ML25177A125
| ML25177A125 | |
| Person / Time | |
|---|---|
| Site: | Millstone, Summer, Surry, North Anna  |
| Issue date: | 06/25/2025 |
| From: | James Holloway Dominion Energy, Dominion Energy Services |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| 25-163 | |
| Download: ML25177A125 (1) | |
Text
Dominion Energy Services, Inc.
5000 Dom inion Boulevard, Glen Allen, VA 23060 DominionEnergy.com June 25, 2025 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 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
~
Dominic
~
nergy*
Serial No.: 25-163 NRA/JH: RO Docket Nos.: 50-336/423 50-338/339 50-280/281 50-395 License Nos.: DPR-65/NPF-49 NPF-4/7 DPR-32/37 NPF-12 2024 ANNUAL REPORT OF EMERGENCY CORE COOLING SYSTEM (ECCS) MODEL CHANGES PURSUANT TO THE REQUIREMENTS OF 10 CFR 50.46 In accordance with 10 CFR 50.46(a)(3)(ii), Dominion Energy Nuclear Connecticut, Inc.,
Virginia Electric and Power Company, and Dominion Energy South Carolina, Inc. hereby submit the annual summary of permanent changes to the emergency core cooling system (ECCS) evaluation models (EMs) for Millstone Power Station Unit 2 (MPS2) and Unit 3 (MPS3), North Anna Power Station Unit 1 (NAPS1) and Unit 2 (NAPS2), Surry Power Station Unit 1 (SPS1) and Unit 2 (SPS2), and Virgil C. Summer Nuclear Station Unit 1 (VCSNS), 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 MPS2, MPS3, NAPS1, NAPS2, SPS1, SPS2, and VCSNS as applicable.
Information regarding the effect of the ECCS EM changes upon the reported SBLOCA and LBLOCA analyses of record results is provided for MPS2, MPS3, NAPS1, NAPS2, SPS1, SPS2, and VCSNS in Attachments 2, 3, 4 and 5 respectively. The calculated peak cladding temperatures (PCT) for the SBLOCA and LBLOCA analyses for MPS2, MPS3, NAPS1, NAPS2, SPS1, SPS2, and VCSNS are summarized below:
Serial No.25-163 Docket Nos. 50-336/423/338/339/280/281 /395 Page 2 of 3 Millstone Unit 2 Small break - Framatome EM:
1714°F Millstone Unit 2 Large break - Framatome EM (Zr4 fuel):
1845°F Millstone Unit 2 Large break - Framatome EM (M5 fuel):
1615°F Millstone Unit 3 Small break - Westinghouse EM:
1193°F Millstone Unit 3 Westinghouse FSLOCA EM Region 11 Large break:
1712°F North Anna Units 1 and 2 FVI Small break - Framatome EM:
1801 °F North Anna Units 1 and 2 Westinghouse FSLOCA EM Region 11 Large break:
1893°F Surry Units 1 and 2 FVI Small break - Framatome EM:
1694°F Surry Units 1 and 2 Westinghouse FSLOCA EM Region 11 Large break:
1921°F Virgil C. Summer Unit 1 Westinghouse Full Spectrum LOCA EM Region I Small break:
1108°F Virgil C. Summer Unit 1 Westinghouse FSLOCA EM Region 11 Large break:
1879°F The LOCA results for MPS2, MPS3, NAPS1, NAPS2, SPS1, SPS2, and VCSNS 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 2024 annual reporting requirements of 10 CFR 50.46(a)(3)(ii).
If you have any questions regarding this submittal, please contact Julie Hough at (804) 273-3586.
Respectfully, James Holloway Vice President - Nuclear Engineering and Fleet Support Dominion Energy Nuclear Connecticut, Inc.
