ML21168A261

(Vcsns), Unit 1 - NRC Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-water Reactors - Final Supplemental Response

ML21168A261
Person / Time
Site:	Summer
Issue date:	06/17/2021
From:	Mark D. Sartain Dominion Energy South Carolina
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
21-017, GL-2004-02
Download: ML21168A261 (25)

Text

Dominion Energy Carolina, South Inc.

Glen 5000 Dominion Boulevard, Allen, VA23060 DominionEnergy.com

@Q June17,2021 ATTN:Document Control Desk Serial No.: 21-017 U.S. Nuclear Regulatory Commission NRA/GDM: RO Washington, DC20555-0001 Docket No.: 50-395  !

License No.:NPF-12 l

)

[

ONEMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURizED-WATER REACTORS" j

f Thepurpose ofthis submittal istoprovide theDominion Energy South Carolina, Inc.

(DESC) final supplemental response forV CSNS Unit 1 to Generic Letter (GL)2004-02, "Potential Impact ofDebris Blockage on Emergency Recirculation during Design Basis i Accidents atPressurized-Water Reactors," dated September13, 2004. /

Byletter dated- May16,2013(ADAMS Accession No.ML13140A007), DESC submitted j a letter ofintent perSECY-12-0093, "Closure Options for Generic Safety Issue (GSI) -

191,Assessment ofDebris Accumulation on Pressurized-Water Reactor Sump Performance," indicating VCSNSUnit 1 would pursue Closure Option 2 Deterministic oftheSECYrecommendations (refinements toevaluation methods andacceptance criteria). The finaloutstanding issue identifiedinthatletter for VCSNS Unit 1with respect toGL 2004-02 closure isthein-vessel downstream effects evaluation todemonstrate '

long-term core cooling (LTCC) can be adequately maintained forp ostulated accident scenarios requiring sumprecirculation. i I

Thein-vessel downstream effects evaluation hasbeencompleted forVCSNSUnit 1with f satisfactory results asdocumented intheenclosure tothis letter. Thecompletion ofthis activity andthe update ofthe Final SafetyAnalysis Report following NRCacceptance of j thefinal supplemental response satisfythefinal GSl-191 commitments identifiedinthe l VCSNS Unit 1 May16,2013Closure Option letter.

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Serial No.21-017 DocketNo.50-395 Page2 of3 Ifyou have any questions regarding this submittal, please contact Mr.GaryD.Miller at (804)273-2771.

Sincerely,

( '

Mark D.Sartain Vice President -

Nuclear Engineering andFleet Support Commitment contained inthisletter:

1, DESCwill accordance update thecurrent licensing with10 CFR 50.71(e)) following basis (Final Safety NRC acceptance AnalysisReport ofthefinal in l supplemental response for VCSNS Unit 1 j

I I

I

Enclosure:

Final Supplemental Response toGL2004-02 l

/

COMMONWEALTH OFVIRGINIA )

COUNTY OFHENRICO

)

) )

Theforegoing document wasacknowledged before me,inandfor County the andCommonwealth aforesaid, today byMarkD.Sartain, whoisVice President Nuclear Engineeringand Fleet I

SupportofDominion EnergySouth Carolina, Inc. He hasaffirmed before methat he is duly I authorized toexecute andfiletheforegoing document inbehalf ofthat Company, andthat the statements inthe document are true tothe best ofhis knowledge andbelief.

Acknowledged before methis F76 dayofE, 2021.

MyCommission Expires: .

CRAIGDSLY -

Notary Public Commonwealth ofVirginia otary P ic Reg. # 7518653 y MyCommission Expires 31,2b December

Serial No.21-017 No.50-395 Docket Page3 of3 cc: U.S. Nuclear Regulatory Commission -

Region II Marquis OneTower 245 Peachtree Center Avenue, NE Suite 1200 Atlanta, Georgia 30303-1257 Mr. VaughnThomas NRCProject Manager -

VCSNS U.S.Nuclear Regulatory Commission One White FlintNorth Mail Stop 04F12 11555 Rockville Pike Rockville, MD 20852-2738 NRCSenior Resident Inspector V.C.Summer Nuclear Station Mr. G.J.Lindamood Santee Cooper Nuclear Coordinator

Serial No.21-017 No.50-395 Docket Enclosure SUPPLEMENTAL FINAL RESPONSETOGENERIC LETTER 2004-02 Energy Dominion South Carolina, inc.

(DESC)

V.C.SummerNuclear (VCSNS)

Station Unit1

No.21-017 Serial DocketNo.50-395 GL2004-02 Final Response Supplemental Enclosure Table ofContents 1 Overall Compliance..-.--....-....-.-....-...-...-...--..=-.-.........--.2 1.1 Overview ofV. C. Summer Resolution toGL200402--.................-...2 1.2 CorrespondenceBackground --.........-.....-........-...-....3 1.3 General Plant SystemDescription....--......,..-.....-.......-.4 1.4 General Description ofContainment SumpStrainers.-......-...-.-5 2 General Description andSchedule for Corrective Actions-.,.............7 3 Specific information for Review Areas.-.......--........-...-.-.10 3.n Downstream Effects -

Fuel andVessel...-......-..-...........-..11 3.o Chemical Effects.--.---...-...--.-.-.-.....-....- --.-.-.19 3.p Licensing Basis .,............- --.......-..-........-.19 4 References.-..-........-...--.-..........---......-.-.-.20 Page1of21

Serial No.21-017 Docket No.50-395 GL2004-02 Final Supplemental Response Enclosure 1 Overall Compliance NRCissue:

Provide information requested inGL 2004-02, "Requested Information," Item2(a) regarding compliance with regulations. That is,provide confirmation that the Emergency CoreCooling System (ECCS) andthe[Containment Spray System (CSS)) CSS recirculationfunctions under debris loading conditions areorwill beincompliance with theregulatory requirements listed inthe Applicable Regulatory Requirements section of generic this letter. This submittal should address theconfiguration ofthe plant that will exist onceall modifications required forregulatory compliance have been madeandthis licensingbasis hasbeen updated to reflect the results oftheanalysis described above.

DE.SCRes.ponsel Inaccordance with SECY-12-0093, andasidentified inthe May16, 2013DESCletter to theNRC(ADAMS Accession No.ML13140A007),V. C. Summer Nuclear Station (VCSNS)

Unit 1elected topursue Generic Safety Issue (GSI)-191 Closure Option 2 Deterministic.

