Text

Connecticut, Inc - 2021 Annual Report of Emergency Core Cooling System (ECCS) Model Changes Pursuant to the Requirement of 10 CFR 50.46
	ML22179A310
Person / Time
Site:	Millstone, Summer, Surry, North Anna
Issue date:	06/22/2022
From:	Adams W; Dominion Energy Nuclear Connecticut, Dominion Energy Services, Dominion Energy South Carolina, Virginia Electric & Power Co (VEPCO)
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	Serial No.22-165
	Download: ML22179A310 (48)
	v • d • e

Dominion Energy Services, Inc.

5000 Dominion Boulevard, Glen Allen, VA 23060 DominionEnergy.com Attn: Document Control Desk June 22, 2022 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 DOMINION ENERGY NUCLEAR CONNECTICUT, INC VIRGINIA ELECTRIC AND POWER COMPANY DOMINION ENERGY SOUTH CAROLINA, INC MILLSTONE POWER STATION UNITS 2 AND 3 NORTH ANNA POWER STATION UNITS 1 AND 2 SURRY POWER STATION UNITS 1 AND 2 VIRGIL C. SUMMER NUCLEAR STATION UNIT 1

Dominion

iii" Energy Serial No.

22-165 NRANG:

RO Docket No.:50-336/423 50-338/339 50-280-281 50-395 License No.:

DPR-65/NPF-49 NPF-4/7 DPR-32/37 NPF-12 2021 ANNUAL REPORT OF EMERGENCY CORE COOLING SYSTEM (ECCS}

MODEL CHANGES PURSUANT TO THE REQUIREMENT OF 10 CFR 50.46 Pursuant to the provisions of 10 CFR 50.46(a)(3)(ii), Dominion Energy Nuclear Connecticut, Inc. (DENG), Virginia Electric and Power Company (Dominion Energy Virginia), and Dominion Energy South Carolina, Inc. (DESC) hereby submit the annual summary of permanent changes to the emergency core cooling system (ECCS) evaluation models (EMs) for Millstone Power Station (MPS) Units 2 and 3, North Anna Power Station (NAPS) Units 1 and 2, Surry Power Station (SPS) Units 1 and 2, and Virgil C. Summer Nuclear Station (VCSNS) Unit 1, respectively. of this letter provides a report describing plant-specific evaluation model changes associated with the Westinghouse and Framatome Small Break Loss of Coolant Accident (SBLOCA) and Large Break Loss of Coolant Accident (LBLOCA) ECCS EMs for MPS 2 and 3, NAPS 1 and 2, SPS 1 and 2, and VCSNS 1 as applicable.

Information regarding the effect of the ECCS EM changes upon the reported SBLOCA and LBLOCA analysis of record results is provided for MPS 2 and 3, NAPS 1 and 2, SPS 1 and 2, and VCSNS 1 in Attachment 2, 3, 4 and 5, respectively. The calculated peak cladding temperature (PCT) for the SBLOCA and LBLOCA analysis for MPS 2 and 3, NAPS 1 and 2, SPS 1 and 2, and VCSNS 1 are summarized below:

Millstone Unit 2 Millstone Unit 2 Millstone Unit 2 Millstone Unit 3 Small break-Framatome EM:

Large break-Framatome EM (Zr4 fuel):

Large break - Framatome EM (MS fuel):

Small break - Westinghouse EM:

1714°F 1845°F 1615°F 1193°F

Serial No.22-165 Docket No. 50-336/423/338/339/280/281 /395 Page 2 of 4 Millstone Unit 3 North Anna Units 1 and 2 North Anna Units 1 and 2 North Anna Units 1 and 2 Surry Units 1 and 2 Surry Units 1 and 2 Surry Units 1 and 2 Virgil C. Summer Unit 1 Virgil C. Summer Unit 1 Virgil C. Summer Unit 1 Virgil C. Summer Unit 1 Large break - Westinghouse EM:

Small break - Westinghouse EM:

FVI Small break - Framatome EM:

Large break - Westinghouse EM:

Small break - Westinghouse EM:

FVI Small break - Framatome EM:

Large break - Westinghouse EM:

Small break - Westinghouse EM:

Westinghouse Full Spectrum LOCA EM Region I Small break:

Large break - Westinghouse EM:

Slowdown:

Reflood 1:

Reflood 2:

Composite:

Westinghouse FSLOCA EM Region II large break:

1933°F 1834.1°F 1801°F 1982°F 2012°F 1673°F 2071°F 1923°F 1108°F 1814°F 1814°F 1961°F 1961°F The LOCA results for MPS 2 and 3, NAPS 1 and 2, SPS 1 and 2, and VCSNS 1 are confirmed to have sufficient margin to the 2200°F limit for PCT specified in 10 CFR 50.46.

Based on the evaluation of this information and the resulting changes in the applicable licensing basis PCT results, no further action is required to demonstrate compliance with the 10 CFR 50.46 requirements.

The information contained herein satisfies the 2021 annual reporting requirements of 10 CFR 50.46(a)(3)(ii).

Should you have any questions regarding this submittal, please contact Yan Gao at (804) 273-2768.

R~ sp, ctfully, a 1VV{Jf--i1 J--

Wayne M. Adams Director - Nuclear Engineering and Fuel Dominion Energy Nuclear Connecticut, Inc.

Virginia Electric and Power Company Dominion Energy South Carolina, Inc.

Commitments made in this letter: None.

Attachments:

Serial No.22-165 Docket No. 50-336/423/338/339/280/281 /395 Page 3 of 4

1. Report of Changes in Framatome and Westinghouse ECCS Evaluation Models

2. 2021 Annual Reporting of 10 CFR 50.46 Margin Utilization - Millstone Power Station Units 2 and 3

3. 2021 Annual Reporting of 10 CFR 50.46 Margin Utilization -

North Anna Power Station Units 1 and 2

4. 2021 Annual Reporting of 10 CFR 50.46 Margin Utilization - Surry Power Station Units 1 and 2

5. 2021 Annual Reporting of 10 CFR 50.46 Margin Utilization - Virgil C. Summer Nuclear Station Unit 1 cc:

U.S. Nuclear Regulatory Commission, Region I Regional Administrator 475 Allendale Road, Suite 102 King of Prussia, PA 19406-1415 U.S. Nuclear Regulatory Commission, Region II Regional Administrator Marquis One Tower 245 Peachtree Center Avenue, NE Suite 1200 Atlanta, Georgia 30303-1257 Mr. G. Edward Miller NRG Senior Project Manager - North Anna Power Station and Virgil C. Summer Nuclear Station U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 09 E-3 11555 Rockville Pike Rockville, Maryland 20852-2738 Mr. R. Guzman NRG Project Manager - Millstone Power Station U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 C2 11555 Rockville Pike Rockville, MD 20852-2738

Mr. L. John Klos Serial No.22-165 Docket No. 50-336/423/338/339/280/281 /395 Page 4 of 4 NRC Project Manager - Surry Power Station U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 09 E-3 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector V.C. Summer Nuclear Station NRC Senior Resident Inspector Millstone Power Station NRC Senior Resident Inspector North Anna Power Station NRC Senior Resident Inspector Surry Power Station Old Dominion Electric Cooperative Electronically Distributed

Serial No.22-165 Docket No. 50-336/423/338/339/280/281 /395 2021 Annual 10 CFR 50.46 Report REPORT OF CHANGES IN FRAMATOME AND WESTINGHOUSE ECCS EVALUATION MODELS Millstone Power Station Units 2 and 3 North Anna Power Station Units 1 and 2 Surry Power Station Units 1 and 2 Virgil C. Summer Nuclear Station Unit 1 Dominion Energy Nuclear Connecticut, Inc.

Virginia Electric and Power Company Dominion Energy South Carolina, Inc.

Serial No.22-165 Docket No. 50-336/423/338/339/280/281 /395 2021 Annual 10 CFR 50.46 Report : Page 1 of 5 REPORT OF CHANGES IN FRAMATOME AND WESTINGHOUSE ECCS EVALUATION MODELS MILLSTONE POWER STATION UNIT 2

1. Framatome identified no changes or errors applicable to the EMF-2328(P)(A)

Revision 0, with Supplement 1 evaluation model for Small Break LOCA (SBLOCA) for Millstone Unit 2 during 2021.

2. Framatome identified no changes or errors applicable to the SEM/PWR-98 evaluation model for Large Break LOCA (LBLOCA) for Millstone Unit 2 during 2021.

This evaluation model is applicable to the Millstone Unit 2 fuel with Zr-4 cladding.

3. On January 24, 2017, a new LBLOCA analysis was approved by the NRC based upon the EMF-2103(P)(A), Revision 3, "Realistic Large Break LOCA (RLBLOCA)

Methodology for Pressurized Water Reactors." The new analysis is applicable to the AREVA Standard CE14 HTP fuel product with the MS' fuel rod cladding only.

The analysis predicted a PCT of 1615°F.

Framatome identified no changes or errors applicable to the EMF-2103(P)(A),

Revision 3, evaluation model for RLBLOCA for Millstone Unit 2 during 2021.

MILLSTONE POWER STATION UNIT 3

1. Westinghouse identified the following changes applicable to the 1985 Westinghouse SBLOCA Evaluation Model with NOTRUMP for Millstone Unit 3 during 2021:

Reduction in Flow Area to the Bottom of the Barrel/Baffle Region For plants without holes in the edge of the lower core plate, the flow area from the bottom of the core to the barrel/baffle region has historically been modeled as the gap between the baffle plate and the lower core plate, and this flow area did not consider the reduced flow area due to the presence of the bottom nozzle flow skirt.

