RS-19-103, Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors
| ML19291B124 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 10/18/2019 |
| From: | Simpson P Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RS-19-103 | |
| Download: ML19291B124 (16) | |
Text
4300 Wmf1eld Road F Warrenville. IL 60555 Exelon Generation 630 65 7 2000 Office RS-19-103 10 CFR 50.46 October 18, 2019 U.S. Nuclear Regulatory Commission ATTN : Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-19 and DPR-25 NRC Docket Nos. 50-237 and 50-249
Subject:
Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors for Dresden Nuclear Power Station, Units 2 and 3 In accordance with 10 CFR 50.46, "Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors ," paragraph (a)(3)(ii), Exelon Generation Company, LLC (EGC) is submitting this letter and its attachments to meet the annual reporting requirements of the Emergency Core Cooling System (ECCS) Evaluation Model changes and errors for Dresden Nuclear Power Station, Units 2 and 3. This report covers the period from October 20, 2018, through October 18, 2019.
There are no regulatory commitments conta ined in this letter. If there are any questions concerning this letter, please contact Mr. Mitchel A. Mathews at (630) 657-2819.
Rr~~
Patrick R. Simpson Sr. Manager Licensing Exelon Generation Company, LLC Attachments:
- 1. Dresden Nuclear Power Station, Unit 2 10 CFR 50.46 Report (Westinghouse Fuel -
Evaluation Model - USA5)
- 2. Dresden Nuclear Power Station, Unit 2 10 CFR 50.46 Report (Westinghouse Fuel -
Evaluation Model- USA6)
- 3. Dresden Nuclear Power Station, Unit 3 10 CFR 50.46 Report (Westinghouse Fuel -
Evaluation Model - USA5)
- 4. Dresden Nuclear Power Station, Unit 2 10 CFR 50.46 Report (Framatome Fuel)
- 5. Dresden Nuclear Power Station , Unit 3 10 CFR 50.46 Report (Framatome Fuel)
- 6. Dresden Nuclear Power Station, Units 2 and 3 10 CFR 50.46 Report Assessment Notes
Attachment 1 Dresden Nuclear Power Station, Unit 2 10 CFR 50.46 Report (Westinghouse Fuel - Evaluation Model - USA5)
PLANT NAME: Dresden Nuclear Power Station, Unit 2 ECCS EVALUATION MODEL: USA5 REPORT REVISION DATE: October 18, 2019 CURRENT OPERATING CYCLE: 26 ANALYSIS OF RECORD Evaluation Model: WCAP-16078-P-A, "Westinghouse BWR ECCS Evaluation Model: Supplement 3 to Code Description, Qualification and Application to SVEA-96 Optima2 Fuel,"
Revision 0, dated November 2004 Calculations: 1. OPTIMA2-TR021DR-LOCA, "Dresden 2 and 3 LOCA Analysis for SVEA-96 Optima2 Fuel,"
Revision 6, dated September 2010
- 2. NF-BEX-13-111-NP, "Dresden Nuclear Power Station Unit 2 Cycle 24 MAPLHGR Report,"
Revision 0, dated September 2013 Fuel Analyzed in Calculation: SVEA-96 Optima2 Limiting Fuel Type: SVEA-96 Optima2 Limiting Single Failure: Low Pressure Coolant Injection system injection valve Limiting Break Size and Location: 1.0/0.8 Double-Ended Guillotine Break in the Recirculation Pump Suction Line Reference Peak Cladding 2150°F Temperature (PCT)
Page 1 of 2
Attachment 1 Dresden Nuclear Power Station, Unit 2 10 CFR 50.46 Report (Westinghouse Fuel - Evaluation Model - USA5)
MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS 10 CFR 50.46 report dated October 30, 2009 (See Note 1) PCT = 0°F 10 CFR 50.46 report dated October 29, 2010 (See Note 2) PCT = 0°F 10 CFR 50.46 report dated October 28, 2011 (See Note 3) PCT = 0°F 10 CFR 50.46 report dated October 26, 2012 (See Note 4) PCT = 0oF 10 CFR 50.46 report dated October 25, 2013 (See Note 5) PCT = 0oF 10 CFR 50.46 report dated October 24, 2014 (See Note 6) PCT = 0oF 10 CFR 50.46 report dated October 23, 2015 (See Note 7) PCT = 0oF 10 CFR 50.46 report dated October 21, 2016 (See Note 8) PCT = 0°F 10 CFR 50.46 report dated October 20, 2017 (See Note 9) PCT = 0°F 10 CFR 50.46 report dated October 19, 2018 (See Note 10) PCT = 0°F Net PCT 2150°F B. CURRENT LOCA MODEL ASSESSMENTS None (See Note 11) PCT = 0°F Total PCT change from current assessments PCT = 0°F Cumulative PCT change from current assessments PCT = 0°F Net PCT 2150°F Page 2 of 2