Dominion Energy South Carolina, Inc Virginia Electric and Power Company Commitments made in this letter: None
Serial No.25-163 Docket Nos. 50-336/423/338/339/280/281/395 Page 3 of 3 Attachments:
- 1. Report of Changes in Framatome and Westinghouse ECCS Evaluation Models
- 2. 2024 Annual Reporting of 10 CFR 50.46 Margin Utilization - Millstone Power Station Units 2 and 3
- 3. 2024 Annual Reporting of 10 CFR 50.46 Margin Utilization - North Anna Power Station Units 1 and 2
- 4. 2024 Annual Reporting of 10 CFR 50.46 Margin Utilization - Surry Power Station Units 1 and 2
- 5. 2024 Annual Reporting of 10 CFR 50.46 Margin Utilization - Virgil C. Summer Nuclear Station cc:
U. S. Nuclear Regulatory Commission, Region I Regional Administrator U. S. Nuclear Regulatory Commission, Region II Regional Administrator NRC Senior Resident Inspector Millstone Power Station NRC Senior Resident Inspector North Anna Power Station NRC Senior Resident Inspector Surry Power Station NRC Senior Resident Inspector Virgil C. Summer Power Station Mr. L. John Klos NRC Project Manager - Surry Mr. R. Guzman NRC Project Manager - Millstone Units 2 and 3 U. S. Nuclear Regulatory Commission Mr. G. Edward Miller NRC Project Manager - North Anna and Virgil C. Summer U. S. Nuclear Regulatory Commission Old Dominion Electric Cooperative Electronically Distributed
Serial Number 25-163 Docket Nos. 50-336/423/338/339/280/281/395 2024 ANNUAL REPORT OF EMERGENCY CORE COOLING SYSTEM (ECCS) MODEL CHANGES PURSUANT TO THE REQUIREMENTS OF 10 CFR 50.46 REPORT OF CHANGES IN FRAMATOME AND WESTINGHOUSE ECCS EVALUATION MODELS 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
Serial No.25-163 Docket Nos. 50-336/423/338/339/280/281/395, 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 MPS2 during 2024.
Note: The SBLOCA margin utilization table contains a +4 °F penalty for the Zr-4 fuel product. While Zr-4 fuel product is no longer used in MPS2 starting in Cycle 30, Zr-4 fuel product was used for part of 2024. Therefore, the penalty is still included in the 2024 Annual Report. Future 10 CFR 50.46 reports for cores not using Zr-4 will not include this penalty.
- 2.
Framatome identified no changes or errors applicable to the SEM/PWR-98 evaluation model for Large Break LOCA (LBLOCA) for MPS2 during 2024. This evaluation model is applicable to the MPS2 fuel with Zr-4 cladding.
While Zr-4 fuel product is no longer used in MPS2 starting in Cycle 30, Zr-4 fuel product was used for part of 2024. Therefore, this analysis is still included in the 2024 annual report. Future 10 CFR 50.46 reports for cores not using Zr-4 will not include this analysis.
- 3.
Framatome identified the following change applicable to the EMF-2103(P)(A),
Revision 3, evaluation model for RLBLOCA applicable to the AREVA Standard CE14 HTP fuel product with M5' fuel rod cladding for MPS2 during 2024.
- Typographical error in packing factor correlation in S-RELAP5 A minor error was identified in the S-RELAP5 code related to the packing factor model that is used to capture the effect of fuel relocation. The documented model is correct, but a typographical error was made when implementing the model in S-RELAP5. The error has been corrected and an evaluation was conducted to determine the impact the error has on the affected analyses.
The PCT impact for the MPS2 RLBLOCA analysis is 0 ºF.
Millstone Power Station Unit 3
- 1.
Westinghouse identified no changes or errors applicable to the 1985 Westinghouse SBLOCA Evaluation Model with NOTRUMP for MPS3 during 2024.
Serial No.25-163 Docket Nos. 50-336/423/338/339/280/281/395, Page 2 of 5
- 2.
Westinghouse identified the following changes or errors applicable to the FSLOCA Region 2 Large Break WCAP-16996-P-A, Revision 1, Realistic LOCA Evaluation Methodology Applied to the Full Spectrum of Break Sizes (FSLOCA) for MPS3 during 2024.
- STEAM/FISSION GAS SPECIFIC HEAT CALCULATION An error was identified in WCOBRA/TRAC-TF2 related to an incorrect specific heat value used in the calculation of superheated steam thermal conductivity, as part of the post-burst pellet-to-cladding gap heat transfer calculation. The incorrect specific heat value results in the superheated steam thermal conductivity being slightly under-predicted at the burst node after rupture is predicted. This leads to a minimal reduction in the gap conductance and slight over-prediction of the fuel average temperatures at the rod burst location after burst is predicted. The deficiency was evaluated to give PCT impact of 0°F.