Topical Report (TR) WCAP-17788-P, Rev. 1,"Comprehensive Analysis andTest Program forGSl-191 Closure (PA-SEE-1090)," provides evaluation methods andresults to address in-vessel downstream effects. As discussed in NRC "Technical Evaluation ReportofIn-Vessel Debris Effects" (ADAMS Accession No. ML19178A252), theNRC hasperformed staff a detailed review ofWCAP-17788-P. Although the NRCstaff did not issuea Safety Evaluation for WCAP-17788, as discussed further in"U.S.Nuclear Regulatory Commission Staff Review Guidance forIn-Vessel Downstream Effects Supporting Review ofGeneric Letter 2004-02 Responses" (ADAMS Accession No.

ML19228A011), the staff expects manyofthe methods developed intheTR can beused bypressurized water reactor (PWR) licensees todemonstrate adequate long term core cooling(LTCC). Completion oftheanalyses demonstrates compliance with10 CFR "Acceptance 50.46, criteria for emergency core cooling systems for light-water nuclear powerplants," (b)(5), "Long-term cooling," asit relates toin-vessel downstream debris effects for VCSNS Unit 1.

1.1Overview ofVCSNS Unit 1 Resolution toGL2004-02 On February 29,2008(ADAMS Accession No.ML080640545), DESCsubmitted a Supplemental Response toGL 2004-02 forVCSNSUnit 1 that provided specific information regarding themethodology usedfordemonstrating compliance with the applicableregulations, aswell asthe corrective actions that hadeither been implemented orplanned tosupport theresolution ofGSl-191 Byletters dated November 29,2009 (ADAMS Accession No.ML093360336) andDecember 17, 2010 (ADAMS Accession No.

ML103610171), DESCsubmitted additional information for VCSNS U nit 1 regarding the analysesandcorrective actions that hadnotbeencompleted atthetime ofthe2008 response. Thecontent andlevel ofdetail provided wereconsistent with theNRC Page2 of21

Serial No.21-017 Docket No.50-395 GL2004-02 FinalSupplemental Response Enclosure guidance dated November 21,2007, "Revised Content Guide forGeneric Letter 2004-02 Supplemental Responses," (ADAMS Accession No. ML073110389). in the November29, 2009 andtheDecember 17, 2010letters, DESCcommitted toaddress the resolution ofdownstream in-vessel effects for VCSNSUnit 1 following theissuance of revised WCAP-16793, "Evaluation ofLong-Term Cooling Considering Particulate, Fibrous andChemical Debris intheRecirculating Fluid," andthe associated NRCSafety Evaluation Report (SER).

However, byletter dated May 16,2013 (ADAMS Accession No.ML13140A007), DESC provided its plan for resolving in-vessel downstream effects pursuant tothePWROG comprehensive program underway todevelop new acceptance criteria forin-vessel debris (i.e.,

WCAP-17788) for VCSNS Unit 1. That l etteralso included a summary ofthe corrective actions andanalyses thathad been implemented for VCSNS Unit 1toaddress GSl-191, aswell asinherent margins and conservatisms included intheanalyses. The plant analyses, modifications, margins, and conservatisms summarized andupdated in theMay16,2013correspondence remain valid.

Theresolution ofin-vessel downstream effects for VCSNS Unit1isprovided inSection 3.nbelow. DESCopted toapply theNElclean plant methodology, as described in Reference 4.1 andasapproved bythe NRCinReference 4.2, toconservatively determine theamountoffiber that canbypass theReactor Building (RB) recirculation sump strainers.

1.2Correspondence Background Table 1 provides a listofthepertinent GL2004-02 correspondence issued bythe NRC orsubmitted byDESCapplicable toVCSNS Unit 1 TABLE1 GENERIC LETTER 2004-02 CORRESPONDENCE ADAMS Document Date Accession Document Number September 13,2004 ML042360586 NRCGL2004-02 March 7,2005 ML050690207 90-day Response toGL2004-02 September 1,2005 ML052520333 Follow-up response toGL2004-02 February 8,2006 ML060410214 Supplemental Response toNRCGL2004-02 February 21,2006 ML060380003 NRCRequest for AdditionalInformation March 28,2006 ML060870274 NRC Response Alternative Approach forGL2004-02 Page3 of21

Serial No.21-017 DocketNo.50-395 GL2004-02 Final SupplementalResponse Enclosure TABLE 1 GENERIC LETTER 2004-02 CORRESPONDENCE ADAMS DocumentDate Accession Document Number November21,2007 ML073110389 NRCRevised Content Guide December21,2007 ML073601006 Preliminary Supplemental Response toNRCGL 2004-02 andExtension Request December28,2007 ML073620338 NRCApproval ofExtension Request February 29,2008 ML080640545 Supplemental Response toGL2004-02 identification ofcommitment tosubmitAlternate March18,2008 ML080810190 Source Term(AST) licensing submittal to facilitate resolution ofGL200402 December10,2008 ML083510086 Newprojected datefor ASTlicensing submittal February 3,2009 ML090270927 NRCRequestfor Additional Information License Amendment Request (LAR) to February 17,2009 ML090720887 implement full scopeAlternative Source Term (AST) inaccordance with 10 CFR 50.67 May1,2009 ML091270196Request for Extension torespond toRAl November29,2009 ML093360336 Response toNRCGL200402 RAl January14,2010 ML100210969 Supplemental Response toASTLARRAl October 4,2010 ML102160020 ASTLicense Amendment (LA) No.183 December17,2010 ML103610171 Follow-up response toRAl May16,2013 ML13140A007 GSI-191 Closure Option 1.3General PlantSystem Description VCSNSUnit 1 isa Westinghouse three-loop pressurized water reactor (PWR). The NuclearSteamSupply System (NSSS) consists of one reactor pressure vessel (RPV),

three steam generators(SGs), three reactorcoolant pumps(RCPs), onepressurizer,and theReactor Coolant System (RCS) piping and instrumentation. The VCSNS Unit1 containmentiscompartmentalized, there i.e., aredistinct robust structuressurrounding themajor components (steam generators,pressurizer, RCPs, etc.) RCS.The ofthe containmentcompartmentalization slows the transport of debris to the sump.

