duke 10 david culp cfr r* energy. 10 engineering · duke 10 cfr 50.54(f) david c. culp r* energy....

David C. CulpDuke 10 CFR 50.54(f) Acting Vice President

r* Energy. 10 CFR 50.46(a)(3)(ii) Nuclear Engineering

Duke Energy Corporation526 South Church StreetCharlotte, NC 28202

Mailing Address:ECO8H / P. 0. Box 1006Charlotte, NC 28201-1006

March 16, 2012 704 382 8833

704 382 7852 fax

U. S. Nuclear Regulatory Commission [email protected]

Attn: Document Control DeskWashington, DC 20555-0001

Subject: Duke Energy Carolinas, LLC (Duke Energy)Catawba Nuclear Station, Units 1 and 2, Docket Nos. 50-413, 50-414McGuire Nuclear Station, Units 1 and 2, Docket Nos. 50-369, 50-370Response to Information Request Pursuant to 10 CFR 50.54(f) Related to theEstimated Effect on Peak Cladding Temperature Resulting from ThermalConductivity Degradation in the Westinghouse-Furnished Realistic Emergency CoreCooling System Evaluation and 30-Day Report Pursuant to 10 CFR 50.46, Changesto or Errors in an Evaluation Model

References:

1. Letter, M. G. Evans (NRC) to J. R. Morris (Duke Energy), "Catawba Nuclear Station, Units 1and 2 - Information Request Pursuant to 10 CFR 50.54(f) Related to the Estimated Effect onPeak Cladding Temperature Resulting from Thermal Conductivity Degradation in theWestinghouse-Furnished Realistic Emergency Core Cooling System Evaluation(TAC NO. M99899)," February 16, 2012

2. Letter, M. G. Evans (NRC) to Regis T. Repko (Duke Energy), "McGuire Nuclear Station,Units 1 and 2 - Information Request Pursuant to 10 CFR 50.54(f) Related to the EstimatedEffect on Peak Cladding Temperature Resulting from Thermal Conductivity Degradation inthe Westinghouse-Furnished Realistic Emergency Core Cooling System Evaluation(TAC NO. M99899)," February 16, 2012

3. Letter, J. A. Gresham (Westinghouse) to USNRC Document Control Desk, "WestinghouseInput Supporting Licensee Response to NRC 10 CFR 50.54(f) Letter Regarding NuclearFuel Thermal Conductivity Degradation (Proprietary/Non-Proprietary)," LTR-NRC-12-27,March 07, 2012

On February 16, 2012 (References 1 and 2), the U.S. Nuclear Regulatory Commission (NRC)issued 10 CFR 50.54(f) letters regarding the impact on peak cladding temperature (PCT) fromthermal conductivity degradation (TCD). This information is specific to the application of theWestinghouse Electric Company, LLC (Westinghouse) realistic emergency core cooling systemevaluation and the potentially significant error, as defined in 10 CFR 50.46(a)(3)(i). Thepurpose of the request is to verify continued compliance with the PCT acceptance criterion forloss-of-coolant accidents (LOCAs) promulgated in 10 CFR 50.46(b)(1). Specifically, thecalculated maximum fuel element cladding temperature shall not exceed 22000 F.

www.duke-energy.corn

SAcoD

U.S. Nuclear Regulatory CommissionMarch 16, 2012

The purpose of this letter is twofold:

1. Pursuant to 10 CFR 50.54(f), Enclosure 1 contains Duke Energy's 30-day response for therequested information related to the Estimated Effect on Peak Cladding TemperatureResulting from Thermal Conductivity Degradation in the Westinghouse Furnished RealisticECCS Evaluation for Catawba and McGuire Nuclear Stations;

2. Pursuant to 10 CFR 50.46(a)(3)(ii), Enclosure 2 contains a 30-day report required on thechanges to or errors in the ECCS Evaluation Models. In support of Duke Energy'sresponse, Westinghouse submitted directly to the NRC, a description of the methodologyand assumptions used to determine the estimated PCT impact due to TCD.

References are found in Enclosure 3.

Commitments made by this letter:

Before December 15, 2016, Duke Energy will submit to the NRC for review and approval aLBLOCA analysis that applies an NRC-approved ECCS Evaluation Model that includes theeffects of fuel thermal conductivity degradation.

