Text

Response to Request for Additional Information Regarding Thermal Conductivity Degradation
	ML12164A746
Person / Time
Site:	Byron, Braidwood
Issue date:	06/11/2012
From:	Simpson P; Exelon Generation Co
To:	; Office of Nuclear Reactor Regulation, Document Control Desk
Shared Package
ML121640840	List: RS-12-100, Response to Request for Additional Information Regarding Thermal Conductivity Degradation;
References
	RS-12-100, TAC M99899
	Download: ML12164A746 (45)
	v • d • e

Proprietary Information Proprietary Information-- Withhold From Public Disclosure Under Under 1010 CFR CFR 2.390 2.390 1

Generation, ti 10 10 CFR CFR 50.46 RS-12-100 RS-12-100 11, 2012 June 11,2012 u.s.

U.S. Nuclear Regulatory Regulatory Commission Control Desk ATTN: Document Control Washington, DC Washington, DC 20555-0001 Braidwood Station, Unit 2 Braidwood Facility Operating Facility Operating License No. NPF-77 NPF-77 NRC Docket No. STN 50-457 Byron Station, Unit 2 Byron Facility Operating License No. No. NPF-66 NPF-66 NRC Docket No. STN 50-455 50-455

Subject:

Response

Responseto toRequest RequestforforAdditional Additional Information Information Regarding Regarding Thermal Thermal Conductivity Conductivity Degradation

References:

1. Letter fromMichele Letter from Michele G.G. Evans (U.S.

(U.S. NRC)

NRC) to to Michael Michael J.J.Pacilio Pacilio (Exelon Nuclear),

Nuclear), "Information Request Pursuant "Information Request Pursuant to to 50.54(f) Related Related to the Estimated Estimated Effect Effect on on Peak PeakCladding CladdingTemperature TemperatureResulting Resultingfromfrom Thermal Conductivity Degradation in Conductivity Degradation in the the Westinghouse Westinghouse Furnished Furnished Realistic Emergency Emergency CoreCore Cooling Cooling System SystemEvaluation Evaluation (TAC (TAC No.

No.

M99899),"

M99899)," dated February February 16,16, 2012 2012

2. Letter from Patrick Letter from PatrickR.R.Simpson Simpson (Exelon Generation Generation Company, Company, LLC) to to U.S.

U.S. NRC, NRC, "Response "ResponsetotoRequest Requestfor forInformation InformationRegarding RegardingThermal Thermal Conductivity Degradation and and 10 10 CFR 50. 50.46 Report," dated March 46 Report," March 19, 19, 2012 2012 3.

3. Letter Letter from Joel S. Wiebe (U.S.

(U.S. NRC)

NRC) to to Michael Michael J.J. Pacilio Pacilio (Exelon (Exelon Nuclear),

Nuclear), "Request "Requestfor forAdditional Additional Information Information Related Related toto 10 10 CFR CFR 50.46 50.46 30-Day 30-Day Report,"

Report," dated dated May May 10, 10, 2012 2012 Attachment Attachment 33 contains contains Proprietary Proprietary Information.

Information.

Withhold Withhold From From Public Public Disclosure Disclosure UnderUnder10 10CFR CFR2.390.

2.390.

When When separated separated from from Attachment Attachment 3, 3, this this document document is is decontrolled.

decontrolled.

June 11,11,20122012 U.S. Nuclear Regulatory Commission U.S.

Page 2 In Reference In Reference 1, 1, the NRC issued an an information information request request for for Exelon Generation Generation Company,

LLC, LLC, (EGC) associated with associated with the the effect effect ofof thermal thermal conductivity degradation on peak conductivity degradation cladding temperature in the Westinghouse cladding WestinghouseElectric ElectricCompany Companyfurnished furnished realistic realistic emergency core emergency core cooling cooling system systemevaluation evaluationmodelsmodelsfor forBraidwood Braidwood Station, Station, Unit Unit 2 and and Byron Station, Unit Byron Unit 2.

2. EGC EGC provided provided the requested informationinformation in in Reference 2.

Subsequent NRC Subsequent NRC review review of of Reference Reference22has hasidentified identifiedthe theneedneedfor forthe theadditional additional informationrequested information requested in in Reference Reference 3. to this letter letter contains the requested requested information.

information. providesprovides Westinghouse Westinghouseletter letterCAW-12-3496, CAW-12-3496,"Application"Applicationfor for Withholding Withholding Proprietary Information from from Public Disclosure," with with accompanying accompanyingaffidavit. affidavit. provides WestinghouseWestinghouse document documentNF-CB-12-101 NF-CB-12-101 Revision Revision 11 P-Attachment, "Byron Unit22 and "Byron Unit and Braidwood Braidwood Unit Unit2 Response Response to NRC NRC Formal Formal Request Request for Additional for Additional Information Information(RAI) (RAI)fromfromthetheReactor ReactorSystems Systems Branch Branch Related Related toto the 10 CFR 50.46, 30-Day Report," June June 2012 2012 (Proprietary).

(Proprietary). provides WestinghouseWestinghouse document documentNF-CB-12-101 NF-CB-12-101 Revision Revision 11 NP-Attachment, "Byron NP-Attachment, Unit22and "Byron Unit and Braidwood Braidwood Unit Unit2- 2-Response Response to NRC Formal Request Request for Additional Information (RAI) from the Reactor Systems for Additional Information (RAI) from the Reactor Systems Branch Related to Branch Related to the 10 CFR 50.46, 30-Day Report," June June 2012 2012 (Non-Proprietary).

(Non-Proprietary).

As Attachment 3 contains contains information information proprietary to Westinghouse WestinghouseElectric Electric Company Company LLC, itit isis supported LLC, supported by by anan affidavit affidavit signed by Westinghouse, the the owner owner ofof the the information. The information. The affidavit affidavit sets sets forth forth the the basis basison onwhich whichthe theinformation informationmay maybe bewithheld withheld from public from public disclosure disclosure by the NRC and and addresses addresses with with specificity specificity the the considerations considerations listed in listed in paragraph (b)(4)(b)(4) of 10 CFR 2.390, "Public "Public inspections, exemptions, requests requestsforfor withholding."

withholding." Accordingly, Accordingly, itit isis respectfully respectfully requested requested that the the information information that is Westinghouse be proprietary to Westinghouse bewithheld withheld fromfrom public public disclosure disclosure in in accordance accordancewith with 10 CFR 2.390.

Correspondence Correspondence with with respect respect to to the the copyright copyright oror proprietary proprietary aspects aspects of of Attachment Attachment 33or or the supporting Westinghouse affidavit supporting Westinghouse affidavitshould shouldreference referenceCAW-12-3496 CAW-12-3496 and and should should be addressed to J. A. Gresham, Manager, Manager, Regulatory Regulatory Compliance, Compliance, Westinghouse Westinghouse Electric Electric Company, Suite Suite 428, 1000 Westinghouse 428,1000 Westinghouse Drive, Drive, Cranberry CranberryTownship, Township, PA, PA, 16066.

16066.

There are are no no new new regulatory regulatory commitments commitments made made in in this this letter.

letter. IfIf you you have have anyany questions questions about thisthis letter, letter, please please contact me at (630) 657-2823. 657-2823.

Respectfully, Respectfully, Wt<,

Patrick R. Simpson Manager - Licensing Exelon Generation Company, LLC LLC

June 11,2012 June 11, 2012 U.S. Nuclear U.S. Nuclear Regulatory Regulatory Commission Page 33 Page Attachments:

Attachments:

1.

1. Response to Response to NRC NRC Request Requestfor forAdditional Additional Information Information 2.

2. Westinghouse Affidavit Westinghouse Affidavit and Authorization Letter Letter CAW-1 2-3486 CAW-12-3486 3.

3. Westinghouse Document NF-CB-12-101 Westinghouse NF-CB-12-101 Revision 11 P-Attachment P-Attachment (Proprietary)

(Proprietary) 4.

4. Westinghouse Westinghouse Document NF-CB-12-101 NF-CB-12-101 Revision 1 1 NP-Attachment (Non-NP-Attachment (Non-Proprietary)

Proprietary) cc: Regional cc: Regional Administrator, Administrator, U.S. NRC Region III U.S. NRC Senior Resident Inspector, Braidwood Station U.S. NRC U.S. NRC U.S. NRC Senior Resident Inspector, Byron Station

ATTACHMENT 11 Response to to NRC Request for Additional Information In Reference In Reference 1, 1, the the NRC NRC issued issued an aninformation information request requestfor forExelon Exelon Generation GenerationCompany, Company,LLC, LLC, (EGC) associated (EGC) associated withwith the effect effect of thermal conductivity degradation on peak cladding conductivity degradation cladding temperature in in the Westinghouse Westinghouse Electric Electric Company Company furnished furnished realistic realistic emergency emergency core core cooling cooling system evaluation evaluation models models for for Braidwood Braidwood Station, Station, Unit Unit 2 and Byron Byron Station, Unit 2. 2. EGC EGC provided the provided the requested information information in in Reference Reference 2. 2. Subsequent SubsequentNRC NRC review review ofof Reference Reference 22 has identified identified the need need for for the the additional additional information requested in information requested in Reference Reference3. 3.

NRC RAIRAI1 1 Provide a table of Provide of data that that includes the following ASTRUM inputs for AOR AOR and integrated analyses: (1)(1) AOR AOR Run Run #, (2) TCD TCD Run #, (3) PCT, PCT, (4) (4) Time of of PCT, (5)

(5) Fq, Fq, (6)

(6) FdH, FdH, (7)

(7)

Cycle Burnup, (8) MarginMargin Only PCT, (9) (9) TCD Minus Minus Margin Only Delta.

Response

The response to NRC RAI RAI 11 isis provided provided inin Attachment Attachment 33 to to this this submittal submittal asas the the response response toto NRC RAIRAI1.1.

NRC RAIRAI2 2 Highlight the Highlight the limiting limitingcases cases in the ASTRUM ASTRUM run run matrices matricesand and explain explainhowhowthese these cases cases were were chosen. Provide details and explain the approach explain the approach used to estimate (1) the effects effects of TCD TCD and (2) the compensating model changes.

(2) changes. Justify Justifythe the selection selection of the number numberof of WCOBRA/TRAC WCOBRAITRAC cases that cases that were were re-executed, re-executed, as asopposed opposedto toaalarger larger number number of of cases.

cases.

Response

The response to NRC NRC RAI RAI 22 isis provided provided inin Attachment Attachment 33 to to this this submittal submittal as as the the response response toto NRC RAIRAI2.2.

