ML21175A247

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2020 Annual Report of Emergency Core Cooling System (ECCS) Model Changes Pursuant to the....-
ML21175A247
Person / Time
Site: Millstone, Summer, Surry, North Anna  Dominion icon.png
Issue date: 06/24/2021
From: Mark D. Sartain
Dominion Energy Nuclear Connecticut, Dominion Energy South Carolina, Virginia Electric & Power Co (VEPCO)
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
21-183
Download: ML21175A247 (42)
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Text

5000 omno ou vard e Allen,VA 23060 Dorninion DominionEnergy.com bR@@f June24,2021 10CFR50.46 U.S. Nuclear Regulatory Commission Serial No.: 21-183 Attention :Document Control Desk NRA/CLT RO Washington, DC 20555 DocketNos.:50-336/423 50-338/339 50-280/281 50-395 LicenseNos.:DPR-65/NPF-49 NPF-4/7 DPR-32/37 NPF-12 VIRGINIA!ELECTRIC ANDPOWER COMPANY MILLSTONE POWERSTATIONUNITS2 AND 3 NORTHANNAPOWER STATIONUNITS1AND 2 SURRYPOWERSTATION UNITS1AND2 VIRGIL C.S.UMMER 'NUCLEAR STATION UNIT1 Inaccordance with010 CFR50.46(a)(3)(ii), Dominion EnergyNuclear Connecticut, Inc.

(DENC), Virginia El6ctric andPower Company (DominionEnergyVirginia), andDominion Energy South Garolina, Inc.(DESC) hereby submittheannualsummary ofpermanent  !

changes semergency to )the core cooling system(ECCS) evaluation models (EMs) for Millstone Power :StAtion (MPS) Units2 and3,North AnnaPower Station (NAPS) Units1 and2,SurryPower Station(SPS) Units 1and 2,and C.

Virgil Summer Nuclear Station (VCS) Unitt1,Jrespectively. j

, ,ofsthis' provides I,etter a report describing plant-specificevaluation model changes associat'ed/with theWestinghouse andFramatome Small Break Loss ofCoolant Accident (SBLOCA) andLarge Break Loss ofCoolantAccident(LBLOCA) ECCSEMs forMPS2 and13,-NAPS 1and2,SPS1and2,andVCS1,as'applicable.

Information regarding theeffectoftheECCSEMchanges uponthereported SBLOCA andLBLOCA,analyses ofrecordresultsisprovided forMPS and NAPS1and2,SPS 2 3, 1 and2,and'VCS 1din Attachments 2,3,4 and5,respectively. Thecalculated peak cladding temperatures (PCT)for t heSBLOCA andLBLOCA analyses for M PS 2 and 3, NAPS1and2,nSPS 1and2,andVCS1aresummarized below:

Millstone Unit 2 Small breakFramatome EM: 1714F l

j Millstone Unit 2 Large breakFramatome EM(zr4 fuel): 18450F  !

Millstone Unit 2 Large breakFramatome EM(MS fuel): 16150F I

f f

SerialNo.21-183 DocketNos. 50-336/423/338/339/280/281/

2020Annual 10CFR50.46 Report Page2 of4 Millstone Unit 3 SmallbreakWestinghouse EM: 11930F Millstone Unit 3 LargebreakWestinghouse EM: 19330F North Anna Units 1 and2 Small breakWestinghouse EM: 1834.10F North AnnaUnits 1 and2 Large breakWestinghouse EM: 1982F Surry Units1and 2 SmallbreakWestinghouse EM: 2012F Surry Units1and2 LargebreakWestinghouse EM: 20710F Virgil C.SummerUnit 1 Small break-Westinghouse EM: 19230F Virgil C.SummerUnit 1 Large breakWestinghouse EM Blowdown: 1814F Reflood 1: 18140F Reflood 2: 1961F Composite: 19610F TheLOCAresults forMPS2and3,NAPS 1and 2,SPS1and2,andVCS1are confirmed tohavesufficient margintothe2200Flimit for PCTspecifiedin10CFR50.46. Based onthe evaluation information ofthis andtheresulting changes inthe applicable licensing basis PCTresults, nofurtheractionisrequired to demonstrate compliance withthe10 CFR50.46 requirements.

Theinformation contained herein satisfies the2020annual reporting requirements of10 CFR50.46(a)(3)(ii).

youhaveanyquestions If this regarding submittal, please contact Ms. Cathie Tiernanat (804) 432-2596.

Respectfully, w /

MarkD.Sartain Vice President -

Nuclear EngineeringandFleet Support Dominion Energy Nuclear Connecticut,Inc.  !

Dominion Energy South Inc Carolina, Virginia Electric andPower Company Commitments madeinthis letter:

None

, I

Serial No.21-183 Docket Nos.50-336/423/338/339/280/281/3 2020 10CFR50.46 Annual Report Page3 of4 Attachments: , Report ofChanges inFramatome andWestinghouse ECCSEvaluation Models .2020 Annual Reporting of10CFR50.46 MarginUtilization Millstone PowerStation Units 2and3 .2020 Annual Reporting of 10CFR50.46 MarginUtilization North Anna Power StationUnits 1 and2 .2020 Annual Reporting of10CFR50.46 MarginUtilization Surry Power Station Units1and2 .2020 Annual Reporting of10 CFR 50.46 MarginUtilization C.

Virgil SummerNuclear Station cc: U.S.Nuclear Regulatory Commission, Region I Regional Administrator 2100Renaissance Blvd., Suite 100 King ofPrussia, PA 19406-2713 U.S.Nuclear Regulatory Commission, Region II Regional Administrator Marquis OneTower 245Peachtree Center Ave., NESuite 1200 Atlanta, Georgia 30303-1257 NRCSenior Resident Inspector Millstone Power Station NRCSenior Resident Inspector North AnnaPower Station NRCSenior Resident Inspector Surry Power Station NRCSenior Resident Inspector Virgil C.SummerPower Station Mr.G.Edward Miller NRCProject ManagerNorth Anna U.S.Nuclear Regulatory Commission OneWhite Flint North Mail Stop 09E3 11555 Rockville Pike Rockville, MD 20852-2738

Serial No.21-183 Docket 50-336/423/338/339/280/281/

Nos.

10CFR50.46 2020Annual Report Page 4 of4 Mr. R.Guzman NRC Project ManagerMillstone Units 2 and3 U.S. Nuclear Regulatory Commission OneWhite Flint North Mail Stop O8 C2 11555 Rockville Pike Rockville, MD 20852-2738 Mr.Vaughn Thomas NRCProject Manager Surry andVirgil C.Summer U.S.Nuclear Regulatory Commission OneWhite FlintNorth Mail Stop 04F12 11555 Rockville Pike Rockville, MD 20852-2738 Mr. Marcus Harris OldDominion ElectricCooperative Innsbrook Corporate Center,Suite 300 4201Dominion Blvd.

Glen Allen, Virginia23060

Attachment 1 2020ANNUALREPORT OF EMERGENCY CORE PURSUANT TOTHEREQUIREMENTS OF 10CFR50.46 REPORT OFCHANGES IN FRAMATOMEANDWESTINGHOUSE ECCSEVALUATION MODELS DOMINIONENERGYNUCLEAR CONNECTICUT, INC.

VIRGINIA ELECTRICANDPOWER COMPANY DOMINIONENERGY SOUTH CAROLINA, INC.

MILLSTONEPOWER STATION UNITS2AND3 NORTH ANNAPOWER STATION UNITS 1AND2 SURRYPOWER STATION UNITS 1AND2 VIRGILC.SUMMERNUCLEAR STATION UNIT1

Serial Number 21-183 Docket Nos.50-336/423/338/339/280/281 Attachment 1 Page2 of5 REPORTOF CHANGESIN FRAMATOME ANDWESTINGHOUSE ECCSEVALUATION MODELS Millstone Power Station Unit 2 1 Framatome identified nochanges orerrors applicable tothe EMF-2328(P)(A), Revision 0 withSupplement 1 evaluation model for Small Break Loss ofCoolant Accident (SBLOCA) forMillstone Unit 2 during 2020.

