ML21259A085

North Ann, and Surry, Units 1 and 2, Millstone, Units 2 and 3, Request for Approval of Appendix E of Fleet Report DOM-NAF-2-A Qualification of the Framatome BWU-I CHF Correlation in the Vipre-D Computer Code Response to Request for Addition

ML21259A085
Person / Time
Site:	Millstone, Surry, North Anna
Issue date:	09/15/2021
From:	Mark D. Sartain Dominion Energy Nuclear Connecticut, Virginia Electric & Power Co (VEPCO)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ML21259A079	List: ML21259A085
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21-042B
Download: ML21259A085 (18)

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PROPRIETARY INFORMATIONWITHHOLD UNDER10CFR2.390 VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND,VIRGINIA23261 September 15,2021 U.S.Nuclear Regulatory Commission No. 21-042B Serial ATTN:Document Control Desk NRA/GDM RO Washington,D.C.20555 DocketNos. 50-336/423 50-338/339 50-280/281 Nos.DPR-65/NPF-49 License NPF-4/7 DPR-32/37 NORTHANNAANDSURRYPOWERSTATIONSUNITS 1AND2 MILLSTONE POWER STATIONUNITS2 AND3 REQUEST FORAPPROVAL OFAPPENDIX E OFFLEETREPORT DOM-NAF-2-A QUALIFICATION OFTHEFRAMATOME BWU-ICHFCORRELATION INTHE DOMINION ENERGY VIPRE-D COMPUTER CODE RESPONSE TOREQUEST FORADDITIONAL INFORMATION datedFebruary By letter 11,2021[Serial No.21-042 (ADAMS Accession No.

ML21042B321)), Dominion Energy Virginia andDENC(collectively,Dominion Energy)

Appendix"Qualification submitted E, oftheFramatome BWU-ICHFCorrelation in the Energy Dominion VIPRE-D Computer Code," Report toFleet DOM-NAF-2-A for NRCreview andapproval.Byletter dated August 13,2021, theNRCrequested additionalinformation tofacilitate theirreview. Dominion Energy's responsetotheNRCrequest isprovided in Attachment 1

Attachment 1 contains information proprietary toFramatome Inc.andissupported byan (Attachment affidavit 3) signed byFramatome, theowner oftheinformation.Theaffidavit forth sets the basis onwhich theinformation maybewithheld frompublic disclosure bythe Commissionandaddresses withspecificitytheconsiderations inparagraph listed (b)(4)of Section 2.390 oftheCommission's regulations. Accordingly,isrespectfully it requested theproprietaryinformation bewithheld frompublic inaccordance disclosure with 10CFR2.390. A redacted, non-proprietary responsetotheNRCrequest for additional isprovided information inAttachment 2.

Attachment1contains information thatisbeing withheldfrompublicdisclosure under 10CFR2.390. Uponseparation fromAttachment 1,thispageisdecontrolled.

Serial No.21-042B DocketNos.50-336/423/338/339/280/281/395 RAlResponse DOM-NAF-2, Appendix E Page2 of3 lf youhave questions orrequire information, additional please contactMr.Gary D.Miller at (804) 273-2771 Respectfully,

~-

p -

MarkD.Sartain Vice President -

Nuclear Engineeringand Fleet Support Commitments madeinthis letter:

None

Attachment:

Response toNRCRequest forAdditional Information 1 Response toNRCRequest forAdditional Information, Appendix E toFleet Report DOM-NAF-2, "QualificationoftheFramatome BWU-I CHFCorrelation inthe Dominion Energy VIPRE-D Computer Code." [PROPRIETARY) 2.Response toNRCRequest forAdditional Information, Appendix E to Fleet Report DOM-NAF-2, "QualificationoftheFramatome BWU-I CHFCorrelation in the Dominion Energy VIPRE-D Computer Code." [Non-Proprietary) 3.Framatome Affidavit Withholding for Proprietary Information from Public Disclosure

Serial No.21-0428 Nos.50-336/423/338/339/280/281/39 Docket RAlResponse Appendix DOM-NAF-2, E Page3 of3 cc:U.S. Nuclear Regulatory Commission -

RegionI 2100Renaissance Blvd, Suite100 Kingof Prussia, Pennsylvania 19406-2713 U.S.NuclearRegulatory Commission -