NRC RAIRAI3 3 Justify the the containment containment pressure pressure changes made made to to obtain obtain margin.

margin. Provide Provide reference reference toto excerpts excerpts from from the applicable applicable methodologies methodologies to to clarify clarify the response.

response.

Response

The response to to NRC NRC RAI RAI 33 isis provided provided inin Attachment Attachment 33 to to this this submittal submittal as as the the response response toto NRC RAI RAI3.3.

NRC RA14a RAI4a Your submittal submittal referenced aa March March 7, 2012, letter letter sent sentbyby Westinghouse WestinghouseElectric ElectricCompany Companyto to the NRC.

the NRC.

11

a. The

a. The final final paragraph paragraph on Page 22 of on Page of 99 refers refers to to small small differences differences inin fuel characteristics that were that were claimed claimed toto be be compared.

compared. The The paragraph paragraph also alsodiscusses discussesconfirmatory confirmatory evaluations concluding evaluations concludingthat that other other operating operating characteristics characteristics werewere acceptable.

acceptable. Provide Provide the results ofof this comparison comparison for for Braidwood Braidwood Unit Unit 2 and and Byron Byron Unit Unit No.2, including including the the relevant relevant conclusions conclusions and and the the technical technical basis basis supporting supporting those those conclusions.

conclusions. For For any conclusion that differences in any in a particular particular fuel or operating characteristic characteristic are are offset offset by by other otherconservatisms, conservatisms, list listthose those conservatisms conservatisms and provideprovide a quantitative estimate of of each each conservatism, as as well well as as aa brief brief description of the rigorrigor associated associated with that with that estimate.

estimate.

Response

Response The response response toto NRC NRC RAIRAI 4a is provided provided in in Attachment Attachment 33 to to this this submittal submittal asas the response response to to NRC RAI 4a.

RAI4a.

RAI 4b NRC RAI4b Your submittal Your submittal referenced referenced a March 7, 2012, letter letter sent sent byby Westinghouse WestinghouseElectricElectricCompany Companytoto the NRC.

NRC.

b. Provide the

b. the values values for the coefficients used in the PAD 4.0 ++ TCD PAD 4.0 TCD UO2U02 thermal thermal conductivity equation.

Response

Response The response to NRC RAI 4b is provided in in Attachment Attachment 33 to to this this submittal submittal asas the the response response to to NRC RAI 4b.

RAI4b.

NRC RAI RAI4c4c Your submittal referenced Your submittal referenced a March March 7, 2012, letterletter sent sentby byWestinghouse WestinghouseElectricElectricCompany Companytoto the NRC.

NRC.

c. Explain any error Explain any errorcorrections, corrections,code code improvements, improvements, and and miscellaneous miscellaneous code code cleanup cleanup between thethe WCOBRA/TRAC WCOBRAffRAC and and HOTSPOT HOTSPOT code versions versions used used in the TCD TCD evaluations and those thoseused usedininthe theplant's plant'sAOR.

AOR.

Response

Response The response to NRC NRC RAIRAI 4c 4c is is provided provided in in Attachment Attachment 33 to to this this submittal submittal asas the the response response to to NRC RAI 4c.

RAI4c.

NRC RAI RAI4d4d Your Your submittal submittal referenced referenced aaMarch March 7, 2012, 2012, letter letter sent sent byby Westinghouse WestinghouseElectricElectric Company Company to to the the NRC.

NRC.

d.

d. What What is the thermal conductivity model thermal conductivity model impact impact of of code code version changes changesinin HOTSPOT?

HOTSPOT?

22

Response

The response to NRC RAI 4d is provided in The in Attachment Attachment 33 to to this this submittal submittal as as the the response response to to NRC RAI NRC RAI4d. 4d.

NRC NRC RAI4e RAI 4e Your submittal Your submittal referenced referenced aa March March 7, 7, 2012, 2012, letter sent sent by Westinghouse Electric Electric Company to the NRC.

Explainthe

e. Explain thedifferences differences between between the HOTSPOT and PAD PAD thermal thermal conductivity models and the impact impact of those those differences.

differences. Provide Providegraphsgraphsororother otherquantified quantified descriptions that aid in explanation.

Response

The response responseto toNRC NRC RAIRAI 4e is is provided provided in Attachment Attachment 33 to to this this submittal submittal as as the the response response to to NRC RAIRAI4e. 4e.

NRC RAIRAI4f 4f Your submittal referenced a March Your submittal March 7, 2012, letterletter sent sentby by Westinghouse WestinghouseElectricElectricCompany Companytoto the NRC.

NRC.

f. Provide additional additional detail detail concerning concerning the steady steady-state

-state ASTRUM/CQD initialization process.

process.InInparticular, particular, explain explain what whatfuel fuel characteristics characteristicsare areadjusted adjustedwithin within the the applicable applicable models to obtainobtain convergence among among HOTSPOT, HOTSPOT, WCOBRA-TRAC, WCOBRA-TRAC, and and PAD 4.0 ++ TCD.

Response

Response The response to to NRC NRC RAI RAI 4f 4f is is provided provided inin Attachment Attachment 33 to to this this submittal submittal as as the the response response to to NRC RAIRAI4f. 4f.

RAI5 NRC RA15 Explain Explain how the changed changed design designvalues valueswill will be beverified verified during during operation operationofofthe theplant, plant,i.e.,

i.e.,

technical specification specification limits, surveillances, etc. Also, limits, surveillances, Also, explain explain whatwhat compensatory compensatoryactionsactionswill will be be taken taken ifif a value isis found to be outside outside of of the limits assumed in limits assumed in the analysis.

analysis.

Response

Response The The following following Best-Estimate Best-Estimate LargeLarge Break Break LOCA (BE-LBLOCA)

(BE-LBLOCA) design design input input values values were were modified in in the quantitative evaluation performed quantitative evaluation performedtotoassessassess thethe PCT effect effect of TCD and peaking peaking factor factor burndown burndown for Braidwood Station Unit Unit 22 and and Byron Byron Station Station Unit 22 (Reference (Reference 2). 2).

Upper bound Steam Steam Generator GeneratorTubeTubePlugging Plugging (SGTP)

(SGTP)

- Upper Upper bound nominal nominal vessel average average temperature temperature 33

Containment pressure boundary condition Procedures ER-AP-420-002, Procedures ER-AP-420-002, Revision Revision 10a, 10a, "Byron "Byron /Braidwood IBraidwood Unit 2: Steam Unit 2: Steam Generator Generator Eddy Eddy Activities,"and Current Activities," andER-AP-420-0051, ER-AP-420-0051,RevisionRevision15a, 15a, "Conduct "Conduct of ofSteam Steam Generator Management Program Management Program Activities," have been revised Activities," have revised to to administratively administratively control the upper upper bound bound SGTP level.

level. TheThe SGTP SGTPlevel level limit of 5%

limit of 5% cannot cannot be exceeded exceeded without without proper proper evaluation evaluation and and approval.

EGC's reload process process defines defines the the acceptable acceptableboundaries boundarieswithin within which which the reload reload cycle cycle must comply. This process comply. process will be used to reflect the new upper bound nominal vessel average will be average temperature for for both Braidwood Station Unit 22 and Byron Station Unit 2. This Unit 2. This temperature temperatureisis chosen to to be be sufficiently above the nominal vessel average sufficiently above averagetemperature temperatureatatwhich whichBraidwood Braidwood Station Unit 22 and Byron Station Unit 2 operate.operate.

As discussed in in the response responseto toNRC NRC RAIRAI 7,7, the change change in in containment pressure pressure boundary boundary condition is condition is aa reduction reduction inin analysis input conservatism. Verification Verification of of margin margin during during plant plant operation is is not not required.

required.

The peaking factor burndown burndown included included inin the the quantitative quantitative evaluation evaluation performed performedto to assess assess the the PCT effect of of TCD TCD and and peaking factor burndown for Braidwood Station Unit 2 and Byron Byron Station Unit 22 were Unit were provided providedininReference Reference2.2. They are included included in in this this response response as as Tables Tables 11to to 3.

3.

Table 1: FDHFDH Burndown Burndown Considered in Table 2: Steady Steady State State FQ FQ Burndown Burndown the the Evaluation Evaluationof ofTCD TCD Considered in the Evaluation Evaluation of of TCD TCD Rod Burnup Rod Burnup (MWD/MTU)

(MWDIMTU) FDH(1)(2)

FDH(12) (MWD/MTU) FQ Steady-FQ 0 1.7 State 28,000 1.7 0 2.1 40,000 1.513 30,000 2.1 50,000 1.411 40,000 1.953 60,000 1.326 50,000 1.806 70,000 1.258 60,000 1.722 (1) Includes uncertainties.

(1) 70,000 1.701 (2) Hot assembly average power (2) power uses uses same burndown, since it is a function of FDH.

4

Table 3: Transient Table Transient FQ FQ Burndown Considered in the Evaluation of TCD Rod Burnup Rod (MWDIMTU)

(MWD/MTU) FQ FQ Transient(1)

Transient(')

00 2.6 2.6 40,000 2.6 50,000 2.314 60,000 2.184 70,000 2.106 (1) Includes uncertainties.

(1)

These tables tables are arealready alreadyincluded includedin in the thecycle cycle specific specific Reload Reload Safety Safety Analysis Analysis Checklist Checklist Verification of limits. Verification of BE-LBLOCA BE-LBLOCAlimits limitsspecified specifiedininTables Tables11through through 33 is is performed performed as as of the part of the normal normal reload reload design design process process for each reload core. Steady Steadystate stateFQ Falimits limits are verified verified byby comparing comparing predicted steady-state steady-state peaking peaking factors factorsfrom from full full power conditions against conditions against the steady-state steady-stateburnup burnupdependent dependentFQ Fapeaking peakingfactor factorlimits limits shown shown in in Table 2. Transient TransientFQ FaandandFDHFDHlimits limits areareverified verified by by comparing comparing power power distributions distributions predicted forfor normal normal operation operation and for operational transients transients against againstthe theapplicable applicablelimitslimits specified in specified in Tables Tables 11 and and 3.3. Predicted Predicted transient transient power power distributions distributions are are generated generated based on the methodology described in in Reference 4. Predicted Predictedpower powerdistribution distribution used used inin reload analyses are reload are based basedon oncore coremodels modelsdeveloped developedusing usingthetheNRC-approved NRC-approvedANC ANC code described in References 55 and and 6. 6.