2. Framatome identified nochanges orerrors applicable tothe SEM/PWR-98 evaluation model forLarge Break LOCA (LBLOCA) for Millstone Unit2 during 2020. This evaluation model isapplicable tothe Millstone Unit2fuel with zr-4 cladding.
3. OnJanuary 24,2017, a newLBLOCA analysis wasapproved bytheNRC,Reference 8, based upontheEMF-2103(P)(A), Revision 3,"Realistic Large Break LOCA(RLBLOCA)

Methodology for Pressurized Water Reactors" Thenewanalysis isapplicable tothe AREVAStandard CE14HTPfuel product with the M5 fuel TM rod cladding only. The analysispredicted a PCTof1615F.

Framatome identified the following change anderrorapplicable tothe EMF-2103(P)(A),

Revision 3 evaluation model for RLBLOCA for Millstone Unit 2 during2020.

  • M An inconsistency wasidentified inS-RELAP5 inputs related tofuel rod radiation enclosures. The error occurs only inapplications of theFramatome EMF-2103(P)(A),

Revision3,Realistic Large Break LOCA(RLBLOCA) methodology.Fuel stored energy uncertaintyestablished forsimulation oflimiting fuel rods wasinadvertently applied to thehot fresh andonce-burned UO2rod radiation enclosures. Theintentof the methodology isthat theuncertainty for enclosure stored energy simulation matches that ofthehot fuel assembly, which hasnoapplied uncertainty.

Enclosures account for the effect ofrod-to-rod thermal radiation. Rod-to-rod radiation comprises a fraction ofthe total heat transfer characteristic offuel rods ina steam environment. Theeffect oftheinput error issmall since the totalheat transfer from an uncovered fuel rodisrelatively small. Theimposition ofstored energy uncertainty can cause radiation heat transfer from a limiting rod tosurrounding rods toeither increase or decrease asa result oftheerror.

Corrections have beenmadetotheinput sothat uncertainty adjustments arenotmade tothehot fresh andonce-burned UO2rod radiation enclosures. Before andafter runs ofCombustion Engineering (CE) sample case sets were subsequently compared.

Differences intheresults arenegligible. Thus, there isnoeffect ontheRevision 3 RLBLOCA analyses of record peak clad temperature calculations. Effects oftheinput onmaximum error local andwhole core oxidation calculations arenegligible aswell.

SerialNumber 21-183 Docket Nos. 50-336/423/338/339/280/281 Attachment 1 Page3of5 Millstone Power StationUnit 3 1 Westinghouse identified thefollowing changes applicable tothe1985 Westinghouse SBLOCA Evaluation Model with NOTRUMP for Millstone Unit 3 during 2020.

TheWestinghouse Performance Analysis andDesign Model (PAD) isused togenerate fuel performance input data for useinSBLOCA analyses. A newapproved PADmodel (PAD5, WCAP-17642-P-A, Revision 1) isnowavailable forgeneration offuel performance input data. PAD5 implementation hasbeen evaluated through theuseof qualitative examination andsensitivity calculations tohave a negligible effect onthe SBLOCA analysis results, leading to anestimated peak cladding temperature impact of 0F.

2. Westinghouse identified thefollowing change applicable tothe 2004Westinghouse Best Estimate (BE) LBLOCA Evaluation Model(EM) using the Automated Statistical Treatment ofUncertainty Method (ASTRUM) for Millstone Unit 3 during 2020:

TheMillstone Unit 3 Cycle 21reload core design resulted inviolations ofthe PBOT/PMID envelope used intheLBLOCA analysis. These violations wereevaluated forMillstone Unit 3 Cycle 21operation. Thepeakcladdingtemperature impact ofthe PBOT/PMID violations forMillstone Unit 3 Cycle 21wasdetermined via a plant-specific evaluation tobe0F.

North AnnaPower Station Units 1 and2

1. Westinghouse identified nochanges orerrors applicable tothe 1985 Westinghouse SBLOCA Evaluation Model with NOTRUMP for North AnnaUnits 1and2 during 2020.
2. Westinghouse identified nochanges orerrors applicable tothe 2004WestinghouseBE LBLOCA EMusing ASTRUM for North AnnaUnits 1and2 during 2020.

M

1. Westinghouse identified nochanges orerrors applicable tothe1985 Westinghouse SBLOCA Evaluation Model with NOTRUMP for Surry Units 1and2 during 2020.
2. Westinghouse identified nochanges orerrors applicable tothe 2004 Westinghouse BE LBLOCA EMusing ASTRUM for Surry Units 1and2 during 2020.

Serial Number 21-183 Docket Nos. 50-336/423/338/339/280/281/

Attachment1 Page4of5 C Surnmer Virgil

1. Westinghouse identified thefollowing change applicable tothe 1985 Westinghouse SBLOCAEvaluation Model with NOTRUMP forVirgil C.Summer during 2020.
  • Evaluationof an increased Vessel Average Temperature Uncertainty Anupdate tothe analysis ofrecord (AOR) for setpoint andcontrol uncertainties resulted inanincrease tothevessel average temperature (Tavg) uncertainty range for consideration intheLOCA analyses. Theuncertainty rangechanged from +5.40F /-

6.3Fto+ 6.4F/-6.30F. The change intemperatureuncertainty hasbeenevaluated fortheSBLOCA analysis basis. This change represents a Change inPlant Configuration orSetpoints, distinguished from anevaluation model change inSection 4 ofWCAP-3451.

Theevaluation determined that theincreased Tavg uncertainty will have a negligible effect onthe SBLOCA transient results, leading to anestimated peak cladding temperature impact of0F.

2. Westinghouse identified thefollowing change applicable tothe1996 Westinghouse Best Estimate LBLOCA Evaluation Model for Virgil C.Summer during 2020.
  • Evaluation ofanIncreased Vessel Average Temperature Uncertainty An update totheAORfor setpoint andcontrol uncertainties resulted inanincrease to thevessel average temperature (Tavg) uncertainty range forconsideration intheLOCA analyses. Theuncertainty range changed from +5.4F/-6.3F to+ 6.4F /-6.30F. The change intemperature uncertainty hasbeen evaluated forthebest-estimate LBLOCA andFULLSPECTRUM LOCA(FSLOCA) Evaluation Model (EM) analyses. This change represents a Change inPlant Configuration orSetpoints, distinguished from an evaluation model change inSection 4 ofWCAP-13451.

A qualitative evaluation based onthe modeled Tavgdetermined that theincreased uncertainty range will have a negligible effect ontheanalysis results for thebest-estimate LBLOCA andFSLOCA EManalyses, leading toanestimated PCTimpact of 0F.

Conclusion TheLOCAresults forMillstone Units 2 and3,North AnnaUnits 1and2,Surry Units 1and2 and C.Summer Virgil Unit 1 areconfirmed inthePCTrackup tables, Attachments 5,to 2 through havemargin tothe 22000F limitfor PCTspecified in10CFR50.46. Based ontheevaluation of information this andtheresulting changes intheapplicable licensing basis PCTresults, no further action isrequired todemonstrate compliance with the10CFR50.46 requirements.

Reportingofthis information isrequired per10CFR 50.46(a)(3)(ii), which obligates each

Serial Number 21-183 Nos.

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

Attachment 1

Page5of5 licenseeto report theeffect uponcalculated ofanychange temperature inevaluation orerror models ortheir application onanannual basis.

Thisinformation satisfies theannualreporting of10 CFR 50.46(a)(3)(ii requirements for calendaryear 2020.

Attachment 2

2020ANNUALREPORTOFEMERGENCY CORE PURSUANTTOTHEREQUIREMENTSOF 10CFR50.46 ANNUALREPORTING 2020 OF10CFR50.46 MARGIN UTILizATION DOMINION ENERGYNUCLEARCONNECTICUT, INC.

POWER MILLSTONE STATION UNITS2 AND3

Serial Number 21-183 Docket Nos.50-336/423 Attachment 2

Page 8 2 of 10CFR 50.46 MARGIN UTILIzATIONSMALLBREAKLOCA PlantName: Millstone Power Unit Station, 2 Utility Name: DominionEnergy Nuclear Connecticut, Inc.