The impact of reducing the flow area between the core and barrel baffle region due to including the bottom nozzle flow skirt has been qualitatively evaluated. The evaluation determined that considering a reduced flow area from the bottom of the core to the barrel/baffle region when considering the bottom nozzle flow skirt has a negligible effect on the SBLOCA analysis results, leading to an estimated peak cladding temperature (PCT) impact of 0°F.

Measurement Uncertainty Recapture (MUR) Uprate The Analysis of Record was examined for the impact of a planned MUR which will be implemented in Cycle 22. It was determined that the MUR would have a 0° impact on the SBLOCA PCT.

Serial No.22-165 Docket No. 50-336/423/338/280/281/395 2021 Annual 10 CFR 50.46 Report : Page 2 of 5

2. Westinghouse identified the following change applicable to the 2004 Westinghouse Best Estimate (BE) LBLOCA Evaluation Model (EM) using the Automated Statistical Treatment of Uncertainty Method (ASTRUM) for Millstone Unit 3 during 2021:

Measurement Uncertainty Recapture (MUR) Uprate The Analysis of Record was examined for the impact of a planned MUR which will be implemented in Cycle 22. As discussed in the MUR LAR, a reduction in peaking factors fully offsets the impact of the MUR power increase on the MPS3 ASTRUM BE LBLOCA AOR. Therefore, the MUR would have a 0°F impact on the BE LBLOCAPCT.

NORTH AN NA POWER STATION UNITS 1 AND 2

1. Westinghouse identified the following change applicable to the 1985 Westinghouse SBLOCA Evaluation Model with NOTRUMP for North Anna Units 1 and 2 during 2021:

Reduction in Flow Area to the Bottom of the Barrel/Baffle Region For plants without holes in the edge of the lower core plate, the flow area from the bottom of the core to the barrel/baffle region has historically been modeled as the gap between the baffle plate and the lower core plate, and this flow area did not consider the reduced flow area due to the presence of the bottom nozzle flow skirt.

The impact of reducing the flow area between the core and barrel baffle region due to including the bottom nozzle flow skirt has been qualitatively evaluated. The evaluation determined that considering a reduced flow area from the bottom of the core to the barrel/baffle region when considering the bottom nozzle flow skirt has a negligible effect on the SBLOCA analysis results, leading to an estimated peak cladding temperature (PCT) impact of 0°F.

2. On March 19, 2021, a new Fuel Vendor Independent (FVI) SBLOCA analysis was approved by the NRG based upon the Framatome Topical Report EMF-2328(P)(A), Revision 0, PWR [pressurized water reactor] Small Break LOCA [loss-of-coolant accident] Evaluation Model, S-RELAP5 Based. The analysis predicted a PCT of 1801 °F. This analysis became the Analysis of Record during 2021.

Framatome identified no changes or errors applicable to the EMF-2328(P)(A),

Revision 0, PWR Small Break LOCA EM using S-RELAP5 for North Anna Units 1 and 2 during 2021.

3. Westinghouse identified no changes or errors applicable to the 2004 Westinghouse BE LBLOCA EM using ASTRUM for North Anna Units 1 and 2 during 2021.

SURRY POWER STATION UNITS 1 AND 2 Serial No.22-165 Docket No. 50-336/423/338/280/281/395 2021 Annual 10 CFR 50.46 Report : Page 3 of 5

1. Westinghouse identified the following change applicable to the 1985 Westinghouse SBLOCA Evaluation Model with NOTRUMP for Surry Units 1 and 2 during 2021:

Reduction in Flow Area to the Bottom of the Barrel/Baffle Region For plants without holes in the edge of the lower core plate, the flow area from the bottom of the core to the barrel/baffle region has historically been modeled as the gap between the baffle plate and the lower core plate, and this flow area did not consider the reduced flow area due to the presence of the bottom nozzle flow skirt.

The impact of reducing the flow area between the core and barrel baffle region due to including the bottom nozzle flow skirt has been qualitatively evaluated. The evaluation determined that considering a reduced flow area from the bottom of the core to the barrel/baffle region when considering the bottom nozzle flow skirt has a negligible effect on the SBLOCA analysis results, leading to an estimated peak cladding temperature (PCT} impact of 0°F.

2. On March 19, 2021, a new Fuel Vendor Independent (FVI} SBLOCA analysis was approved by the NRC based upon the Framatome Topical Report EMF-2328(P}(A}, Revision 0, PWR [pressurized water reactor] Small Break LOCA [loss-of-coolant accident] Evaluation Model, S-RELAP5 Based. The analysis predicted a PCT of 1673°F. This analysis became the Analysis of Record during 2021.

Framatome identified the following error applicable to the EMF-2328(P}(A},

Revision 0, PWR Small Break LOCA EM using S-RELAPS for Surry Units 1 and 2 during 2021:

SBLOCA Rod History Truncation (FVI-SBLOCA downflow baffle)

Framatome topical EMF-2328(P}(A}, for W&CE SBLOCA methods, specifies that the end of first cycle rod conditions are to be used. This is done by running RODEX2-2A with the identified power history and then truncating it to a point which exceeds the targeted end of-cycle (EOG} rod average burnup. The SBLOCA analysis guidelines were not explicitly followed in preparing the RODEX2-2A initialization for the Surry FVI-SBLOCA analysis of record (downflow baffle}. The result was that the RODEX2-2A initialization was truncated prior to reaching the desired target rod average burnup.

Properties such as pin pressure and gap conductance would differ depending on the truncation. However, the difference is <3000 MWd/MTU and the SBLOCA event itself has a strong impact on the evolution of the properties and significance of the difference. The differences in fuel rod properties between the RODEX initialization time-in-cycle point used in the analysis and that prescribed by the guidance is negligible in consideration of the SBLOCA event. The b.PCT for the Surry Units 1 and 2 FVI-SBLOCA analysis (downflow baffle} is 0°F.

Serial No.22-165 Docket No. 50-336/423/338/280/281/395 2021 Annual 10 CFR 50.46 Report : Page 4 of 5

3. Westinghouse identified no changes or errors applicable to the 2004 Westinghouse BE LBLOCA EM using ASTRUM for Surry Units 1 and 2 during 2021.

VIRGIL C. SUMMER NUCLEAR STATION UNIT 1

1. Westinghouse identified the following change applicable to the 1985 Westinghouse SBLOCA Evaluation Model with NOTRUMP for Virgil C. Summer during 2021:

Reduction in Flow Area to the Bottom of the Barrel/Baffle Region For plants without holes in the edge of the lower core plate, the flow area from the bottom of the core to the barrel/baffle region has historically been modeled as the gap between the baffle plate and the lower core plate, and this flow area did not consider the reduced flow area due to the presence of the bottom nozzle flow skirt.

The impact of reducing the flow area between the core and barrel baffle region due to including the bottom nozzle flow skirt has been qualitatively evaluated. The evaluation determined that considering a reduced flow area from the bottom of the core to the barrel/baffle region when considering the bottom nozzle flow skirt has a negligible effect on the SBLOCA analysis results, leading to an estimated peak cladding temperature (PCT) impact of 0°F.

2. On June 20, 2021, a new analysis was approved by the NRC based upon the Westinghouse Topical Report WCAP-16996-P-A, Revision 1, "Realistic LOCA Evaluation Methodology Applied to the Full Spectrum of Break Sizes (FSLOCA)."

The new SBLOCA AOR analysis is defined as the Region I spectrum. The analysis predicted a PCT of 1108°F which includes a 12°F correction to account for gamma energy redistribution. This analysis became the Analysis of Record during 2021.

Westinghouse identified no changes or errors applicable to the WCAP-16996-P-A Region I EM for VCSNS during 2021.

3. Westinghouse identified no changes or errors applicable to the 1996 Westinghouse Best Estimate Large Break LOCA Evaluation Model for Virgil C.

Summer during 2021.

4. On June 20, 2021, a new analysis was approved by the NRC based upon the Westinghouse Topical Report WCAP-16996-P-A, Revision 1, "Realistic LOCA Evaluation Methodology Applied to the Full Spectrum of Break Sizes (FSLOCA)."

The new LBLOCA AOR analysis is defined as the Region II spectrum.

The analysis predicted a PCT of 1879°F which includes a 31°F correction to account for gamma energy redistribution. This analysis became the Analysis of Record during 2021.

Westinghouse identified no changes or errors applicable to the WCAP-16996-P-A Region II EM for VCSNS during 2021.

CONCLUSION Serial No.22-165 Docket No. 50-336/423/338/280/281/395 2021 Annual 10 CFR 50.46 Report : Page 5 of 5 The LOCA results for Millstone Units 2 and 3, North Anna Units 1 and 2, Surry Units 1 and 2 and Virgil C. Summer Unit 1 are confirmed in the PCT rackup tables, Attachments 2 through 5, to have margin to the 2200°F limit for PCT specified in 10 CFR 50.46. Based on the evaluation of this information and the resulting changes in the applicable licensing basis PCT results, no further action is required to demonstrate compliance with the 10 CFR 50.46 requirements.

Reporting of this information is required per 10 CFR 50.46(a)(3)(ii), which obligates each licensee to report the effect upon calculated temperature of any change or error in evaluation models or their application on an annual basis.

This information satisfies the annual reporting requirements of 10 CFR 50.46(a)(3)(ii) for calendar year 2021.

Serial No.22-165 Docket No. 50-336/423 2021 ANNUAL REPORTING OF 10 CFR 50.46 MARGIN UTILIZATION - MILLSTONE POWER STATION UNITS 2 AND 3 Dominion Energy Nuclear Connecticut, Inc.