Please address any comments or questions regarding this matter to Jeff Thomas at704 382-3438 ([email protected]).

Sincerely,

David 0. Culp

Enclosure 1: 10 CFR 50.54(f) Response

Enclosure 2: 10 CFR 50.46 Reporting Requirements

Enclosure 3: References


Oath or Affirmation

David C. Culp affirms that he is the person who subscribed his name to matters in response tothe 10 CFR 50.54(f) request as found in Enclosure 1 and that all the matters and facts set forththerein are true and correct to the best of his knowledge.

David C. Culp rActing Vice PresidentNuclear Engineering

Subscribed and sworn to me: .1-cA_4, /4, .O/Date /

Notary Public ' /.: (,

My Commission Expires: dpl.(e c " ( /Date

SEAL


xc:

V. M. McCree, Region II AdministratorU.S. Nuclear Regulatory CommissionMarquis One Tower245 Peachtree Center Avenue NE,Suite 1200Atlanta, Georgia 30303-1257

E. J. LeedsDirector, Office of Nuclear Reactor RegulationU.S. Nuclear Regulatory Commission11555 Rockville PikeMail Stop 13-H16MRockville, MD 20852-2738

J. H. Thompson, Project ManagerU. S. Nuclear Regulatory Commission11555 Rockville PikeMail Stop 0-8 G9ARockville, MD 20852-2738

J. ZeilerNRC Senior Resident InspectorMcGuire Nuclear Station

G. A. Hutto, IIINRC Senior Resident InspectorCatawba Nuclear Station

U.S. Nuclear Regulatory CommissionMarch 16, 2012Page 1 of 6 Enclosure 1

10 CFR 50.54(f) Response

The NRC has issued 10 CFR 50.54(f) letters to Catawba Nuclear Station and McGuire NuclearStation [References 1 and 2] which request that, within 30 days of the letter date, Duke Energyprovide information regarding the effect of a potentially significant error, as defined in10 CFR 50.46(a)(3)(i), associated with fuel pellet thermal conductivity degradation (TCD), onpeak cladding temperature (PCT) in the Westinghouse-furnished realistic emergency corecooling system (ECCS) evaluation model (EM). Specifically, the 10 CFR 50.54(f) lettersindicated that the response shall address the following specific issues:

1) An estimation of the effect of the TCD error on the peak fuel cladding temperaturecalculation for the emergency core cooling system evaluations at Catawba 1 and 2/McGuire I and 2.

2) A description of the methodology and assumptions used to determine the estimates. Thisdescription shall include consideration of experimental data relevant to TCD and specificinformation regarding any computer code model changes which were necessary to addressthese data.

Background

On December 13, 2011, the NRC held a conference call with Duke Energy and others in theindustry to discuss the contents of Information Notice 2011-21 which would be issued on thesame day. Duke Energy promptly entered the concerns raised by the NRC into the correctiveaction program and evaluated the potential impact of these concerns on continued safeoperation of the plant. Westinghouse was contacted to evaluate the impact of these concerns.The operability process was entered to evaluate the basis for continued operation by boundingthe potential impacts with existing conservatism in the analysis of record.

Duke Energy Response to Question 1

The estimated impact on the Catawba / McGuire Best Estimate Large Break Loss of CoolantAccident (BELOCA) analysis of record PCT due to the effects of fuel pellet TCD represents asignificant change or error in PCT for the limiting transient (reflood 2 for Catawba / McGuire), asdefined in 10 CFR 50.46(a)(3)(i). This is due to the combination of:

1) a change in Westinghouse fuel performance code from PAD 3.4 to PAD 4.0 (both PADversions are approved by NRC), resulting in a PCT change of -75 OF for both reflood 1and reflood 2 (limiting PCT); and

2) an error estimating the effect of TCD using a fuel performance model labeled 'PAD 4.0 +TCD', which has not been approved by the NRC, with peaking factor burndown, resultingin a PCT change of +114 OF for reflood 1, and a PCT change of +15 OF for reflood 2(limiting PCT); and

3) Planned plant modification change associated with a proposed MeasurementUncertainty Recapture (MUR) power uprate analysis at McGuire. The effect on PCT ofthe MUR power uprate to 101.7% of 3411 MWt is +4 °F for reflood 1, and a PCT changeof +16 OF for reflood 2 (limiting PCT).