Ajialy.sis I.ggLormatLn EM: 2015, Supp. 1,SBLOCA, S-RELAP5Based Break Limiting Size:3.78 Inches AnalysisDate: April 2015 Vendor: Framatome PeakLinear Power: 15.1 kW/ft Notes: None ClfidTe!np.f.D LICENSING BASIS Analysis ofRecord PCT 1707 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments

1. zirc-4 Product Penalty 4
2. M5 LOCASwelling andRupture 0
3. S-RELAP5 OxidationCalculations 3 B. Planned Plant Modification Evaluations
1. None 0 C. 2020 ECCSModel Assessments 1 None 0 D. Other 1 None 0 LICENSING BASISPCT+ PCTASSESSMENTS PCT= 1714

Serial Number 21-183 Docket Nos.50-336/423 Attachment 2

Page3 of8 10CFR50.46 MARGINUTILIzATIONLARGEBREAKLOCA Plant Name: Millstone Power Unit Station, 2 Utility Name: DominionEnergy NuclearConnecticut, Inc.

Agly.sis In[ogm.gitig EM: SEM/PWR-98 Limiting Break Size: DECLG 1.0 Analysis Date: November 1998 Vendor: Framatome PeakLinear Power: 15.1 kW/ft Notes: None C-.liLdT.egItp.[?Fj LICENSING BASIS Analysis ofRecord PCT 1814 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments

1. Corrected Corrosion Enhancement Factor -1
2. ICECONCoding Errors 0
3. Setting RFPACFuel TemperaturesatStart ofReflood -2
4. SISPUNCH/ujun98 Code Error 0
5. Error inFlow Blockage Model inTOODEE2 0
6. Change inTOODEE2-Calculation ofQMAX 0
7. Change inGadolinia Modeling 0
8. PWRLBLOCASplit BreakModeling 0
9. TEOBYCalculation Error 0
10. Inappropriate Heat TransferinTOODEE2 0 11 End-of-Bypass Prediction byTEOBY 0
12. R4SSOverwrite ofJunctionInertia 0
13. Incorrect Junction InertiaMultipliers 1
14. Errors Discovered During RODEX2 V&V 0
15. Error inBroken Loop SGTube Exit Junction Inertia 0
16. RFPACRefill and R eflood Calculation Code Errors 16
17. Incorrect PumpJunction AreaUsed inRELAP4 0
18. Error inTOODEE2 CladThermal Expansion -1
19. Accumulator Line Loss Error -1
20. Inconsistent Loss Used Coefficients for Robinson LBLOCA 0
21. PumpHead Adjustment forPressure Balance Initialization -3
22. ICECONCode Errors 0
23. Containment Sump ModificationandReplacement P2R 2
24. Non-Conservative RODEXFuel Pellet Temperature 20
25. Array Index Issues intheRELAP4 Code 0 B. Planned Plant Modification Evaluations
1. None 0 C. 2020 ECCSModel Assessments
1. None 0

Serial Number 21-183 Docket Nos.

50-336/423 Attachment 2

of Page4 8 D. Other 1 None 0 LICENSINGBASIS PCT+ PCTASSESSMENTS PCT= 1845

Serial Number 21-183 Nos.

Docket 50-336/423 Attachment 2

Page5 of8 10CFR50.46 MARGINUTILIzATION -

LARGEBREAKLOCA Plant Name: Millstone PowerS tation, Unit(M5 2 Fuel)

Utility Name: DominionEnergy NuclearConnecticut, Inc.

An.ajysis JJ1form.atta.

EM: EMF-2103 Limiting Break Size: DEGB

1.0 AnalysisDate

May 2016 Vendor: Framatome PeakLinear Power: 15.1 kW/ft Notes: None h

LICENSING BASIS AnalysisofRecord PCT 1615 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments

1. Placement ofHotLegPiping Form Loss Coefficient 0
2. M5LOCASwelling andRupture 0
3. S-RELAP5 OxidationCalculations 0
4. Cathcart-Pawel correlation implementation 0
5. Rodpressure notresetafter inS-RELAPS rupture LOCAcalculations B. Planned Plant Modification Evaluations 1 None 0 C. 2020ECCSModelAssessment
1. Radiation enclosureinput error 0 D. Other 1 None 0 LICENSING BASISPCT+ PCTASSESSMENTS PCT= 1615

Serial Number 21-183 Nos.

Docket 50-336/423 Attachment 2

Page6of8 10CFR 50.46 MARGIN UTILIzATION -

SMALL BREAKLOCA Plant Name: Millstone Power Station,Unit 3 Utility Name: DominionEnergy Nuclear Connecticut, Inc.

A.nalygisjkrmatta EM: NOTRUMP Limiting Break Size:4inches Analysis Date: 02/07/07 Vendor: Westinghouse FQ: 2.6 FdH: 1.65 Fuel: RFA-2 SGTP(%): 10 Notes: None

.C[ajLTempCF)

LICENSING BASIS Analysis ofRecord PCT 1193 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModelAssessments 1 inReactor Errors VesselLower Plenum Surface Area Calculations 0

2. DiscrepancyinMetal Masses Used FromDrawings 0
3. Urania-Gadolinia Pellet Thermal Conductivity Calculation 0
4. Pellet Crack andDish Volume Calculation 0
5. ofVessel Treatment Average Temperature Uncertainty 0
6. Maximum Fuel RodTimeStep Logic 0
7. Radiation Heat Logic Transfer 0
8. NOTRUMP-EM Evaluation ofFuel Pellet Thermal 0 ConductivityDegradation
9. SBLOCTA Cladding Strain Requirement for Fuel 0 RodBurst
10. Fuel RodGapConductance Error 0
11. Radiation Heat Transfer Model Error 0
12. SBLOCTA Pre-DNB CladdingHeat Transfer 0 Calculation Coefficient
13. Insertion ofAXIOM'rM Cladding LTAs 0
14. Average Vessel Uncertainty Temperature 0
15. ErrorintheUpper PlenumFluid Volume Calculation g .
16. UO2Fuel Pellet HeatCapacity 0 B. Planned PlantModification Evaluations 1 None C. 2020 ECCSModel Assessments 1 Small Break LOCAPAD5Implementation 0 D. Other l < None 0 LICENSING BASISPCT+ PCTASSESSMENTS PCT= 1193

Number Serial 21-183 Docket Nos.50-336/423 Attachment 2

Page7of8 10CFR50.46 MARGINUTILIzATION -

LARGEBREAKLOCA Plant Name: Millstone Power Unit Station, 3 Utility Name: DominionEnergy Nuclear Connecticut, Inc.

Ana.lysisinfoLma.tion EM: ASTRUM (2004) Limiting Break Size:Guillotine Analysis Date: 04/17/07 Vendor: Westinghouse FQ: 2.6 FdH: 1.65 Fuel: RFA-2 SGTP(%): 10 Notes: None Ch LICENSING BASIS Analysis ofRecord PCT 1781 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments

1. HOTSPOT BurstTemperatureLogicErrors 0
2. CCFLGlobal Volume Error 0
3. HOTSPOT GapHeat Logic Transfer 0
4. Discrepancy inMetal Masses Used FromDrawings 0
5. Error inASTRUMProcessing ofAverage RodBurnup andRodInternal Pressure 0
6. Treatment ofVessel AverageTemperature Uncertainty 0
7. PBOTandPMIDEvaluation 0 8 Evaluation ofFuel Thermal Pellet Conductivity 222 Degradation
9. HOTSPOT BurstTemperatureCalculation 0 for zIRLOCladding
10. RodInternal Pressure Calculation 0
11. HOTSPOT Algorithm Iteration Calculating for the 0 Fuel Initial PelletAverage Temperature
12. WCOBRA/TRAC Thermal-Hydraulic History File 0 Dimension used inHSDRIVER Background
13. WCOBRA/TRAC Automated Restart Process Logic Error 0
14. Initial Fuel PelletAverage TemperatureUncertainty 0 Calculation
15. Elevations for Heat Slab Initialization0 Temperature
16. Heat Transfer Model ErrorCorrections 0
17. Correction toHeat TransferNodeInitialization 0
18. Mass Conservation ErrorFix 0 19 Correction toSplitChannel Momentum Equation 0
20. Heat Transfer Logic for Correction RodBurst Calculation 0
21. Changes toVessel SuperheatedSteamProperties 0
22. Update toMetal Density Reference Temperatures 0
23. Decay Heat Model ErrorCorrections 0
24. Correction tothe Pipe Exit Drop Pressure Error 0
25. WCOBRA/TRAC Ul9File DimensionError Correction0

Serial Number 21-183 Docket Nos.