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SerialNo.21-017 Docket No.50-395 GL2004-02 FinalSupplemental Response Enclosure TheEmergency CoreCooling System (ECCS) components aredesigned suchthat a minimum of two accumulators, oneCharging pumpandoneResidual HeatRemoval (RHR) pump, together with theirassociatedvalves andpiping, will assure adequate core coolinginthe event ofa Design BasisAccident (DBA). The Charging and RHR pumps serveastheSafety Injection (SI) pumps. Theemergency core coolinginjectionmodeis initiated byanSIsignal.

Whenthe SIsystem isactuated inresponse toa LOCA,twoCharging pumps andtwo RHRpumps are started and aligned toinjectinto the RCScold legs.TheCharging pumps providehigh head, lowflow,and the RHRpumpsprovide highflow,lowheadinjection.

Thepumps' suction isaligned to the Refueling Water Storage Tank(RWST) for the injection phase. Asthe RCSpressure decreases, three accumulators will alsodischarge theRCScold into legs.

ThetwoRBSpray pumpsareactuatedby a High Containment Pressure signal. The pumps' suction isalso aligned totheRWST. The Spray Additive Tank(SAT) also providesflowtothe pumpsuction for sodium hydroxide (NaOH) addition. The RB Spray pumps discharge tospray ring headers located inthe RB dome. AstheSIandRBSpray systems operate, theRWSTvolume isdepleted. At the RWST Lo-Lo Level, theRHR pumpandRBSpray pumpsuctions areautomatically realigned from theRWSTtotheRB recirculation sumps. Eachpumphasa separate suctionline and suction bell inside the RBrecirculationsumps.

TherearetwoRBrecirculation sumps. Onesumpsupplies TrainA of theRHRandRB Spraypumps, andthesecond sumpsupplies Train B.After theRHR pumps' suction is alignedtotheRBrecirculation sumps, theCharging pumpsuction ismanually aligned to theRHRpumpdischarge downstream oftheRHRheat exchanger. Thealignment istrain specific withoneCharging pumptaking suction from oneRHRpump.

Within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> following a LOCA,simultaneous hot leg andcold legrecirculationwill be initiated toavoid boron precipitation inthecore andtoterminate boiling.

1.4 General Description ofContainment SumpStrainers Asstated intheVCSNS Unit 1 Supplemental Response dated February 29,2008, two separatestrainerassemblies have been designed andinstalled toaddress RBSpray and RHRsystem requirements. Thestrainerswereprovided byAtomic Energy Canada, Ltd.

(AECL). TheRBhastworecirculation sumps, SumpA andSumpB,that areinternally separatedinto twosumppits, onefor RHRandonefor RB Spray, eachofwhich is protectedbya commonstrainer assembly against theentry ofpotential types and ofdebris quantities generated astheresultofhypothetical, postulatedLOCApipe break events.Each sumpsupports oneredundant train ofRHRandRBSpray equipment.

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SerialNo.21-017 Docket No.50-395 GL2004-02 Final Supplemental Response Enclosure TheRHR and RBSpray strainer modules ineachsumpareinterconnected bya cross-ducttoallow water toflow from onemodule tothe other,conservatively assuming oneof thestrainer modules becomesblocked bypostulated debris. Eachstrainer assembly is composed of a single squaremodule, theheader box, equipped with forty-four hollow

fins, eleven oneach ofthe four sides ofthe strainerheader box. Thefins areconnected laterally tothe approximately 4.75-foothigh sides oftheheader boxlocated directly over each sumppit. Thefins are ofvaried length andaredesigned tofit within theavailable space inthesump.Each vertically oriented strainer finconsists of18gauge stainless steel sheet, perforated with nominal 0.0625-inch diameter holes. Theperformance ofthe strainerisenhanced bythe extremely lowapproach velocity tothe perforated fins ofless than0.1inch/second. Thearea ratio ofholes isabout 41percent, andthesurfaces of thefins arecorrugated toincrease their surface area. Asthewater level rises inthe strainerduring filling,aircanescape through the finsandthrough the vent holes provided '

atthe topofthe strainer header box. This design precludes air ingestion duetotrapped airpockets during filling.

Asnoted above, thedesign ofboth the SumpA and Sump B strainers includes a closed crossduct connecting theRHRandRBSpray header boxes within thesump. Thecross ductprovides aflow area approximately 5 inches high by 30 inches wide for flow between theinteriorofthetwoheader boxes andisconnected on the side andnear the topofthe header boxes. Thecross duct isdesigned andfabricated to thesamecriteria asthe strainersandserves toprovide additional redundancy tothe strainer design for both SumpA andSumpB.Fora postulated event where thefin strainers oneither theRHR ortheRBSpray sides ofthesumpareassumed tobeblocked by debris generated by thepostulated LOCApipe break event, theflow intotheunblockedstrainer headerbox provides sufficient recirculation flow through thecross duct tosatisfy the netpositive suctionhead(NPSH) requirements for the pumps onboth theRHRandRB Spray sides ofthatsump. Theheader boxes, strainer fins,andcross ducts are designed, fabricated, andinstalled inaccordance with ASMECodeandSeismic Category 1 requirements.

Thesurface areas for thecontainment sumpstrainers aresummarized inTable 2 below.

TABLE2 CONTAINMENT SUMPSTRAINERS SURFACE AREAS SumpA Strainer Surface Area(fta) Total (ft2)

RHRStrainer ~1404

~2939 RBSpray Strainer ~1534 SumpB Strainer Surface Area(ft2) Total (ft2)

RHRStrainer ~1251

~2380 RBSpray Strainer ~1129 Page6 of21

Serial No.21-017 Docket No.50-395 GL2004-02 FinalSupplemental Response Enclosure 2 General Description andSchedule forCorrective Actions NRCIssue:

Provideageneral description ofactions taken orplanned, anddates for each. For actions plannedbeyond December 31,2007, reference approved extension requests orexplain howregulatory requirements will bemetasper"Requested Information" Item 2(b). That provide is, ageneral description ofandimplementation schedule for allcorrective actions, includinganyplant modifications, thatyouidentified while responding tothis generic letter.

Efforts toimplement theidentified actionsshould beinitiated nolater than the first refuelingoutage starting after April 1,2006. All actions should be completed by December 31,2007.Provide justification for notimplementing theidentified actions during the refueling first outage startingafter April 1,2006. Ifallcorrectiveactions willnot be completed by December 31,2007,describe how theregulatory requirements discussed intheApplicable Regulatory Requirements section will be met until the actions corrective arecompleted.