The TCD assessment for impacts to Catawba / McGuire BELOCA PCT required usage of aseparate ECCS model change which represents a change in fuel rod design input parametersfrom Westinghouse fuel performance code PAD 3.4 to PAD 4.0 without consideration of TCD.In References 3 and 7, Westinghouse quantified a reflood phase PCT reduction of 750F for theCatawba / McGuire BELOCA analysis when PAD 4.0 results for initial fuel temperatures wereconsidered, as compared to the PAD 3.4 results. Specifically, the fuel temperature and rodinternal pressure inputs from the PAD 3.4 data to PAD 4.0 were updated in the referencetransient, and the 75 OF PCT reduction was assigned based on the plant-specific results. Then,the impact of TCD on PCT was evaluated separately, as a change from PAD 4.0 to "PAD 4.0 +TCD" and peaking factor burndown, to provide an estimated effect from TCD that does notinclude unrelated PAD version differences. This evaluation resulted in an increase of 15°F forthe Catawba / McGuire BELOCA analysis for reflood 2 (limiting PCT).

In addition, the effects of a proposed Measurement Uncertainty Recapture (MUR) power uprateare also included in the TCD evaluation because Duke Energy has recently submitted a LicenseAmendment Request for an MUR power uprate at McGuire [Reference 4]. The effects areincluded herein for completeness because the TCD assessment performed by Westinghousefor Catawba / McGuire also addressed MUR conditions. Including the effects of the MURresulted in a PCT increase of 16'F.

Table 1 summarizes the estimated effects of these changes on the Catawba / McGuireBELOCA limiting PCT. To date, an MUR power uprate License Amendment Request has notbeen submitted for Catawba, so the 160 F PCT impact is not included in PCT summary Table 1below for Catawba.

Table I

Composite Large Break LOCA PCT for Catawba / McGuire Including TCD

PCT for Reflood 2(OF)

Currently Reported Limiting PCT 2145

2012 ECCS Model AssessmentsChange from PAD 3.4 to PAD 4.0 -75Change from PAD 4.0 to "PAD 4.0 + TCD" and Peaking Factor Burndown 15Planned Plant Modification EvaluationsMcGuire MUR Uprate to 101.7% of 3411 MWt 16

Licensing Basis + PCT Assessments for McGuire 2101Licensing Basis + PCT Assessments for Catawba 2085

Additional Information Supporting Duke Energy Response to Question I

For Large Break Loss of Coolant Accidents, Catawba and McGuire are currently licensed to theWestinghouse "Code Qualification Document (CQD) for Best Estimate LOCA Analysis"Evaluation Model [Reference 5]. A composite BELOCA analysis of record is performed, whichis bounding for Catawba Units 1 & 2 and McGuire Units 1 & 2. To characterize the BELOCA


event, the CQD EM develops PCT values for the blowdown, first reflood, and second refloodphases of the transient. The limiting PCT result for the composite BELOCA analysis of recordoccurs in the second reflood time period, as shown in Catawba / McGuire UFSAR Section15.6.5. The limiting second reflood PCTs for Catawba / McGuire have historically been reportedto the NRC under 10 CFR 50.46, while the non-limiting first reflood PCTs have not beenreported. For the sake of completeness, Duke Energy's response to this information requestpursuant to 10 CFR 50.54(f) addresses both reflood phases of the BELOCA transient.

The NRC-approved CQD ECCS evaluation model is based on the PAD 3.4 fuel performancecode. PAD 3.4 was licensed without explicitly considering fuel pellet TCD with burnup. Explicitmodeling of fuel pellet TCD in the fuel performance code leads directly to increased fuel pellettemperatures. Increases in fuel pellet temperatures increase the stored energy in the fuel at thebeginning of the simulated BELOCA event. For BELOCA, increased in stored energy in the fuelcan lead to an increase in PCT if off-setting effects such as peaking factor burndown are notmodeled.

The TCD assessment performed by Westinghouse for Catawba / McGuire is consistent with theapproach detailed in Westinghouse letter to NRC dated March 7, 2012 [Reference 6]. NewPAD fuel performance data was generated with a model that includes explicit modeling of fuelpellet TCD. The fuel performance data was used as input to the Catawba Units 1 & 2 andMcGuire Units 1 & 2 evaluation.