Each reload cycle, these these limits limits are are analytically analytically confirmed and verified. verified. IfIf the the analytical analytical verificationproduces verification produces unacceptable unacceptable results, then the core is is either either redesigned redesigned or or the the BE BE--

analysis isis re-performed LBLOCA analysis re-performed with with revised input input parameters. The acceptabilityacceptability of of analysis results results is is based basedon onconfirming confirming that that the reactor reactor core is operating operating as as designed.

designed.

Measured powerpower distributions distributions and core reactivity reactivity are compared against againstpredicted predicted power power distributions distributions and and core core reactivity.

reactivity. These These comparisons, comparisons, when when coupled coupled with with startup startup physics testing results following refueling, are following refueling, are used used to verify verifythe the core core isis operating operating as as designed.

designed.

This confirmation provides confidence in confirmation provides in the the predictive predictive capability of the core design design model used to verify peaking factors used in BE-LBLOCA accident analysis. IfIf the the core core is determined to to not be operating as designed, designed,an anevaluation evaluationwouldwould be beperformed performed to to assess assessanalysis analysismargins, margins,understand understandthe thereasons reasonsfor forthe the deviation, deviation, and and make make appropriate adjustments on a appropriate adjustments on a case-by-case case-by -case basisbasistotoplant plantoperations operations or or setpoints setpoints to to ensure ensure operation operation within within BE-LBLOLCA BE-LBLOLCA analysis analysis limits.

limits.

In In summary, transient transient FQ, FQ, FDH, FDH, andand steady steadystate stateFQ Falimits limitsare areanalytically analyticallyconfirmed confirmedfor for each reload reload core core as as part part ofof the the reload reload design design process.

process. IfIfpeaking peakingfactorfactor assumptions assumptionsto to the BE-LBLOCA BE-LBLOCA analysis analysisare are exceeded, exceeded, then either the reload core core isis redesigned redesignedor orthe the BE-LBLOCA BE-LBLOCA analysisanalysisisis re-performed re-performed with withrevised revised inputinput parameters.

parameters. The Theacceptability acceptability of the peaking factors factors assumptions assumptionsused usedininthe theBE-LBLOCA BE-LBLOCAanalysis analysisisisconfirmed confirmedby by verifying the core verifying the core isis operating operating as as designed. This This is is accomplished accomplished throughthrough aa startup startup physics physics test testprogram programfollowing following refueling refueling and and through throughperiodic periodicpower powerdistribution distributionand and reactivity measurements performed reactivity measurements performed throughout throughout the thecycle.

cycle.

55

NRC RAI6 NRC RAI 6 Atthe At the top top of of Page Page 2 of Attachment 1 to your March March 19, 2012, submittal, it is stated that, it is "EGCand "EGC and its its vendor, vendor, Westinghouse Westinghouse Electric Electric Company, LLC, utilized processes LLC, utilized processes whichwhich ensure that the LOCA analysis input LOCA analysis input values values conservatively bound the as-operated as-operated plantplant values for values forthose those parameters."

parameters." Explain these processes, Explain these processes,

Response

Response response to The response to NRC NRC RAI RAI 6 is provided in Attachment 3 to this submittal as as the the response to response to NRC NRC RAI RAI 6.

NRC RAI7

RAI 7

Based on the review review of your your March March 19, 19, 2012, 2012, submittal submittal ititappears appears that you revised the inputs to inputs to aa method method of of evaluation evaluation as as described in in the FSAR FSAR (as updated) used used in in establishing the establishing the design design bases bases or or in in the safety analyses.

Revision 1 to NEI Revision 96-07, "Guidelines for NEI 96-07, for 10 CFR 50.59 Implementation," Section 3.8, 3.8, "Input Parameters,"

"Input Parameters," provides provides clarifying information concerning clarifying information concerning whether an an input input parameter is considered to be be anan element elementof of aa methodology methodology for for the purposes purposes of of addressing the the applicable applicable requirements requirements found found at 10 10 CFR CFR 50.59, "Changes, "Changes, Tests, Tests, and and Experiments." Address whether the methodology Experiments." methodology permits the licensee to establish how how to select the value value of of an input input parameter parameterto to yield yield adequately adequately conservative conservative results resultsand and whether the revised value value isis more more conservative conservative than than that thatrequired required by bythe theselection selection method.

Address whether whether any any ofof the the changes changes(i.e.,(Le.,totothe theU02 U02thermal thermalconductivity conductivityequation) equation) constitutes aa change changeininthe thecalculational calculationalframework framework used usedforforevaluating evaluatingbehavior behavioror or response response of of aa system, system, structure structure or or component.

component. Explain Explainwhether whetherand andhow how10 10CFR CFR 50.59(c)(4) might might apply apply to to such such a change.

change.

Response

Response The response to NRC NRC RAIRAI 77 is is provided provided in in Attachment Attachment 33 to to this this submittal submittal asas the the response to NRC NRC RAI RAI 7.7.

References References

1. Letter from from Michele Michele G. G. Evans (U.S.(U.S. NRC)

NRC) to to Michael Michael J. J. Pacilio Pacilio(Exelon (ExelonNuclear),

Nuclear),

"Information "Information RequestRequest Pursuant Pursuant to to 50.54(f) 50.54(f) Related Related to to the the Estimated EstimatedEffect Effect on on Peak Peak Cladding Cladding Temperature TemperatureResulting Resultingfrom fromThermal ThermalConductivity ConductivityDegradation Degradationinin the Westinghouse Westinghouse FurnishedFurnishedRealistic Realistic Emergency EmergencyCore CoreCooling Cooling System System Evaluation (TAC No. M99899),"

(TAC No. M99899)," dated dated February 16, 2012 16, 2012

2. Letter from from Patrick Patrick R. R. Simpson Simpson (Exelon (Exelon Generation Generation Company, Company, LLC) LLC) to U.S.U.S. NRC, NRC, "Response "Responseto toRequest Requestfor forInformation Information Regarding Regarding Thermal Thermal Conductivity Conductivity Degradation and 10 10 CFR CFR 50.46 50.46Report,"

Report," dated March March 19, 2012 2012 66

3. Letter

3. Letterfrom fromJoel JoelS.

S.Wiebe Wiebe (U.S. NRC) to (U.S. NRC) to Michael Michael J.

J. Pacilio Pacilio (Exelon Nuclear), "Request for (Exelon AdditionalInformation for Additional InformationRelated Relatedtoto10 10CFR CFR50.46 50.46 30-Day Report,"

30-Day Report,"dated dated May May10,10, 2012 2012 WCAP- 9272-P- A, "Westinghouse Reload

4. WCAP-9272-P-A, Reload Safety SafetyEvaluations EvaluationsMethodology,"

Methodology," July July 1985 1985

5. WCAP-10965-P-A,

5. WCAP-10965-P- A, "ANC:

"ANC: A Westinghouse Advanced Advanced Nodal Computer Code,"

September 1986 September 1986 WCAP- 11596- P-A, "Qualification

6. WCAP-11596-P-A, ofthe "Qualification of the PHOENIX-P/ANC PHOENIX - P/ANC Nuclear Design System for System for Pressurized Pressurized Water Reactor Cores," June 1988 1988 77

ATTACHMENT 2 ATTACHMENT Westinghouse Affidavit and Authorization Letter Letter CAW-12-3496

(8 Westinghouse Westinghouse Electric Company Nuclear Services 1000 Westinghouse Drive 1000 Westinghouse Cranberry Cranberry Township, Drive Township, Pennsylvania Pennsylvania16066 16066 USA USA U.S. Nuclear Regulatory Commission Commission (412) 374-4643 Direct tel: (412)374-4643 Document Control Desk Directfax:

Direct fax: (724) 720-0754 11555 Rockville Pike 11555 greshajawestinghouse.com e-mail: greshaja@westinghouse.com Rockville, MD Rockville, MD 20852 Proj letter: NF-CB-12-101 Revision Revision 11 CAW-12-3496 June 8, 2012 APPLICATION FOR WITHHOLDING PROPRIETARY INFORMATION FROM PUBLIC DISCLOSURE NF-CB-12-101

Subject:

NF-CB-12-1 0 1 Revision 1 P-Attachment, P-Attachment, "Byron "Byron Unit Unit 22 and andBraidwood BraidwoodUnit Unit22--Response Response to NRC Formal Request Request for for Additional Additional Information Information(RAI)

(RAI)from from thethe Reactor ReactorSystems SystemsBranch Branch Related to the 1010 CFR CFR 50.46, 50.46, 30-Day 30-Day Report" Report" (Proprietary)

(Proprietary)

The proprietary proprietary information information for for which whichwithholding withholdingisisbeing beingrequested requestedininthe theabove-referenced above-referencedreport reportisis further identified in Affidavit CAW-12-3496 signed by the owner of the proprietary in Affidavit CAW-12-3496 signed by the owner of the proprietary information, information, Westinghouse Electric Company LLC. The Theaffidavit, affidavit,which whichaccompanies accompanies this thisletter, letter,sets sets forth forth the the basis basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b)(4) of of 10 CFR Section 2.390 of Commission's of the Commission's regulations.

Accordingly, this letter authorizes authorizes the utilization ofof the accompanying affidavit by Exelon Generation Company, LLC.

Correspondence with Correspondence with respect respect to to the the proprietary prop"rietaryaspects aspects of ofthe the application applicationfor forwithholding withholdingororthe the Westinghouse Westinghouse affidavit affidavit should should reference referenceCAW-12-3496 CAW-12-3496and andshould shouldbe beaddressed addressedtotoJ.J.A.A.Gresham, Gresham, Manager, Regulatory Compliance, Compliance, Westinghouse Westinghouse Electric Electric Company, Company, Suite Suite 428, 428, 1000 1000 Westinghouse Westinghouse Drive, Cranberry Township, Pennsylvania Pennsylvania 16066.

16066.