Millstone Power Station Units 2 and 3

10 CFR 50.46 MARGIN UTILIZATION - SMALL BREAK LOCA Plant Name:

Millstone Power Station. Unit 2 Utility Name:

Dominion Energy Nuclear Connecticut, Inc.

Analysis Information Serial No.22-165 Docket No. 50-336/423 : Page 1 of 6 EM:

2015, Supp. 1, SBLOCA, S-RELAP5 Based Limiting Break Size: 3. 78 Inches Analysis Date:

April 2015 Vendor:

AREVA Peak Linear Power:

15.1 kW/ft Notes:

None Clad TempC°f)

LICENSING BASIS Analysis of Rec.ord PCT 1707 PCT ASSESSl\\fENTS (Delta PCI)

A.

Prior ECCS l\\lodel Assessments

1.

Zirc-4 Product Penalty 4

2.

M5 LOCA Swelling and Rupture 0

3.

S-RELAP5 Oxidation Calculations 3

B.

Planned Plant l\\lodification En luations

l.

None 0

C.

2021 ECCS Model Assessments

1.

None 0

D.

other

l.

None 0

LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=

1714

Serial No.22-165 Docket No. 50-336/423 : Page 2 of 6 10 CFR 50.46 A-URGIN UTILIZATION - LARGE BREAK LOCA Plant Nam.e:

Millstone Power Station, Unit 2 Utility Name:

Dominion Energy Nuclear Connecticut, Inc.

An1lvsis Information EM:

SEMIPWR.-98 Limiting Break Size: 1.0 DECLO A.ulysis Date:

November 1998 AREVA Vendor:

Peak Linear Power:

15.1 k\\V/ft None Notes:

Clad Temp(°I)

LICENSING BASIS Analysis ofRecord PCT 1814 PCT ASSESSMENTS (Delta PCT)

A.

Prior ECCS Model Assessments B.

C.

D.

1.

Corrected Corrosion Euhancement Factor

-1

2.

ICECON Coding Etrors 0

3.

Setting RFPAC Fuel Temperatnres at Start ofReflood

-2

4.

SISPUNCH/uj11n98 Code Error 0

5.

Eiror in Flow Blockage Model in TOODEE2 0

6.

ChangeinTOODEE2-Cuc:ulationofQ~IAX 0

7.

Change in Gadolinia Modeling 0

8.

P\\l.lR. LBLOCA Split Break Modeling 0

9.

TEOBY Calculation Eiror 0

10.

Inappropriate Heat Transfer in TOODEEl 0

11.

End-of-Bypass Prediction by TEOBY 0

12.

R4SS OvemTite of Junction Inertia 0

13.

Incorrect Junction Inertia Multipliers 1

14.

EmnsDiscoveredDuringRODEX2V&V 0

15.

Eiror in Broken Loop SG Tube ExitJunction Inertia 0

16.

RFP AC Refill and Reflood Calculation Code Emns 16

17.

Incorrect Pump Junction Area Used inRELAP4 0

18.

Eiror in TOODEE.2 Clad Themial Expansion

-1

19.

Accumulator Line Loss Enor

-1

20.

JncODSistent Loss Coefficients Used for Robinson LBLOCA 0

21.

Pump Head Adjustment for Pressure Balance Initialization

-3

22.

ICECON Code Errors 0

23.

Containment Sump Modification and Replacement PZR.

2

24.

Non-Comervative RODEX Fuel Pellet Temperature 20

25.

Array Index Issues in the RELAP4 Code 0

PW111ed Plant Modification Evaluations

1.

None 1021 ECCS Model Assessments

1. None Other

1.

None 0

0 0

LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=

1845

Serial No.22-165 Docket No. 50-336/423 : Page 3 of 6 10 CFR 50.46 MARGIN UTILIZATION -LARGE BRE..\\K LOCA Plant Name:

Utility Name:

Millstone Power Station, Unit 2 ~15 Fuel)

Dominion Energy Nuclear Connecticut, Inc.

Analysis Information EM:

El\\lIF-2103 Jamwy2017 AREVA Limiting Break Size:

Analysis Daie:

Vendor.

Peak Lin.ear Power:

Notes:

LICENSING BASIS 15.1 kW/ft None Analysis of Record PCT PCT ASSESSMENTS (Delta PCT)

A.

Prior ECCS Model Assessments

1.

Placement ofHot Leg Piping Form Loss Coefficient B.

C.

D.

2.

lv!5 LOCA Swelling and Rupture

3.

S-RELAP5 Oxidation Calculations

4.

~m-Pawel correlation implementation

5.

Rod pressure not reset after rupture in S-RELAP5 LOCA calculations

6.

Radiation enclosure input error Pwmed Plant Modification Evaluations

1.

None 2021 ECCS Model Assessments

1.

None Other

1.

None LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=

1615 1.0DEGB Clad TempC'F) 1615 0

0 0

10 CFR 50.46 MARGIN UTil.IZATION - SMALL BREAK LOCA Pbnt Name:

Millstone Power Station, Unit 3 Utility Name:

Dominion Energy Nuclear Connecticut, Inc.

AJtatysis Information EM:

NOTR.UMP 02/07/07 Westinghouse 2.6 Limiting Break Size:

Analysis Date:

Vendor:

FQ:

EdJl:

Fuel:

RFA-2 SGTP (%):

Notes:

None LICENSING BASIS Analysu of Record PCT PCT ASSESSMEi."IITS (Delta PCT)

A.

Prior ECCS Model Assessments

1.

fuOf'S in Reactor Vessel Lower Plenum Surface Area Calculations

2.

Discrepancy in Metal hsses Used From Dra~ings 1.65 10

3.

Urania-Gadolinia Pellet Thermal Conductivity Calculation B.

C.

D.

4.

Pellet Crack and Dish Volume Calculation

5.

Treatment ofVessel Average Temperature Uncertainty

6.

Maximum Fuel Rod Time Step Logic

7.

Radiation Heat Trarufer Logic

8.

NOTRUMP-filvI Evaluation of Fuel Pellet Thermal Conducti\\-ity Degradation

9.

SBLOCTA Cladding Strain Requirement for Fuel RodBurst

10.

Fuel Rod Gap Conductance Error

11.

Radiation Heat Transfer Model Error

12.

SBLOCTA Pre-DNB Cladding Heat Transfer Coefficient Calculation

13.

Insertion ofAXIO:MJM Cladding LT.As

14.

Vessel Average Temperature Uncertainty

15.

Error in the Upper Plenum Fluid Volume Calculation

16.

U01 Fuel Pellet Heat Capacity

17.

Small Break LOCA P AD5 Implementation Planned Plant Modification Evaluations

1.

Measurement Uncertainty Recapture Uprate 2021 ECCS Model Assessments

1.

Reduction in Flow Area to the Bottom of the Barrel'Baffle Region Other

1.

None LICENSING BASIS PCT+ PCT ASSESS~IENTS PCT=

Serial No.22-165 Docket No. 50-336/423 : Page 4 of 6 4 inches Clad Temp ("F) 1193 0

0 0

0 1193

10 CTR 50.46 MARGIN UTILIZATION - LARGE BREAKLOCA Plant Name:

Millstone P<mw Station, Unit 3 Utility Name:

Dominion Energy Nuclear Connecticut, Inc.

Analnis Inform~tion EM:

ASTRUM (1004)

Limiting Break Siu:

Guillotine Analysis Date:

04/17{07 Vt: dor:

Westinghoure FQ:

2-6 EdB;:

1.65 Fuel:

RFA-2 SGTP(%):

10 NMM:

None Serial No.22-165 Docket No. 50-336/423 : Page 5 of 6 LICENSING BASIS Analysis of Record PCT Clad Temp ('f) 1781 PCT ASSESSA-fEJll"TS (Delta PCI)

A.

Prior ECCS Model Assemntnts

1.

HOTSPOT Burst Temperature Logic ~

0

2.

CCFL Global VolumeEnor 0

3.

HOTSPOTGapHeat TransferLogic 0

4.

Discrepancy in Metal Masses Used Emm Draniings 0

5.

Error in ASlRUM Processing of Average Rod Bunmp and Rod lntemal Pressure 0

6.

TrealmffltofVesselAverage Temperature Uncertainl}'

0

7.

PBOT and PMID Evaluation 0

8.

Evaluation of Fuel Pellet 1hamal Coaductn,ity 222 Degradation

9.

HOTSPOT Burst Temperature Calculation 0

for ZIRLO Cladding

10.

Rod IJJtemal Pressure Calculation 0

1 L HOISPOT Iteration Algorithm for Calculating the 0

Initial Fuel Pellet Aver~ e Temperature

12.

\\VCOBRAITRAC Thmnal-Hydraulic History File 0

Dimemion used inHSDRIVER Baclcwound

13.

WCOBRAITRAC Automated Restart Process Logic Error 0

14.

Initial Fuel Pellet Aver~ e Temperatme Uncertainty 0

Calculation

15.

Ele\\ -ations fur Heat Slab T empernture Initializ.,tion 0

16.

Heat Transfer Model F.nor Corrections 0

17.

Conection to Heat Transfer Node Initialization 0

18.

Mass Conservation Euor Fix 0

19.

Correction to SplitChannelMomenlmnEquation 0

20.

Heat Transfer Logic Correction for Rod Bum Calculation 0

21.

Changes to Vessel Supelheated Steam Properties 0

22.

Update to Metal Density Reference Temperatures 0

23.

Decay Heat Model Error Corrections 0

24.

ConectiontothePipeExitPressme DropError 0

25.

WCOBR.A/I'RAC U19 File Dimension Error Correction 0

26.

