similar. The
NRC staff also concluded that, because of the limited number of
AXIOMTM clad fuel rods and the similarity in material
composition to other advanced cladding materials, the application of
the Baker-Just equation in the analysis of the four Byron LTAs with
AXIOMTM clad fuel rods was acceptable. Based on the NRC
staff's previous conclusions for four LTAs with AXIOMTM clad
fuel rods, the NRC staff concludes that an exemption from 10 CFR Part
50, Appendix K, as requested by the licensee, is not necessary for the
licensee's request to apply the Baker-Just equation to the one LTA with
AXIOMTM clad fuel rods planned for insertion in the Byron 2
Cycle 16 reactor core, because application of the Baker-Just equation
in this circumstance will achieve the underlying purpose of the rule.
4.0 Conclusion
Accordingly, the Commission has determined that, pursuant to 10 CFR
50.12(a), an exemption from the
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requirements of 10 CFR 50.46(a)(1)(i) 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 the
licensee an exemption from the requirement of 10 CFR 46(a)(1)(i)
related to fuel cladding material to allow one LTA containing
AXIOMTM clad fuel rods to be irradiated in Byron 2 during
Cycle 16 up to a lead rod average burnup of up to 75,000 MWD/MTU. The
remaining requirements of 10 CFR 50.46 remain in effect for the Byron 2
Cycle 16 reactor core.
Furthermore, for the reasons stated in the previous section, the
Commission has determined that an exemption from the requirements of 10
CFR Part 50, Appendix K, is not required. Therefore, the Commission is
not issuing an exemption from 10 CFR Part 50, Appendix K for the Byron
2 Cycle 16 reactor core.
Pursuant to 10 CFR 51.32, the Commission has determined that the
granting of the exemption from 10 CFR 46(a)(1)(i) will not have a
significant effect on the quality of the human environment (74 FR
20000; April 30, 2009).
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 30th day of April 2009.
For the Nuclear Regulatory Commission.
Joseph Giitter,
Director, Division of Operating Reactor Licensing, Office of Nuclear
Reactor Regulation.
[FR Doc. E9-10619 Filed 5-6-09; 8:45 am]
BILLING CODE 7590-01-P