D.ESC.Respo.nsel DESCperformed analyses todetermine thesusceptibility of the ECCSandRB Spray system functions forVCSNSUnit 1 totheadverse effects of post-accident debris blockage andoperation with debris-laden fluids. Theanalyses considered postulated DBAsforwhich theRB sumprecirculation modeofthesesystems isrequired.

Mechanistic analyses supporting the evaluation satisfied thefollowing areas oftheNRC approved methodology intheNuclear Energy Institute (NEI) 04-07,"Pressurized Water Reactor Sump Performance Evaluation Methodology" Guidance Report (GR), as submittedbyNElonMay28,2004(Reference 4.3),andasmodified bytheNRC Safety Evaluation(SE) dated December 6, 2004 (Reference 4.4):

Break Selection Debris Generation andzone ofInfluence Debris Characteristics Latent Debris Debris Transport HeadLoss Vortexing NetPositive Suction HeadAvailable Debris Source Term Structural Analysis Upstream Effects Detailedanalyses ofdebris generation andtransport wereperformed toensure a boundingquantity andalimiting mixofdebris are assumed attheRBrecirculation sumps' following strainers a DBA.Theresults oftheanalyses, conservative evaluations, and testing strainer wereused todetermine worst-case strainer headloss anddownstream effects.

Chemical effects bench-top tests conservatively assessed thesolubilities and behaviorsofprecipitates andtheapplicability ofindustry data onthedissolution and precipitation testsofstation-specific conditions andmaterials. Reduced-scale testing was Page 7 of21

Serial No.21-017 Docket No.50-395 GL2004-02 Final Supplemental Response Enclosure performed byAECLandestablished theinfluence ofchemical products onheadloss across the strainer surfaces bysimulating theplant-specific chemical environment present inthe water oftheRBrecirculation sumps after a LOCA.

Inaddition, several plant modifications werecompleted for VCSNSUnit 1 insupport of GSl-191 resolution including the following:

• ThetwoRBrecirculation sumps' original strainers hadasurface area of23ft2 for each oftheTrain A andB RHR andRB Spray pumps, with nominal 1/4-inch square openings. Thestrainerswere replaced with AECLfin-type strainers having surface areas ofapproximately 2939 ft2 and2380ft2, with nominal 0.0625-inch circular openings.

• Twelve HighHeadSafety injection (HHSI) throttle valves werereplaced with Flowserve Pressure-Combo valves. These valves feature anoutlet flow nozzlethat takes upmostoftherequired pressure drop for the flow balance, permitting the alve v

tohave adequate clearance for thedownstream effects ofdebris. Theminimum valve opening based o n the ECCS flow balancing criteria is approximately 0.0938 inches compared tothe0.0625-inch screen openings.

• Twovertical trash rack gates wereinstalled intheRB annulus on the412-foot elevation. Thegates arelocated oneither side ofthe recirculation sumps tostop large debris from entering the sumparea. Thegates have 8-inch openings toallow smaller material topass through. Thegates area non-deterministic design feature added to enhance thesumpdesign based ontheguidance provided inSection 1.1.1.3of Regulatory Guide 1.82, Revision 3 (Reference 4.5). No credit istaken for these gates intheGSl-191 analysis.

Inaddition tothemodifications listed above, thefollowing actions werecompleted in support ofGSl-191 resolution:

• AnASTLOCADoseAnalysis LARwassubmitted andapproved VCSNS for Unit1to address a downstream effects analysis concern regarding pumpseal backup bushing failures. Incorporating theASTanalysis intothelicensing basis eliminated thepump seal backup bushing failure from thedoseanalysis basis, thereby addressing the concern.

• Latent debris sampling wascompleted andestablished a 105-pound load that includes a 50 percent margin. Walkdowns forunqualified material werealso completed consistent with NEl02-01 (Reference 4.6). A design input of 200 ft2 area sacrificial wassetbased onthe walk downs.

• Debris generation anddebris transport analyses were completed andincluded theuse ofcomputer-aided design (CAD) modeling ofthe R Band target insulation. The debris Page8 of21

Serial No.21-017 Docket No.50-395 GL2004-02 Final Supplemental Response Enclosure transport analyses usedcomputational fluid dynamic (CFD) modeling anddebris transport trees toestablish debris loading atthe strainers.

Ex-vesseldownstream effects analysis wascompleted perPWROG WCAP-16406-P, Revision 1 (Reference 4.7), withaugmented data fromWCAP-16571-P (Reference 4.8). Application of WCAP-16571-P was reviewed and approved bythe NRC.

Chemical effects testing was performed anddatawas collected at various temperatures andflow rates. Thestrainer headloss supported NPSHcalculations.

TheRHRpumpandRBSpray pump NPSHvalues werecalculated at700Fconsistent with the original design basis. No credit wastaken forsubcooling. Theupdated RHR andRBSpray PumpNPSHmargins are asfollows:

TABLE3 UPDATED RHRANDRB SPRAY PUMPS NPSHMARGINS PumpFlow NPSHRequired NPSHAvailableNPSHMargin Rate [gpm) [ft) [ft) [ft)

RHRPumpA 4300 17 20.2 3.2 RHRPumpB 4200 16 20.8 4.8 RBSpray PumpA 3300 17 22.1 5.1 RBSpray PumpB 3300 17 21.9 4.9 A cumulative effects program was established fortabulating, controlling, and evaluating changes toquantities ofinsulation inside theRB. Thisincluded the development ofa calculation listing the type, andquantities location, ofinsulation.

• A cumulative effects program was established fortabulating, controlling, and evaluating changes toquantities ofunqualified coatingsinside theRB.This included the development ofacalculation listingthetype, andquantities location, ofunqualified coatings.

A Level 1 coatings program wasestablished for theRBthat includesthetracking of qualified coatings within a4Dzone ofInfluence (zOI).

To ensure themodifications implemented andtheanalyses performed effectively addressed uncertainties with sufficientmargin, thefollowingmargins andconservatisms wereincorporated into the GSl-191 corrective actions asdetailed below:

TheTemp-Mat debris loading casehasthegreatest fiber load atthe strainers. The Page9 of21

Serial No.21-017 Docket No.50-395 GL2004-02 Final Supplemental Response Enclosure transport calculations conservatively assume 10percent erosion. However, the tested erosion rates wereinthe1percent range.