By letters to Duke Energy dated March 7, 2012, Westinghouse provided the formal results of theTCD assessment for the composite Catawba / McGuire BELOCA analysis [References 7 and 8].Westinghouse provided burnup-dependent peaking factor burndown curves to ensure that thecomposite LBLOCA analysis of record PCT for Catawba / McGuire remains valid. Thefunctional form of the peaking factor burndown curves are shown below in Table 2.

Table 2Normalized Peaking Factor Burndown Curves for

Catawba / McGuire BELOCA PCT

Hot Rod Average Burnup Normalized Fa Normalized FAH, Pbar(MWD/MTU)

0 1.0 1.035,000 1.0 1.055,000 0.9 0.9562,000 0.8 0.9

In Table 1, normalized Fa applies to transient FQ and steady-state FQ. The values arenormalized to Fa(transient) = 2.7 (with uncertainties) for the bottom third of the core,FQ(transient) = 2.5 (with uncertainties) for the top two-thirds of the core, FQ(steady-state) = 2.1(without uncertainties), FAH = 1.67 (with uncertainties), and Pbar = 1.67/1.04 (withuncertainties).

Clarification note on Allowed Transient FQ Peaking Factor in the BELOCA analysis

When the BELOCA analysis of record for Catawba / McGuire was initially performed in2000, a transient FQ value of 2.5 was assumed for all core elevations. In 2010,

U.S. Nuclear Regulatory CommissionMarch 16, 2012Page 4 of 6 Enclosure I

Westinghouse performed an assessment to examine impacts to the BELOCA analysis ofrecord when a transient Fa allowance of 2.7 was considered for the bottom one-third of thecore, i.e. core elevations between 0 and 4 feet. Westinghouse confirmed that there was noadverse impact to the limiting PCT in the reflood 2 time period [Reference 3]. This axialpower shape PCT assessment (APCT = 28 OF for reflood 1 and a APCT = 0 °F for reflood 2)will be included in this response, as well as the Catawba / McGuire 10 CFR 50.46 annualreport for the year 2011.

As noted earlier, the current composite Catawba / McGuire Best-Estimate Large Break LOCAanalysis of record is based on fuel temperature predictions obtained from Westinghouse PADcomputer code version 3.4. In 2000, Westinghouse received NRC approval for the PAD codeversion 4.0 [Reference 9]. For consistent inputs (e.g. same local linear heat rate and fuel type),PAD 4.0 will predict lower fuel average temperatures than PAD 3.4. Lower initial fueltemperatures corresponds to lower stored energy in the core, and translates to lower PCTvalues during a postulated LBLOCA transient. At the time of PAD 4.0 approval by the NRC,Westinghouse indicated that its usage would be on a forward-fit basis, per Reference 9. TheCatawba / McGuire Best-Estimate Large Break LOCA analysis of record was performed in2000, and it has not been formally updated to reflect the newer PAD 4.0 results for initial fueltemperatures.

For the TCD assessments performed by Westinghouse, the PAD 4.0 code was modified toinclude TCD effects, as described by Westinghouse letter to the NRC dated March 7, 2012[Reference 6]. As a result, the TCD assessment for Catawba / McGuire PCT required usage ofa separate ECCS model change, which represents a change in fuel rod design input parametersfrom Westinghouse fuel performance code PAD 3.4 to PAD 4.0 without consideration of TCD.In References 3 and 7, Westinghouse quantified a reflood phase PCT reduction of 75°F for theCatawba / McGuire BELOCA analysis when PAD 4.0 results for initial fuel temperatures wereconsidered, versus the PAD 3.4 results. Specifically, the fuel temperature and rod internalpressure inputs from the PAD 3.4 data to PAD 4.0 were updated in the reference transient, andthe 75 OF PCT benefit was assigned based on the plant-specific results. Then, the impact ofTCD on PCT was evaluated separately, as a change from PAD 4.0 to "PAD 4.0 + TCD" andpeaking factor burndown, to provide an estimated effect from TCD that does not includeunrelated PAD version differences.