Very truly yours, l~;J. A. Gresham, Manager Regulatory Compliance Enclosures Enclosures

CAW-12-3496 CAW-12-3496 AFFIDAVIT AFFIDAVIT COMMONWEALTH OF PENNSYLVANIA:

COMMONWEALTH ss ss COUNTY OF BUTLER:

COUNTY BUTLER:

Before me, the undersigned authority, personally personally appeared appeared J. J. A. Gresham, who, A. Gresham, who, being being by by me me duly duly sworn according to law, deposes and says says that that he he is is authorized authorized to to execute execute this this Affidavit Affidavit on on behalf behalfof of Westinghouse Electric Company LLC (Westinghouse), (Westinghouse), and and that that the the averments averments of offact fact set set forth in in this Affidavit are true and correct correct to the best best of of his knowledge, knowledge, information, information, andand belief.

belief:

1~

J. A. Gresham, Manager Regulatory Compliance Sworn to and subscribed subscribed before before me me this 8th day ofofJune June 2012 2012 COMMONWEAlTH OF COMMONWEALTH OFPENNSYLVANIA PENNSYLVANIA Notarial NotarialSeal Seal Cynthia CynthiaOlesky, Olesky,Notary NotaryPublic Public Manor ManorBoro, Boro, Westmoreland westmorelandCounty County My My Commission Commission Expires expires July July 16, 16,2014 2014 Member, Member.Pennsylvania Assodatlon of PennsvlvanlaAssociation ofNotaries Notaries

22 CAW-12-3496 CAW- 12-3496 (1)

(1) II am am Manager, Manager, Regulatory Regulatory Compliance, Compliance, in Nuclear Services, Services, Westinghouse Westinghouse Electric Company LLC Company LLC (Westinghouse), and as as such, such, I have have beenbeen specifically delegated the the function of reviewing the proprietary information sought to to be be withheld from from public public disclosure in connection with nuclear power plant licensing and rule making proceedings, and am authorized to apply for behalf of its withholding on behalf of Westinghouse.

(2) I am making this Affidavit in conformance with the provisions of 10 CFR Section 2.390 of of the Commission's regulations Commission's regulations andand inin conjunction conjunction with with thethe Westinghouse Westinghouse Application Application for for Withholding Withholding Proprietary Information from Public Disclosure Disclosure accompanying accompanying this this Affidavit.

Affidavit.

(3) I have personal knowledge of the criteria and procedures procedures utilized by Westinghouse in designating information as a trade secret, privileged privileged or as confidential confidential commercial commercial or or financial financial information.

information.

(4) Pursuant to the provisions of of paragraph (b)((b)(4) Commission's regulations,

4) of Section 2.390 of the Commission's regulations, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld withheld fromfrom public public disclosure disclosure should shouldbe bewithheld.

withheld.

(i)

(i) The information sought to be withheld from public disclosure is owned and has been held in confidence by Westinghouse.

(ii) The information is of of a type customarily held in confidence by Westinghouse and not customarily disclosed to to the the public.

public. Westinghouse has a rational basis for determining the types ofof information customarily customarily held held inin confidence confidence by byitit and, and, ininthat thatconnection, connection, utilizes a system system toto determine determine when when and and whether whether to to hold holdcertain certaintypes typesof ofinformation informationinin confidence. The Theapplication applicationof ofthat thatsystem systemand andthe the substance substanceof ofthat thatsystem systemconstitutes constitutes Westinghouse policypolicy and and provides provides thethe rational rational basis basis required.

required.

Under that system, system, information information is is held held inin confidence confidenceififititfalls falls ininone oneor ormore moreof ofseveral several types, the release of ofwhich which might might result result inin the the loss loss of ofanan existing existingor orpotential potentialcompetitive competitive advantage, advantage, as as follows:

follows:

(a)

(a) The information The information reveals reveals the the distinguishing distinguishing aspects aspects of ofaaprocess process(or(orcomponent, component, structure, tool, method, etc.) etc.) where prevention prevention of ofits its use use byby any any of of

33 CAW-12-3496 CAW-12-3496 Westinghouse's competitors without Westinghouse's without license license from from Westinghouse Westinghouse constitutes constitutes aa competitive economic advantage over other competitive other companies.

companies.

(b)

(b) It consists It consists of of supporting data, including test test data, data, relative to a process (or(or component, structure, component, tool, method, etc.), the structure, tool, the application application of of which which data data secures secures a competitive economic advantage, e.g., by competitive by optimization optimization or improved marketability.

(c) Its use by a competitor would reduce his expenditure of Its of resources or improve his competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing aa similar similar product.

product.

(d) It reveals cost or price information, production capacities, budget levels, or commercial strategies of of Westinghouse, Westinghouse, its its customers customers or orsuppliers.

suppliers.

(e) It reveals aspects ofof past, present, oror future future Westinghouse Westinghouse or or customer customerfunded funded development plans and and programs programs of ofpotential potential commercial commercialvaluevalueto toWestinghouse.

Westinghouse.

(f) It contains patentable ideas, ideas, for for which which patent patent protection protection maymaybe be desirable.

desirable.

There are sound policy reasons behind the Westinghouse system which include include the the following:

(a) The use ofof such such information information by by Westinghouse Westinghouse gives gives Westinghouse Westinghouse aa competitive competitive advantage over its competitors. ItItis, is,therefore, therefore, withheld withheldfromfromdisclosure disclosuretoto protect the Westinghouse Westinghouse competitive competitive position.

position.

(b) It is information that is marketable in in many ways. The Theextent extenttotowhich whichsuch such information is available available to to competitors competitors diminishes diminishes the theWestinghouse Westinghouseability abilitytoto sell products products and and services services involving involvingthetheuseuseof ofthe theinformation.

information.

(c) Use byby our competitor would would putput Westinghouse Westinghouse at at aa competitive competitivedisadvantage disadvantageby by reducing his his expenditure expenditure ofofresources resources atat our our expense.

expense.

44 CA W-12-3496 CAW-12-3496 (d)

(d) Each Each component of proprietary information pertinent to a particular particular competitive competitive advantage advantage isis potentially potentiallyasasvaluable valuableas asthe thetotal totalcompetitive advantage. If competitiveadvantage. If competitors competitors acquire acquire components components of of proprietary proprietary information, information, anyone any one component may bebe the the key toto the the entire entire puzzle, puzzle, thereby thereby depriving depriving Westinghouse Westinghouse of a competitive advantage.

competitive (e) disclosure would jeopardize Unrestricted disclosure jeopardize the position of prominence of of Westinghouse in the world market, and thereby thereby give aa marketmarket advantage advantage to to the the competition of those countries.

(f) The Westinghouse capacity to invest corporatecorporate assets assets in in research research and and development depends upon the success success in obtaining and maintaining a competitive advantage.

(iii) The information is being transmitted to the Commission in confidence and, under the provisions of of 10 CFR Section 2.390, it is to be received in confidence by the Commission.

(iv) The information sought to be protected is not available in public sources or available previously employed information has not been previously employed in in the the same same original originalmanner manneror ormethod methodtoto the best of of our knowledge and and belief.

belief.

(v) The proprietary information sought sought toto be be withheld withheld in in this this submittal submittalisisthat thatwhich whichisis appropriately marked in NF-CB-12-101 Revision Revision 1I P-Attachment, P-Attachment,"Byron "ByronUnit Unit22 and Braidwood Unit 2 - Response Response toto NRC NRC Formal Formal Request Requestfor for Additional Additional Reactor Systems (RA!) from the Reactor Information (RAI) Systems Branch Branch Related Related to to the the 10 10CFR CFR50.46, 50.46, 30-Day 30-Day Report" Report" (Proprietary)

(Proprietary) for for submittal submittal to to the the Commission, Commission,being beingtransmitted transmittedbyby Generation Company, Exelon Generation Company, LLCLLC letter letter and and Application Applicationfor forWithholding WithholdingProprietary Proprietary Information from Public Disclosure, to the Document Control Desk. The Theproprietary proprietary information as information as submitted submitted by Westinghouse isis that by Westinghouse that associated associatedwith withfuel fuelthermal thermal conductivity conductivity degradation, degradation, andand may may bebe used used only onlyfor forthat thatpurpose.

purpose.

55 CA W-12-3496 CAW-12-3496 This infonnation This information is is part of that which will enable Westinghouse to: to:

(a)

(a) Assist customers in providing responses to RAIs RAls dealing with the 10 10 CFR 50.46, 50.46, 30-day report.

30-day this infonnation Further this information hashas substantial substantial commercial value as follows:

(a) Provide licensing support with respect to thermal thennal conductivity degradation.

(b) The infonnation information requested to be withheld reveals the distinguishing aspects of of a methodology which was developed by by Westinghouse.

Public disclosure ofof this proprietary information infonnation is likely to cause substantial harm hann to the competitive position of of Westinghouse because it would enhance the ability of of competitors to provide similar fuel design and licensing defense services for for commercial without commensurate power reactors without commensurate expenses.

expenses. Also, Also, public disclosure of the ofthe information would enable others to use the information infonnation infonnation to meet NRC requirements for licensing documentation without purchasing the right to use the information.

infonnation.

The development of of the technology technology described described inin part part by by the the information infonnation isis the the result result of of applying the results of of many years of of experience in an intensive Westinghouse effort and the expenditure of of a considerable considerable sum sum of ofmoney.

money.

In order for competitors of ofWestinghouse Westinghouse toto duplicate duplicatethis thisinformation, infonnation,similar similartechnical technical programs would have to be performed perfonned and and aa significant significant manpower manpower effort, effort, having having the requisite talent and and experience, experience, would would have have toto be beexpended.

expended.

Further the deponent deponent sayeth sayeth not.

not.

PROPRIETARY INFORMATION NOTICE Transmitted herewith are proprietary and/or non-proprietary non-proprietary versions versions of ofdocuments documents furnished furnishedtotothe theNRC NRC in connection with requests for plant-specific review of thermal conductivity degradation review of thermal conductivity degradation impacts. impacts.

requirements of 10 CFR 2.390 of the Commission's In order to conform to the requirements Commission's regulations regulations concerning concerningthe the protection of proprietary information so submitted to the NRC, the information which is proprietary in the proprietary versions is contained within brackets, and where the proprietary information has been deleted in the non-proprietary versions, only the brackets brackets remain (the information that was was contained within the brackets in the proprietary versions having been deleted). The Thejustification justificationforforclaiming claimingthe theinformation information so designated as proprietary is indicated indicated inin both both versions versions by by means means of lower case oflower caseletters letters(a)

(a)through through(f) (f) as a superscript immediately following the brackets located as brackets enclosing each item of information being identified as proprietary or in the margin opposite such information. These Theselower lowercase caseletters letters refer referto to the the types of information Westinghouse customarily holds in confidence identified in Sections (4)(ii)(a) through (4)(ii)(f) of of the affidavit accompanying accompanying this this transmittal transmittal pursuant pursuanttoto 10 10CFR CFR2.390(b)(1).

2.390(b)(l).