- BARREL/BAFFLE REGION VOLUME ERROR An error was identified related to the incorrect modeling of the volume between the core barrel and the baffle plates within the active fuel length was modeled incorrectly. The corrected values have been evaluated for impact on the current licensing basis analysis results. The error was evaluated to have an estimated PCT impact of 0°F.
- CCFL (COUNTER CURRENT FLOW LIMITATION) GLOBAL VOLUME ERROR An error was identified related to the incorrect modeling of the volume in the global channel in the CCFL region above the active fuel length. The corrected values have been evaluated for impact on the current licensing basis analysis results. The CCFL global volume modeling error has been generically evaluated leading to an estimated PCT impact of 0°F.
North Anna Power Station Units 1 and 2
- 1.
Framatome identified no changes or errors applicable to the EMF-2328(P)(A),
Revision 0, PWR Small Break LOCA EM using S-RELAP5 for NAPS1 and NAPS2 during 2024.
- 2.
Westinghouse identified the following changes or errors applicable to the WCAP-16996-P-A FSLOCA Region II Large Break EM for NAPS1 and NAPS2 during 2024.
- STEAM/FISSION GAS SPECIFIC HEAT CALCULATION
Serial No.25-163 Docket Nos. 50-336/423/338/339/280/281/395, Page 3 of 5 An error was identified in WCOBRA/TRAC-TF2 related to an incorrect specific heat value used in the calculation of superheated steam thermal conductivity, as part of the post-burst pellet-to-cladding gap heat transfer calculation. The incorrect specific heat value results in the superheated steam thermal conductivity being slightly under-predicted at the burst node after rupture is predicted. This leads to a minimal reduction in the gap conductance and slight over-prediction of the fuel average temperatures at the rod burst location after burst is predicted. The deficiency was evaluated to give PCT impact of 0°F.
- CCFL GLOBAL VOLUME ERROR An error was identified related to the incorrect modeling of the volume in the global channel in the CCFL region above the active fuel length. The corrected values have been evaluated for impact on the current licensing basis analysis results. The CCFL global volume modeling error has been generically evaluated leading to an estimated PCT impact of 0°F.
Surry Power Station Units 1 and 2
- 1.
Framatome identified no changes or errors applicable to the EMF-2328(P)(A),
Revision 0, PWR Small Break LOCA EM using S-RELAP5 for SPS1 and SPS2 during 2024:
- 2.
Westinghouse identified the following error applicable to the FSLOCA Region 2 Large Break WCAP-16996-P-A, Revision 1, Realistic LOCA Evaluation Methodology Applied to the Full Spectrum of Break Sizes (FSLOCA) for SPS1 and SPS2 during 2024.
- STEAM/FISSION GAS SPECIFIC HEAT CALCULATION An error was identified in WCOBRA/TRAC-TF2 related to an incorrect specific heat value used in the calculation of superheated steam thermal conductivity, as part of the post-burst pellet-to-cladding gap heat transfer calculation. The incorrect specific heat value results in the superheated steam thermal conductivity being slightly under-predicted at the burst node after rupture is predicted. This leads to a minimal reduction in the gap conductance and slight over-prediction of the fuel average temperatures at the rod burst location after burst is predicted. The deficiency was evaluated to give PCT impact of 0°F.
Virgil C. Summer Nuclear Station Unit 1
- 1.
Westinghouse identified the following errors applicable to the WCAP-16996-P-A Region I EM for VCSNS during 2024.
- STEAM/FISSION GAS SPECIFIC HEAT CALCULATION
Serial No.25-163 Docket Nos. 50-336/423/338/339/280/281/395, Page 4 of 5 An error was identified in WCOBRA/TRAC-TF2 related to an incorrect specific heat value used in the calculation of superheated steam thermal conductivity, as part of the post-burst pellet-to-cladding gap heat transfer calculation. The incorrect specific heat value results in the superheated steam thermal conductivity being slightly under-predicted at the burst node after rupture is predicted. This leads to a minimal reduction in the gap conductance and slight over-prediction of the fuel average temperatures at the rod burst location after burst is predicted. The deficiency was evaluated to give PCT impact of 0°F.