The results of the TCD assessment for Catawba / McGuire PCT are shown below in Table 3.The effects of a proposed Measurement Uncertainty Recapture (MUR) power uprate are alsoincluded, as Duke Energy has recently submitted a License Amendment Request for an MURpower uprate at McGuire [Reference 4]. It is included herein for completeness, because theTCD assessment performed by Westinghouse for Catawba / McGuire also addressed MURconditions. Including the effects of MUR resulted in a PCT increase of 16*F for McGuire. Todate, an MUR power uprate License Amendment Request has not been submitted for Catawba,so the 160 F PCT impact is not included in PCT summary Table 3 below for Catawba.


Table 3Catawba and McGuire Best Estimate LBLOCA Peak Cladding Temperatures

Composite BELOCA PCT for Catawba / McGuire PCT for PCT forReflood 1 (OF) Reflood 2 (OF)

Licensing Basis Analysis of Record PCT, as describedin the UFSAR 1692 2028Prior ECCS Model AssessmentsMONTECF Decay Heat Uncertainty Error 4 8MONTECF Power Uncertainty Correction 8 20Input Error Resulting in Incomplete Solution Matrix 1 25Revised Blowdown Heatup Uncertainty Distribution 5 5Plant Input / Modification EvaluationsSafety Injection Temperature Range Evaluation 0 59Currently Reported Limiting PCT 1710 2145

[Values below have not been previously reported]2011 ECCS Model AssessmentsAxial Power Shape Evaluation 28 0

2012 ECCS Model AssessmentsChange from PAD 3.4 to PAD 4.0 -75 -75Change from PAD 4.0 to "PAD 4.0 + TCD" and Peaking 114 15Factor BurndownPlanned Plant Modification EvaluationsMcGuire MUR Uprate to 101.7% of 3411 MWt 4 16

Licensing Basis + PCT Assessments for McGuire 1781 2101Licensing Basis + PCT Assessments for Catawba 1777 2085

Plant-Specific Validation of Peaking Factor Burndown Curves used for TCD Assessment

Cycle-specific analyses were performed by Duke Energy for all operating cores for Catawbaand McGuire. Additionally, Catawba Unit 2 Cycle 19 (Catawba Unit 2 Cycle 18 shutdown onMarch 10, 2012, and Cycle 19 is scheduled to start operation in April of 2012) to verify theacceptability of the peaking factor burndown curves used in the TCD assessment. The cycle-specific analyses also confirmed the acceptability of LOCA operational Axial Flux Difference(AFD) limits and Monitoring Factors specified in the applicable Core Operating Limits Report(COLR). Steady-state FQ limits were verified by comparing code predictions of steady-statepeaking factors from nominal rated thermal power conditions against the steady-state FQpeaking factor burndown curve shown in Table 2. Transient FQ, FAH, and Pbar limits wereverified by comparing power distributions that could be produced from normal operationaltransients against applicable limits specified in Table 2. Transient power distributions weregenerated based on the methodology described in Reference 10, and were generated to spanoperational AFD limits and rod insertion limits. All calculations were performed with the NRC-approved CASMO-4/SIMULATE-3 methodology [Reference 11]. Cycle-specific confirmation ofBELOCA initial condition assumptions and transient FQ, FAH, and Pbar limits are performed inDuke Energy calculations referred to as "maneuvering analysis".


The following cycle-specific core maneuvering analyses were revised to evaluate theacceptability of the revised BELOCA peaking factor burndown limits in Table 2:

Catawba 1 Cycle 20, Catawba 2 Cycle 18, Catawba 2 Cycle 19McGuire 1 Cycle 22, McGuire 2 Cycle 21

Results from the cycle-specific core maneuvering analysis calculations confirmed theacceptability of steady-state FQ, transient FQ, Pbar and FAH initial condition input assumptionsassumed in TCD assessment. The revised core maneuvering analyses also showed no changein the limiting transient FQ margins, verifying that fuel at burnups where TCD is a concern isnon-limiting. This later result is important because it confirms the acceptability of theoperational AFD limits and F0 Monitoring Factors specified in the COLR. Fuel at burnups whereTCD is a concern is non-limiting because the reactivity, and therefore the power producingcapability of the fuel, decreases with increasing burnup at a rate sufficient to offset the effects ofthe TCD peaking factor burndown curves. For the reactor cores analyzed, more peaking factormargin exists to the transient FAH and FQ limits at burnups where TCD starts becomingimportant (> 30 GWD/MTU) relative to the limiting FAH and FQ peaking factor margins in thecore for burnups < 30 GWD/MTU.