RegionII Marquis OneTower 245Peachtree Center Avenue, NE Suite 1200 Atlanta,Georgia 30303-1257 R.V.Guzman NRCSenior Project ManagerMillstone PowerStation U.S.Nuclear Regulatory Commission OneWhite Flint North, Mail Stop 08-C2 11555 Rockville Pike Rockville,Maryland 20852-2738 Mr.G.Edward Miller NRCSenior Project ManagerNorth AnnaPower Station U.S.Nuclear Regulatory Commission OneWhite Flint North, MailStop 09E-3 11555Rockville Pike Rockville,Maryland 20852-2738 Mr.J.J.Klos NRCProject ManagerSurry Power Station U.S.Nuclear Regulatory Commission OneWhite Flint Mail North, Stop 09E-3 11555 Rockville Pike Rockville, MD20852-2738 NRCSenior Resident Inspector MillstonePower Station NRCSenior Resident inspector NorthAnnaPower Station NRCSenior Resident Inspector SurryPower S tation

Serial No.21-042B DocketNos.50-336/423/338/339/280/281

[NonProprietary)

ATTACHMENT 2 M

Energy Dominion Nuclear (DENC)

Inc.

Connecticut, Millstone PowerStation 2and3 Units Virginia andPowerCompany Electric (DominionEnergyVirginia)

AnnaandSurry North PowerStations 1 and2 Units

SerialNo.21-042B Docket Nos.50-336/423/338/339/280/281 Attachment 2 Page1of12 RESPONSE TONRCREQ UESTFORADDITIONAL INFORMATION:

FRAMATOME BWU-I CHFCORRELATION INTHEDOMINION ENERGY VIPRE-D COMPUTER CODE" h

Byletter dated February11,2021 (Agencywide Documents Access andManagement System (ADAMS) Accession No. ML21042B321), as supplemented byletter dated May 13,2021(ADAMS AccessionNo ML21133A285), Dominion Energy requested ofAppendix approval E offleet report DOM-NAF-2, "QualificationoftheFramatome BWU-ICHF[Critical HeatFlux) Correlation in the Dominion Energy VIPRE-D Computer Code."Byletter datedAugust 13,2021, theNRC staff requested additional information tocompletetheir TheNRCrequest review. andDominion Energy's responses are provided below.

NRCRAl1 Please confirm thatDominion willusea process togenerate the predicted CHF[Critical Heat value Flux) thatisconsistent withthe process used w hendetermining thepredicted CHFvalue ofthe validationdata.

h:

Yes,Dominion Energyuses a process toqualify CHFcorrelations which isconsistent with theapproach usedby thevendor during thedevelopment ofthecorrelation as documented inSection4.9and4.10 ofReference 7.

NRCRAl- 2:

Please identifywhich fueltypes havebeenvalidated using theBWU-1 CHFmodel. For application topreviouslyunanalyzed fuel types, suchasAFAfuel, please demonstrate that thenumber ofdatapoints used forvalidation ofthat fueltypeissufficient for ensuring theaccuracy oftheDNBR[Departure from Nucleate BoilingRatio) limit.Specifically,

((

M 11

Serial No.21-042B Docket Nos.50-336/423/338/339/280/281 Attachment 2 Page2 of12 M:

Theresponse to this RAIisaddressed byseparating the requested informationinto three sections:

1 Please identify which fuel typeshave beenvalidated using the BWU-ICHFmodel.

Dominion Energy is not aware ofanyfuel designs that havebeenlicensed for reactor operations with the BWU-ICHF correlation; however, theBWUCritical HeatFluxCorrelations Topical Report (Reference 1, Section4.2) contains information on thefuelassemblies forwhich theBWU-ICHF correlation is applicable:

"Inthis report, then,theInconel mixingvanedesign correlation (BWU-I) isestablished asthe basic correlation for fuelassemblies with mixing vane grids.

Theenhanced mixing vane (BWU-correlation z) ispresently onlyvalid forthe Mark-BW17 design. Fuel assemblies with anyother type ofmixingvane spacer grid would require analysis with BWU-Iunless an enhancement could be demonstrated from CHFdata for that specific design."

Note that theterm "Inconel" isdescribed byFramatometo be a "convenient term foruseindescribing theoriginalmixing vaneconceptnot the material itself" (Reference 1,Section 4.2).

2.Forapplication topreviously unanalyzed fuel types, suchasAFA fuel, please demonstrate thatthe number ofdata points used for validation ofthatfuel type is sufficient for ensuring the accuracyofthe DNBR[Departure fromNucleate Boiling RatioJlimit.