• Marinite XL insulation isinstalled around the RCSloop piping inside theprimary shield wall. With the pipe whipwithinshield theMarinite the wall, XLisassumed be100to percent particulate with all fiberreleased, andall theMarinite XL isassumed to transport tothesump strainer.

• Thechemical debris load includes a 100 ft2 operating margin outofa total of320ft2 ofaluminum inside theRB.

• Eachstrainer ineachRB recirculation sumpprovides a suction source for anRHR pumpandanRBSpray pump. The flow andassociated fiber totheRBSpray nozzles will notenter thereactor vessel onthe first pass through thestrainer. Theflow rates with twotrains operating are as follows:

TABLE4 FLOWSPLIT WITHTWOOPERATING TRAINS RHRFlow[gpm) Spray Flow [gpm)

Train A 3669 3300 Train B 3590 3300

• Flow inthebottom ofthereactor vessel isdirected upthrough thecoreand through holes inthe baffle former plates. Eachformer plateisprovided withholes so that flow travels upthrough the former plates. If flow through the core becomes restricted, flow will continue through theformer plate holes thereby providing flow tothe topof the core plate. This core bypass flow willprovide somelevel ofcore cooling.

Resolution ofDownstream Effects- Fuel andVessel: This item is dispositioned inSection 3.nbelow.

With thecompletion ofthe downstream effects analysisfor thefuel andvessel detailed below, DESChasresolved theissues identifiedinGL2004-02 for VCSNSUnit 1 andis incompliance with theapplicable regulations.

3 Specific Information for Review Areas Asstated inthe VCSNS Unit 1GL2004-02 Supplemental Response dated February 29, 2008(ADAMS Accession No.ML080640545), asamended on November 29,2009 (ADAMS Accession No.ML093360336), December 17,2010(ADAMS Accession No.

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Serial No.21-017 Docket No.50-395 GL2004-02 FinalSupplemental Response Enclosure ML103610171), andMay16,2013(ADAMS Accession No.ML13140A007), review areas 3.athrough 3.m have beenaddressed for VCSNS Unit 1;therefore,only theoutstanding review areas 3.n through 3.p areaddressed inthis submittal.

3.nDownstream Effects -

Fuel andVessel NRCIssue:

Theobjective ofthe downstream effects, fuel andvessel section istoevaluate the effects that debris carried downstream of the containment sumpscreen andinto thereactor vessel hasoncore cooling.

Showthat theinvessel effects evaluation isconsistent with, orbounded by,the industry generic guidance (WCAP-16793), as modified byNRCstaff comments on that document. Briefly summarize the application ofthemethods. Indicate where the WCAPmethods werenotusedorexceptions were taken andsummarize the evaluation ofthose areas.

DESCRes.ponse; TRWCAP-17788-P, Rev. 1,(Reference 4.9) provides evaluation methods andresults to address in-vessel downstream effects. As discussed inNRC"Technical Evaluation Report ofIn-Vessel Debris Effects," (ADAMS Accession No.ML19178A252), theNRC staffhasperformed a detailed review ofWCAP-17788. Although theNRC staff did not issue a Safety Evaluation forWCAP-17788, as discussed furtherin"U.S. Nuclear Regulatory Commission Staff Review Guidance forin-Vessel Downstream Effects Supporting Review ofGeneric Letter 2004-02 Responses" (ADAMS Accession No.

ML19228A011) (Reference 4.10), thestaff expects manyofthemethods developed in theTR maybeusedbyPWRlicensees todemonstrate adequate LTCC.DESCused methods andanalytical results developed inWCAP-17788-P, Rev. 1,toaddress in-vessel downstream debris effects for VCSNS Unit 1 andhasevaluated theapplicability ofthe methods andanalytical results from W CAP-17788-P, Rev. for 1 , VCSNS Unit 1.

3.n.1 W DESChasapplied theNEIclean plant criteria todetermine theamount offibrous debris penetratingthe sumpstrainers for usein the downstream in-vesseldebris effects analysis VCSNSUnit for 1.Theclean plant criteria, asapplied toin-vessel effects, utilize a fiber penetration (bypass) fraction of45%anda debris transport fractionof75%.

To determine theappropriate debris loading tousefor thein-vessel debris effects analysis,the massoffiber that penetrates the strainer andisfree totravel into the SIand RBSpray systems wasdetermined.

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Serial No.21-017 DocketNo.50-395 GL2004-02 Final Supplemental Response Enclosure Sourcesof fiber inthe VCSNS Unit 1 RBare Temp-Mat exposed blankets, largepieces, fines,andlatent fiber. Considering the quantities ofthese fiber sources, thefiber load that could bypass thestrainersandtransport tothecoreinlet wasdetermined by evaluatingthe latent debris sources andthe large pieces andfines originatingfromTemp-Matblankets (including erosion). Thefollowing steps wereperformed todetermine the totalfiberload for usein the strainer bypass calculation:

• Determine the totalquantity of fibrous insulation debrisgenerated inthebounding break, fiber finesandlatent fiber.

• Determine thequantity oferosion products created during a LOCAat8hours into theevent from exposed insulation blankets andsmall pieces ofTempMat.

• Addthebreak-generated fiber tothe amount offiber created byerosion to determine the totalfiber load.

Analysis fiberfinesandlatent fiber TheRCSA Loop31"crossover line double-ended guillotinebreak creates thelargest amountoffibrous 15.49debris, ft3. Table 5 breaks downtheamount ofTemp-Mat destroyed aseither large pieces orfines:

TABLE5 TEMPMATFIBROUS INSULATION DEBRIS SOURCE TERM CASE1 LBLOCA Large Pieces Fines Amount Destroyed Intact Exposed Small Amount Size Blankets Blankets Pieces 15.49ft3 5.27 ft3 4,96ft3 4 j8 ft3 1.08ft3 2.95E-05ft (34%) (32%) (27%)

NEl04-07 (Reference 4.3) classifies thedestroyed insulationdebris created into two categories:fines andlarge pieces. Fines include individualfibers andsmall piecesless than 4 inches x4 inches, andlarge pieces include material 4 inches andlarger. Thissize distribution isused for materials for which debris generation data isprovided inNEl04-07,with theexception ofhigh-density fiberglass andreflective metal insulation materials.