- CCFL GLOBAL VOLUME ERROR An error was identified in which the volume in the global channel in the CCFL region above the active fuel length was modeled incorrectly. The corrected values have been evaluated for impact on the current licensing-basis analysis results.
The CCFL global volume modeling error has been generically evaluated leading to an PCT impact of 0°F.
- 2.
Westinghouse identified the following errors applicable to the WCAP-16996-P-A Region II EM for VCSNS during 2024.
- STEAM/FISSION GAS SPECIFIC HEAT CALCULATION An error was identified in WCOBRA/TRAC-TF2 related to an incorrect specific heat value used in the calculation of superheated steam thermal conductivity, as part of the post-burst pellet-to-cladding gap heat transfer calculation. The incorrect specific heat value results in the superheated steam thermal conductivity being slightly under-predicted at the burst node after rupture is predicted. This leads to a minimal reduction in the gap conductance and slight over-prediction of the fuel average temperatures at the rod burst location after burst is predicted. The deficiency was evaluated to give PCT impact of 0°F.
- CCFL GLOBAL VOLUME ERROR An error was identified related to the incorrect modeling of the volume in the global channel in the CCFL region above the active fuel length. The corrected values have been evaluated for impact on the current licensing-basis analysis results. The CCFL global volume modeling error has been generically evaluated leading to an estimated PCT impact of 0°F.
Conclusion The LOCA results for MPS2, MPS3, NAPS1, NAPS2, SPS1, SPS2, and VCSNS are confirmed in the PCT margin utilization 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
Serial No.25-163 Docket Nos. 50-336/423/338/339/280/281/395, Page 5 of 5 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 2024.
Serial Number 25-163 Docket Nos. 50-336/423 2024 ANNUAL REPORT OF EMERGENCY CORE COOLING SYSTEM (ECCS) MODEL CHANGES PURSUANT TO THE REQUIREMENTS OF 10 CFR 50.46 2024 ANNUAL REPORTING OF 10 CFR 50.46 MARGIN UTILIZATION DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNITS 2 AND 3
Serial Number 25-163 Docket Nos. 50-336/423, Page 1 of 5 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 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 Temp(°F)
LICENSING BASIS Analysis of Record PCT 1707 PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments
- 1.
Zirc-4 Product Penalty 4
- 2.
M5 LOCA Swelling and Rupture 0
- 3.
S-RELAP5 Oxidation Calculations 3
B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
None 0
D.
Other
- 1.
None 0
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1714
Serial Number 25-163 Docket Nos. 50-336/423, Page 2 of 5 10 CFR 50.46 MARGIN UTILIZATION - LARGE BREAK LOCA Plant Name:
Millstone Power Station, Unit 2 Utility Name:
Dominion Energy Nuclear Connecticut, Inc.
Analysis Information EM:
SEM/PWR-98 Limiting Break Size: 1.0 DECLG Analysis Date:
November 1998 Vendor:
AREVA Peak Linear Power:
15.1 kW/ft Notes:
None Clad Temp(°F)
LICENSING BASIS Analysis of Record PCT 1814 PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments
- 1.
Corrected Corrosion Enhancement Factor
-1
- 2.
ICECON Coding Errors 0
- 3.
Setting RFPAC Fuel Temperatures at Start of Reflood
-2
- 4.
SISPUNCH/ujun98 Code Error 0
- 5.
Error in Flow Blockage Model in TOODEE2 0
- 6.
Change in TOODEE2-Calculation of QMAX 0
- 7.
Change in Gadolinia Modeling 0
- 8.
PWR LBLOCA Split Break Modeling 0
- 9.
TEOBY Calculation Error 0
- 10.
Inappropriate Heat Transfer in TOODEE2 0
- 11.
End-of-Bypass Prediction by TEOBY 0
- 12.
R4SS Overwrite of Junction Inertia 0
- 13.
Incorrect Junction Inertia Multipliers 1
- 14.
Errors Discovered During RODEX2 V&V 0
- 15.
Error in Broken Loop SG Tube Exit Junction Inertia 0
- 16.
RFPAC Refill and Reflood Calculation Code Errors 16
- 17.
Incorrect Pump Junction Area Used in RELAP4 0
- 18.
Error in TOODEE2 Clad Thermal Expansion
-1
- 19.
Accumulator Line Loss Error
-1
- 20.