Historically,thetesting anddevelopment ofolder CHFcorrelations hasconsisted ofa wide array ofgrid types, operating conditions, axialpower distributions,array sizes,andgrid spacings. Morerecently, CHFcorrelations tend tobedeveloped for specific fuel orgrid designs whichproduce moreaccurate DNBRs, leadingtolower DNBRlimits for thecorrelations which provide moremargin inDNBanalyses.

Forexample, theWestinghouse WRB-2CHFcorrelation wasdeveloped using testswith various heated lengths,axial power profiles, both unitandguide tube aswell cells, asdifferent mixing vanegrid designs (Reference 5,Section A.2.3).

Assuch, the WRB-2CHFcorrelation database contains a wide variety oftest data for17x17 nuclear fuel products.

Serial No.21-042B Docket Nos.50-336/423/338/339/280/281 Attachment 2 Page3 of12 Elaborating onthis example, theWRB-2MCHFcorrelation waslater introduced for fuel assemblies with theModified LowPressure Drop(LPD) mixing vanegrid andModified Intermediate FlowMixer (IFM) grid (Reference 6, Section 1).

Westinghouse conducted additional CHFtests withtheModified LPDandIFM grids. TheWRB-2M CHF correlation isa modification totheWRB-2 CHF correlation developed tooptimize the CHF predictionsto provide moreaccurate DNBpredictions, as it was determined during testing that WRB-2significantly underpredicted theCHF performance (Reference 6,Section 3.1). Thetests conducted forthedevelopment ofthe WRB-2M CHFcorrelation aredocumented inReference 6,Section 2.

Assuch, theWRB-2M CHFcorrelation is a morefine-tuned correlation than WRB-2 andisspecifically intended for more accurate DNBanalysis offuel assemblies with the Modified LPDandIFMgrid designs.

Westinghouse determined a minimum DNBR (95/95) limit of1.17 for theWRB-2 CHFcorrelation 5, Section (Reference A.2.3.4)and a limit of 1.14 for the WRB-2M CHF correlation (Reference 6,Section 3.4). The reduction inthelimit clearly demonstrates that theWRB-2MCHF correlation, which was correlated and optimized especially for those fuels with Modified LPD and IFMgrids, offers an improved predictive capabilityofthe thermal performancecompared totheWRB-2 CHFcorrelation. Reference 6,Section 1also statesthat the WRB-2 correlation DNBRlimit of1.17 maybeconservatively applied tofuels with the Modified LPD andIFMgrids; however, it wasdesired todevelop a correlation which willmore accurately predict DNBfor fuelswith Modified LPDandIFMgrids.

Similarly, Framatome hasestablished theBWU-ICHFcorrelation asthe basic correlation forfuel assemblies with mixing vanegrids (Reference 1,Section 4.2).

Thethermal-hydraulic testsupon which the BWU-I CHFcorrelation constants were developed (herein referred toas the BWU-I E xperimental Database), consider a widevariety oftest geometries suchas roddiameters, pinpitches, axial flux shapes, heated lengths, andmixing vanegrid spacings. As such,theBWU-I correlation isa generic correlation andtherefore applicable tothedifferent types offuel assemblies that arerepresented bytheconstituent test sections and approved bytheNRC(Reference 2).

Framatome hasdetermined a DNBRlimit of1.21 fortheBWU-ICHFcorrelation using LYNX2(Reference 1, Section 4.1). Dominion Energy's benchmark to LYNX2/BWU-I (Reference E.5.1) 3,Section using VIPRE-D/BWU-I (Experimental Database)ina DNBRlimit results of1.23.

Serial No.21-042B Docket Nos.50-336/423/338/339/280/281 Attachment 2 Page4 of12 Recall that Westinghouse stated that theWRB-2DNBRlimit (1.17) may be conservatively appliedtothose fuelassemblies with Modified LPDandIFMgrids.

Oncethe WRB-2M correlation wasoptimized forthese grid designs, the applicable DNBRlimitdecreased (1.14), thereby allowing moremargin for DNBanalyses. It isexpected that, should a CHFcorrelation bedeveloped solely upon the AFA-type mixing vaneandmid-span mixing grid data collected attheColumbia University Heat Transfer Research Facility (HTRF)1 (referred toasthe CUTests) theresulting 95/95 DNBRlimit would be lowerthanthat determined forVIPRE-D/BWU-I Combined Database inReference 3 (1.23). Inother words, applying theDNBR limit derived usingthegeneric VIPRE-D/BWU-I Combined Database is conservative.