Thetotal fiber load for evaluation ofin-vessel effects consists oferoded large Temp-Mat pieces (4.96 ft3 from e xposed blankets and 4.18 ft3from s mallpieces) and fines ft3),

(1.08 Fines areconservatively considered tocompletely pass through thesumpstrainers, so thefiberload of1.08 ft3isadded tothefiber created through erosion oflarge piecesof Page12of21

Serial No.21-017 Docket No.50-395 GL2004-02 Final Supplemental Response Enclosure Temp-Mat toestablish the totalfiberload tobeused for in-vessel debris effects. NEl04-07,Table Vl-1, notesthat intactblankets arenotsubject toerosion andcanbeexcluded from the fiber strainer bypass calculation. This calculation ofVCSNS Unit 1downstream in-vessel effects used the WCAP-17788-P methodology whichonlyrequires consideration offibrous andchemical product debris. This method bounds all particulate loads,soit wasnotnecessary toconsider particulate debris inthe evaluation.

• j1,g Converting the volume of Temp-Mat fines fiber toIbm: 1.08 ft3 lbm/ft3 = 12,74lbm, TheRBlatent debris loadingused in theGSl-191 sumpevaluation wasconservatively determined tobe105Ibm(which includes significant margin). Perthe NRCSERfor NEl 04-07 (Reference 4.4), the distribution s ize of latent debris isconsidered15%fibrous to be and85%particulate. Consequently,the latent fiber load considered inthis calculationis 105Ibmx 0.15 = 16lbm.

Therefore, the total fibertransportedtothe strainers is12.74 Ibm+ 16Ibm= 28.74 Ibm.

FromTable 5 above, the amount offiber available for erosion from exposed blankets and small pieces ofTemp-Mat isequal to:

Temp-Mat (exposed blankets) + Temp-Mat (small pieces) = 4.96 ft3 + 4,18 ft3 = g,14fj3 TheNRCSERfor NEl04-07 (Reference 4.4) includes thefollowingequation for the calculation ofthepercentage oferoded fiber (feroaea)generated from the s mall pieces and exposed Temp-Mat blankets:

feroasa

= 1 -

(1rate)number

- ofhours Using anerosion rate of0.3 %from NEl04-07 andtheVCSNS Unit 1HotLegSwitchover (HLSO) time of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> inthe a bovee quation, the percentage of eroded fines generated atHLSOwould be:

= 1-(1-ferodea 0.003)8 = 0.02375 = 2.375%

Applying theerosion percentage tothe amount ofexposed blankets andsmall pieces of Temp-Mat insulation:

Erosion fines from Temp-Mat exposed blankets = 4.96 ft3*

2.375% = 0.118 ft3 Erosion fines from Temp-Mat smallpieces = 4.18 ft3*

2.375% = 0.0993 ft3 Page13of21

Serial No.21-017 DocketNo.50-395 GL2004-02 FinalSupplemental Response Enclosure Therefore, total a totalof0.218 fiber load thatreaches ft3 (

the

= 0.118 ft3 sumpstrainers.

+ 0.0993 ft3)

Oferoded Converting 0.218 fines ft3 wasadded 10lbm tothe

• jj,g 0.218 ft3 lbm/ft3= 2.57 Ibm Total fiber transported tothe strainers = Eroded Fines+ Temp-Mat Fines + LatentDebris (fiber)

Total fiber transported tostrainers= 2.57 Ibm+ 12.74 Ibm+ 16lbm= 31.31 lbm Theamount offibrous debris calculatedto arrive atthe reactor vessel wasdetermined for VCSNSUnit 1 bycalculating thestrainer bypass usingthe NElclean plant45%bypass factor.

g/FA= (M* T *CF* P)/N where:g/FA = grams offiber per fuel assembly M= massoftransported andlatent fiber, including erosion products T = transportfraction tostrainer CF= conversion from Ibmtograms P = strainerfiber bypass fraction, and N = number offuel assemblies Thegrams offiber perfuel assembly (g/FA) forVCSNSUnit 1wascalculated using the equation above. Thisequation accounts for thefiber debris source terms atthe strainer being fiber from insulation, erosion fines, andlatent debris (Reference 4.1).

Theg/FA forVCSNS Unit 1wasdetermined using thefollowing values:

M = massoftransported andlatent fiber,including erosion products = 31.31Ibm T = transportfraction tostrainer = 0.75 (DESC did notapply thetransportfactor of0.75 foradded conservatism.)

CF= conversion from lbmtograms = 453.6 grams/lbm P = strainerfiberbypass fraction = 0.45 (Reference 4.2)

N = number offuel assemblies = 157 assemblies Page14of21

Serial No.21-017 Docket No.50-395 GL2004-02 Final Supplemental Response Enclosure Using the clean plant 45% strainer bypass fraction, thecalculated gramsperfuel assembly is:

• 453.6

• g/FA = (31.31 0.45) /157 = 40.71or40.7 g/FA This istheVCSNS Unit 1 specificin-vessel fiber loadthat will becompared tothe applicable WCAP-17788-P, Rev.1,in-vessel debris acceptancecriterion, which assumes all fibrous debris calculated topenetrate the strainer reach will the reactor core.

Conservatisms intheabove calculation include the following:

. Theentire 16Ibmoflatent fiber load was assumed toreach thestrainer.

The75%transport factor wasnotapplied when calculatingthe fiber load for in-vessel debris effects, i.e., 100%ofthe fiber load was assumed totransport tothe strainer.

• Allfines, particulate, transportable miscellaneous debris(tags, labels, etc.), eroded fines,andlatent debris wereassumed totransport inunity (100%) tothe recirculation sumps with anequal fraction toeachrespective sump.

3.n.2 VCSNSUnit 1 isa Westinghouse 3-loop upflow configuration barrel/baffle plant design.

PerSection 3.0oftheNRCStaff Review Guidance (Reference 4 .10), it i s necessary to confirm VCSNSUnit 1 iswithin thekeyparameters oftheWCAP-17788-P, Rev.1, methods andanalysis. Eachofthekeyparameters isdiscussed below.

3.n.3 F.uel Desjign TheVCSNSUnit 1 core consists of157VANTAGE+ 17x 17optimized fuel assemblies (OFAs) Asdocumented inWCAP-17788-P, Volume 1,Table RAl-1.1-1, thisfuel design wasincluded intheWCAPtesting program. Since theVCSfuel assembly type was tested,thecore inlet debris load doesnotrequire adjustment orscaling toaccount for differences between theastested andVCSNSUnit 1OFAs.