50-336/423 Attachment 2

Page8 of8

26. RevisedHeat Transfer Multiplier Distributions -91
27. HOTSPOT Burst StrainError Correction 21
28. Changes toGrid Blockage RatioandPorosity 0
29. Grid HeatTransfer Enhancement Calculation 0
30. Burst Elevation Selection 0
31. Errors in Decay Group Uncertainty Factors 0
32. Errorsin Support Plate, Core Barrel, andVesselWall 0 UnheatedConductor
33. Error inOxidation Calculations 0
34. Error inuseofASME Steam Tables 0
35. Insertion ofAXIOMTM Cladding LTAs 0
36. Vessel Average Temperature Uncertainty 0
37. Inconsistent Applicationof Numerical Ramp Applied 0 tothe Entrained Liquid /Vapor Interfacial Drag Coefficient
38. Inappropriate Resetting ofTransverse LiquidMassFlow 0
39. Steady-State Fuel Temperature Calibration Method 0
40. MillstoneUnit 3Cycle 20PBOT/PMID Violations 0 41 Vapor Temperature Resetting 0 42 Core Barrel Heat SlabError 0
43. Cold LegVolume Error 0
44. Core Barrel Wetted Perimeter Error 0
45. Removal ofthe VesselInterfacialHeat Limit Transfer 0 B. Planned Plant Modification Evaluations 1 None C. 2020ECCSModel Assessments
1. Cycle 21PBOT/PMID Envelope Violations 0 D. Other
1. None 0 LICENSINGBASISPCT+ PCTASSESSMENTS PCT= 1933

Attachment3 2020ANNUALREPORT OFEMERGENCY CORE PURSUANTTOTHEREQUIREMENTS OF 10CFR50.46 ANNUALREPORTING 2020 OF10CFR50.46 MARGINUTILIzATION VIRGINIA ELECTRICANDPOWER COMPANY NORTHANNAPOWER STATION UNITS 1AND2

Serial 21-183 Number Nos.

Docket 50-338/339 Attachment 3

Page2 of7 10CFR 50.46 MARGIN UTILI2ATIONWESTINGHOUSE SMALLBREAKLOCA PlantName: North AnnaPower Unit Station, 1 Utility Name: Virginia Electric andPower Company Agga.lyjs Inform.atiog1 EM: NOTRUMP Limiting Break Size:2.75 inches AnalysisDate: 12/20/2010 Vendor: Westinghouse FQ: 2.32 FAH: 1.65 Fuel: RFA-2 SGTP(%): 7 Notes: None h

LICENSING BASIS Analysis ofRecord PCT 1834.1 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments

1. NOTRUMP-EM Evaluation ofFuel Pellet Thermal 0 Conductivity Degradation
2. SBLOCACladding Strain Requirement for Fuel 0 RodBurst
3. Fuel RodGapConductance Error .

0

4. Radiation Heat Model Transfer Error 0
5. SBLOCTAPre-DNB Cladding Heat Transfer 0 Coefficient Calculation
6. Error intheUpper PlenumFluid Volume Calculation 0
7. UO2Fuel PelletHeat Capacity 0 B. Planned Plant Modification Evaluations 1 None 0 C. 2020 ECCSModel Assessments 1 None 0 D. Other
1. None 0 LICENSING BASISPCT+ PCTASSESSMENTS PCT= 1834.1

Serial Number21-183 DocketNos.50-338/339 Attachment 3

Page3 of7 10CFR 50.46 MARGIN UTILIzATIONWESTINGHOUSE LARGEBREAKLOCA PlantName: North AnnaPower Station,Unit 1 Utility Name: VirginiaElectric andPower Company Ah EM: ASTRUM (2004) Limiting Break Size:DEGB Analysis Date: 8/25/2010 Vendor: Westinghouse FQ: 2.32 FAH: 1.65 Fuel: RFA-2 SGTP(%): 7 Notes:Core Power5 100%of2951 MWt; SG Model 17xl7 54F; RFA-2 Fuel zIRLO@orOptirnized with zIRLOTM

cladding, Non-IFBA orIFBA,IFMs CladT.e!!!p.LCFj LICENSING BASIS Analysis ofRecord PCT 1852 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments 1 Evaluation ofFuel Pellet Thermal Conductivity 135 Degradation

2. HOTSPOT Burst Temperature Calculation 0 for zIRLOCladding
3. RodInternal Pressure Calculation 0
4. HOTSPOT Iteration Algorithm. for Calculating the 0 InitialFuel PelletAverage Temperature
5. WCOBRA/TRAC Thermal-Hydraulic History File 0 Dimension used inHSDRIVER Background
6. WCOBRA/TRAC Automated RestartProcess Logic Error 0
7. Initial Fuel Pellet Average Temperature Uncertainty 1 Calculation
8. Elevations for Heat Slab Temperature Initialization0
9. Heat Transfer Model Error Corrections 0
10. Correction toHeat Transfer NodeInitialization 0 11 MassConservation Error Fix 0
12. Correction toSplit Channel Momentum Equation 0
13. Heat Transfer Logic Correction for RodBurst Calculation 0
14. Changes to Vessel Superheated Steam Properties 0
15. Update toMetal Density Reference Temperatures 0
16. Decay Heat Model Error Corrections 0
17. Correction tothe Pipe Exit PressureDrop Error 0
18. WCOBRA/TRAC Ul9File Dimension Error Correction 0
19. Revised Heat Transfer Multiplier Distributions -27
20. HOTSPOT Burst Strain Error Correction 21
21. Changes toGrid Blockage RatioandPorosity 0
22. Grid Heat Transfer Enhancement Calculation 0

SerialNumber 21-183 Nos.

Docket 50-338/339 Attachment 3

Page4of7

23. VesselSection 7Mid-Level ElevationModeling 0
24. Burst Elevation Selection 0
25. Errors in Decay Group Uncertainty Factors 0
26. Error in Oxidation Calculations 0
27. Error inuseof ASMESteam Tables 0
28. Support Column Core Barrel Unheated Conductor Errors0 0
29. Inconsistent Application ofNumerical RampApplied 0 tothe Entrained Liquid /Vapor Drag Interfacial Coefficient
30. InappropriateResetting ofTransverseLiquid MassFlow 0
31. Steady-State Fuel Temperature Calibration Method 0
32. Correction toFuel Pellet TCD Assessment 0
33. Vapor Temperature Resetting 0
34. Removal ofthe Vessel Limit Interfacial Heat Transfer 0 B. PlannedPlant Modification Evaluations
1. None 0 C. 2020ECCSModel Assessments
1. None 0 D. Other
1. None LICENSINGBASISPCT+ PCTASSESSMENTS PCT= 1982

Number Serial 21-183 Docket Nos.50-338/339 Attachment 3

Page5 of7 10CFR 50.46 MARGIN UTILIzATIONWESTINGHOUSE SMALLBREAKLOCA Plant Name: Notth AnnaPower Unit Station, 2 Utility Name: VirginiaElectric andPowerCompany An.a.lysisJnforg!1ation EM: NOTRUMP Limiting Break Size:2.75inches Analysis Date: 12/20/2010 Vendor: Westinghouse FQ: 2.32 FAH: 1.65 Fuel: RFA-2 SGTP(%): 7 Notes: None M

LICENSING BASIS Analysis ofRecord PCT 1834.1 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments

1. NOTRUMP-EM Evaluation ofFuelPellet Thermal 0 Conductivity Degradation
2. SBLOCTACladding Requirement Strain forFuel 0 RodBurst
3. Fuel RodGapConductance Error 0
4. Radiation Heat Transfer ModelError 0
5. SBLOCTA Pre-DNB Cladding Transfer Heat 0 Coefficient Calculation
6. Error inthe Upper Plenum FluidVolume Calculation 0
7. UO2Fuel Pellet HeatCapacity 0 B. Planned PlantModification Evaluations l None 0 C. 2020 ECCSModel Assessments
1. None 0 D. Other
1. None 0 LICENSING BASIS PCT+ PCTASSESSMENTS PCT= 1834.1