TheBWU-ICHFcorrelation wasnotdeveloped using the CUTests. Asmentioned previously, theBWU-I CHFcorrelation is a generic correlation intended for fuel assemblies with mixing vanegrids. Therefore, a statistical analysis ofthetwodata sets (the BWU-ICHFcorrelation Experimental Database andtheCU Tests) is performed to determine ifthedataaresimilar enough to combine and conservatively apply one-sided tolerance theory for the determination ofa 95/95 DNBRlimit. Section E.5.2 ofReference 3documents this statistical analysis ofthe VIPRE-D/BWU-I Experimental Database andtheCUTests, which demonstrates that the twodata groups areofsimilar populations andtherefore may becombined forfurther analysis. This total database isreferred toasthe VIPRE-D/BWU-I Combined Database. TheDNBRlimits for both the VIPRE-D/BWU-I Experimental andCombined Databases weredetermined tobe1.23. Additionally, the CHF results ofthe twodatabases areindistinguishable inFigures E.5.2-1 through E.5.2-4 ofReference 3,demonstrating that theBWU-ICHFcorrelation accurately predicts CHFfor assemblies which employ AFA-type mixing vaneandmid-span mixing grids.

Insummary, thehistorical experience ofgeneric versus optimized correlations, the generic applicability oftheBWU-ICHF correlation toa widevariety offuel assembly configurations, theextensive history oftheColumbia HTRFwith the development of NRC-approved CHF correlations, and theresults of the aforementioned statisticalandvisual analysis provide confidence that theDNBR limits for theVIPRE-D/BWU-I code/correlation pair documented inReference 3 provide adequate protection at a 95/95 confidence level. Therefore, thelimit of 1 TheColumbia HTRFhasanextensive history withthetesting anddevelopment ofvarious NRC-approved CHFcorrelations, such astheFramatome BWU-zandthe Westinghouse WRB-2M CHFcorrelations.

Serial No.21-042B Nos.

Docket 50-336/423/338/339/280/281 Attachment 2

Page5 of12 1.23 as documented inReference forapplication 3 isconservative tofuel assemblies withAFA-typemixing vaneandmid-span mixing grids.

3.Specifically, ((

M 11 M

TABLEREDACTED Figures RAI2-1through 2-4

Serial No.21-042B Nos.50-336/423/338/339/280/281 Docket 2

Attachment Page6 of12 RAl2-1 Figure M

FIGURE REDACTED RAI2-2:

Figure M

FIGURE REDACTED

Serial No.21-042B Nos.50-336/423/338/339/280/281 Docket Attachment 2

Page7 of12 RAl2-3:

Figure M

FIGURE REDACTED Figure RAl2-4:

M FIGURE REDACTED

Serial No.21-042B Docket Nos.50-336/423/338/339/280/281 Attachment 2 Page8of12 As noted intheRAl, MassVelocity Dominion Energy analyses using the thermal-hydraulic VIPRE-Dcodearenot conducted at Thermal-hydraulic analyses performed inVIPRE-D are conducted atconservative initial flow conditions.

Forexample,theminimum measured flowrate usedin VIPRE-D for PowerStation Surry forcurrent andintended future operation is 273,000 gpm,whichtranslates toapproximately 2.37MIbm/hr-ft2. Similarly, for North AnnaPower theminimum Station, measured flow rateis 295,000 gpm, which translates 2.51MIbm/hr-ft2.

toapproximately ForMillstone Unit 3,the minimum measuredflow is379,200 rate gpm,which translates toapproximately 2.55Mlbm/hr-ft2 Assuch, theflow usedinVIPRE-D rates analyses shallM AsDominion Energy thermal-hydraulic analyses donotutilize M theBWU-ICHFcorrelation M

Ibeanody.namic.Quality

Serial No.21-042B DocketNos.50-336/423/338/339/280/281 Attachment 2

Page9 of12 M

FromFigures RAI 2-3and2-4,it appearsthat by very conservativepoints inthetests These considered. conservativepoints have M

Points with (Figure RAI2-3) areM andappear tobe Assuch, Similarly, points M with M (FigureRAl2-4)are andappear tobe Thesepoints M Figures RAl2-5and2-6areidenticalto Figures RAl2-3and2-4,respectively,

Serial No.21-042B Docket 50-336/423/338/339/280/281 Nos.