Inconsistent 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-Conservative RODEX Fuel Pellet Temperature 20
- 25.
Array Index Issues in the RELAP4 Code 0
B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
None 0
D.
Other
- 1.
None 0
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1845
Serial Number 25-163 Docket Nos. 50-336/423, Page 3 of 5 10 CFR 50.46 MARGIN UTILIZATION - LARGE BREAK LOCA Plant Name:
Millstone Power Station, Unit 2 (M5 Fuel)
Utility Name:
Dominion Energy Nuclear Connecticut, Inc.
Analysis Information EM:
EMF-2103 Limiting Break Size: 1.0 DEGB Analysis Date:
January 2017 Vendor:
AREVA Peak Linear Power: 15.1 kW/ft Notes:
None Clad Temp(°F)
LICENSING BASIS Analysis of Record PCT 1615 PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments
- 1.
Placement of Hot Leg Piping Form Loss Coefficient 0
- 2.
M5 LOCA Swelling and Rupture 0
- 3.
S-RELAP5 Oxidation Calculations 0
- 4.
Cathcart-Pawel correlation implementation 0
- 5.
Rod pressure not reset after rupture in S-RELAP5 LOCA calculations 0
- 6.
Radiation enclosure input error 0
- 7.
Downcomer to upper head bypass error 0
- 8.
Fuel model open porosity input error 0
B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
Typographical error in packing factor correlation 0
D.
Other
- 1.
None 0
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1615
Serial Number 25-163 Docket Nos. 50-336/423, Page 4 of 5 10 CFR 50.46 MARGIN UTILIZATION - SMALL BREAK LOCA Plant Name:
Millstone Power Station, Unit 3 Utility Name:
Dominion Energy Nuclear Connecticut, Inc.
Analysis Information EM:
NOTRUMP Limiting Break Size:
4 inches Analysis Date:
02/07/07 Vendor:
Westinghouse FQ:
2.6 FdH:
1.65 Fuel:
RFA-2 SGTP (%):
10 Notes:
None Clad Temp (°F)
LICENSING BASIS Analysis of Record PCT 1193 PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments
- 1.
Errors in Reactor Vessel Lower Plenum Surface Area Calculations 0
- 2.
Discrepancy in Metal Masses Used From Drawings 0
- 3.
Urania-Gadolinia Pellet Thermal Conductivity Calculation 0
- 4.
Pellet Crack and Dish Volume Calculation 0
- 5.
Treatment of Vessel Average Temperature Uncertainty 0
- 6.
Maximum Fuel Rod Time Step Logic 0
- 7.
Radiation Heat Transfer Logic 0
- 8.
NOTRUMP-EM Evaluation of Fuel Pellet Thermal 0
Conductivity Degradation
- 9.
SBLOCTA Cladding Strain Requirement for Fuel 0
Rod Burst
- 10.
Fuel Rod Gap Conductance Error 0
- 11.
Radiation Heat Transfer Model Error 0
- 12.
SBLOCTA Pre-DNB Cladding Heat Transfer 0
Coefficient Calculation
- 13.
Insertion of AXIOM' Cladding LTAs 0
- 14.
Vessel Average Temperature Uncertainty 0
- 15.
Error in the Upper Plenum Fluid Volume Calculation 0
- 16.
UO2 Fuel Pellet Heat Capacity 0
- 17.
Small Break LOCA PAD5 Implementation 0
- 18.
Reduction in Flow Area to the Bottom of the Barrel/Baffle 0
Region
- 19.
Measurement Uncertainty Recapture Uprate 0
B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
None 0
D.
Other
- 1.
None 0
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1193
Serial Number 25-163 Docket Nos. 50-336/423, Page 5 of 5 10 CFR 50.46 MARGIN UTILIZATION - LARGE BREAK LOCA Plant Name:
Millstone Power Station, Unit 3 Utility Name:
Dominion Energy Nuclear Connecticut, Inc.
Analysis Information EM:
FSLOCA (Region II)
Limiting Break Size:
Guillotine Analysis Date:
October 2020 Vendor:
Westinghouse FQ:
2.6 FdH:
1.65 Fuel:
RFA-2 SGTP (%):
10 Notes:
None Clad Temp (°F)
LICENSING BASIS Analysis of Record PCT 1712 PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments
- 1.