Number Serial 21-183 DocketNos.50-338/339 Attachment 3

Page 7 6 of 10CFR 50.46 MARGIN UTILIzATIONWESTINGHOUSE-LARGEBREAKLOCA PlantName: North AnnaPower Station, Unit2 Utility Name: Virginia Electric andPower Company Ah EM: ASTRUM (2004) Limiting Break Size:DEGB AnalysisDate: 8/25/2010 Vendor: Westinghouse FQ: 2.32 FAH: 1.65 Fuel: RFA-2 SGTP(%): 7 Notes:Core Power 5 100%of2951 MWt;SG Model 54F;17xl7RFA-2 Fuel zIRLO@orOptimized with 2IRLOTM

cladding, Non-IFBA orIFBA,IFMs M

LICENSING BASIS Analysis ofRecord PCT 1852 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments

1. Evaluation ofFuel PelletThermal Conductivity 135 Degradation
2. HOTSPOT Burst Temperature Calculation 0 for zIRLOCladding
3. RodInternal Pressure Calculation 0
4. HOTSPOT IterationAlgorithm forCalculating the 0 InitialFuel PelletAverage Temperature
5. WCOBRA/TRAC Thermal-Hydraulic History File 0 Dimension used inHSDRIVER Background
6. WCOBRA/TRAC Automated Restart Process Logic Error 0
7. InitialFuel Pellet Average Temperature Uncertainty I Calculation 8 Elevations for Heat Slab Temperature Initialization 0
9. Heat Transfer Model Error Corrections 0
10. Correction toHeat Transfer NodeInitialization 0 l1. MassConservation ErrorFix 0
12. Correction toSplit Channel Momentum Equation 0
13. Heat Transfer Logic Correction forRodBurst Calculation 0
14. Changes toVessel Superheated SteamProperties 0
15. Update toMetal Density Reference Temperatures 0
16. Decay Heat Model Error Corrections 0
17. Correction tothe Pipe Exit Pressure Drop Error 0
18. WCOBRA/TRAC Ul9File Dimension Error Correction 0
19. Revised Heat TransferMultiplier Distributions -27
20. HOTSPOT Burst StrainError Correction 21
21. Changes toGrid Blockage Ratio andPorosity 0

Serial 21-183 Number Docket Nos.50-338/339 Attachment 3

Page7 of7

22. Grid Heat Transfer Enhancement Calculation 0
23. Vessel Section 7Mid-Level Elevation Modeling 0
24. Burst Elevation Selection 0
25. Errors inDecay Group Uncertainty Factors 0
27. Error in Oxidation Calculations 0
28. Errorin use ofASMESteam Tables 0
29. SupportColumn Core Barrel Unheated Errors 0 Conductor
30. InconsistentApplication ofNumerical RampApplied 0 tothe Entrained Liquid /Vapor Interfacial DragCoefficient 31 Inappropriate Resetting of Transverse Liquid MassFlow 0
32. Steady-State Fuel Temperature Calibration Method 0
33. Correction toFuel Pellet TCD Assessment 0
34. Vapor Temperature Resetting 0
35. Removal ofthe Vessel Interfacial Heat Transfer Limit 0 B. Planned Plant Modification Evaluations 1 None 0 C. 2020ECCSModel Assessments
1. None 0 D. Other 1, None LICENSINGBASISPCT+ PCTASSESSMENTS PCT= 1982

4 Attachment 2020ANNUALREPORTOFEMERGENCY CORE ANNUALREPORTING 2020 OF10CFR50.46 MARGINUTILIzATION VIRGINIA ANDPOWERCOMPANY ELECTRIC SURRYPOWER STATIONUNITS1AND2

Number Serial 21-183 Nos.

Docket 50-280/281 Attachment 4

Page2 of7 10CFR 50.46 MARGIN UTILIzATIONWESTINGHOUSE SMALLBREAKLOCA Plant Name: Surry Power Unit Station, 1 Utility Name: VirginiaElectricandPower Company An.alyjsln&rma.1ion EM: NOTRUMP Limiting Break Size:2.75 inches Analysis Date: 5/7/2009 Vendor: Westinghouse FQ: 2.5 FAH: 1.7 Fuel: Upgrade SGTP(%): 7 Notes: None M

LICENSING BASIS Analysis ofRecord PCT 2012 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments

1. Urania-Gadolinia Thermal Pellet Conductivity Calculation. 0
2. Pellet Crack andDish Volume Calculation. 0
3. Treatment ofVessel AverageTemperature Uncertainty 0
4. 15X15 Upgrade Fuel 0
5. Maximum Fuel RodTime Logic Step 0
6. RadiationHeat Logic Transfer 0
7. NOTRUMP-EM Evaluation ofFuel Pellet Thermal 0 Conductivity Degradation
8. SBLOCTACladding Requirement Strain for Fuel 0 RodBurst
9. FuelRodGapConductance Error 0
10. RadiationHeat Transfer Model Error 0
11. SBLOCTA Pre-DNB Cladding Heat Transfer 0 CoefficientCalculation
12. Errorinthe Upper Plenum Fluid Volume Calculation 0
13. UO2Fuel PelletHeatCapacity 0 B. Planned Plant Modification Evaluations
1. None 0 C. 2020 ECCSModel Assessments
1. None 0 D. Other
1. None 0 LICENSING BASISPCT+ PCTASSESSMENTS PCT= 2012

Serial Number 21-183 Docket Nos.50-280/281 Attachment 4

Page 7 3 of 10CFR 50.46 MARGIN UTILIzATION- WESTINGHOUSE LARGEBREAKLOCA Plant Name: Surry Power S Unit tation, 1 Utility Name: VirginiaElectric andPower Company Analy.sisln[oLmation EM: ASTRUM (2004) Limiting Break Size:DEG Analysis Date: 10/6/2010 Vendor: Westinghouse FQ: 2.5 FAH: 1.7 Fuel: Upgrade SGTP(%): 7 Notes: None ClagLT.emILCF)

LICENSING BASIS Analysis ofRecord PCT 1853 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments

1. Evaluation ofFuel PelletThermalConductivity 183 Degradation
2. PelletRadial Profile Option -13
3. HOTSPOT Burst TemperatureCalculation 0 for zIRLOCladding
4. RodInternal Pressure Calculation 0
5. HOTSPOT IterationAlgorithmforCalculating the 0 Fuel Initial PelletAverage Temperature
6. WCOBRA/TRAC History Thermal-Hydraulic File 0 Dimension used inHSDRIVER Background
7. WCOBRA/TRAC Automated Restart Process Logic Error 0
8. Initial Fuel Pellet Average TemperatureUncertainty 0 Calculation
9. Elevationsfor Heat SlabTemperatureInitialization0
10. Heat Transfer Model ErrorCorrections 0 11 Correction toHeat TransferNodeInitialization 0
12. MassConservation ErrorFix 0
13. CorrectiontoSplit Channel Momentum Equation 0
14. Heat Transfer Logic Correction forRodBurst Calculation 0
15. Changes toVessel S.uperheated SteamProperties 0
16. Update toMetal DensityReferenceTemperatures 0
17. Decay Heat Model Error Corrections 0
18. Correctiontothe Pipe ExitPressure Drop Error 0
19. WCOBRA/TRAC Ul9File DimensionError Correction 0
20. Revised Heat TransferMultiplier Distributions -7 21 HOTSPOT Burst Strain Correction Error 51
22. Changes toGrid Blockage Ratio andPorosity 0
23. Grid HeatTransfer Enhancement Calculation 0
24. VesselSection 7Mid-Level Modeling Elevation 0

SerialNumber 21-183 DocketNos.