Re,iired Heat Transfer Multiplier Distn'butions

-91

27.

HOTSPOT Burst Strain F.nor Correction 21

28.

Changes to Grid Blockage Ratio and Porosity 0

29.

Grid Heat Tram:fPr Enhancement Calculation 0

30.

Bum Elevation Selection 0

31.

Errors in Decay Group Uncertainty Facto1:1 0

32.

Errors in Support Plate, Core Barrel, and Vessel Wall 0

Unheated Conductor

33.

Error in Oxidation CalcuJatiom 0

34.

Error in use of ASME Steam Tables 0

35.

InsertionofAXIOMJMCladdin,!!; LTAs 0

36.

Vessel Average Temperatme Uncertamty 0

37.

Inconmtent Application of Numerical Ramp Applied 0

to the Entrained Liquid/ Vapor lntezfacial Drag Coefficient

38.

Inappropriate Resetting ofT~

Liquid Malls Flow 0

39.

Steady-StrteFuel Temperature Calibrationl\\,lethod 0

40.

Millstone Unit 3 Cycle 20 PBOTt'PlvllD Violations 0

41.

VaporTemperatmeR.esetting 0

42.

Core Bane! Heat Slab Error 0

43.

Cold Leg Volume Error 0

44.

Core Barrel Wetted Perimeta-Error 0

45.

Removal of the Vwiel Intetf.acial HeatTruisfer Limit 0

46.

Cycle 21 PBOT/PMID Emrelope Violations 0

B.

Planned Plant Modifica.tion Evaluation&

1.

Measurement Uncertaimy Recaptme Uprate 0

C.

2021 ECCS Model Assessments

1.

None 0

D.

Other

1.

None 0

LICENSING BASIS PCT + PCT ASSESS. IENTS PCT =

1933 Serial No.22-165 Docket No. 50-336/423 : Page 6 of 6 Serial No.22-165 Docket No. 50-338/339 2021 ANNUAL REPORTING OF 10 CFR 50.46 MARGIN UTILIZATION - NORTH ANNA POWER STATION UNITS 1 AND 2 Virginia Electric and Power Company North Anna Power Station Units 1 and 2

Serial No.22-165 Docket No. 50-338/339 : Page 1 of 8 10 CIR 50.46 MARGIN" UTILIZATION - WESTINGHOUSE SMALL BREAK LOCA Plant Name:

Utility Name:

North.AmaaPower Station, Unit 1 Virginia Electric and Power Company Analysis Information EM:

NOTRUMP 12120/2010 Weninghouse 2.32 Limiting Break Size:

Analysis Date:

Vendor:

FQ:

FAIi:

Fuel:

RFA-2 SGTP (%):

Notes:

None LICENSING BASIS Analysis of Record PCT PCT ASSESSME.i"1S (Delta PCT)

A.

Prior ECCS Model Assessments B.

C.

1.

NOTRUMP-EM Evaluation ofFuel Pellet Thennal

2.

3.

4.

5.

6.

7.

Conductivity Degradation SBLOCA Claddmg Strain Requirement for Fuel RodBurst Fuel Rod Gap Conductance Error Radiation He-at Transfer 1'.fudel Error SBLOCTA Pre-DNB Cladding H eat Transfer Coefficient Calculation Error in the Upper Plenum Fluid Volume Calculation UO.1 Fuel Pellet Heat Capacity Planned Plant Modification Evalu tions

1.

None 2021 ECCS Model Assessments 1.65 7

1.

Reduction in Flow Area to the Bottom of the BarreJ/Baffle Region D.

Other

1.

None 2.75 inche-S Clad Temp (°F) 1834.1 0

0 0

0 LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=

1834.l

Serial No.22-165 Docket No. 50-338/339 : Page 2 of 8 10 CFR 50.46 M ARGIN UTILIZATIO.i: - FRAMATOME F\\'I SA.L.\\LL BREAK LOCA Plant Name:

Utility Name:

Alulvsis Information North Anna Power Station, Unit 1 Virginia Electric and Power Company EM:

W&CE SBLOCA EMF-2328 Limiting Break Size: 6.5 inches Analysis Date:

May 2018 Vendor:

Framatome FQ:

2.5 Fuel:

Representative 17xl7Non-M5 Notes:

None LICENSING BASIS Analysis of Record PCT PCT ASSESSl\\fE...'l"ITS (Delta PCT)

A.

Prior ECCS Model Assessments

1.

None B.

Planned Plant :Modification Evaluations

1.

None C.

2021 ECCS Model Assessments

1.

None D.

Other

1.

None LICENSING BASIS PCT+ PCT.ASSESSMENTS FAD:

1.65 SGTP(%):

7 PCT=

Clad Temp CF) 1801 0

0 0

0 1801

Serial No.22-165 Docket No. 50-338/339 : Page 3 of 8 10 CFR 50.46 lL.\\RGIN UTILIZATION - WESTINGHOUSE LARGE BREAK LOCA Plant_ 'ame:

Utility Name:

An.alvsis Information North Anna Power Station, Unit 1 Virginia Electric and Power Company EM:

ASTRUM (2004)

Limiting Break Size:

DEGB Analysis Date:

8/25/2010 Vendor:

Westinghouse FQ:

2.32 FAIi:

1.65 Fuel:

RFA-2 SGTP (%):

7 Notes: C.ore Power !!: 100% of29Sl MWt; SG }.fodel 54F; I 7xl7 RF A-2 Fuel wilh ZIRLOi> OT Optimized ZJRLODI chdding, Non-IFBA or 1PBA, IFMs LICENSING BASIS Analysis ofReoord PCT PCT ASSESSMENTS (Delta PCT)

A.

Prior ECCS Model Assessments

1.

Evaluation of Fuel Pellet Thennal Conductivity Degradation

2.

HOTSPOT Burst Tempecature Calculation for ZIRLO Cladding

3.

Rod lntemal Pre.srure Calcolation

4.

HOTSPOT Iteration Algorithm. for Calculating the Initial Fuel Pellet Average Temperature

5.

WCOBRA/fRAC Thermal-Hydraulic HistOf)' File Dimension used in HSDRIVER. Baclcgrolll:ld

6.

WCOBRAffRAC Automated Restart Proc~.ss Logic Error

7.

Initial Fuel Pellet Average Temperature Uncertainty Calculation

8.

Elevations for Heat Slab Tempecatnre Initialization

9.

Heat Transfer Model Error Conections

10.

Correction to Heat Transfer Node Initialization

11.

lvfass Conservation Error Fix

12.

Correction to Split Channel Momentum Equation

13.

Heat Tramfer Logic Correction for Rod Bum Calculation

14.

Changes to Vessel Superheated Steam Properties

15.

Update to Metal Density Reference Temperatures

16.

Decay Heat Model Error Corrections

17.

Correction to the Pipe Exit Pressure Drop Error

18.

WCOBRAffRAC 019 File Dimension Error Correction

19.

Revised Heat Transfer Multiplier Distributions

20.

HOTSPOT Bum Strain Error Correction

21.

Changes to Grid Blockage Ratio and Porosity

22.

Grid Heat Transfer Enhancement Calculation

23.

Vessel Section 7 :Mid-Level ElevationlModeling

24.

Burst Elevation Selection

25.

Errors in Decay Group Uncertainty Factors

26.

Error in Oxidation Calculations

27.

Error in use of AS:ME Steam Tables

28.

Support Column Core Barrel Unheated Conductor Errors CJadTemp("I) 1852 135 0

0 0

1 0

0 0

-27 21 0

0 0

0

B.

C.

29.

30.

31.

32.

33.

34.

Inconsistent Application ofNumerical Ramp Applied to the Entrained Liquid / V apoc lnterfa.cial Drag Coefficient Inappropriate Resetting ofTrans1i'ene Liquid Mass Flow Steady-State Fuel Temperature Caliblati.on Method Conection to Fuel Pellet TCD AMes.sment Vapor Temperature Resetting Removal of the Vessel Imerfacial Heat Transfer Limit Planned Plant Modification Enln.alions

1.

None 2021 ECCS l\\lodel Assessments

1.

None D.

Other

1.

None Serial No.22-165 Docket No. 50-338/339 : Page 4 of 8 0

0 0

0 LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=

1982

Serial No.22-165 Docket No. 50-338/339 : Page 5 of 8 10 CFR 50.46 :MARGIN U1Il,IZATION - WESTINGHOUSE SMALL BREAK LOCA Plant Name:

North Anna Power Stdion,, Unit 2 Virginia Electric and Power Company Utility Name:

Anab:sis Information EM:

NOTRUMP 12.120/2010 Westinghouse 232 Limiting Bruk Size:

Analysis Date:

Vendor:

FQ:

FAH:

1.65 Fuel:

RFA-2 SGTP(%):

7 Notes:

None LICENSING BASIS Analysis of Record PCT PCT ASSESSME..llITS (Delta PCT)

A.

Prior ECCS Model Assessm.ena B.

c.

D.

1.

NOTR.lTh..W-EM Evaluation ofFuel Pellet Thennal

2.

3.

4.

5.

6.

7.

Conductivity Degradation SBLOCTA Cladding Strain Requirement for Fuel Rod Burst Fuel Rod Gap Conductance Erroc Radiation Heat Transfer Model Eiror SBLOCTA Pre-DNB Cladding Heat Transfer Coefficient Calculalion Error in the Upper Plenum Fluid Volwne Calculation UO1 Fuel Pellet Heat Capacity Planned Plant :Modification Evaluations

1.

None 2021 ECCS Model Assessments

1.

Reduction in Flow Area to the Bottom of the Barrel/Baffle Region Other

1.