Non-Conservation of Energy in the 0
Generalized Energy Deposition Model
- 2.
Error in Hoop Stress Used in Cladding Rupture Model 0
- 3.
Error in Flow Area and Volume of Thimble Components 0
- 4.
Vapor / Continuous Liquid Interfacial Drag Coefficient 0
in Churn-Turbulent Flow Regime B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
Steam/Fission Gas Specific Heat Calculation 0
- 2.
Barrel/Baffle Region Volume Error 0
- 3.
CCFL Global Volume Error 0
D.
Other
- 1.
None 0
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1712
Serial Number 25-163 Docket Nos. 50-338/339 ATTACHMENT 3 2024 ANNUAL REPORT OF EMERGENCY CORE COOLING SYSTEM (ECCS) MODEL CHANGES PURSUANT TO THE REQUIREMENTS OF 10 CFR 50.46 2024 ANNUAL REPORTING OF 10 CFR 50.46 MARGIN UTILIZATION VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 AND 2
Serial Number 25-163 Docket Nos. 50-338/339, Page 1 of 4 10 CFR 50.46 MARGIN UTILIZATION - FRAMATOME FVI SMALL BREAK LOCA Plant Name:
North Anna Power Station, Unit 1 Utility Name:
Virginia Electric and Power Company Analysis Information EM:
W&CE SBLOCA EMF-2328 Limiting Break Size: 6.5 inches Analysis Date:
May 2018 Vendor:
Framatome FQ:
2.5 FH:
1.65 Fuel:
Representative 17x17 Non-M5 SGTP (%):
7 Notes:
None Clad Temp (°F)
LICENSING BASIS Analysis of Record PCT 1801 PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments
- 1.
None 0
B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
None 0
D.
Other
- 1.
None 0
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1801 NOTES:
Serial Number 25-163 Docket Nos. 50-338/339, Page 2 of 4 10 CFR 50.46 MARGIN UTILIZATION - WESTINGHOUSE LARGE BREAK LOCA Plant Name:
North Anna Power Station, Unit 1 Utility Name:
Virginia Electric and Power Company Analysis Information EM:
FSLOCA (Region II)
Limiting Break Size:
DEGB Analysis Date:
August 2019 Vendor:
Westinghouse FQ:
2.5 FH:
1.70 Fuel:
RFA-2 SGTP (%):
2%
Clad Temp (°F)
LICENSING BASIS Analysis of Record PCT 1893 PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments
- 1.
Evaluation of Containment Spray Flow Increase 0
- 2.
Error in Hoop Stress used in Cladding Rupture Model 0
- 3.
Non-Conservation of Energy in the 0
Generalized Energy Deposition Model
- 4.
Vapor / Continuous Liquid Interfacial Drag Coefficient 0
in Churn-Turbulent Flow Regime B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
Steam/Fission Gas Specific Heat Calculation 0
- 2.
CCFL Global Volume Error 0
D.
Other
- 1.
None LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1893
Serial Number 25-163 Docket Nos. 50-338/339, Page 3 of 4 10 CFR 50.46 MARGIN UTILIZATION - FRAMATOME FVI SMALL BREAK LOCA Plant Name:
North Anna Power Station, Unit 2 Utility Name:
Virginia Electric and Power Company Analysis Information EM:
W&CE SBLOCA EMF-2328 Limiting Break Size: 6.5 inches Analysis Date:
May 2018 Vendor:
Framatome FQ:
2.5 FH:
1.65 Fuel:
Representative 17x17 Non-M5 SGTP (%):
7 Notes:
None Clad Temp (°F)
LICENSING BASIS Analysis of Record PCT 1801 PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments
- 1.
None 0
B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
None 0
D.
Other
- 1.
None 0
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1801
Serial Number 25-163 Docket Nos. 50-338/339, Page 4 of 4 10 CFR 50.46 MARGIN UTILIZATION - WESTINGHOUSE LARGE BREAK LOCA Plant Name:
North Anna Power Station, Unit 2 Utility Name:
Virginia Electric and Power Company Analysis Information EM:
FSLOCA (Region II)
Limiting Break Size:
DEGB Analysis Date:
August 2019 Vendor:
Westinghouse FQ:
2.5 FH:
1.70 Fuel:
RFA-2 SGTP (%):
2%
Clad Temp (°F)
LICENSING BASIS Analysis of Record PCT 1893 PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments
- 1.