50-280/281 Attachment 4

Page4 of7

25. Burst Elevation Selection 0
26. Errors inDecay Gt;oup Uncertainty Factors 4
27. Evaluation ofAdditional Containment Metal 0
28. Error inOxidation Calculations 0
29. Error in useofASMESteam Tables 0
30. Core Barrel Unheated Conductor Errors 0
31. Discrepancy inWetted Perimeter Inputs 0
32. InconsistentApplication ofNumerical RampApplied 0 tothe Entrained Liquid /Vapor InterfacialDrag Coefficient
33. Inappropriate Resetting of Transverse Liquid Mass Flow 0
34. Steady-State Fuel Temperature Calibration Method 0
35. Vapor Temperature Resetting 0
36. Removal ofthe Vessel Interfacial Heat Transfer Limit 0 B. PlannedPlant Modification Evaluations
1. None 0 C. 2020ECCSModel Assessments 1, Removal oftheVessel Interfacial Heat Transfer Limit 0 D. Other
1. None 0 LICENSINGBASISPCT+ PCTASSESSMENTS PCT= 2071

Serial Number21-183 Docket Nos.50-280/281 Attachment 4

Page5 of7 10CFR 50.46 MARGIN UTILI2ATIONWESTINGHOUSE SMALLBREAKLOCA PlantName: Surry Power Station, Unit2 Utility Name: VirginiaElectricandPower Company h

EM: NOTRUMP Limiting Break Size:2.75 inches Analysis Date: 5/7/2009 Vendor: Westinghouse FQ: 2.5 FAH: 1.7 Fuel: Upgrade SGTP(%): 7 Notes: None fF.)

Clad.Temp LICENSING BASIS Analysis ofRecord PCT 2012 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments

1. Urania-Gadolinia Pellet Thermal Conductivity Calculation. 0
2. PelletCrack andDish Volume Calculation. 0
3. Treatment ofVessel AverageTemperature Uncertainty 0
4. 15X15 Upgrade Fuel 0
5. Maximum Fuel RodTime Logic Step 0
6. Radiation Heat Logic Transfer 0
7. NOTRUMP-EM Evaluation ofFuel Pellet Thermal 0 Conductivity Degradation
8. SBLOCTA Cladding Requirement Strain for Fuel 0 RodBurst
9. Fuel RodGapConductance Error 0
10. Radiation Heat Model Transfer Error 0 11 SBLOCTAPre-DNB Cladding Heat Transfer 0 Coefficient Calculation
12. Error inthe Upper Plenum Fluid Volume Calculation 0
13. UO2Fuel PelletHeatCapacity 0 B. Planned Plant Modification Evaluations
1. None 0 C. 2020 ECCSModel Assessments
1. None 0 D. Other 1 None 0 LICENSING BASISPCT+ PCTASSESSMENTS PCT= 2012

Serial Number 21-183 Docket Nos.

50-280/281 Attachment 4

Page6of7 10CFR 50.46 MARGIN UTILIzATIONWESTINGHOUSE -

LARGEBREAKLOCA Plant Name: Surry Power Unit Station, 2 Utility Name: VirginiaElectric andPower Company An.a.lysisJnfomation EM: ASTRUM (2004) Limiting BreakSize:DEG Analysis Date: 10/6/2010 Vendor: Westinghouse FQ: 2.5 FAH: 1.7 Fuel: Upgrade SGTP(%): 7 Notes: None M

LICENSING BASIS Analysis ofRecord PCT 1853 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments

1. Evaluation ofFuel Pellet Thermal Conductivity 183 Degradation
2. PelletRadial Profile Option -13
3. HOTSPOT Burst Calculation Temperature 0 for zIRLOCladding
4. RodInternal Pressure Calculation 0
5. HOTSPOT IterationAlgorithmfor Calculating the 0 Initial Fuel PelletAverageTemperature
6. WCOBRA/TRAC Thermal-Hydraulic History File 0 Dimension used inHSDRIVER Background
7. WCOBRA/TRAC AutomatedRestart Process Logic Error 0
8. Initial Fuel Pellet AverageTemperature Uncertainty 0 Calculation
9. Elevations forHeat Slab Temperature Initialization 0
10. Heat Transfer Model Corrections Error 0
11. Correction toHeat Transfer NodeInitialization 0
12. MassConservation Fix Error 0
13. CorrectiontoSplit ChannelMomentum Equation 0
14. Heat Transfer Logic Correction for RodBurst Calculation0
15. Changes toVessel SuperheatedSteam Properties 0
16. Update toMetal Reference Density Temperatures 0
17. Decay Heat Model ErrorCorrections 0
18. Correction tothe Pipe Exit Pressure Drop Error 0
19. WCOBRA/TRAC U19FileDimension Error Correction 0
20. Revised Heat TransferMultiplierDistributions -7
21. HOTSPOT Burst Strain Correction Error 51
22. Changes toGrid BlockageRatio andPorosity 0
23. Grid HeatTransfer Enhancement Calculation 0
24. Vessel Section 7Mid-Level Elevation Modeling 0
25. Burst Elevation Selection 0

Number Serial 21-183 Docket Nos.50-280/281 Attachment 4

Page 7 7 of

26. Errorsin Decay Group Uncertainty Factors 4
27. Evaluation ofAdditional Containment Metal 0
28. Error in OxidationCalculations 0
29. Error in useofASMESteam Tables 0
30. Core Barrel Unheated Conductor Errors 0
31. Discrepancy in WettedPerimeter Inputs 0
32. Inconsistent Application ofNumerical RampApplied 0 tothe Entrained Liquid /Vapor Drag InterfacialCoefficient
33. Inappropriate Resetting of TransverseLiquid MassFlow0
34. Steady-State FuelTemperature Calibration Method 0
35. Vapor TemperatureResetting 0
36. Removal oftheVessel Interfacial Heat Limit Transfer 0 B. PlannedPlant Modification Evaluations
1. None 0 C. 2020ECCSModel Assessments
l. None 0 D. Other l None 0 LICENSINGBASISPCT+ PCTASSESSMENTS PCT =

2071

Attachment 5 2020ANNUALREPORTOF EMERGENCY CORE PURSUANTTOTHEREQUIREMENTS OF10CFR50.46 ANNUALREPORTING 2020 OF10CFR50.46 MARGIN UTlLlzATION DOMINION ENERGY SOUTH CAROLINA, INC.

C.SUMMER VIRGlL NUCLEAR STATION UNIT1

Serial Number21-183 Docket Nos.50-395 Attachment5 Page2 of11 Plant Name: V.C.Summer Utility Name: Dominion Energy SouthCarolina Ah EM: NOTRUMP Limiting Break Size:3Inch Analysis Date: February 2003 Vendor: Westinghouse FQ: 2.45FdH: 1.62 Notes: None Clad.[em.p.EF)

LICENSING BASIS AnalysisofRecord PCT 1775 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments 1 NOTRUMP-EM Refined BreakSpectrum 0

2. inReactor Errors Vessel NozzleData Collections 0
3. PumpWeir Resistance Modeling 0 4 inReactor Errors Vessel Lower Plenum Surface AreaCalculations 0
5. ModelingofAnnular Pellets 0
6. DiscrepancyinMetal MassesUsed FromDrawings 0
7. V.C.Summer Upflow Conversion 148
8. ofVessel Treatment Average Temperature Uncertainty 0
9. Urania-Gadolinia Pellet ThermalConductivity Calculation 0
10. Pellet Crack andDish Volume Calculation 0
11. Radiation Heat Transfer Logic 0
12. Maximum Fuel RodTimeStep Logic 0
13. NOTRUMP-EM EvaluationofFuel Pellet Thermal Conductivity Degradation 0
14. SBLOCTACladding StrainRequirement for Fuel RodBurst 0
15. Fuel RodGapConductance Error 0
16. Radiation Heat Transfer ModelError >

0

17. SBLOCTA Pre-DNB Surface Cladding Heat Transfer Coefficient Calculation 0
18. Control RodDrop TimeTechnical Specification Change 0
19. VesselAverage Temperature Uncertainty 0
20. ErrorintheUpper Plenum Fluid Volume Calculation 0
21. UO2Fuel Pellet Heat Capacity 0 B. Planned PlantModification Evaluations 1 None 0 C. 2020 ECCSModel Assessments

Serial Number21-183 Docket Nos.50-395 Attachment 5

Page3of11

1. Increased Vessel Average Uncertainty Temperature 0 D. Other
1. None 0 LICENSING BASIS PCT + PCTASSESSMENTS PCT= 1923

Serial Number21-183 DocketNos.50-395 Attachment 5

Page4of11 Plant Name: V.C.Summer Utility Name: Dominion Energy SouthCarolina Analysisinformation EM: CQD (1996) Limiting Break Size:DEGB Analysis Date: February 2003 Vendor: Westinghouse FQ: 2.5 FdH: 1.7 Notes: None