COPYRIGHT NOTICE The reports transmitted herewith each bear a Westinghouse copyright notice. notice. The The NRC NRC isis permitted permittedto to make the number of of copies copies ofofthe the information information contained contained in inthese thesereports reportswhich whichare arenecessary necessaryfor forits its internal use in connection with genericgeneric and and plant-specific plant-specific reviews reviews andand approvals approvalsas aswell wellasasthe theissuance, issuance, denial, amendment, transfer, renewal, renewal, modification, modification, suspension, suspension, revocation, revocation,or orviolation violationofofaalicense, license, permit, order, or or regulation subject subject to to the the requirements requirements of of1010 CFR CFR2.3902.390regarding regardingrestrictions restrictionson onpublic public disclosure to the extent such such information information has has been been identified identifiedas as proprietary proprietarybybyWestinghouse, Westinghouse,copyright copyright protection notwithstanding. With respect to the non-proprietary versions of ofthese these reports, reports, the the NRC NRC isis permitted to make the number of of copies beyond those necessary for its internal use which are necessary in order to have one copy available for public viewing in the appropriate docket files in the public document room in Washington, DC and in in local public document rooms as may be required by NRC regulations ifif the number of of copies submitted is insufficient for this purpose. CopiesCopiesmade madeby bythe theNRC NRCmustmustinclude include the copyright notice in in all instances and the proprietary notice if the original was identifiedasasproprietary.

all instances and the proprietary notice if the original was identified proprietary.

ATTACHMENT 44 ATTACHMENT Westinghouse Document Document NF-CB NF-C8-12-101

-1 2-101 Revision Revision 11 NP-Attachment (Non-Proprietary)

Westinghouse Non-Proprietary Non-Proprietary Class Class 33 NF-CB-12-101 Revision 11 NP-Attachment NP-Attachment Byron Unit 2 and Braidwood Unit 2 - Response Byron Response to NRC Formal Request NRC Formal Request for Information for Additional Information (RAI) from (RAI) from the Reactor Reactor Systems Branch Related Systems Branch Related toto the the 10 CFR 50.46, 30-Day CFR 50.46, 30-Day Report Report June 2012 Westinghouse Electric Company Westinghouse Electric CompanyLLCLLC 1000 Westinghouse Drive Drive Cranberry Township, Township, PAPA 16066

Westinghouse Non-Proprietary Class 3 Westinghouse NF-CB-12-101 NF-CB-12-101 Revision Revision 1 NP-Attachment NRC RA11 NRCRAll Provide aa table Provide table of data that thatincludes includes the thefollowing followingASTRUM ASTRUMinputs inputsfor forAOR AOR and andintegrated integratedanalyses:

analyses:(1)

(1)AOR AOR Run #,

Run #, (2) TCD TCD Run Run #,

, (3)

(3) PCT, PCT,(4)

(4) Time Time of of PCT, PCT, (5)

(5) Fq, Fq, (6)

(6) FdH, FdH, (7)

(7) Cycle Cycle Burnup, Burnup, (8) Margin MarginOnly OnlyPCT, PCT,(9)

(9)TCD TCD Minus Margin Minus Margin Only Only Delta.

Delta.

Response

Response Table 1: Byron/

Table Braidwood (CBE/CDE)

Byron/Braidwood Integrated TCD (CBE/COE) Integrated TCO Evaluation Runset Runset Data Data a,c a,c I'=====!I-----L---IL----l--L-----L-----II-~L_______L_----D

All All Rights Rights Reserved Reserved NP-2 NP-2

Westinghouse Non-Proprietary Class 33 NF-CB-12-101 NF-CB-12-101 Revision 1 NP-Attachment a,c

Westinghouse Non-Proprietary Class 3 Westinghouse NF-CB-12-101 NF-CB-12-101 Revision Revision 1 NP-Attachrnent NP-Attachment Table 2:

Table 2: Byron/Braidwood Byron/ Braidwood Unit Unit 22 (CBE/CDE)

(CBE/COE) AOR Runset Data a,c a,c

Westinghouse Non-Proprietary Westinghouse Non-Proprietary Class 3 NF-CB-12-101 NF-CB-12-101 Revision Revision 1 NP-Attachment a,c a,c I I U

N 002012 Westinghouse

Westinghouse Non-Proprietary Class 3 Westinghouse NF-CB-12-101 NF-CB-12-101 Revision 1 NP-Attachment a,c a,c

Westinghouse Non-Proprietary Class 3 NF-CB-12-101 Revision 1 NP-Attachment NF-CB-12-101 NP-Attachrnent a,c I

NRC RAI 2 NRCRAI2 Highlight the Highlight thelimiting limitingcases casesininthe theASTRUM ASTRUM runrun matrices matricesand andexplain explainhow howthese thesecases cases were werechosen.

chosen. Provide Provide details and explain thethe approach approach used used to estimate (1) to estimate the effects (1) the effectsofofTCD TCD and (2) the compensating compensating model model changes. Justify the changes. Justify theselection selectionofofthe thenumber numberofofWCOBRA/TRAC WCOBRA/TRAC cases cases that thatwere werere-executed, re-executed,as asopposed opposedtotoaa larger numberofofcases.

larger number cases.

Response

The cases cases from from the ASTRUM ASTRUM run run matrices matrices that that were were chosen chosen to toassess assess the effects effects of TCD are highlighted ofTCD highlighted in in the the response response totoRAI-CBE-1.

RAI-CBE-l.

a,c L J

Westinghouse Non-Proprietary Class 33 NF-CB-12-101 NF-CB-12-101 Revision 11 NP-Attachment a,c The estimate of of effect effect of of the the compensating compensating model model changes changes was provided by the difference difference between between the theAOR AOR PCT and the peT and the Margin Margin peT.

PCT. The estimate ofof effect effect of of TCD TeD was was provided provided by by the the difference difference between the TCD PCT Integrated teD and the Margin peT and Margin PCT.

peT.

a,c l

Westinghouse Non-Proprietary Westinghouse Non-Proprietary Class 3 NF-CB-12-101 NF-CB-12-101 Revision Revision 1 NP-Attachment a,c a,c Inthis In thisevaluation, evaluation,engineering engineeringjudgment judgment was was applied applied to to select select a small runset of limiting limiting cases for the purpose purpose of evaluating the effects effects of ofthe thedesign designinput inputmargins marginsand andTCDTCD on thethe Byron Byron and Braidwood Braidwood Unit 2 large break LOCA PCT. The LOCA The remaining remaining cases from thethe ASTRUM ASTRUM AOR AORwhich whichwere werenotnot explicitly explicitlyevaluated evaluated are are expected to expected to remain non-limiting remain non-limitingand andtherefore therefore would would not not be expected expected to to influence influencethethePCT estimate. The PCT estimate. The evaluation evaluation of of TCDand TCD andpeaking peakingfactor factorburndown burndown supports supports the the full life ofthe full life of the fuel operation.

operation.

Table 2-1: [ t,e

]afor forByron Byron and and Braidwood Braidwood Unit 22 a,c a,c

Westinghouse Non-Proprietary Non-Proprietary Class Class 33 NF-CB-12-101 Revision 11 NP-Attachment NP-Attachrnent Table 2-2: (( t,C

]a'` for Byron and Braidwood Braidwood Unit Unit 22 a,c

Westinghouse Non-Proprietary Westinghouse Non-Proprietary Class 3 NF-CB-12-101 NF-CB-12-101 Revision 1 NP-Attachment NRC RAI 3 NRCRAI3 Justify the Justify the containment containment pressure changeschangesmade made to to obtain margin. ProvideProvide reference reference to to excerpts excerptsfrom from the applicable methodologies to applicable to clarify the response.

response.

Response

Response The analysis The analysis ofof record record (AOR)

(AOR)contained contained 'analysis

'analysis margin' margin' based on the difference differencebetween betweenthe theCOCO COCO (Reference 1)

(Reference 1) calculated calculated containment containment backpressure backpressure and and the theWCOBRA/TRAC containment backpressure WCOBRA/TRAC containment backpressure input. In input. In order order to to recapture recapture this this margin margin while stillstill assuring a conservatively low containment backpressure, containment backpressure, the COCO containment pressure COCO containment pressure response response was was calculated calculated with with the design design input inputchanges changes (reduced (reduced vessel vessel average temperature average temperature and and assumed assumed steam generator generator tubetubeplugging) plugging) andand the theanalysis analysis margin marginwas wasreduced reducedby by increasing the increasing the containment containment pressure pressure assumed assumed in WCOBRA/TRAC WCOBRA/TRAC totomore moreclosely closelyreflect reflect the the calculated pressure. The new pressure. new containment containmentpressure pressureassumed assumedininWCOBRA/TRAC WCOBRA/TRAC in the TCD evaluation was compared TCD evaluation compared to to the updated updatedCOCO COCO calculated pressure pressure consistent consistentwith withWestinghouse WestinghouseBELOCA BELOCAanalysis analysis guidance guidanceand andisis conservatively low conservatively low (in (in accordance accordance with withSections Sections11-3-1, 11-4-11, and 11-3-1,11-4-11, and12-3-4 12-3-4ofofWCAP-16009-P-A, WCAP-16009-P-A, Reference Reference 2).

References:

1. WCAP-8327 (Proprietary), WCAP-8326 (Non-Proprietary), "Containment Pressure (Non-Proprietary), "Containment Pressure Analysis Analysis Code Code (COCO)," 1974.

(COCO)," 1974.

2. WCAP-16009-P-A (Proprietary), "Realistic WCAP-16009-P-A (Proprietary), "Realistic Large-Break Large-Break LOCA LOCAEvaluation Evaluation Methodology Methodology Using Using the the Automated Automated Statistical Statistical Treatment Treatmentof ofUncertainty UncertaintyMethod Method(ASTRUM),"

(ASTRUM)," January 2005 2005 NRC RAI 4a The final The final paragraph on Page Page 22 of of 99 refers to small refers to small differences differences inin fuel fuel chargctefistics characteristics that were were claimed claimed to be to be compared. The compared. The paragraph also discusses confirmatory evaluations concluding that also discusses confirmatory evaluations concluding that other operating operating characteristics were acceptable. Provide Provide the the results results ofofthis this comparison comparison for forBraidwood BraidwoodUnit Unit22and andByron ByronUnitUnit including the 2, including the relevant relevantconclusions conclusions and and the thetechnical technicalbasis basissupporting supportingthose thoseconclusions.

conclusions. For Forany anyconclusion conclusion that differences that differences in a particular particular fuel fuel oror operating operatingcharacteristic characteristicare are offset offsetbybyother otherconservatisms, conservatisms, list list those those conservatisms and provide a quantitative estimateofofeach quantitative estimate each conservatism, conservatism, as as well well as as aa brief briefdescription description of ofthe the rigor associated rigor associated with that estimate.

that estimate.