None 2.75 inches Clad Temp eD 1834.1 0

0 0

0 LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=

1834.1

Serial No.22-165 Docket No. 50-338/339 : Page 6 of 8 10 CFR 50.46 MARGIN UTILIZATIO - FRAMATO:ME F\\'I S~IALL BREAK L OCA PJant_Yame:

Utility Name:

AnIJysis Information North Amla Power Station, Unit 2 Virginia Electric and Power Company EM:

W&CE SBLOCA EfvlF-2328 Limiting Break Size: 6.5 inches Analysis Date:

t,tay 2018

, endor:

Framatome FQ:

2.5 Fuel:

Representative 17x17 Non-M5 Notes:

None LICENSING BASIS AnaJysu ofRecord PCT PCT ASSESSM:EJ ITS (Delta PCT)

A.

Prior ECCS :Model Assessments

1.

None B.

Planned Plant Modification Evaluations

1.

None C.

2021 ECCS Model Assessments

1.

None D.

Other

1.

None LICENSING BASIS PCT+ PCT ASSESSMENTS FAR:

SGTP(%):

1.65 7

PCT=

Clad Temp ("F) 1801 0

0 0

0 1801

Serial No.22-165 Docket No. 50-338/339 : Page 7 of 8 10 CFR 50.46 A,IARGIN UTILIZATION - WESTINGHOUSE LARGE BREAK LOCA Plant Name:

Utility Name:

Aoalvsis lnformition North Ami.a Power Station, Unit 2 Vicginia. Electric and Pcm,-er Company EM:

ASTRUM (2004)

Limiting Break Size:

DEGB Analysis Date:

8/25/2010 Vendor:

Westinghouse FQ:

2.32 F AH:

1.65 Fuel:

RFA-2 SGTP (%):

7 Notes: Core Power!!: 100% of2951 MWt; SG Model 54F; l 7xl 7 RF A-2 Fuel with ZIRLOi> or Optimized ZIRLODI c:bddmg, on-lFB...o\\. or lFBA, lFMs LICENSING BASIS AnalysaofRecmdPCT PCT ASSESSI\\ffi ITS (Delta PCT)

A Prior ECCS Model Assusmmts

l.

Evaluation of Fuel Pellet Thennal Conductivity Degradation 2_

HOTSPOT Bum Temperature Calculation for ZIRLO Cladduig 3_

Rod Intema1 Pressure Calculation 4_

HOTSPOT Iteration Algorithm for Calculating the Initial Fuel Pellet A,-erage Temperature 5_

WCOBRAlIRAC Thermal-Hydraulic History File Dimension used in HSDRIVER Background 6_

WCOBRA/TRAC Automated Restart Process Logic Error 7 _

Initial Fuel Pellet A "wage T emperatme Uncertainty Calculation 8_

Elevations for Heat Slab T emperatore Initialization 9_

Heat Transfer Model Error Collections 10_

Correction to Heat Transfer Node Initialization 1 L Mass Conservation Error Fix 12_

Conection to Split Channel :Momentum Equation 13 _

Heat Transfer Logic Correction for Rod Bum: Calculation 14_

Changes to Vessel Superheated Steam Properties 15_

Update to Metal Demity Reference Temperatures 16_

Decay Heat Model Error Corrections 17 _

Correction to the Pipe Exit Pressure Drop Error 18_

WCOBR.A/fRA.C U19 File Dimension Error Correction 19_

Revised Heat Transfer Multiplier Distributions 20_

HOTSPOT Bum Strain Error Coaection 2L Changes to Grid Block.age Ratio and Porosity 22_

Grid Heat Transfer Enhancement Calculation 23_

Vessel Section 7 Mid-Level Elevation Modeling 24_

Burst Elevation Selection 25_

Errors in Decay Group Uncertainty Factors 27 _

Error in Oxidation Ca1cu1atioDS 28_

Error in use of ASME Steam Tables CladTempC'F) 1852 135 0

0 0

1 0

0 0

-27 21 0

0 0

B.

C.

Serial No.22-165 Docket No. 50-338/339 : Page 8 of 8

29.

Support Column Core Barrel Unheated Conductor Errors 0

30.

Incomistent Application ofNumerical Ramp Applied 0

to the Entrained Liquid/ Vapor Interracial Ong Coefficient

31.

Inappropriate Re-Setting ofTransi.--erse Liquid Mass Flow 0

32.

Steady-State Fuel Tempenture Calibration Method 0

33.

Conection to Fuel Pellet TCD.Assessment 0

34.

Vapor TemperatureResetting 0

35.

Removal ofth.e Vessel Imerfacial Heat Transfer Limit 0

Planned Plant Modification Evaluations

1.

None 0

2021 ECCS Model Assessments

1.

None 0

D.

Other

1.

None LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=

1982 Serial No.22-165 Docket No. 50-280/281 2021 ANNUAL REPORTING OF 10 CFR 50.46 MARGIN UTILIZATION - SURRY POWER STATION UNITS 1 AND 2 Virginia Electric and Power Company Surry Power Station Units 1 and 2

Serial No.22-165 Docket No. 50-280/281 : Page 1 of 8 10 CFR 50.46 MARGIN UTILIZATION - WESTINGHOUSE SMALL BREAK LOCA Plant Name:

SlJff}" Power Station, Unit 1 Utility Name:

Virginia Electric and Power Company Analysis Information El\\f:

NO1RUMP 5nt2009 Westinghouse 2.5 Limiting Break Size:

Analysis Date:

Vendor~

FQ:

Fuel:

Notes:

LICENSING BASIS Upgrade None Analysis of Record PCT PCT ASSESSMF..i"ITS (Delta PCT)

A.

Prior ECCS Mode] Assessments FMI:

SGTP(%):

1.7 7

1.

2.

3.

4.

5.

6.

7.

Urania-Gadolinia Pellet Thermal Conductivity Calculation.

Pellet Crack and Dish Volume Calculation.

B.

c.

D.

8.

9.

10.

11.

12.

13.

Treatment ofVessel Average Temperature Uncertainty 15X15 Upgrade Fuel

tvfaximum Fuel Rod Time Step Logic Radiation Heat Transfer Logic NO1RUMP-EM Evaluation ofFuel Pellet Thermal Conducti,,ity Degradation SBLOCTA Cladding Strain Requirement for Fuel RodBum Fuel Rod Gap Conductance Enor Radiation He.at Transfer Model Error SBLOCTA Pre-DNB Cladding Heat Transfer Coefficient CaJculation Enor in the Upper Plenum Fluid Volume Calculation UO2 Fuel Pellet Heat Capacity Planned Plant Modification Evaluations

1.

None 2021 ECCS Model Assessments

1.

Reduction in Flow Alea to the Bottom of the BarreLIBaftle Region Other

1.

None LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=

2.75 inche-S Clad TempC'fl 2012 0

0 0

0 2012

Serial No.22-165 Docket No. 50-280/281 : Page 2 of 8 10 CFR 50.46 MARGIN UTil,IZATIOr - FRAMATO:ME F\\'I SMALL BREAK LOCA Plant Name:

Smty Power Station, Unit 1 Utility Name:

Virginia Electric and Power C-Otnpany Au1ysis Information EM:

W&CE SBLOCA EMF-2328 Analysis Date:

July 2018 Vendor:

Framatome FQ:

2.5 Fuel:

Representative 15x15 Non-M5 Notes:

None LICENSING BASIS Analysis ofRec.ord PCT PCT ASSESSMENTS (Delta PCT)

A.

Prior ECCS Model Assessments B.

C.

D.

1.

None Planned Plant Modification Evaluations

1.

None 2021 ECCS Model Asses:iments

1.

SBLOCA Rod History-Trnncation (FVI-SBLOCA dmnrllow baffle)

Other

1.

None LICEr'iSING BASIS PCT + PCT ASSESSMENTS Limiting Break Size: 2.6 inches FAH:

SGTP(%):

1.70 7

PCT=

Cl.ad Temp(°F) 1673 0

0 0

0 1673

Serial No.22-165 Docket No. 50-280/281 : Page 3 of 8 10 CFR 50.46 MARGIN UTILIZATION - WESTINGHOUSE LARGE BREAK LOCA Plant Name:

Suuy Power Statioo, Unit 1 Utility Name:

Virginia Electric and Power Company Au{ysis Information El\\f:

ASTRIDA (2004) 10/6/2010 Westinghouse 2.5 Limiting Break Size:

Analysis Date:

Vendor:

FQ:

FAIi:

1-7 Fuel:

Upgrade SGTP(%):

7 Notes:

None LICENSING BASIS Analysis. ofR.ecord PCT PCT ASSESSMENTS (DeJm PCI)

A.

Prior ECCS Model Assessments

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

Eiraluation of Fuel Pellet Theim.al Conductivity Degradation Pellet Ra.dial Profile Option HOTSPOT Burst Temperature Calculation for ZIRLO Cladding Rod Internal Pressure Calculation HOTSPOT Iteration Algorithm for Calculating the Initial Fuel Pellet Average Temperature WCOBRA/IRAC Thermal-Hydraulic History File Dimension used in HSDRIVER Background WCOBRA/IRAC Automated Restart Process Logic furor Initial Fuel Pellet Avenige Temperature Uncertainty Calculation Elevations for He.at Slab Temperature Initialization Heat Transfer Model Error Corrections Correction to Heat Transfer Node Initialization Mass Conservation Error Fix Conection to Split Channel Momentum Equation Heat Transfer Logic Correction for Rod Bum Calculation Changes to Vessel Superheated Steam Properties Update to Metal Density Reference Temperatures Decay Heat Model Error Conections Correction to the Pipe Exit Pressure Drop furor WCOBRA/IRAC Ul9 File Dimension Enor Correction Revised Heat Transfer Multiplier Distributions HOTSPOT Burst Strain Error Correction Changes to Grid Blockage Ratio and Porosify Grid Heat Transfer Enhancement Calculation Vessel Section 7 Mid-Level Elevation Modeling Burst Elevation Selection Enon in Decay Group Uncertainty Factors fa--aluation of Additional Containment Metal furor in Oxidation Calculations Error in use of ASME Steam Tables Core Barrel Unheated Conductor Errors DEG Clad Temp C1) 1853 183

-13 0

0 0

-7 51 0

0 0

0 4

0 0

B.