.ChLdTemp.fFj LICENSING BASIS Analysis ofRecord PCT 1860 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments

1. FanCooler Performance Increase 0
2. Improved Automation ofEndofBlowdown Time 0
3. Implementation ofASTRUMCapability inHOTSPOT 0 4 Revised Blowdown Heatup Uncertainty Distribution 49
5. Revised IterationAlgorithm forCalculating TheAverage Fuel Temperature 0
6. Improved Automation ofEndofBlowdown Time 0
7. Thermodynamic Propertiesfrom Thermo 0
8. Pressurizer Fluid Volumes 0
9. VesselUnheated Conductor Noding 0
10. Containment Relative HumidityAssumption 0
11. HOTSPOT Fuel Relocation 0
12. Steam Generator Nozzle Volume Accounting Error 0
13. Cold LegVolume Discrepancy 0
14. ErrorsinReactor Vessel Nozzle DataCollection 0
15. HOTSPOT Burst Temperature Logic Errors 0
16. V.C.Summer Upflow Conversion -7
17. zero Cross-Flow Boundary Condition Error 0
18. Discrepancy inMetal Masses UsedFromDrawings 0
19. HOTSPOT GapHeat Logic Transfer 0
20. HOTSPOT Statistical OutputLogic -

0

21. TreatmentofVessel Average TemperatureUncertainty 0
22. AdditionalHeat Sinks andMaximum Spray Flow 0
23. Fuel Pellet Thermal ConductivityDegradation andPeaking Factor Burndown 0
24. PAD4.0 Implementation -83
25. zero Cross-Flow Boundary Condition Error 0
26. HOTSPOT Burst Temperature Calculation ForzIRLO Cladding 0
27. HOTSPOT Iteration Algorithm forCalculating TheInitial Fuel Pellet Average Temperature 0

Serial Number21-183 DocketNos.50-395 Attachment 5

Page5of11

28. WCOBRA/TRAC Automated Restart Process Logic Error 0
29. RodInternal PressureCalculation 0
30. WCOBRA/TRAC Thermal-Hydraulic History File Dimension used inHSDRIVER 0
31. Burst Elevation Selection 0
32. Elevation forHeat Slab Temperature Initialization 0
33. Heat Transfer Logic for RodBurst Calculation 0
34. WCOBRA/TRAC Ul9File Dimension Error Correction 0
35. Heat TransferModel ErrorCorrections 0
36. Correction toHeat Transfer Node Initialization 0
37. MassConservationError Fix 0
38. Correction toSplit Channel Momentum Equation 0
39. Changes toVessel Superheated Steam Properties 0
40. Update toMetal Density Reference Temperatures 0 41 Decay Heat Model Error Correction 0
42. Correction tothe PipeExit Pressure Drop Error 0
43. Vessel Section 7Mid-Level Elevation Modeling 0
44. Grid Heat Transfer Enhancement Calculation 0
45. Revised Heat Multiplier Transfer Distributions -5
46. Changes toGrid Blockage Ratio andPorosity 0
47. Error inBurst Application Strain 0
48. Code Uncertainty inBELBLOCAMonte Carlo Simulations 0
49. Error inOxidation Calculations 0
50. Support Column Unheated Conductor Error 0 51 Vessel Average Temperature Uncertainty 0
52. Numerical RampEntrained Liquid/Vapor Interfacial Drag 0
53. Inappropriate ResettingofTransverse Liquid MassFlow 0
54. Vapor Temperature Resetting 0
55. Removal ofthe Vessel Interfacial Heat Transfer Limit 0 B. PlannedPlant Modification Evaluations 1 None 0 C. 2020ECCSModel Assessments
1. Increased Vessel Average Temperature Uncertainty 0 D. Other 1 None 0 LICENSINGBASIS PCT+ PCTASSESSMENTS PCT= 1814

Serial Number 21-183 DocketNos.

50-395 Attachment 5

Page 11 6 of Plant Name: V.C.Summer Utility Name: Dominion Energy SouthCarolina Ag1aly.sisinformatio!1 EM: CQD (1996) Limiting Break Size:DEGB Analysis Date: February 2003 Vendor: Westinghouse FQ: 2.5 FdH: 1.7 Notes: None h

LICENSING BASIS Analysis ofRecord PCT 1808 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments

1. FanCooler Performance Increase 1
2. Improved Automation ofEndofBlowdown Time 0
3. Implementation ofASTRUM inHOTSPOT Capability 0 4 Revised Blowdown Heatup Uncertainty Distribution 5
5. Revised IterationAlgorithm forCalculating TheAverage Fuel Temperature 0
6. Improved Automation ofEndofBlowdown Time 0
7. Thermodynamic Propertiesfrom Thermo 0
8. Pressurizer Fluid Volumes 0
9. VesselUnheated Conductor Noding 0
10. Containment Relative Humidity Assumption 0 11 HOTSPOT Fuel Relocation 0
12. Steam Generator Nozzle Volume Accounting Error 0
13. Cold LegVolume Discrepancy 0
14. Errors inReactor Vessel Nozzle Collection Data 0 l5. HOTSPOT Burst Temperature Logic Errors 0
16. V.C.Summer Upflow Conversion -44
17. zero Cross-Flow Boundary Condition Error 0
18. Discrepancy inMetal Masses UsedFromDrawings 0
19. HOTSPOT GapHeat TransferLogic 0
20. HOTSPOT Statistical OutputLogic 0
21. Treatment ofVessel Average TemperatureUncertainty 0
22. Additional Heat Sinks andMaximum Spray Flow 0
23. Fuel Thermal Pellet ConductivityDegradation andPeaking Factor Burndown I13
24. PAD4.0 Implementation -118
25. zero Cross-Flow Boundary Condition Error 0
26. HOTSPOT Burst Temperature Calculation ForzIRLOCladding 0
27. HOTSPOT Iteration Algorithm forCalculating TheInitialFuel Pellet Average Temperature 0

Serial Number 21-183 DocketNos.

50-395 Attachment 5

Page 11 7 of

28. WCOBRA/TRAC Automated Restart Process Logic Error 0
29. RodInternal PressureCalculation 0
30. WCOBRA/TRAC Thermal-Hydraulic History File Dimension used inHSDRIVER 0
31. Burst Elevation Selection 0
32. Elevation forHeat Slab Temperature Initialization 0
33. Heat Transfer Logic for RodBurst Calculation 0
34. WCOBRA/TRAC Ul9File Dimension Error Correction 0
35. Heat TransferModel ErrorCorrections 0
36. Correction toHeat Transfer NodeInitialization 0
37. MassConservationError Fix 0
38. Correction toSplit Channel Momentum Equation 0
39. Changes toVessel Superheated Steam Properties 0
40. Update toMetal Density Reference Temperatures 0
41. Decay Heat Model Error Correction 0
42. Correction tothe PipeExit Pressure Drop Error 0
43. Vessel Section 7Mid-Level Elevation Modeling 0 44 Grid Heat Transfer Enhancement Calculation 0
45. Revised Heat Transfer Multiplier Distributions 5
46. Changes toGrid Blockage Ratio andPorosity 24
47. Error inBurst Application Strain 20
48. CodeUncertainty inBELBLOCAMonte Carlo Simulations 0
49. Error inOxidation Calculations 0 50 Support Column Unheated Conductor Error 0
51. Vessel Average Temperature Uncertainty 0
52. Numerical Ramp Entrained Liquid/Vapor Interfacial Drag 0
53. Inappropriate ResettingofTransverse Liquid MassFlow 0
54. Vapor Temperature Resetting 0
55. Removal ofthe Vessel Interfacial Heat Transfer Limit 0 B. PlannedPlant Modification Evaluations
1. None 0 C. 2020ECCSModel Assessments
l. Increased Vessel Average Temperature Uncertainty 0 D. Other
1. None 0 LICENSINGBASISPCT+ PCTASSESSMENTS PCT= 1814