3.n.4 WCAP-17788 Debris Limit TheProprietary inSection total 6.5ofWCAP-17788-P, (core in-vesselinlet Volume 1,Rev.

core) andheated fibrous 1,applies toVCSNS debris limit Unit 1 contained 3.n.5 As described inSection 3.n.1 ofthis submittal, VCSNSUnit 1 assumes that allfibrous debriscalculated topenetrate thestrainer reaches thereactorvessel.

Page15of21

Serial No.21-017 DocketNo.50-395 GL2004-02 FinalSupplementalResponse Enclosure 3.n.6 Asshowninthesump strainer fiber penetration section(3.n.1),themaximum amount of fiber forVCSNSUnit 1 calculated topotentially reach thereactor vessel is40.7 g/FA, whichisless thanthe proprietary in-vessel fibrous debris limitprovided inSection6.5of WCAP-17788-P,Volume 1, Rev. 1, 3.n.7Confirmation that theCore Inlet Fiber Amount isLess than theWCAP-17788-P R.eL1 Thresho.Ld VCSNSUnit 1 isa Westinghouse 3-loop upflow barrel/baffle configuration design with VANTAGE Westinghouse + 17x 17OFAs. The applicable WCAP-17788-P,Rev. 1,core inlet fiber isprovided threshold inTable 6-3 for Westinghouse fuel. Thecore inlet fiber amountforVCSNS Unit 1iscalculated tobe40.7 g/FA, which islessthan theapplicable WCAP-17788-P,Rev. 1,core inletfiber threshold.

3.n.8 r Greater TheSSOtime for maximum ECCSflow (using the design basis RB Spray pump flowrate of3,000gpm/pump for LOCApressure andtemperature) is1460 sec, or24.4 minutes.

TheSSOtime with a maximum RBSpray pumpflow of3381gpmresulting from anoverfill oftheRWSTwhenthe containment backpressure is0 psig, is1382sec, or 23.0minutes.

BothSSOtimesaregreater than the 20minutes assumed inTable 6-1of WCAP-17788-P,Rev.1,Volume4.

3.n.9 Chemical timing precipitation isdependent onthe plantbuffer, sumppool pH,volume and anddebris temperature, types andquantities. Table 4.4-1 ofPWROG-16073 (Reference identifies 4.11) TestGroup 11 as representative of VCSNS U nit1, the therefore, predicted precipitation chemical timing (tchem)is24hours.

that Confirmation 3.n.10 Chemical Effects will notOccur EarlierthanLatest Timeto M

PerSection ofthe 6.2.1.3 VCSNSUnit 1Final Safety Analysis Report(FSAR), switchover tohotlegrecirculation occurs nolater than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> afterevent initiation (post-LOCA) to mitigate thepotential forboric acid precipitation, which isless than24hours.

Page16of21

Serial No.21-017 Docket No.50-395 GL2004-02 Final Supplemental Response Enclosure 3.n.11 VCSNS aWestinghouse 3-loop Unit 1 is baffle/barrel upflow configuration design. Based onWCAP-17788-P, Rev.1,Volume 1,Table 6-1, for tblock VCSNSUnit 1 is143minutes.

3.n.12 Confirmation that Chemical Effects donotOccur Prior totblock PerTable 4.4-1 ofPWROG-16073 (Reference4.11), theearliest time ofchemical precipitation forVCSNS Unit 1was determined tobe24hours, which isgreater thanthe applicable value tbiock of 143 minutes.

3.n.13 DesigrLC.at.egoJy VCSNS Unit 1hasa rated thermal power of2900 MWt. VCSNS Unit 1isaWestinghouse 3-loop design; therefore, the applicable analyzed thermal power is3658MWtasprovided inWCAP-17788-P, Rev. 1,Volume 4,Table 6-1. The VCSNS Unit 1rated thermal power isless than theanalyzed power; therefore, this parameter isbounded bytheWCAP-17788-P, Rev. 1,alternate flow path analysis.

3.n.14 VCSNSUnit 1 isa 3-loop Westinghouse upflow barrel/baffle configuration design. The Proprietary analyzed AFPresistance isprovided inTable 6-1 ofWCAP-17788-P, Volume 4,Rev. 1.TheProprietary VCSNSUnit 1 specific AFPresistance isprovided inTable RAl-4.2-24. TheVCSNSUnit 1specific AFPresistance isless than theanalyzed value; therefore,theVCSNS Unit 1AFPresistance isbounded bytheresistance applied tothe AFPanalysis.

3.n.15 W

VCSNSUnit 1 isa Westinghouse upflow barret/baffle configuration design. TheAFP analysis for Westinghouse upflow plants analyzed a range ofECCSrecirculation flow ratesasshown inTable 6-1 ofWCAP-17788-P, Volume 4,Rev. 1,Theminimum VCSNS Unit1 ECCSrecirculation flow rate analyzed is21.9 gpm/FA, andthemaximum ECCS recirculationflow rateis37.7 gpm/FA. TheVCSNS Unit 1 ECCSrecirculation flowrate corresponding tothemostlimiting fiber injectionhot legbreak scenario is22.7 gpm/FA.

Therefore, all ofthese flow rates arewithin therange ofECCSrecirculation flow rates considered inthe AFPanalysis.

Page17of21

Serial No.21-017 Docket No.50-395 GL2004-02 Final Supplemental Response Enclosure 3.n.16 Summ.ary Thecomparison ofkeyparameters used inthe WCAP-17788 AFPanalysis tothe VCSNS Unit 1specific values issummarized inTable 6.Based onthese comparisons, VCSNS Unit 1 isbounded by thekeyparameters; therefore, theWCAP-17788 methods and resultsareapplicable.

TABLE6 KEYPARAMETER VALUESFORIN-VESSEL DEBRIS EFFECTS WCAP-17788 V.C.Summer Parameter Value Nuclear Station Evaluation Unit 1 Value Maximum Total In- Volume 1 < WCAP-17788 Maximum in-vessel fiberload is V ssel Fiber Load Section 6.5 Value less than WCAP-17788 limit.

Maximum Core inletVolume 1 40.7 Maximum core inlet fiberload is Fiber Load(g/FA) Table 6-3 less than WCAP-17788 threshold.