Attachment 2

Page10of12 Figure RAI25:

FIGURE REDACTED Figure RAI26:

FIGURE REDACTED

Serial No.21-042B DocketNos.50-336/423/338/339/280/281 ATTACHMENT 3 FramatomeAffidavit:

DominionEnergyNuclear Connecticut, (DENC)

Inc.

PowerStation Milistone Units2and3 Virginia andPowerCompany(Dominion Electric EnergyVirginia)

NorthAnnaandSurry PowerStations 1 and2 Units

Serial No.21-042B Docket Nos.50-336/423/338/339/280/28 Attachment 3

Page 3 1of A F FIDA V IT

1. Myname isGayle Elliott. IamDeputy Director, Licensing andRegulatory for Affairs,Framatome Inc.(Framatome) andassuch Iamauthorized toexecute this Affidavit.

2. Iamfamiliar with the criteria applied byFramatome todetermine whether certain Framatomeinformationisproprietary. Iamfamiliar withthepolicies established by Framatome theproper toensure application of these criteria.

3. Iamfamiliar with theFramatome information contained inAttachment 1, "Response toNRCRequest for Additional Information: Appendix E toFleet Report DOM-NAF-2-A,'Qualification oftheFramatome BWU-I CHFCorrelation intheDominion Energy VIPRE-DComputer Code'," ofa Letter fromMr.MarkSartain(Virginia ElectricandPower Company) toDocument Control Desk (NRC), Serial No.21-042B, Docket Nos. 50-336/423, 50-338/339, dated 50-280/281, September 13, 2021 andreferred herein as "Document."

Information contained inthisDocument hasbeen classified byFramatome asproprietary in with accordance thepolicies established byFramatome for thecontrolandprotection of andconfidential proprietary information.

4. ThisDocument contains information ofa proprietaryandconfidential nature andisofthetypecustomarily held inconfidence byFramatome andnotmadeavailable tothe public.

Based onmyexperience, Iamaware that other companies regard information ofthe kind containedinthis Document asproprietary andconfidential.

5. ThisDocument hasbeen madeavailable totheU.S. Nuclear Regulatory Commissioninconfidence with therequest that the information contained inthis Document be withheld from disclosure.

public Therequest for withholding ofproprietary information ismadein accordance with10CFR2.390. Theinformation for which withholdingfrom disclosure is

Serial No.21-042B Docket Nos.50-33614231338/339/280/28 Attachment 3 Page2 of3 requested qualifies under 10CFR2.390(a)(4) "Trade secrets andcommercial orfinancial information."

6. The following criteria arecustomarily applied byFramatome todetermine whether informationshould beclassifiedasproprietary:

(a)The information revealsdetails ofFramatome's research anddevelopment plans andprograms ortheir results.

(b) Useoftheinformation byacompetitor would permit thecompetitor to significantly reduce itsexpenditures, intime orresources, todesign, produce, ormarket a similarproduct or service.

(c)Theinformation includes test data or analytical techniques concerning a process, methodology, orcomponent,the application ofwhich results ina competitive advantage for Framatome.

(d) Theinformation reveals certain distinguishing aspects ofa process, methodology, orcomponent, the exclusive useofwhich provides a competitive advantage for Framatome inproduct optimization or marketability.

(e)Theinformation isvitaltoacompetitive advantage heldby Framatome, would behelpful tocompetitors toFramatome, andwould likely cause substantial harm tothe competitiveposition ofFramatome.

Theinformation inthisDocument isconsidered proprietary for the reasons set forth in paragraphs 6(d) and6(e) above.

7. Inaccordance with Framatome's policies governing theprotection andcontrol ofinformation, proprietary information contained inthis Document hasbeen madeavailable, on a limited basis, toothers outside Framatome only asrequired andunder suitable agreement providing for nondisclosure andlimited useofthe information.

8. Framatome policyrequiresthat proprietary information bekept ina secured fileorarea anddistributed ona need-to-know basis.

Serial No.21-042B Docket Nos.50-336/423/338/339/280/28 Attachment 3

Page3of3

9. Theforegoing aretrue statements andcorrect tothebestofmyknowledge, information, and belief.

Ideclare under penalty ofperjury the that foregoing istrue andcorrect.

Executed on:September 13,2021 signed Digitally byELUOTT ELLIOTTGayle cavieDate: -04'00' 11:29:11 2021.09.13 Gayle Elliott