Response

Response No comparisons comparisons were made for Byron Unit 2 and Braidwood Unit Unit 22 Exelon Exe10n Nuclear Nuclear Stations.

Stations. A A fuel fuel temperature and rod rod internal internal pressure pressure analysis analysis using using Exelon Exelonspecific specificfuel fuelrod roddimensions, dimensions,plant plantoperating operating parameters, and and rod rod average average linear linear heat heat generation generation using using an anExelon Exe10nspecific specificbounding boundingpowerpowerhistory historywas was documented. ((

] a,c

Westinghouse Non-Proprietary Non-Proprietary Class Class 33 NF-CB-l2-101 Revision 11 NP-Attachment NF-CB-12-101 NP-Attachment NRC RAI 4b Provide the values valuesfor for the coefficients coefficients used used in the PAD 4.0 +

PAD 4.0 TCDV02

+ TCD U02thermal thermal conductivity conductivity equation.

Response

The functional form form used used to tomodel modelTCD TCD (( la,c

]a'` is as is as follows:

a,c NRC RAI 4c Explain any error corrections, Explain corrections, code improvements, and and miscellaneous miscellaneous code cleanup between between the the WCOBRA/TRAC and HOTSPOT code versions and HOTSPOT versions used used inin the TCD TCD evaluations andthose evaluations and those used used in in the theplant's plant'sAOR.

AOR.

Response

The WCOBRA/TRAC WCOBRA/TRACand andHOTSPOT HOTSPOT code codeversions versionsused in in used thethe evaluation evaluationofoffuel fuelpellet pelletthermal thermal conductivity conductivity degradation do not not include include any any error errorcorrections, corrections,code codeimprovements, improvements,orormodelmodelchanges changesfrom fromthetheanalysis-analysis-of-record code code versions.

versions.

NRC RAI 4d What is What is the thermal thermalconductivity conductivitymodel modelimpact impactofofcode codeversion versionchanges changes inin HOTSPOT?

Response

Please refer Please refer to to the response response toto 4c 4c above.

above.

Westinghouse Non-Proprietary Class 3 Westinghouse NF-CB-12-101 NF-CB-12-101 RevisionRevision 1 NP-Attachrnent NP-Attachment NRC RAI 4e NRCRAI4e Explain the Explain the differences differences between between the HOTSPOT HOTSPOT and andPAD PADthermal thermalconductivity conductivitymodels modelsand and the the impact impact ofof those differences. Provide differences. graphs or Provide graphs or other other quantified quantified descriptions thatthat aid aid in explanation.

explanation.

Response

Response For the For the fuel fuel thermal conductivity conductivitydegradation degradation(TCD)

(TCD) evaluation, evaluation,PAD PAD 4.0 4.0 TCD was used TCD was used toto generate the initial initial maximum fuel fuel average average temperature temperatureinput inputinto WCOBRA/TRAC into WCOBRAjTRACand andHOTSPOT.

HOTSPOT. The The PADPAD 4.0 TCD fuel thermal TCD fuel thermal conductivity equation, conductivity equation,forforfuel fuelatataanominal nominaldensity densityofof 95%

95%theoretical theoretical density densityis given is givenin in LTR-NRC-12-11 LTR-NRC-12-11 (Reference1)

(Reference 1)with withthe the coefficients coefficients provided provided inin response responseto topart part b) b)ofofthis this request requestfor for additional additional information information (RAI)and (RAJ) and repeated repeated below.

a,c a,c the TCD For the TCD evaluation, WCOBRA/TRAC WCOBRAjTRAC and and HOTSPOT HOTSPOT usedused a fuel fuel thermal conductivity conductivity model model based based onon

(( la,c

]a'` For Forfuel fuel at at a nominal density density of 95 95% % theoretical density, density, the model model in WCOBRA/TRAC and in WCOBRAjTRAC and HOTSPOT HOTSPOT is is given inin LTR-LTR-NRC-12-27 NRC-12-27 (Reference

2) and repeated below. below.

a,c a,c The The functional form form and and units units between betweenthe thetwo twomodels modelsare aredifferent.

different.ForForease easeof ofcomparison, comparison,the the degradation degradation terms (f(Bu) in both terms (f(Bu) both equations) equations) are are compared compared in in Figure Figure 11 at at burnups burnups of of20, 40 and 20,40 and 6565 GWD/MTU.

GWDjMTU.

As As seen from FigureFigure 1, 1, ((

]a,c

Westinghouse Non-Proprietary Westinghouse Non-Proprietary Class 3 NF-CB-12-101 NF-CB-12-101 Revision Revision 1 NP-Attachment Figures22through Figures through 55 compare compare the the overall overall fuel thermal thermal conductivity conductivitymodels modelsatatburnups burnupsofof0,0,20, 20,40 40and and6565 GWD/MTU, respectively. Also included in GWD/MTU, in the the figures figures isis aa comparison comparison with withthe theFRAPCON FRAPCON 3.43.4 thermal thermal conductivity model conductivity model (Reference (Reference 3). 3). As seen from As seen from the figures, [

]a,c For aa given For givenmaximum maximumfuel fuel average averagetemperature temperature and and burnup, burnup, the differences differences between the PAD 4.0 4 .0 TCD TCD and WCOBRA/TRAC and HOTSPOT HOTSPOT fuel fuel thermal conductivity conductivity models [

]a,c References References

1. LTR-NRC-12-11, "Westinghouse Thermal Conductivity Model for Conductivity Model forTurkey Turkey Point Point Unit Unit3&4 3&4Extended Extended Power Uprate (EPU) License Amendment Request Uprate (EPU) License Amendment Request (LAR) (LAR)(Proprietary)," February 2, (Proprietary)," February 2, 2012.

2012.

2. LTR-NRC-12-27,"Westinghouse LTR-NRC-12-27, "Westinghouse InputInput Supporting SupportingLicensee LicenseeResponse Responseto toNRC NRC 10 10 CFR 50.54(f) Letter CFR 50.54(f) Letter Regarding Nuclear Regarding Nuclear FuelFuelThermal ThermalConductivity Conductivity Degradation Degradation (Proprietary/Non-Proprietary),"

(Proprietary/Non-Proprietary)," MarchMarch7, 7, 2012.

3. NUREG/CR-7022, NUREG/CR-7022, Vol. Vol. 1/

1 / PNNL-19418, Vo1.1, Vol.1, "FRAPCON-3.4:

"FRAPCON-3.4: AAComputer Computer Code Code for for the the Calculation Calculationofof Steady-State Thermal-Mechanical Behavior Behavior of of Oxide Oxide Fuel Fuel Rods for High Rods for High Burnup,"

Burnup," March 2011.

2011.

4. WCAP-12945-P-A, WCAP-12945-P-A, Volume Volume 1 (Revision (Revision 2)2) and and Volumes Volumes 22-- 5 (Revision (Revision 1),

1), "Code "Code Qualification Qualification Document Document for for Best Best Estimate Estimate LOCA Analysis," March 1998. (Proprietary)

LOCA Analysis," (Proprietary)

5. WCAP-16009-P-A, "Realistic Large-Break WCAP-16009-P-A, "Realistic Large-BreakLOCA LOCAEvaluation EvaluationMethodology Methodology Using Usingthe the Automated Automated Statistical Statistical Treatment Treatment OfOf Uncertainty UncertaintyMethod Method(ASTRUM),"

(ASTRUM)," January January 2005.

2005. (Proprietary)

(Proprietary)

Westinghouse Non-Proprietary Class Class 33 NF-CB-12-101 NF-CB-12-101 Revision 1 NP-Attachment Figure 1: Fuel Fuel Thermal Thermal Conductivity Conductivity Degradation Model Comparison a,c 2: Fuel Figure 2: Fuel Thermal Thermal Conductivity Model Model Comparisons -- 00 GWD/MTU GWD/MTU a,c

Westinghouse Non-Proprietary Class 3 NF-CB-12-101 Revision NF-CB-12-101 Revision 1 NP-Attachment Figure 3:

Figure 3: Fuel Fuel Thermal Thermal Conductivity Model Comparisons - 20 20 GWD/MTU GWD/MTU a,c a,c 4: Fuel Figure 4: Fuel Thermal Conductivity Model Comparisons - 40 40 GWD/MTU GWD/MTU a,c J

Figure 5:

5: Fuel Thermal Conductivity Model Comparisons - 65 65 GWD/MTU GWD/MTU a,c a,c

Westinghouse Non-Proprietary Class Class 33 NF-CB-12-101 NF-CB 101 Revision 11 NP-Attachment NRC RAI 4 NRCRAI4(

Provide additional Provide additional detail detail concerning concerning the the steady-state steady-stateASTRUM/CQD initialization process.

ASTRUM/CQD initialization process. In In particular, particular, explain what fuel characteristics are adjusted within thethe applicable applicable models models to to obtain obtain convergence convergence among HOTSPOT, WCOBRA-TRAC, HOTSPOT, WCOBRA-TRAC, and PAD4.0++TCD.

and PAD4.0 TCD.

Response

The following The following twelve twelveparameters parametersininWCOBRA/TRAC WCOBRAjTRAC are are used used toto determine determine steady-state steady-state convergence, convergence, as as discussed in Section 20-5 of ofWCAP-12945-P-A WCAP-12945-P-A (Reference (Reference 1)1) and and Section Section12-4-1 12-4-1ofofWCAP-16009-P-A WCAP-16009-P-A (Reference 2).

a,c

Westinghouse Non-Proprietary Class Class 33 NF-CB-12-101 NF-CB-12-101 Revision 1 NP-Attachment a,c References

1. WCAP-12945-P-A, Volume WCAP-12945-P-A, Volume 11 (Revision (Revision2) 2)and andVolumes (Revision i),

Volumes22- - 55 (Revision 1),IICode "Code Qualification Document Qualification Document for Best Estimate for Best Estimate LOCA LOCA Analysis,"

Analysis," March March 1998. (Proprietary)

Westinghouse Non-Proprietary Non-Proprietary Class Class 33 NF-CB-12-101 Revision 11 NP-Attachment

2. WCAP-16009-P-A, "Realistic WCAP-16009-P-A, "Realistic Large-Break Large-BreakLOCA LOCAEvaluation EvaluationMethodology Methodology Using Using the the Automated Statistical Automated Statistical Treatment Of Uncertainty Treatment Of UncertaintyMethod Method(ASTRUM),"

(ASTRUM)," January January 2005.