Later switchover time results ina Minimum Sump lower decay heat atthe time of Switchover Time 20 23 debris arrival, reducing the (min) potentialfor debris induced core uncovery and heatup.

Potential for complete coreinlet Minimum Chemical 2.4 blockage due tochemical product PrecipitateTime (hr) (tblock) 24 (tchem) generation would occur much later than assumed.

Maximum HotLeg Latest hotleg switchover occurs Switchover Time 24(tchem) 8 Well before the earliest potential (hr) chemical product generation.

Rated Thermal 3658 2900 Lower rated thermal power results Power (MWr) inlower decay heat.

Maximum AFP Volume 4 Volume 4 AFPresistance isless than the Resistance,ft4 Table 6-1 Table RAl-4.2-24analyzed value, which increases the effectiveness oftheAFP.

ECCSrecirculation flow rate ECCSRecirculation Volume 4 corresponding tothe mostlimiting Flow (gpm/FA) Table 6-1 M.7 @erinWon hot leg Weak scenario iswithin the analyzed flow range.

Page18of21

Serial No.21-017 Docket No.50-395 GL2004-02 FinalSupplemental Response Enclosure 3.o Chemical Effects NRCIssue:

Theobjective ofthe chemical effects section istoevaluate theeffect that chemical precipitates have onhead lossandcore cooling.

1)Providea summary ofevaluation results that showthat chemical precipitates formed inthepost-LOCA containment environment, either bythemselves orcombined with

debris, donotdeposit atthe sump screen tothe extent anunacceptable that headloss

results, ordeposit downstream of the sump screen totheextent that long-term core isunacceptably cooling impeded.

DESCResponse; TheVCSNSUnit 1chemical effects analysis of the sump strainerswassubmitted inits Supplemental Response dated February 29,2008 and further supplemented byletters datedNovember 29,2009andDecember 17,2010. The VCSNS Unit 1sumpstrainer chemical effects analysis isunchanged.

3.p Licensing Basis NRCIssue:

Theobjective ofthelicensing basis section istoprovide informationregarding any changestothe plantlicensing basis duetothe sumpevaluation orplantmodifications.

1)Provide theinformation requested inGL 04-02 Requested Information Item 2(e) regarding changes tothe plant licensing basis. Theeffective dateforchanges tothe licensing basis should bespecified. This date should correspondtothat specified inthe 10CFR50.59 evaluation forthe change tothe licensing basis.

DE C Resp.onse; License Amendment DESC's February 29,2008Supplemental Response discussed thelicensing basis changeforVCSNS Unit 1 associated with the resolutionofthe sumpissues considered inGSl-191andGL2004-02. Specifically, a LARwassubmitted byletter dated February 17,2009(ADAMS Accession No.ML090720887) forNRCreview andapproval insupport oftheresolutionofGSI-191 andNRCGL2004-02. Asdetailed further below, theNRC approved the LAR,andDESCimplemented theapproved licenseamendment for VCSNS Page19of21

SerialNo.21-017 Docket No.50-395 GL2004-02 FinalSupplemental Response Enclosure Unit1. Specifically, theLAR implemented an alternativesource termapplication methodology foranalyzing theradiological consequences for design-basis six accidents.

TheASTamendment eliminated the need toassume a passivefailure ofa pumpseal at 24hours after an accident asrequired bythe previous licensing basis dose analysis. This eliminated a concern regarding theuseofcarbon/graphite disaster bushings inpump seals. With noprimary seal failure assumption inthe ASTlicensing basis dose analysis, there wasnodesign requirement tolimit thepumpseal leakage to50gpm, andthe carbon/graphite disaster bushings werenolonger required tobereplaced.

TheNRCapproved theLARfor VCSNS Unit 1 inAmendment No.183dated October 4, 2010(ADAMS Accession No.ML102160020).

Final Safety Analysis Report TheVCSNSUnit 1 FSARwaspreviouslyupdated todescribethe installation ofthenew strainers. DESCwill update thecurrentlicensing basis (FinalSafety Analysis Report in accordance with 10CFR50.71(e)) following NRC acceptance ofthefinal supplemental response forVCSNSUnit 1.

4 References 4.1 Letter fromJ.Butler (NEl)toS.Bailey (NRC) dated December 22,2011, Transmittal ofGSl-191 Resolution Criteria for"LowFiber" Plants (with enclosure)

(ADAMS Accession Numbers ML113570219 andML113570226).

4.2 Letter from W.Ruland (NRC)toJ.Butler (NEl) datedMay2,2012,NRC Review ofNuclear Energy Clean Institute Plant Acceptance Criteriafor Emergency Core Cooling Systems (ADAMS Accession Number ML120730181).

4.3 NEl04-07, Revision0,"Pressurizer Water Reactor SumpPerformance Evaluation Methodology," May28,2004.

4.4 NRCSERfor NEl04-07, "Safety Evaluation bytheOffice ofNuclear Reactor Regulation RelatedtoNRCGeneric Letter 2004-02, Nuclear Energy Institute Guidance Report (Proposed Document Number NEl04-07), 'Pressurized Water Reactor SumpPerformance Evaluation Methodology'," dated December 6,2004.

4.5 NRCRegulatory Guide "Water 1.82, Sources for Long-Term Recirculation Cooling Following a Loss-of-Coolant Accident," November 2003.

4.6 NEl02-01, Revision1,"Condition Assessment Guidelines:Debris Sources Inside PWRContainments."

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Serial No.21-017 Docket No.50-395 GL2004-02Final Supplemental

Response

Enclosure 4.7 PWROG WCAP-16406-P, Revision 1,"EvaluationofDownstreamSumpDebris Effects inSupport ofGSI-191."

4.8 WCAP-16571-P, "Test ofPumpandValve toAssess Surfaces theWearfromPaint Chip Debris Laden Water."

4.9 WCAP-17788-P, Rev. 1,"Comprehensive Analysis Program andTest GSl-191 for Closure (PA-SEE-1090)," December 2019.

4.10NRCStaff Review Guidance for In-Vessel Downstream Effects Review Supporting ofGeneric Letter 2004-02 Responses, ADAMSAccessionsNo.ML19228A011, September 2019.

4.11PWROG-16073-P, Rev. 0,"TSTF-567 Implementation Guidance,Evaluation ofIn-Vessel Debris Effects,Submittal Template for FinalResponsetoGeneric Letter 2004-02 andFSARChanges," February 2020.

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