In summary, it has been analytically demonstrated that limiting locations with respect toBELOCA peaking limits are not occurring in high burnup fuel, and the natural reduction inachievable local rod powers as a function of burnup is enough to satisfy the peaking factorburndown curves utilized in the TCD assessment. Therefore, the FQ(x,y,z) power distributionmeasurements required by Technical Specification 3.2.1 coupled with continuous global powerdistribution monitoring through Technical Specification 3.2.3 (Axial Flux Difference), TechnicalSpecification 3.2.4 (Quadrant Power Tilt) and Technical Specification 3.1.6 (Control BankInsertion Limits) will continue to provide assurance that the Catawba / McGuire reactor coresare operating as designed, and provide continued verification of the acceptability of theBELOCA analysis.

The peaking factor bumdown limits shown in Table 2 will be incorporated into Duke Energy'score reload design process for Catawba / McGuire, to ensure adequate verification of thebumup-dependent peaking factor limits used in the TCD assessment for future core designs.

Duke Energy Response to Question 2

Describing the methodologies and assumptions used to estimate PCT and to determine theeffect of TCD as a function of burnup, Westinghouse submitted information to the NRC by letterdated March 7, 2012 [Reference 6]. This description includes consideration of experimentaldata relevant to TCD and specific information regarding any computer code model changeswhich were necessary to address these data.

As discussed in the response to Question 1, the TCD assessment for Catawba / McGuirerequired a separate step in which PCT impacts were quantified for an ECCS model change fromPAD 3.4 to PAD 4.0. Both of these versions of PAD are approved by the NRC. The TCDimpacts were then separately assessed using the "PAD 4.0 + TCD" version, which is describedby Westinghouse in Reference 6.


10 CFR 50.46 Reporting Requirements

The estimated impact on the Catawba / McGuire BELOCA analysis of record PCT due to theeffects of fuel pellet TCD represents a significant change in PCT for the limiting transient(reflood 2 for Catawba / McGuire), as defined in 10 CFR 50.46(a)(3)(i). This is due to thecombination of:

1 ) a change in Westinghouse fuel performance inputs from PAD 3.4 to PAD 4.0 (both PADversions are approved by NRC), resulting in a PCT change of -75 OF for both reflood 1and reflood 2, and

2) an error estimating the effect of TCD using a fuel performance model labeled 'PAD 4.0 +TCD', which has not been approved by the NRC, with peaking factor burndown, resultingin a PCT change of +114 °F for reflood 1, and a PCT change of +15 OF for reflood 2(limiting PCT).

The sum of the absolute value of these changes to PCT is greater than 50 OF, and is thereforeconsidered to be significant. 10 CFR 50.46(a)(3)(ii) requires the licensee to provide a reportwithin 30 days, including a proposed schedule for providing a reanalysis or taking other actionas may be needed to show compliance with 10 CFR 50.46. Duke Energy has reviewed theinformation provided by Westinghouse and determined that the adjusted BELOCA PCT valuesand the manner in which they were derived continue to conform to the requirements of10 CFR 50.46. Duke Energy has evaluated the requirement for reanalysis specified in10 CFR 50.46(a)(3)(ii) and proposes the following schedule for reanalysis.

Before December 15, 2016, Duke Energy will submit to the NRC for review and approval aLBLOCA analysis for Catawba and McGuire that apply NRC-approved fuel thermal performancemethods which will include the effects of fuel pellet TCD. The date for the LBLOCA reanalysissubmittal is contingent on the following licensing actions that are needed to perform a LBLOCAanalysis with an NRC-approved ECCS Evaluation Model that explicitly models TCD, incompliance with 10 CFR 50.46(a)(1)(i):

1) Prior NRC approval of a fuel performance analysis methodology that includes the effectsof fuel pellet TCD. The new fuel performance methodology would replace the currentlicensing basis methodology for Catawba / McGuire that is described inWCAP-1 2945-P-A for PAD 3.4, and WCAP-1 5063-P-A, Rev. 1 for PAD 4.0.