C.

D.

31.

32.

33.

34.

3.5.

36.

Discrepancy in Wetted Perimeter Inputs Inconsistent Application of Numerical Ramp Applied to the Entram.ed Liquid / Vapor Ime:rfacial Drag Coefficient Inapprnpriate Resetting ofTram,;erse Liquid M ass Flow Steady-State Fuel Temperature Calibration Method Vapor Temperature R~etting Removal of the Vessel lmerfacial Heat Transfer Limit PJan.ned Plant Modification Evaluations

1.

None 2021 ECCS Model Assessments

1.

None Other

1.

None LICENSING BASIS PCT+ PCT ASSESS~IENTS PCT=

Serial No.22-165 Docket No. 50-280/281 : Page 4 of 8 0

0 0

2071

Serial No.22-165 Docket No. 50-280/281 : Page 5 of 8 IO CFR. 50.46 A.IARGIN UIIl,IZATION - WESTINGHOUSE SMALL BREAK LOCA PJa.nt a.me:

Smry Power Station, Unit 2 Utility Name:

Virginia Electric and Power Company Ana!):--sis Intormation EM :

NOTRUMP 5/7/2009 Westinghouse 2.5 Limiting Break Size:

2.75 inches

.Analysis Date:

Vendor:

FQ:

Fuel:

Notes:

Upgrade None FAIi:

1.7 SGTP(%):

7 Clad Temp C'.F)

LICENSING BASIS Analysis ofRecord PCT 2012 PCT ASSESSME~"'l'S (Delta PCT)

A.

Prior ECCS Model Assessments B.

C.

D.

1.

Utania-Gadolinia Pellet Thennal Conductivity Calculation.

0

2.

Pellet Crack and Dish Volume Calculation.

0

3.

Treatment ofVessel Average Temperature Uncertainty 0

4.

15X15 Upgrade Fuel 0

5.

M".aximum Fuel Rod Time Step Logic 0

6.

Radiation Heat Transfer Logic 0

7.

NOTR.UMP-EM Evaluation of Fuel Pellet Thermal 0

Conductii,ity Degradation

8.

SBLOCTA Cladding Strain Requirement for Fuel 0

Rod Burst

9.

10.

11.

12.

13.

Fuel Rod Gap Conductance Enor Radiation Heat Transfer Model Enor SBLOCTA Pre-DNB Cladding Heat Transfer Coefficient Calculation Enor in the Upper Plenum Fluid Volume Calculation U02 Fuel Pellet Heat Capacity Planned Plan.t l\\lodification Evaluations

1.

None 2021 ECCS Model Assessments

1.

Reduction in Flow Area to the Bottom of the Barrel/Baffle Region Other

1.

None 0

0 0

0 LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=

2012

Serial No.22-165 Docket No. 50-280/281 : Page 6 of 8 10 CFR 50.46.MARGIN UTILIZATIO - FRAMATOl\\fE F\\'I S1L.\\LL BREAK LOCA Plant 1ame:

SUfl}' P<m'ef Station, Unit 2 Utility Name:

Virginia Electric and Power Company Analvsis lnforma1ion EM:

W&CE SBLOCA EMF-2328 Analysis Date:

Jwy 2018 Vendor:

Framatome FQ:

25 Fuel:

Representative 15xl5 Non-M5 Notes:

None LICENSING BASIS Analysis of Record PCT PCT ASSESSMENTS (Delt2 PCT)

A.

Prior ECCS Mod.el Assessments B.

C.

D.

1.

None Planned Plant Modffication Evaluations

1.

None 2021 ECCS Model Assessments

1.

SBLOCA Rod Histocy Truncation (FVI-SBLOCA dov,nflow baffle)

Other

1.

None LICENSING BASIS PCT+ PCT ASSESS}.fENTS Limiting Break Size: 2.6 inches FAIi:

SGTP(%):

1.70 7

PCT=

Clad Temp C'F) 1673 0

0 0

0 1673

Serial No.22-165 Docket No. 50-280/281 : Page 7 of 8 10 CFR. 50.46 MARG.ffl" UTILIZATION - WESTINGHOUSE LARGE BREAK LOCA Plmt Nam.e:

Suny Power Station, Unit 2 Utility Name:

Virginia Electric and Power Company Analysis Information EM:

ASTRUM (2004) 10/6/2010 Wesfulghouse 2.5 Limiting Break Size:

Analysis Date:

Vendor:

FQ:

Fuel:

Notes:

Upgrade None FAIi:

SGTP(%}:

1.7 7

LICENSING BASIS AnalysuofRecordPCT PCT ASSESSMENTS (Delta PCT}

A.

Prior ECCS Model Assessments

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

Evaluation of Fuel Pellet Then:nal Conductivity Degradation Pellet Radial Profile Option HOTSPOT Bum Temperature Calculation for ZJRLO Cladding Rod Internal Pressure Calculation HOTSPOT Iteration Algorithm. for Calculating the Initial Fuel Pellet Average Temperature WCOBRA/TRAC Thermal-Hydraulic History File Dimension used in HSDRIVER Background WCOBRA/TRACAutomaredRestart:ProceM LogicEnor Initial Fuel Pellet Average Temperature Uncertainty Calculation Elevations for Heat Slab Temperature Initialization Heat Tramfer Model Error Corrections Correction to Heat Transfer Node Initialization Mass Conservation Error Fix Correction to Split Channel Momentum Equation Heat Transfer Logic Correction for Rod Bur.rt Calculation Changes to Vessel Superheated Steam Properties Update to Metal Density Reference Temperatures Decay Heat Model Error Corrections Couection to the Pipe Exit Pressure Drop Error WCOBRA/TRAC U19 File Dimension Error Correction Revised Heat Transfef" Multiplier Distributions HOTSPOT Bum Strain Error Correction Changes to Grid Blockage Ratio and Porosity Grid He.at Transfer Enhancement Calculation Vessel Section 7 Mid-Level Elevation ?vfodeling Bur.rt Elevation Selection Emm in Decay Group Uncertainty Factors Evaluation of Additional Containment Metal Error in Oxidation Calculations Error in use of ASME Steam Tables Core Barrel Ullheated Conductor Errors Discrepancy in Wetted Perimeter Inputs DEG Clad Temp ("I) 1853 183

-13 0

0 0

-7 51 0

0 0

0 4

0 0

0

B.

C.

D.

Serial No.22-165 Docket No. 50-280/281 : Page 8 of 8

32.

Inconsistent Application ofNmnerical Ramp Applied 0

to the Entrained Liquid /Vapor Interl'.acial Thag Coefficient

33.

Inappropriate Resetting ofTransven.e Liquid Mau Flow 0

34.

Steady-State Fuel Temperature Calibration Method 0

35.

Vapor Temperature Resetting 0

36.

Removal of the Vessel Interl"acial Heat Transfer Limit 0

Planned Plant Modification Evaluations

1.

None 2021 ECCS Model Assessments

1.

None Other

1.

None 0

0 0

LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=

2071 Serial No.22-165 Docket No. 50-395 2021 ANNUAL REPORTING OF 10 CFR 50.46 MARGIN UTILIZATION - VIRGIL C.

SUMMER NUCLEAR STATION Dominion Energy South Carolina, Inc.

Virgil C. Summer Nuclear Station Unit 1

10 CFR 50.46 Margin Utilization - Appendix K Small Break Plant Name:

V.C. Summer Utility Name:

Dominion Energy South Cacolina Amlysis Information EM :

NOTRUMP February 2003 Westinghouse 2.45 Limiting Break Size:

Aulysis Da.te:

Vendor :

FQ:

Notes:

None LICENSING BASIS Analysis ofRecord PCT PCT ASSESSME NTS (Delta PCT)

A Prior ECCS Model Assessments B.

C.

1.

2.

3.

4

5.

6.

7.

g_

9.

10.

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

NOTRUMP-EM Refined Break Spectrum Errors in Reactor Vessel Nozzle Data Collections Pomp Weir Remtmce Modeling Errors in Reactor Vessel Lower Plenum Surface Area Calculations Modeling of Annular Pellets Discrepancy in Metal Masses Used Emm Drawings V. C. Summer Upflow Conversion Treatment ofVessel Average Temperature Uncertainty Urania-Gadolinia Pellet Thermal Conductivity Calculation Pellet Crack and Dish Volume Calculation Radiation Heat Transfer Logic Maximum Fuel Rod Time Step Logic NOTRUMP-EM Evaluation of Fuel Pellet Thermal Conductivity Degradation SBLOCI'A Cladding Strain Requirement for Fuel RodBurst Fuel Rod Gap Conductance Error Radiation He.at Transfer Model Error SBLOCI'A Pr~DNB Cladding Smface Heat Transfer Coefficient Calculation Control Rod Drop Time Technical Specification Change Vessel Average Temperature Uncertainty Error in the Upper Plenwn Fluid Volume Calculation U02 Fuel Pellet Heat Capacity Increased Vessel Average Temperature Uncertainty Planned Plant Modification Enlnations

1.