Number Serial 21-183 DocketNos.50-395 Attachment 5

Page8of11 Plant Name: V.C.Summer Utility Name: Dominion Energy South Carolina An.alyjs.Informa.tion EM: CQD (1996) Limiting Break DEGB Size:

Analysis Date: February 2003 Vendor: Westinghouse FQ: 2.5 FdH: 1.7 Notes: None h

LICENSING BASIS Analysis ofRecord PCT 1988 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments

1. FanCooler Performance Increase 2
2. Improved Automation ofEndofBlowdown Time 0
3. Implementation ofASTRUM inHOTSPOT Capability 0 4 Revised Blowdown Heatup Uncertainty Distribution 5
5. Revised IterationAlgorithm forCalculating TheAverage Fuel Temperature 0
6. Improved Automation ofEndofBlowdown Time 0
7. Thermodynamic PropertiesfromThermo 0
8. Fluid Pressurizer Volumes 0
9. VesselUnheated Conductor Noding 0
10. Containment Relative Humidity Assumption 0 11 HOTSPOT Fuel Relocation 0
12. Steam Generator Nozzle Volume Accounting Error 0
13. Cold LegVolume Discrepancy 0
14. ErrorsinReactor Vessel NozzleDataCollection 0
15. HOTSPOT Burst TemperatureLogicErrors 0
16. V.C.Summer Upflow Conversion -29
17. zero Cross-Flow Boundary Condition Error 0
18. Discrepancy inMetal MassesUsedFrom Drawings 0
19. HOTSPOT GapHeat Logic Transfer 0
20. HOTSPOT StatisticalOutputLogic 0
21. TreatmentofVessel Average TemperatureUncertainty 0
22. AdditionalHeat Sinks andMaximum Spray Flow 1
23. Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Burndown 123
24. PAD4.0 Implementation -118
25. zero Cross-Flow Boundary Condition Error 0
26. HOTSPOT Burst Temperature Calculation ForzIRLOCladding 0
27. HOTSPOT Iteration AlgorithmforCalculating TheInitial Fuel PelletAverageTemperature 0

SerialNumber21-183 DocketNos.50-395 Attachment5 Page9 of11

28. WCOBRA/TRAC Automated Restart Process Logic Error 0
29. RodInternal PressureCalculation 0
30. WCOBRA/TRAC Thermal-Hydraulic History File Dimension used inHSDRIVER 0 31 Burst Elevation Selection 0
32. Elevation forHeat Slab Temperature Initialization 0
33. Heat Transfer Logic for RodBurst Calculation 0
34. WCOBRA/TRAC U19File Dimension Error Correction 0
35. Heat TransferModel ErrorCorrections 0
36. Correction toHeat Transfer NodeInitialization 0
37. MassConservationError Fix 0
38. Correction toSplitChannel Momentum Equation 0
39. Changes toVessel Superheated Steam Properties 0
40. Update toMetal Density Reference Temperatures 0
41. Decay Heat Model Error Corrections 0
42. Correction tothePipe Exit Pressure Drop Error 0
43. Vessel Section 7Mid-Level Elevation Modeling 0
44. Grid Heat TransferEnhancement Calculation 0
45. Revised Heat Transfer Multiplier Distributions -35
46. Changes toGrid Blockage Ratio andPorosity 24
47. Error inBurst StrainApplication . 0
48. Code Uncertainty inBELBLOCAMonte Carlo Simulations 0
49. Error inOxidation Calculations 0
50. Support Column Unheated Conductor Error 0
51. Vessel Average Temperature Uncertainty 0
52. Numerical RampEntrained Liquid/Vapor Interfacial Drag 0
53. Inappropriate Resetting ofTransverse Liquid MassFlow 0
54. Vapor Temperature Resetting 0
55. Removal ofthe Vessel Interfacial Heat Transfer Limit 0 B. PlannedPlant Modification Evaluations
1. None 0 C. 2020ECCSModel Assessments
1. Increased Vessel Average Temperature Uncertainty 0 D. Other
1. None 0 LICENSINGBASISPCT+ PCTASSESSMENTS PCT= 1961

Serial Number21-183 DocketNos.50-395 Attachment 5

Page10of11 Plant Name: V.C.Summer Utility Name: Dominion Energy SouthCarolina AnalysiIn[orm.ation EM: CQD (1996) Limiting Break Size:DEGB Analysis Date: February 2003 Vendor: Westinghouse FQ: 2.5 FdH: 1.7 Notes: None CjadTempfU LICENSING BASIS Analysis ofRecord PCT 1988 PCTASSESSMENTS (Delta PCT)

A. Prior ECCSModel Assessments 1 FanCooler Performance Increase 2

2. ImprovedAutomation ofEndofBlowdown Time 0
3. Implementation ofASTRUMCapability inHOTSPOT 0 4 Revised Blowdown Heatup Uncertainty Distribution 5
5. Revised IterationAlgorithm forCalculating TheAverage Fuel Temperature 0
6. Improved Automation ofEndofBlowdown Time 0
7. Thermodynamic Propertiesfrom Thermo 0
8. Pressurizer Fluid Volumes 0
9. VesselUnheated Conductor Noding 0
10. Containment Relative Humidity Assumption 0
11. HOTSPOT Fuel Relocation 0
12. Steam Generator Nozzle Volume Accounting Error 0
13. Cold LegVolume Discrepancy 0
14. ErrorsinReactor Vessel Nozzle Collection Data 0
15. HOTSPOT Burst Temperature Errors Logic 0
16. V.C.Summer Upflow Conversion -29
17. zero Cross-Flow Boundary Condition Error 0
18. Discrepancy inMetal Masses UsedFromDrawings 0
19. HOTSPOT GapHeat Logic Transfer 0
20. HOTSPOT StatisticalOutputLogic 0
21. TreatmentofVessel AverageTemperatureUncertainty 0
22. AdditionalHeat Sinks andMaximum Spray Flow 1
23. Fuel Pellet Thermal ConductivityDegradation and Peaking Factor Burndown 123
24. PAD4.0 Implementation -118
25. zero Cross-Flow Boundary Condition Error 0
26. HOTSPOT Burst Temperature Calculation ForzIRLOCladding 0
27. HOTSPOT Iteration AlgorithmforCalculating TheInitial Fuel Pellet Average Temperature 0

SerialNumber21-183 DocketNos.50-395 Attachment 5

Page11of11

28. WCOBRA/TRAC Automated Restart Process Logic Error 0
29. RodInternal PressureCalculation 0
30. WCOBRA/TRAC Thermal-Hydraulic History File Dimension used inHSDRIVER 0 31 Burst Elevation Selection 0
32. Elevation forHeat Slab Temperature Initialization 0
33. Heat Transfer Logic for RodBurst Calculation 0
34. WCOBRA/TRAC Ul9File Dimension Error Correction 0
35. Heat TransferModel ErrorCorrections 0
36. Correction toHeat Transfer NodeInitialization 0
37. MassConservationError Fix 0
38. Correction toSplit Channel Momentum Equation 0
39. Changes toVessel Superheated Steam Properties 0
40. Update toMetal Density Reference Temperatures 0
41. Decay Heat Model Error Correction 0 41 Correction tothe PipeExit Pressure Drop Error 0
42. Vessel Section 7Mid-Level Elevation Modeling 0
43. Grid Heat Transfer Enhancement Calculation 0
44. Revised Heat TransferMultiplier Distributions -35
45. Changes toGrid Blockage Ratio andPorosity 24
46. Error inBurst StrainApplication 0
47. Code Uncertainty inBELBLOCAMonte Carlo Simulations 0
48. Error inOxidation Calculations 0
49. Support Column Unheated Conductor Error 0
50. Vessel Average Temperature Uncertainty 0
51. Numerical RampEntrained Liquid/Vapor Drag 0 Interfacial
52. Inappropriate ResettingofTransverse Liquid MassFlow 0
53. Vapor Temperature Resetting 0
54. Removal ofthe Vessel Interfacial Heat Transfer Limit 0 B. PlannedPlant Modification Evaluations 1 None 0 C. 2020ECCSModel Assessments 1 Increased Vessel Average Temperature Uncertainty 0 D. Other
1. None 0 LICENSINGBASIS PCT+ PCTASSESSMENTS PCT= 1961

.

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