2) Prior NRC approval of a LBLOCA Evaluation Model that includes the effects of fuel pelletTCD, and accommodates the ongoing 10 CFR 50.46(c) rulemaking process. PerReference 12, Catawba / McGuire are considered to be on implementation track number2 for the 10 CFR 50.46(c) rulemaking, with compliance demonstrated no later than 48months from the effective date of the rule. The new NRC-approved LBLOCA evaluationmodel would replace the current licensing basis methodology for Catawba / McGuire thatis described in WCAP-12945-P-A, Volume 1, Rev. 2, and Volumes 2-5, Rev. 1.

This information satisfies the 30-day reporting requirement and required proposal for areanalysis schedule as governed by 10 CFR 50.46(a)(3)(ii).

As part of the TCD assessment that was performed by Westinghouse for Catawba / McGuire,other 10 CFR 50.46 acceptance criteria were addressed in addition to PCT. Impacts to


maximum local oxidation, criteria (b)(2), maximum hydrogen generation, criteria (bX3), andcoolable geometry, criteria (bX4) were also evaluated by Westinghouse for Catawba / McGuire,considering the effects of TCD.

Westinghouse confirmed that the current analysis of record results for maximum local oxidation,maximum hydrogen generation, and coolable geometry remain bounding, when the effects ofTCD are considered [Reference 8]. The increased stored energy in the fuel due to higher fuelpellet temperatures with TCD is a short term effect that does not persist into the long-termcooling phase of ECCS performance evaluations. Therefore, impacts to long-term core coolingare considered insignificant when the effects of TCD are considered.

A summary of the PCT changes for McGuire Units 1 and 2 and Catawba Unit 1 and 2 areprovided in the following Tables 4, 5, and 6.


Table 4Peak Cladding Temperature Summary - McGuire Units 1 & 2

LBLOCA Cladding Temp Comments(OF)

Evaluation model: WCOBRA/TRAC, CQD 1996MNS/CNS

Analysis of record PCT (Reflood 2) 2028 CompositeModel

Prior errors (APCT)1. Decay heat in Monte Carlo calculations 8 Reference A2. MONTECF power uncertainty correction 20 Reference B3. Safety Injection temperature range 59 Reference C4. Input error resulting in an incomplete solution matrix 25 Reference D5. Revised Blowdown Heatup Uncertainty Distribution 5 Reference E6. Vessel Unheated Conductor Noding 0 Reference F

Prior evaluation model changes (APCT)1. Revised Algorithm for Average Fuel Temperature 0 Reference F

Errors (APCT)1. Thermal Conductivity Degradation with Peaking 15

Factor BurndownEvaluation model changes (APCT)1. PAD 3.4 to PAD 4.0 -752. MUR Uprate to 101.7% of 3411 MWt 163. Peak FQ = 2.7 in bottom third of core 0

Absolute value of errors/changes for this report (APCT) 106Net change in PCT for this report -44Final PCT 2101

SBLOCAEvaluation model: NOTRUMPAnalysis of record PCT 1323 2 inch breakPrior errors (APCT)

1. None 0Prior evaluation model changes (APCT)

1. None 0Errors (APCT)

1. None 0Evaluation model changes (APCT)1. None 0

Absolute value of errors/changes for this report (APCT) 0Net change in PCT for this report 0Final PCT 1323


Table 5Peak Cladding Temperature Summary - Catawba Unit I


Evaluation model : WCOBRA/TRAC, CQD 1996MNS/CNS





Factor BurndownEvaluation model changes (APCT)

1. PAD 3.4 to PAD 4.0 -752. Peak FQ = 2.7 in bottom third of core 0





1. None 0Evaluation model changes (APCT)

1. None 0Absolute value of errors/changes for this report (APCT) 0Net change in PCT for this report 0Final PCT 1323


Table 6Peak Cladding Temperature Summary - Catawba Unit 2


Evaluation model: WCOBRA/TRAC, CQD 1996MNS/CNS





Factor BurndownEvaluation model changes (APCT)

1. PAD 3.4 to PAD 4.0 -752. Peak FQ = 2.7 in bottom third of core 0





1. None 0Evaluation model changes (APCT)

1. None 0Absolute value of errors/changes for this report (APCT) 0Net change in PCT for this report 0Final PCT 1243


REFERENCES

References for Tables 4, 5. and 6

A. Letter, M. S. Tuckman (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to orErrors in an ECCS Evaluation Model," May 3, 2001