None 2021 ECCS Model Assessments 1.62

1.

Reduction in Flow Area to the Bottom of the Barrel/Baffle Region Serial No.22-165 Docket No. 50-395 : Page 1 of 12 3 Inch Clad T e.m p{°F) 1775 0

0 0

0 148 0

0 0

D.

Other

1.

None LICENSING BASIS PCT+ PCT ASSESS!--IENTS PCT=

Serial No.22-165 Docket No. 50-395 : Page 2 of 12 0

1923

Serial No.22-165 Docket No. 50-395 : Page 3 of 12 10 CIR S0.46 Margjn Utilization - FSLOCA Region I - Small Break Plant Name:

V.C.Summer Utility Name:

Dominion Energy South Carolina Analysis Inrorm~tion EM:

FSLOCA Jamwy 2019 Westinghouse 2.5 Limiting Break Size:

Analysis Date:

Vendor:

FQ:

1.70 Notes:

None LICENSING BASIS

.Analysis of Record PCT (Including gamma energy redistribution)

PCT ASSESSMENTS (Delta PCT)

A.

Prior ECCS lode) Assessments

1.

None B.

Planned Plant ~lodilication Evaluations

1.

None

c.

2021 ECCS Model Assessments

1.

None D.

Other

1.

None LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=

2.6 1nch Clad Temp{°l) 1108 0

0 0

0 n os

Serial No.22-165 Docket No. 50-395 : Page 4 of 12 10 CIR 50.46 Margin Utilization - Bert Estimate Large Break, BLO~O\\VN Plant Name:

V. C. Summer Utility Name:

Dominion Energy South Carolina Anamis Information EM :

CQD (1996)

Februaiy 2003 Westinghouse 2.5 Limiting Break Size:

Analysis Date:

Vendor:

FQ:

Notes:

None LICENSING BASIS AnalysisofRecocd PCT PCT ASSESSMENTS (Delta PCT)

A.

Prior ECCS Model Assessments

1.

Fan Cooler Performance Increase

2.

Improved Automation of End ofBlowdov.-n Time

3.

Implementation of ASTRUM Capability in HOTSPOT 4

Revised Blowdo\\\\'-n Heatup Uncertainty Distribution

5.

Revised Iteration Algorithm for Calculating 1he Average Fuel Temperature

6.

Improved Automation of End ofBlowdov.-n Time

7.

Tbennodynamic Properties from Thermo

8.

Pressurizer Fluid Volume

9.

Vessel Unheated Conductor Noding

10.

Containment Relative Humidity Assumption

11.

HOTSPOT Fuel Relocation

12.

Steam Generator Nozzle Volume Accounting Error

13.

Cold Leg Volume Discrepancy

14.

Errors in Reactor Vessel Nozzle Data Collection

15.

HOTSPOT Bunt Temperature Logic Errors

16.

V. C. Summer Uptlow Conv<<sion

17.

Zeco Cross-Flow Boundary-Condition Error

18.

Discrepancy in Metal Masses Used E.m.m Dt-av.ings

19.

HOTSPOT Gap Heat Transfer Logic

20.

HOTSPOT Statistical Output Logic

21.

Treatment ofVessel Average Temperature Uncertainty

22.

Additional Heat Sinks and lhximum Spray Flow

23.

Fuel Pellet Thermal Conducfa,ity Degradation and Peaking Factor Bumdown

24.

PAD 4.0 Implementation

25.

Zero Cross-Flow Boundary-Condition Error

26.

HOTSPOT Burst Temperature Calculation For ZIRLO Cladding

27.

HOTSPOT Iteration Algorithm for Calculating Toe Initial Fuel Pellet Ave.rage Temperature 1.7

28.

WCOBRA/I'RAC Automated Restart Process Logic Error

29.

Rod Internal Pressme Calculation

30.

WCOBRA.ITRAC Thennal-Hydraulic History File Dimension used in HSDRIVER

31.

Burst Elevation Selection

32.

Etention for Heat Slab Temperature Initialization DEGB Clad Temp(0F) 1860 0

0 0

49 0

0 0

-7 0

0 0

-83 0

0 0

0

B.

C.

D.

33.

34.

35.

36.

37.

38.

39.

40.

41

42.

43.

44.

45.

46.

47.

48.

49.

50.

51.

52.

53.

54.

55.

56.

Heat Transfer Logic for Rod Bum Calculation WCOBRA/I'RAC Ul9 File Dimension Error Correction Heat Tramfer Model Error Corrections Correction to Heat Tramfer Node Initialization l\\fass Comervation Error Fix Correction to Split Channel J\\.lomentum Equation Changes to Vessel Superheated Steam Properties Update to Metal Density Reference Temperatures Decay Heat Model Error Correction Correction to the Pipe Exit Pressure Drop Error Vessel Section 7 Mid-Level Ele,..-ation Modeling Grid Heat Transfer Enhancement Calculation Revised Heat Transfer Multiplier Distributions Changes to Grid Blockage Ratio and Porosity Error in Burst Strain Application Code Uncertainty in BE LBLOCA Monte Carlo Simulations Error in Oxidation Calculations Support Column Unheated Conductor Error Vessel Average Temperature Uncertainty Numerical Ramp Entrained LiquidlV apor futerfacial Drag Inappropriate Resetting of Transverse Liquid Mass Flow Vapor Temperature Resetting Removal of the Vessel futerfacial H eat Transfer Limit Increased Vessel Average Temperature Uncertainty Planned Plant Modification Evalnations L

None 2021 ECCS Model Assessments L

None Other L

None LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=

Serial No.22-165 Docket No. 50-395 : Page 5 of 12 0

0 0

0

-5 0

0 0

0 1814

Serial No.22-165 Docket No. 50-395 : Page 6 of 12 10 CFR S0.46 Margin Utilization - Best Estimate Large Break, REFLOOD 1 PlantName:

V.C.Summer Utility Name:

Dominion Energy South Carolina Analysis Information EM:

CQD(l996)

February 2003 Westinghouse

2.5 Limiting Break Size:

Analysis Date:

Vendor:

FQ:

ldBi Notes:

None LICENSING BASIS Analysis of Record PCT PCT ASSESSMENTS (Delta PCT)

A.

Prior ECCS Model Assessments

1.

2.

3.

4

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

Fan Cooler Perfoimance Increase Impro.--ed Automation of End ofBlowdown Time Implementation of ASTRUM Capability in HOTSPOT Revised Blowdown He.amp Uncertainty Distribution Revised Iteration Algorithm for Calculating The Average Fuel Temperature lmpro,.--ed Automation of End ofBlmvdov.n Time Themi.odynamic Properties from Thermo Pressurizer Fluid Volumes Vessel Unheated Conductor Noding Containment Relatfre Humidity Assumption HOTSPOT Fuel Relocation Steam Generator Nozzle Volume Accomrting Error Cold Leg Volume Discrepancy Errors in Reactor Vessel Nozzle Data Collection HOTSPOT Bunt Temperature Logic Errors V. C. Summer Upflow Convemon Zero Cross-Flow Boundaiy Condition Error Discrepancy in :Metal Masses Used Emm Drawings HOTSPOT Gap Heat Transfer Logic HOTSPOT Statistical Output Logic Treatment ofVessel Average Temperature Uncertainty Additional He.at Sinks and Maximum Spray Flow Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Bumdov,;n PAD 4.0 Implementation Zero Cross-Flow BoUDdaiy Condition Error HOTSPOT Bum Temperature Calculation For ZIRLO Cladding HOTSPOT Iteration Algorithm for Calculating 1.7

27.

28.

29.

30.

The Initial Fuel Pellet A\\'erage Tempera.1me WCOBRA/fRAC Automated Restart Proce-SS Logic Error Rod Internal Pressure Calculation

31.

32.

WCOBRAITRAC Thermal-Hydraulic History File Dimension used in HSDRIVER Burst Elevation Selection Elevation for Heat Slab Temperature Initialization DEGB Clad Temp{°I) 1808 1

0 0

5 0

0 0

-44 0

0 0

0 113

-118 0

0 0

0

B.

C.

D.

33.

34.

35.

36.

37.

38.

39.

40.

41.

42.

43.

44.

45.

46.

47.

48.

49.

50.

51.

52.

53.

54.

55.

56.

Heat Transfer Logic for Rod Bum Calculation WCOBRA/TRAC Ul9 File Dimension Error Correction Heat Transfer Model Error Corrections Con:ection to Heat Transfer Node Initialization Mass COl!Sffllation Error Fix Correction to Split Channel Momentum Equation Changes to Vessel Superheated Steam Properties Update to Metal Density Reference Temperatures Decay Heat Model Error Correction Correction to the Pipe Exit Pressure Drop Error Vessel Section 7 Mid-Level Elevation Jvfudeling Grid Heat Transfer Enhancement Calculation Revised Heat Transfer Multiplier Distributions Changes to Grid Bloclcage Ratio and Porosity Error in Burst Strain Application Code Uncertainty in BE LBLOCA Monte Carlo Simulations Error in Oxidation Calcolations Support Column Unheated Conductor Error Vessel Average Temperature Uncertainty Numerical Ramp Entrained Liquid/Vapor Interfacial Drag Inappropriate Resetting ofT1ann--ene Liquid Mass Flow Vapor Temperature Resetting Remo\\'al of the Vessel Interfacial Heat Transfer Limit Increased Vessel Average Temperature Uncertainty Planned Plant Modification Enluations

1.

None 2021 ECCS Model Assessments

1.

None Other

1.