2005. (Proprietary)

(Proprietary)

Non-Proprietary Class Westinghouse Non-Proprietary Class 33 NF-CB-12-101 NF-CB-12-101 Revision Revision 11 NP-Attachment NP-Attachment Table 1: Initial Gap Thickness and Average Fuel Fuel Temperature Temperature Comparison Comparison for Sample 17x17 Plant for Sample Plant a,c a,c Table 2: Initial Gap Thickness and Average Fuel Fuel Temperature Temperature Comparison Comparison for for Sample Sample 15x15 15x15 Plant Plant a,c a,c

Non-Proprietary Class Westinghouse Non-Proprietary Class 33 NF-CB-12-101 Revision NF-CB-12-101 Revision11NP-Attachment NP-Attachment 3: HOTSPOT Table 3: HOTSPOT and and WCOBRA WCOBRAITRAC State Gap Heat Transfer Coefficient and Steady-State

/TRAC Steady- and Average Fuel Fuel Temperature Temperature Comparison Comparison for Sample 17x1717x17 Plant Plant a,c a,c and WCOBRA Table 4: HOTSPOT and WCOBRAITRAC -State Gap Heat Transfer Coefficient and Average Fuel Steady-State

/TRAC Steady Fuel Temperature Temperature Comparison Comparison for Sample 15x15 15x15 Plant Plant a,c a,c

Non-Proprietary Class Westinghouse Non-Proprietary Class 33 NF-CB-12-101 Revision Revision 1I NP-Attachment NP-Attachment WCOBRAITRAC and Figure 1: WCOBRA/TRAC and HOTSPOT HOTSPOT Cladding Temperature Comparison Comparison for for 17x17 17x17 Plant Plant a,c a,c WCOBRA/TRAC and HOTSPOT Cladding Figure 2: WCOBRAITRAC Cladding Temperature Temperature Comparison Comparison for for15x15 15x15Plant Plant a,c

Westinghouse Non-Proprietary Class Class 33 NF-CB-12-101 NF-CB-12-101 Revision 1I NP-Attachment NP-Attachment NRC RAI 6 NRCRAI6 At the top of ofPage Page 22 of Attachment Attachment 1 to your your March March 19, 19, 2012, 2012, submittal, submittal, ititisisstated statedthat, that,"EGC "EGC andand its its vendor, Westinghouse Electric Company, LLC, utilized processes which ensure that LLC, utilized thatthetheLOCA LDCA analysis input values conservatively bound bound the the as-operated as-operated plant plant values values forfor those those parameters."

parameters." Explain Explainthese these processes.

Response

Exelon and Exelon and its vendor, Westinghouse WestinghouseElectric ElectricCompany CompanyLLC, LLC, ensure ensure the theLOCA LOCA analysis input input values values conservatively bound the as-operated plant values for the relevant parameters via the the relevant parameters via the fuel reload fuel reload process. The purpose of the fuel reload process. reload process process is to evaluate the the plant plantchanges changes resulting resulting from from the the loading of different differentor ornew newfuelfuelinto intothe thecore.

core.AsAsdescribed describedininWCAP-9272-P-A WCAP-9272-P-A(Reference (Reference 1), 1), the the evaluations performed performed for forthe thefuel fuelreload reloadsupport supportaalicensing licensingapproach approachunder underthe theregulations regulationsofof1010CFR CFR 50.59. Safety 50.59. Safety Analyses generally analyze Analyses generally analyze the the relevant relevant parameters in a bounding direction direction compared compared to to the expected operational operational values.

values. The The generic generic fuel fuel reload reload evaluation evaluation approach approach relies relies upon upon thethe bounding bounding approach in which safety analyses analyses are are performed performed to to accommodate accommodate the the plant plantchanges changes resulting resulting from from different or different or new new fuel fuel inin the the core core without withoutrequiring requiringnew newsafety safetyanalyses.

analyses.

As part As part of the reload reload evaluation, evaluation, the the LOCA analyst generates LOCA analyst generates aa listlist of of important important parameters parameters to to the the LBLOCAanalysis, LBLOCA analysis,and andwhich whichshowshowaafuel fuelreload reload dependency, dependency, and and identifies identifies the the values values of ofthose those parameters supported supported by bythe theLBLOCA LBLOCA licensing basis analyses analyses andand evaluations.

evaluations. The The parameters parameters are are confirmed to confirmed to support supportthe thereload reloadcore coredesign designororare areevaluated evaluatedwith with respect respect toto thetheLBLOCA LBLOCAanalysis.

analysis.

Separate from the the fuel fuelreload reloadprocess, process,plant plantchanges changeswhich whichmaymayimpact impactthe theLBLOCA LBLOCAanalysis analysis are are identified to identified toWestinghouse Westinghouseas asneeded, needed,and and10 10CFR CFR 50.46 50.46 evaluations evaluationsare areperformed performedasasnecessary.

necessary.

During the reload process, process, a summary of of plant plant changes changes thatthat have have occurred occurred since since the theprevious previouscyclecycle and and changes planned changes planned for the upcoming cycle is provided by Exelon to Westinghouse.

the upcoming cycle is provided by Exelon to Westinghouse. Westinghouse reviews those changes identified identified by by Exelon Exelon to to ensure ensure thethenon-reload non-reloadrelated relatedparameters parametersanalyzed analyzedininthe theLBLOCA LBLOCA analysis, and analysis, and therefore therefore the the LBLOCA analysis,remain LBLOCA analysis, remainapplicable.

applicable. For example, steam steam generator tube tube plugging level is is one one such such non-reload non-reload related parameter parameter reviewed reviewed as as part part of of the the reload reload analysis analysis to to ensure that that the theLBLOCA analysis remains applicable.

LBLOCA analysis applicable.

References:

1. WCAP-9272-P-A, Westinghouse Reload Safety Safety Evaluation Evaluation Methodology, July 1985. 1985.

NRCRAI7 NRC RAI 7 Based Based on on the the review review of of your March 19, 2012, submittal submittal ititappears appears that thatyouyourevised revised the the inputs inputstotoaa method method of ofevaluation evaluationas as described described in the the FSAR (as updated) used used in establishing establishing the thedesign design bases bases or or in in the safety analyses.

safety analyses.

Revision 11 to NE196-07, Revision NE196-07, "Guidelines "Guidelines for for 10 CFR CFR50.59 50.59Implementation,"

Implementation," Section 3.8, "Input Section 3.8, Parameters,"

"Input Parameters,"

provides clarifying information informationconcerning concerning whether whetheran aninput inputparameter parameterisisconsidered considered to to be be an an element element of of a methodology methodologyfor forthethepurposes purposesofofaddressing addressingthe theapplicable applicablerequirements requirementsfound foundatat1010CFR CFR50.59, 50.59, "Changes, Tests, "Changes, Tests,and andExperiments."

Experiments." AddressAddress whether whetherthe the methodology methodologypermits permitsthe thelicensee licenseetotoestablish establish how to how select the value to select value of of an an input input parameter parametertotoyield yieldadequately adequatelyconservative conservativeresults results and and whether whetherthe the revised value is more conservative than that that required requiredby bythe theselection selectionmethod.

method.

Westinghouse Non-Proprietary Class 3 Westinghouse NF-CB-12-101 NF-CB-12-101 Revision Revision 1 NP-Attachment NP-Attachment Address whether Address whether any any ofof the changes changes (i.e.,

(i.e., to to the the V02UO2 thermal thermal conductivity conductivity equation) constitutesconstitutes aa change in change in the the calculational calculational framework framework used used forfor evaluating evaluating behavior behavioror orresponse response of ofaa system, system, structure structure oror component. Explain whether component. Explain whether and how 10 CFR and how 10 CFR 50.59(c)(4) might apply to such might apply to such a change.a change.

Response

Response Westinghouse currently Westinghouse currently employs three three best best estimate estimate Evaluation Evaluation Model Model(EM) (EM) methodologies methodologiesfor foranalysis analysis of the large of large break break loss-of-coolant loss-of-coolantaccidents accidents(LBLOCA)

(LBLOCA) in in pressurized pressurized water waterreactors reactors(PWRs):

(PWRs):

- 1996 Westinghouse Best Estimate LBLOCA 1996 EvaluationModel LBLOCA Evaluation Model (Code (CodeQualification Qualification Document Document (CQD) EM, (CQD) EM, Reference Reference 1)

- 1999 Westinghouse Best Estimate 1999 Estimate LBLOCA Evaluation Model, LBLOCA Evaluation Model, Application Application to toPWRs PWRs (Pressurized (Pressurized Water Reactors)

Reactors) with with Upper UpperPlenum PlenumInjection Injection(CQD-UPI (CQD-UPI EM, EM, Reference Reference 2) 2)

- Westinghouse Realistic 2004 Westinghouse Realistic LBLOCA Evaluation Model LBLOCA Evaluation Model using ASTRUMASTRUM (Automated (Automated Statistical Statistical Treatment of Treatment of Uncertainty UncertaintyMethod) Method)(ASTRUM(ASTRUMEM, EM, Reference Reference 3) 3)

In application of In of aa Westinghouse Westinghouse best best estimate estimatelarge large break breakLOCA methodology to LOCA methodology to aa plant plantanalysis, analysis, Westinghouse works with with the the licensee licensee to to establish establish several several parameter parameter valuesvalues input input to to the thespecific specific analysis per analysis per the the Nuclear Regulatory Commission Commission (NRC) (NRC)- - approved approved evaluation evaluation model requirements requirements (including applicability applicabilityrestrictions restrictionsspecified specifiedbybythe theNRCNRCinintheirtheirSafety SafetyEvaluation EvaluationReports(SERs)).

Reports(SERs)). The The licensee is licensee is permitted permitted to to establish establish the the values values of of these parameters parameters on the the basis basis of of plant-specific plant-specific considerations; as as such suchthey theyare areinput input toto the the methodology and not part part of of the the methodology, methodology,as as defined defined in NEI 96-07 Revision NEI 96-07 Revision 11 (Reference (Reference 6) 6)Section Section3.8. 3.8. The The input input parameter parametervaluesvalues maymay be be selected selected conservatively in order to support support current currentplantplantoperation, operation,as aswell wellasas accommodate accommodate expected expected future future changes or changes or otherwise otherwise at the discretion discretion of of the the licensee.

licensee. Table Table11summarizes summarizes the the selected selected design design input input changes evaluated in changes evaluated in conjunction conjunction with the execution execution of of the the thermal thermal conductivity conductivitydegradation degradation(TCD) (TCD) evaluation(s) performed performed as as described described in the the Reference Reference 7 submittal, and relevant relevant governing governing topical topical report report references identifying identifying how howthesethesevalues values areare to tobe beselected.

selected.