B. Letter, M. S. Tuckman (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to orErrors in an ECCS Evaluation Model," April 3, 2002

C. Letter, W. R. McCollum, Jr. (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changesto or Errors in an ECCS Evaluation Model," July 29, 2003

D. Letter, W. R. McCollum, Jr. (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changesto or Errors in an ECCS Evaluation Model," May 26, 2004

E. Letter, J. R. Morris (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to orErrors in an ECCS Evaluation Model," June 21, 2005

F. Letter, T. C. Geer (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to orErrors in an ECCS Evaluation Model," March 13, 2007

References for Enclosures 1 and 2

1. NRC letter (M. Evans) to Duke Energy (J. R. Morris), "Catawba Nuclear Station, Units 1 and2 - Information Request Pursuant to 10 CFR 50.54(f) Related to the Estimated Effect onPeak Cladding Temperature Resulting from Thermal Conductivity Degradation in theWestinghouse Furnished Realistic Emergency Core Cooling System Evaluation(TAC No. M99899)," February 16, 2012. [ADAMS Accession No. ML12044A018]

2. NRC letter (M. Evans) to Duke Energy (R. T. Repko), "McGuire Nuclear Station, Units 1 and2 - Information Request Pursuant to 10 CFR 50.54(f) Related to the Estimated Effect onPeak Cladding Temperature Resulting from Thermal Conductivity Degradation in theWestinghouse Furnished Realistic Emergency Core Cooling System Evaluation(TAC No. M99899)," February 16, 2012. [ADAMS Accession No. ML12044A019]

3. Westinghouse letter from D. Warren to Duke Energy (Robert Harvey), DPC-1 0-21, Subject:Catawba and McGuire Nuclear Stations Transmittal of Duke LOCA Axial Power Shape,FAH, and PAD 4.0 Evaluations (Proprietary), dated May 19, 2010.

4. Duke Energy Letter from R. Repko to US NRC, Subject: McGuire Nuclear Station LicenseAmendment Request for Measurement Uncertainty Recapture Power Uprate, datedMarch 5, 2012.

5. Westinghouse WCAP-12945-P-A, Volume 1, Rev. 2, and Volumes 2-5, Rev. 1 (Proprietary),Code Qualification Document for Best Estimate LOCA Analysis, March 1998.


6. Westinghouse letter from J. A. Gresham to U.S. NRC, LTR-NRC-12-27, Subject:Westinghouse Input Supporting Licensee Response to NRC 10 CFR 50.54(f) LetterRegarding Nuclear Fuel Thermal Conductivity Degradation (Proprietary / Non-Proprietary),dated March 7, 2012.

7. Westinghouse letter from C. Trunick to Duke Energy (S. Thomas), DPC-1 2-35, Subject:Information Regarding the McGuire Units 1 & 2 and Catawba Units 1 & 2 Evaluation of FuelPellet Thermal Conductivity Degradation and Peaking Factor Burndown Including DesignInput Changes (Non-Proprietary), dated March 7, 2012.

8. Westinghouse letter from C. Trunick to Duke Energy (S. Thomas), DPC-12-36, Subject:Additional Information for Duke Energy Regarding the Evaluation of Pellet ThermalConductivity Degradation (TCD) for McGuire Units 1 & 2 and Catawba Units 1 & 2(Proprietary / Non-Proprietary), dated March 7, 2012.

9. NRC letter (S. Richards) to Westinghouse Electric Co. (H. A. Sepp), Safety EvaluationRelated to Topical Report WCAP-1 5063, Revision 1, "Westinghouse Improved PerformanceAnalysis and Design Model (PAD 4.0)" (TAC No. MA2086), dated April 24, 2000. [ADAMSAccession No. ML003706392]

10. Duke Energy Methodology Report DPC-NE-201 1-PA, Rev. la, Nuclear Design MethodologyReport for Core Operating Limits of Westinghouse Reactors, June 2009.

11. Duke Energy Methodology Report DPC-NE-1005-PA, Rev. 1, Nuclear Design MethodologyUsing CASMO-4/SIMULATE-3 MOX, November 2008.

12. Preliminary Draft of Federal Register Notice on the 10 CFR 50.46c Performance-BasedEmergency Core Cooling System (ECCS) Cladding Acceptance Criteria, January 10, 2012.[ADAMS Accession No. ML12005A004]

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