Evaluation of Containment Spray Flow Increase 0
- 2.
Error in Hoop Stress used in Cladding Rupture Model 0
- 3.
Non-Conservation of Energy in the 0
Generalized Energy Deposition Model
- 4.
Vapor / Continuous Liquid Interfacial Drag Coefficient 0
in Churn-Turbulent Flow Regime B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
Steam/Fission Gas Specific Heat Calculation 0
- 2.
CCFL Global Volume Error 0
D.
Other
- 1.
None 0
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1893
Serial Number 25-163 Docket Nos. 50-280/281 ATTACHMENT 4 2024 ANNUAL REPORT OF EMERGENCY CORE COOLING SYSTEM (ECCS) MODEL CHANGES PURSUANT TO THE REQUIREMENTS OF 10 CFR 50.46 2024 ANNUAL REPORTING OF 10 CFR 50.46 MARGIN UTILIZATION VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2
Serial Number 25-163 Docket Nos. 50-280/281, Page 1 of 4 10 CFR 50.46 MARGIN UTILIZATION - FRAMATOME FVI SMALL BREAK LOCA Plant Name:
Surry Power Station, Unit 1 Utility Name:
Virginia Electric and Power Company Analysis Information EM:
W&CE SBLOCA EMF-2328 Limiting Break Size: 2.6 inches Analysis Date:
July 2018 Vendor:
Framatome FQ:
2.5 FH:
1.70 Fuel:
Representative 15x15 Non-M5 SGTP (%):
7 Notes:
None Clad Temp (°F)
LICENSING BASIS Analysis of Record PCT 1673 PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments
- 1.
SBLOCA Rod History Truncation 0
(FVI-SBLOCA downflow baffle)
- 2.
Upflow Baffle Modification 21 B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
None 0
D.
Other
- 1.
None 0
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1694
Serial Number 25-163 Docket Nos. 50-280/281, Page 2 of 4 10 CFR 50.46 MARGIN UTILIZATION - WESTINGHOUSE LARGE BREAK LOCA Plant Name:
Surry Power Station, Unit 1 Utility Name:
Virginia Electric and Power Company Analysis Information EM:
FSLOCA (Region II)
Limiting Break Size:
DEG Analysis Date:
August 2019 Vendor:
Westinghouse FQ:
2.5 FH:
1.7 Fuel:
Upgrade SGTP (%):
7 Notes:
None Clad Temp (°F)
LICENSING BASIS Analysis of Record PCT 1875 PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments
- 1.
Advanced Debris Filter Bottom Nozzle Large 0
Break LOCA Evaluation
- 2.
Upflow Conversion 46
- 3.
Evaluation of Containment Spray Flow Increase 0
- 4.
Error in Hoop Stress used in Cladding Rupture Model 0
- 5.
Non-Conservation of Energy in the 0
Generalized Energy Deposition Model
- 6.
Reduction of Total Core Peaking Factor 0
Surveillance Uncertainty
- 7.
Error in Flow Area and Volume of Thimble Components 0
- 8.
Vapor / Continuous Liquid Interfacial Drag Coefficient 0
in Churn-Turbulent Flow Regime B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
Steam/Fission Gas Specific Heat Calculation 0
D.
Other
- 1.
None 0
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1921
Serial Number 25-163 Docket Nos. 50-280/281, Page 3 of 4 10 CFR 50.46 MARGIN UTILIZATION - FRAMATOME FVI SMALL BREAK LOCA Plant Name:
Surry Power Station, Unit 2 Utility Name:
Virginia Electric and Power Company Analysis Information EM:
W&CE SBLOCA EMF-2328 Limiting Break Size: 2.6 inches Analysis Date:
July 2018 Vendor:
Framatome FQ:
2.5 FH:
1.70 Fuel:
Representative 15x15 Non-M5 SGTP (%):
7 Notes:
None Clad Temp (°F)
LICENSING BASIS Analysis of Record PCT 1673 PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments
- 1.
SBLOCA Rod History Truncation 0
(FVI-SBLOCA downflow baffle)
- 2.
Upflow Baffle Modification 21 B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
None 0
D.
Other
- 1.