None LICENSING BASIS PCT+ PCT ASSE SSl\\.IENTS PCT =

Serial No.22-165 Docket No. 50-395 : Page 7 of 12 0

0 0

0 5

24 20 0

. 0 0

0 0

0 1814

Serial No.22-165 Docket No. 50-395 : Page 8 of 12 IO CFR. 50.-46 ~Iargin Utilization - Best Estimate Large Break, REFLOOD 2 Pbnt ame:

V. C. Summer Utility Name:

Dominion Energy South Carolina Analvsis Information DI:

CQD(l996)

Febroaty 2003 Westinghouse 2.5 Limiting Break Size:

Analysis Date:

Vendor:

FQ:

1.7 Notes

None LICENSING BASIS Analysis of Record PCT PCT ASSI.SSMEl'\\'TS (Delu PCT)

A.

Prior ECCS Model Assessments

1.

Fan Cooler Perl"onnance Increase

2.

Improved Automation of End ofBlowdo'Ml Time

3.

Implementation of ASTR.lJ""M Capability in HOTSPOT 4

Revised Blo, down Heatnp Uncertainty Distribution

5.

Revised Iteration Algorithm for Calculating The A1,-erage Fuel Temperature

6.

Improved Automation of End ofBlowdo't\\u Time

7.

Thermodynamic Properties fi"om Thermo

8.

Pressurizer Fluid Volumes

9.

Vessel Unheated Conductor Noding

10.

Containment Relative Humidity Assumption

11.

HOTSPOT Fuel Relocation

12.

Steam Generator Nozzle Volume Accounting Error

13.

Cold Leg Volume Discrepancy

14.

Eaors in Reactor Vessel No.zzte Data Colledion

15.

HOTSPOT Bum Temperature Logic Errors

16.

V. C. Summer Uptlow Convenion

17.

Zero Cross-Flow Boundaiy Condition Error

18.

Discrepancy in Metal Masses Used F.m.m Drav.-ings

19.

HOTSPOT Gap Heat Transfer Logic

20.

HOTSPOT Statistical Cmtput Logic

21.

Treatment ofVegse-1 Average Temperature Uncertainty

22.

Additional Heat Sinks and Maximum Spray Flow

23.

Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Bumdo~

24.

PAD 4.0 Implementation

25.

Zero Cross-Flow Boundaiy Condi.ti.on Error

26.

HOTSPOT Bum Temperature Calculation For ZIRLO Cladding

27.

HOTSPOT Iteration Algorithm for Calculating The Initial Fuel Pellet Average Temperature

28.

WCOBRA/I'RAC Automated Restart Process Logic En-or

29.

Rod Internal Pressure Calculation

30.

WCOBRA/I'RAC Thermal-Hydraulic History File Dimension used in HSDRIVER

31.

Burst Elevation Selection

32.

Elevation for Heat Slab Temperature Initialization DEGB Clad Temp(OF) 1988 2

0 0

5 0

0 0

-29 0

0 0

1 123

-118 0

0 0

0

B.

C.

D.

33_

34_

35_

36_

37_

38_

39_

40_

41-42_

43_

44_

45_

46_

47_

48_

49_

50_

51-52_

53_

54_

55_

56_

Heat Transfer Logic for Rod Bum Calculation WCOBRAITRAC Ul9 File Dimension Eaor Correction Heat Transfer Model Eaor Corrections Correction to Heat Transfer Node Initialization Mass Comervation Eaor Fix Correction to Split Channel Momentum Equation Changes to Vessel Superheated Steam Properties Update to Metal Density Reference Temperatmes Decay Heat Model Eaor Corrections Correction to the Pipe Exit Pressure Drop En-or Vessel Section 7 :Mid-Level Elevation Modeling Grid Heat Transfer Enhancement Calculation Revised Heat Transfer Multiplier Di.mibutions Changes to Grid Blockage Ratio and Porosity En-or in Bum Strain Application Code Uncertainty in BE LBLOCA Moote Carlo Simulations Enor in Oxidation Calculations Support Column Unheated Conductor furor Vessel Average Temperature Uncertainty Numerical Ramp Entrained Liquid/Vapor Jnterfacia.1 Drag Inappropriate Resetting ofTrnnsverse Liquid Mass Flow Vapor Temperatme Resetting Removal of the Vessel Jnt.erfacial Heat Transfer Limit Increased Veuel Average Tempemtme Uncertainty Planned Plant Modification Evaluations L

None 2021 ECCS l\\fodel Assessments L

None Other L

None LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=

Serial No.22-165 Docket No. 50-395 : Page 9 of 12 0

0 0

0

-35 24 0

0 0

1961

Serial No.22-165 Docket No. 50-395 : Page 10 of 12 10 CFR 50.46 A.Jargin Util.iza.tion - Best Estimate Large Break, COl\\llPOSITE Plant Name:

V. C. Summer Utility Name:

Dominion Energy South Carolina Analysis Information EM:

CQD(l996)

Febromy 2003 We5finghouse 2.5 Limiting Break Size:

Analysis Date:

Vendor:

FQ:

Notes:

None LICENSING BASIS Analysis of Record PCT PCT ASSESSl\\:IENTS (Delta PCT)

A.

Prior ECCS Model Assessments

1.

2.

3.

4

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

Fan Cooler Perfonnance Increase Impro-,,--ed Automation of End ofBlowdo\\1,n Time Implementation of ASTRUM Capability in HOTSPOT Revi!ed Blowdown Heatop Uncertainty Distribution Revised Iteration Algorithm for Calculating The Average Fuel Temperature Impro-,,--ed Automation of End ofBlowdovm Time Thermodynamic Properties from Thermo Pressurizer Fluid Volumes Vessel Unheated Conductor Nading Containment Relative Humidity Assumption HOTSPOT Fuel Relocation Steam Generator Nozzle Volume Accounting Error Cold Leg Volume Discrepancy En-ora in Reactor Vessel Nozzle Data Collection HOTSPOT Bw:st Temperatnre Logic Errors V. C. Summer Upflow Conversion Zero Cross-Flow Boundaiy Condition Error Discrepancy in Metal -lasses Used &om Drawings HOTSPOT Gap Heat Transfer Logic HOTSPOT Statistical Output Logic Treatment ofVessel Average Temperature Uncertainty Additioual Heat Sinks and Maximum Spray Flow Fuel Pellet Thenn.a1 Conductivity Degi-adation and Peaking Factor Bumdown PAD 4.0 Implementation Zero Cross-Flow Boundaiy Condition Error HOTSPOT Bum Temperatnre Calculation For ZIRLO Cladding HOTSPOT Iteration Algorithm for Calculating 1.7

27.

28.

29.

30.

The Initial Fuel Pellet Average Temperature WCOBRA/fRAC Automated Restart Process Logic En:or Rod Internal Pre-S3Ufe Calculation

31.

32.

WCOBRA/TRAC Thermal-Hydraulic History File Dimension used in HSDRIVER Burst Elevation Selection Elevation for Heat Slab Temperature Initialization DEGB CladTempffi 1988 2

0 0

5 0

0 0

-29 0

0 0

1 123

-118 0

0 0

0

33.

Heat Transfer Logic for Rod Burst Ca1culation

34.

WCOBRAITRAC U19 File Dimension Etror Correction

35.

Heat Tnimfer Model Etror Corrections

36.

Correction to Heat Transfer Node Initialization

37.

Mass Conrervation Etror Fix

38.

Correction to Split Channel Momentum Equation

39.

Changes to Vessel Superheated Steam Properties

40.

Update to Metal Density Reference Temperatures

41.

Decay Heat Model Etror Correction

41.

Correction to the Pipe Exit Pressure Drop Error

42.

Vessel Section 7 Mid-Level Ele\\.-af:ion Modeling

43.

Grid Heat Ttansfer Enhancement Calculation

44.

Revised Heat Transfer Multiplier Distributions

45.

Changes to Grid Blockage Ratio and Porosity

46.

Etror in Burst Strain Application

47.

Code Uncertainty in BE LBLOCA Monte Carlo Simulations

48.

Error in Oxidation Calculations

49.

Support Column Unheated Conductor Error

50.

Vessel Average Tempetablre Uncertainty

51.

Numerical Ramp Entrained Liquid/Vapor Iuterfacial Drag

52.

Inappropriate Resetting of Tnns,.-erse Liquid Mass Flow

53.

Vapor Temperature Resetting

54.

Removal of the Vessel Interfacial Heat Tnmsfer Limit

55.

Increased Veuel Average Temperature Uncertainty B.

Planned Plant Modification Evaluations

1.

None C.

2021 ECCS Model Assessments

1.

None D.

Other

1.

None LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=

Serial No.22-165 Docket No. 50-395 : Page 11 of 12 0

0 0

0

-35 24 0

0 0

1961

Serial No.22-165 Docket No. 50-395 : Page 12 of 12 10 CFR 50.46 1\\largin Utilization-FSLOC A Region II - Large Break Plant Name:

V_ c_ Summer Utility Name:

Dominion Energy South Carolina Analysis Information EM :

FSLOCA January 2019 Westinghouse 2.5 Limiting Break Size:

Analysis Date:

Vendor:

FQ:

1.70 Notes:

None LICENSING BASIS Analysis of Record PCT (Including gamma energy redistribution)

PCT ASSESSMENTS (Delta PC1)

A.

Prior ECCS Model Assessments

1.

None B.

Planned Plant Modification Evaluations

1.

None C.

2021 ECCS Model Assessments

1.

None D.

Other

1.

None U CENSING BASIS PCT + PCT ASSESSMENTS PCT=

1879 DEGB Clad Temp{°F) 1879 0

0 0

0

ML22179A310

Text

1.7 Notes

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