In the evaluations of of design design inputinput changes changes performed as as described in the Reference Reference 77 submittal, submittal, the the changes changes to to design design input input values valueswere were made madeto to more more closely closelyrepresent representcurrent current plant plant operation.

operation. Selection Selection of of the revised revised input input parameter parametervalues values waswas made in accordance accordance with with the the approved EM. EM. Therefore, Therefore, the the design input input changes changes reflect reduction reduction in in the the conservatism conservatism of ofthese these values values and and are are considered an input input parameter parameter changechange and not not aa change change to to the the methodology, methodology,consistent consistentwith withReference Reference6 6SectionSection3.8.

3.8.

Westinghouse Westinghouse and and itsitslicensees licensees utilize utilizeprocesses processeswhich whichensure ensurethat thatthe theLBLOCA LBLOCAanalysis analysisinput inputvalues values conservatively bound bound the the as-operated as-operated plant plantvalues values for for these these parameters.

parameters.

In the evaluations evaluations of TCD and design input ofTCD input changes changes as as described in the the Reference Reference 77 submittal, submittal,analysis analysis input input conservatism conservatism in the containment containmentpressure pressure input input was was reduced reduced in in order orderto to recover recoverpeak peak cladding cladding temperature temperature(PCT) (PCT) margin. The Theas-approved as-approvedASTRUM ASTRUM EM EM specifies specifies that that a conservative containment containment backpressure will be used. The The degree of of conservatism is not specifically defined by the the EM EM oror constrained constrained by by the the NRC NRC SER. SER. The Theconservatism conservatismretained retained in in the the containment containment backpressure backpressure input inputisis specific toto each each analysis.

analysis. The The magnitude magnitude of ofthe theconservatism conservatismmay mayvary varybetween betweenanalyses analysesdue dueto to(1)

(1) different plant operating parameter ranges considered in each analysis different plant operating parameter ranges considered in each analysis (such as steam generator tube (such as steam generator tube plugging plugging and vessel averagetemperature),

vessel average temperature), (2) (2) different different licensee licensee requirements requirements to to accommodate accommodate

Westinghouse Non-Proprietary Non-Proprietary Class Class 33 NF-CB-12-101 Revision 1I NP-Attachment expected containment containment changes, changes, and /or (3) different engineering and/or engineering judgment judgment during during the the analysis analysis execution execution regarding the regarding the need need toto reduce reducethetheinput inputconservatism conservatismand andrecover recoverassociated associated PCTPCTmargin marginininthetheanalysis.

analysis.

This discretionary This discretionary input input parameter conservatism may may be be recovered recoveredwhilewhileremaining remainingininaccordance accordancewith with the appropriate appropriate as-approved as-approved EM.EM.

Fuel pellet TCD Fuel TCD and and peaking factor burndown burndown werewerenotnotexplicitly explicitlyconsidered consideredininthe theas-approved as-approved Westinghouse best estimateestimate LBLOCA LBLOCA EMs.EMs. In order order to to evaluate evaluatethe thePCT PCTeffect effectofofTCD TCD and and peaking peakingfactor factor burndown as described described in in the the Reference 7 submittal, evaluation techniques were were used used that that are are outside outside of the as-approved as-approved EMs.EMs. This This was was necessary necessary toto explicitly explicitly consider the fuel performance performanceeffectseffectsofofTCD, TCD, and to adequately evaluate the burnup -dependent aspects of the fuel performance changes burnup-dependent aspects of the fuel performance changes considering considering TCD. Specifically, TCD. Specifically, the following following aspects aspects ofof the the TCD TCD evaluation(s) were were outside outsideof ofthe theasas-approved

-approved best best estimate LBLOCA estimate LBLOCA EM:

a,c 10 CFR 50. 46 establishes criteria for reporting and CFR 50.46 and for for action action regarding regardingchanges changes ororerrors errors involving involving methods for loss of coolant loss of coolant analyses.

analyses. ForFor the the evaluation and reporting of PCT impact, of PCT changes to impact, the changes the LBLOCA LBLOCA EM EMto to explicitly explicitly consider consider thethe fuel performance performance effects effects ofof TCD TCD and to adequately evaluate evaluate the burnup-dependent burnup-dependent aspects aspects of the fuel performance performance are are governed governed by 10 CFR CFR50.46.

50.46. Consistent Consistent with with 10 CFR 50.59(c)(4) and Reference 6 Section CFR 50.59(c)(4) Section 4.1.1, 4.1.1, the provisions provisions of of10 10 CFR CFR 50.59 50.59 dodo not apply forfor the the changes for LBLOCA EM changes for evaluations evaluations andand reporting of of PCT impact because the 10 CFR PCT impact CFR 50.46 50 .46 regulation establishes more specific specific criteria for reporting and and for for action action for forchanges changes involving involving methods methods for for loss loss of coolant accidents.

accidents.

In summary, in the evaluations ofTCD of TCD and design input changes as described in the Reference Reference 77 submittal, two typestypes of changes were made:

changes were

Design Design input input values values were changed to more closely were changed closely represent plant plant operation, operation,or oranalysis analysis input input changes changes were made to were made to reduce reduceconservatism conservatismin inas-analyzed as-analyzedvalues.

values. The The licensee licensee isis permitted permitted to establish the establish the value of these parameters parameters on on the the basis basis of of plant plant-specific

-specific considerations; as as such such these are changes changes to the input of of the methodology and are not part of the methodology.

Therefore, thethe design design input input changes changes reflect reduction in in the the conservatism conservatism of of these these values values and are considered an input parameter change and not a change parameter change and not a change to the methodology. methodology.

002012 Westinghouse Electric

Westinghouse Non-Proprietary Class 3 Westinghouse NF-CB-12-101 NF-CB-12-101 Revision Revision 1 I NP-Attachment

- Techniquesto Techniques to appropriately appropriately account for the burnup-dependent burnup-dependent effects effects of TCD were used in the ofTCD evaluation(s) which evaluation(s) which are are outside outside of the as-approved EMs. EMs. These changes changes to to the the calculational framework (as framework (as defined defined inin 10 10CFR 50.46(c)(2)) were CFR 50.46(c)(2)) were required required to to assess assess the TCD phenomena which TCD phenomena which are not are not explicitly accounted for for in in the the as-approved as-approved EMs.EMs. The The provisions provisions ofof1010CFR 50.59 do CFR 50.59 do not not apply for the apply the LBLOCA LBLOCA EM EMchanges changesfor forevaluations evaluations andand reporting reporting of of PCT impact because the 10 PCT impact 10 CFR50.46 CFR 50.46regulation regulationestablishes establishesmore morespecific specificcriteria criteriaforforreporting reporting and and for for action for for changes changes involving methods for loss involving loss of coolant accidents.

Applicable Evaluation Table 1. Applicable Evaluation Model Model Reference(s) for SelectionSelection of of the the Design Design InputInput Parameters Modified in TCDTCD Evaluation Evaluation for Byron Byron Unit Unit 2 and and Braidwood Braidwood Unit 2 Design Input Design Input Change Relevant Section (s) of ASTRUM Topical Section(s) Topical Report Report (Reference 3)

Steam generator Steam generator tube Section 1-2-11 plugging range plugging range Section 11-3-1 Containment pressure Section 11-3-1 input Section 11-4-11 Section 12-3-4 Vessel average Section 1-2-11 temperature range temperature range Table 1-11

References:

WCAP-12945-P-A, Volume

1. WCAP-12945-P-A, Volume 1, 1, Revision Revision 2, 2, and and Volumes Volumes 2-5, 2-5, Revision Revision 1 (Proprietary),

(Proprietary), Bajorek, Bajorek, S.

S.

M. et et al., Code Qualification al., Code Qualification Document Documentfor forBest BestEstimate EstimateLOCA LOCA Analysis, March 1998.

WCAP-14449-P-A, Revision

2. WCAP-14449-P-A, Revision 1 (Proprietary),

(Proprietary), Dederer, Dederer,S. I., Application S. I., Application of ofBest Best Estimate Estimate Large Large LOCAMethodology Break LOCA Methodology to Westinghouse Westinghouse PWRs PWRs with Upper Upper Plenum Plenum Injection, Injection, October 1999.1999.

3. WCAP-16009-P-A WCAP-16009-P-A RevisionRevision 00 (Proprietary),

(Proprietary), Frepoli, c., etetal.,

Frepoli,C., al., Realistic Realistic Large-Break Large-BreakLOCA LOCA Evaluation Methodology Methodology Using the AutomatedAutomated Statistical Statistical Treatment Treatment of ofUncertainty UncertaintyMethod Method (ASTRUM), January 2005.

4. LTR-NRC-12-27, LTR-NRC-12-27, Letter Letter from from J. A.A. Gresham (Westinghouse)

(Westinghouse)to toNRC, Westinghouse Input NRC, Westinghouse Supporting SupportingLicensee Licensee Response Response to NRC NRC 1010 CFR CFR50.54(f) 50.54(f) Letter Letter Regarding NuclearNuclear FuelFuel Thermal Thermal Conductivity Degradation (Proprietary/Non-Proprietary), March March 7, 7, 2012.

2012.

5. Deleted NEI 96-07 Revision 1,

6. NEI 1, Guidelines Guidelinesfor for 10 10 CFR 50.59Implementation, CFR 50.59 Implementation, NovemberNovember 2000. 2000.

7. Letter Letter from fromP. P. R.

R. Simpson (Exelon (Exelon Generation Generation Company, Company, LLC) LLC) toto NRC, "Braidwood, Unit NRC, "Braidwood, Unit2, 2,and and Byron, Unit Unit 2,2, Response Response to to Request Request for for Information Information Regarding Regarding ThermalThermal Conductivity Conductivity Degradation Degradation and and 10 10CFR CFR 50.46 Report,"

Report," March March19,19,2012.

2012.NRC NRCADAMS ADAMS Accession Accession Number Number ML12079A112.

ML12079A112.

RS-12-100, Response to Request for Additional Information Regarding Thermal Conductivity Degradation

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