None 0
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1694
Serial Number 25-163 Docket Nos. 50-280/281, Page 4 of 4 10 CFR 50.46 MARGIN UTILIZATION - WESTINGHOUSE LARGE BREAK LOCA Plant Name:
Surry Power Station, Unit 2 Utility Name:
Virginia Electric and Power Company Analysis Information EM:
FSLOCA (Region II)
Limiting Break Size:
DEG Analysis Date:
August 2019 Vendor:
Westinghouse FQ:
2.5 FH:
1.7 Fuel:
Upgrade SGTP (%):
7 Notes:
None Clad Temp (°F)
LICENSING BASIS Analysis of Record PCT 1875 PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments
- 1.
Advanced Debris Filter Bottom Nozzle Large 0
Break LOCA Evaluation
- 2.
Upflow Conversion 46
- 3.
Evaluation of Containment Spray Flow Increase 0
- 4.
Error in Hoop Stress used in Cladding Rupture Model 0
- 5.
Non-Conservation of Energy in the 0
Generalized Energy Deposition Model
- 6.
Reduction of Total Core Peaking Factor 0
Surveillance Uncertainty
- 7.
Error in Flow Area and Volume of Thimble Components 0
- 8.
Vapor / Continuous Liquid Interfacial Drag Coefficient 0
in Churn-Turbulent Flow Regime B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
Steam/Fission Gas Specific Heat Calculation 0
D.
Other
- 1.
None 0
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1921
Serial Number 25-163 ATTACHMENT 5 2024 ANNUAL REPORT OF EMERGENCY CORE COOLING SYSTEM (ECCS) MODEL CHANGES PURSUANT TO THE REQUIREMENTS OF 10 CFR 50.46 2024 ANNUAL REPORTING OF 10 CFR 50.46 MARGIN UTILIZATION DOMINION ENERGY SOUTH CAROLINA, INC.
VIRGIL C. SUMMER NUCLEAR STATION UNIT 1
Serial Number 25-163 Docket Nos. 50-395, Page 1 of 2 10 CFR 50.46 MARGIN UTILIZATION - WESTINGHOUSE SMALL BREAK LOCA Plant Name:
V. C. Summer Utility Name:
Dominion Energy South Carolina Analysis Information EM:
FSLOCA (Region I)
Limiting Break Size:
2.6 Inch Analysis Date:
January 2019 Vendor:
Westinghouse FQ:
2.5 FdH:
1.70 Notes:
None Clad Temp(°F)
LICENSING BASIS Analysis of Record PCT 1108 (Including gamma energy redistribution)
A.
Prior ECCS Model Assessments
- 1.
Error in Hoop Stress used in Cladding Rupture Model 0
- 2.
Non-Conservation of Energy in the 0
Generalized Energy Deposition Model
- 3.
Vapor / Continuous Liquid Interfacial Drag Coefficient 0
in Churn-Turbulent Flow Regime B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
Steam/Fission Gas Specific Heat Calculation 0
- 2.
CCFL Global Volume Error 0
D.
Other
- 1.
None 0
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1108
Serial Number 25-163 Docket Nos. 50-395, Page 2 of 2 10 CFR 50.46 MARGIN UTILIZATION - WESTINGHOUSE LARGE BREAK LOCA Plant Name:
V. C. Summer Utility Name:
Dominion Energy South Carolina Analysis Information EM:
FSLOCA (Region II)
Limiting Break Size:
DEGB Analysis Date:
January 2019 Vendor:
Westinghouse FQ:
2.5 FdH:
1.70 Notes:
None Clad Temp(°F)
LICENSING BASIS Analysis of Record PCT 1879 (Including gamma energy redistribution)
A.
Prior ECCS Model Assessments
- 1.
Error in Hoop Stress used in Cladding Rupture Model 0
- 2.
Non-Conservation of Energy in the 0
Generalized Energy Deposition Model
- 1.
Vapor / Continuous Liquid Interfacial Drag Coefficient 0
in Churn-Turbulent Flow Regime B.
Planned Plant Modification Evaluations
- 1.
None 0
C.
2024 ECCS Model Assessments
- 1.
Steam/Fission Gas Specific Heat Calculation 0
- 2.
CCFL Global Volume Error 0
D.
Other
- 1.
None 0
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
1879