Attachment 2 Dresden Nuclear Power Station, Unit 2 10 CFR 50.46 Report (Westinghouse Fuel - Evaluation Model - USA6)
PLANT NAME: Dresden Nuclear Power Station, Unit 2 ECCS EVALUATION MODEL: USA6 REPORT REVISION DATE: October 18, 2019 CURRENT OPERATING CYCLE: 26 ANALYSIS OF RECORD Evaluation Model: WCAP-16865-P-A, "Westinghouse BWR ECCS Evaluation Model Updates: Supplement 4 to Code Description, Qualification and Application," Revision 1, dated October 2011 Calculations: 1. NF-BEX-13-68P, "Dresden 2 and 3 LOCA Analysis for SVEA-96 Optima2 Fuel," Revision 0, dated June 2015
- 2. NF-BEX-15-101-NP, "Dresden Nuclear Power Station Unit 2, Cycle 25 MAPLHGR Report,"
Revision 0, dated September 2015 Fuel Analyzed in Calculation: SVEA-96 Optima2 Limiting Fuel Type: SVEA-96 Optima2 Limiting Single Failure: Low Pressure Coolant Injection system injection valve Limiting Break Size and Location: 1.0/0.8 Double-Ended Guillotine Break in the Recirculation Pump Suction Line Reference Peak Cladding 2150°F Temperature (PCT)
Page 1 of 2
Attachment 2 Dresden Nuclear Power Station, Unit 2 10 CFR 50.46 Report (Westinghouse Fuel - Evaluation Model - USA6)
MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS 10 CFR 50.46 report dated October 21, 2016 (See Note 8) PCT = 0oF 10 CFR 50.46 report dated October 20, 2017 (See Note 9) PCT = 0oF 10 CFR 50.46 report dated October 19, 2018 (See Note 10) PCT = 0oF Net PCT 2150°F B. CURRENT LOCA MODEL ASSESSMENTS None (See Note 11) PCT = 0°F Total PCT change from current assessments PCT = 0°F Cumulative PCT change from current assessments PCT = 0°F Net PCT 2150°F Page 2 of 2
Attachment 3 Dresden Nuclear Power Station, Unit 3 10 CFR 50.46 Report (Westinghouse Fuel - Evaluation Model - USA5)
PLANT NAME: Dresden Nuclear Power Station, Unit 3 ECCS EVALUATION MODEL: USA5 REPORT REVISION DATE: October 18, 2019 CURRENT OPERATING CYCLE: 26 ANALYSIS OF RECORD Evaluation Model: WCAP-16078-P-A, "Westinghouse BWR ECCS Evaluation Model: Supplement 3 to Code Description, Qualification and Application to SVEA-96 Optima2 Fuel," Revision 0, dated November 2004 Calculations: 1. OPTIMA2-TR021DR-LOCA, "Dresden 2 and 3 LOCA Analysis for SVEA-96 Optima2 Fuel,"
Revision 6, dated September 2010
- 2. NF-BEX-14-77-NP, "Dresden Nuclear Power Station Unit 3 Cycle 24 MAPLHGR Report,"
Revision 0, dated September 2014 Fuel Analyzed in Calculation: SVEA-96 Optima2 Limiting Fuel Type: SVEA-96 Optima2 Limiting Single Failure: Low Pressure Coolant Injection system injection valve Limiting Break Size and Location: 1.0/0.8 Double-Ended Guillotine Break in the Recirculation Pump Suction Line Reference Peak Cladding 2150°F Temperature (PCT)
Page 1 of 2
Attachment 3 Dresden Nuclear Power Station, Unit 3 10 CFR 50.46 Report (Westinghouse Fuel - Evaluation Model - USA5)
MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS 10 CFR 50.46 report dated October 30, 2009 (See Note 1) PCT = 0°F 10 CFR 50.46 report dated October 29, 2010 (See Note 2) PCT = 0°F 10 CFR 50.46 report dated October 28, 2011 (See Note 3) PCT = 0°F 10 CFR 50.46 report dated October 26, 2012 (See Note 4) PCT = 0oF 10 CFR 50.46 report dated October 25, 2013 (See Note 5) PCT = 0oF 10 CFR 50.46 report dated October 24, 2014 (See Note 6) PCT = 0oF 10 CFR 50.46 report dated October 23, 2015 (See Note 7) PCT = 0oF 10 CFR 50.46 report dated October 21, 2016 (See Note 8) PCT = 0oF 10 CFR 50.46 report dated October 20, 2017 (See Note 9) PCT = 0oF 10 CFR 50.46 report dated October 19, 2018 (See Note 10) PCT = 0oF Net PCT 2150°F B. CURRENT LOCA MODEL ASSESSMENTS None (See Note 11) PCT = 0°F Total PCT change from current assessments PCT = 0°F Cumulative PCT change from current assessments PCT = 0°F Net PCT 2150°F Page 2 of 2
Attachment 4 Dresden Nuclear Power Station, Unit 2 10 CFR 50.46 Report (Framatome Fuel)
PLANT NAME: Dresden Nuclear Power Station, Unit 2 ECCS EVALUATION MODEL: EXEM BWR-2000 REPORT REVISION DATE: October 18, 2019 CURRENT OPERATING CYCLE: 26 ANALYSIS OF RECORD Evaluation Model: EMF-2361(P)(A), "EXEM BWR-2000 ECCS Evaluation Model," Revision 0, dated May 2001 Calculations: 1. ANP-3483P, "Dresden Units 2 and 3 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel," Revision 0, dated July 2016
- 2. ANP-3493P, "Dresden Units 2 and 3 LOCA-ECCS Analysis MAPLHGR Limits for ATRIUM 10XM Fuel," Revision 0, dated August 2016 Fuel Analyzed in Calculation: ATRIUM 10XM Limiting Fuel Type: ATRIUM 10XM Limiting Single Failure: High Pressure Coolant Injection system Limiting Break Size and Location: 0.13 ft2 Split Break Recirculation Discharge Line Reference Peak Cladding 2125°F Temperature (PCT)
Page 1 of 2
Attachment 4 Dresden Nuclear Power Station, Unit 2 10 CFR 50.46 Report (Framatome Fuel)
MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS 10 CFR 50.46 report dated October 19, 2018 (See Note 10) PCT = 14oF Net PCT 2139°F B. CURRENT LOCA MODEL ASSESSMENTS AUTOHUP and HUXY Updates (See Note 11) PCT = 41°F Total PCT change from current assessments PCT = 41°F Cumulative PCT change from current assessments PCT = 41°F Net PCT 2180°F Page 2 of 2
Attachment 5 Dresden Nuclear Power Station, Unit 3 10 CFR 50.46 Report (Framatome Fuel)
PLANT NAME: Dresden Nuclear Power Station, Unit 3 ECCS EVALUATION MODEL: EXEM BWR-2000 REPORT REVISION DATE: October 18, 2019 CURRENT OPERATING CYCLE: 26 ANALYSIS OF RECORD Evaluation Model: EMF-2361(P)(A), "EXEM BWR-2000 ECCS Evaluation Model," Revision 0, dated May 2001 Calculations: 1. ANP-3483P, "Dresden Units 2 and 3 LOCA Break Spectrum Analysis for ATRIUM 10XM Fuel," Revision 0, dated July 2016
- 2. ANP-3493P, "Dresden Units 2 and 3 LOCA-ECCS Analysis MAPLHGR Limits for ATRIUM 10XM Fuel," Revision 0, dated August 2016 Fuel Analyzed in Calculation: ATRIUM 10XM Limiting Fuel Type: ATRIUM 10XM Limiting Single Failure: High Pressure Coolant Injection system Limiting Break Size and Location: 0.13 ft2 Split Break Recirculation Discharge Line Reference Peak Cladding 2125°F Temperature (PCT)
Page 1 of 2
Attachment 5 Dresden Nuclear Power Station, Unit 3 10 CFR 50.46 Report (Framatome Fuel)
MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS 10 CFR 50.46 report dated October 20, 2017 (See Note 9) PCT = 0oF 10 CFR 50.46 report dated October 19, 2018 (See Note 10) PCT = 14oF Net PCT 2139°F B. CURRENT LOCA MODEL ASSESSMENTS AUTOHUP and HUXY Updates (See Note 11) PCT = 41°F Total PCT change from current assessments PCT = 41°F Cumulative PCT change from current assessments PCT = 41°F Net PCT 2180°F Page 2 of 2
Attachment 6 Dresden Nuclear Power Station, Units 2 and 3 10 CFR 50.46 Report Assessment Notes Assessment Notes
- 1. Prior Loss of Coolant Accident (LOCA) Model Assessment (2009)
The referenced letter provided the annual 10 CFR 50.46, "Acceptance criteria for emergency core cooling systems (ECCS) for light-water nuclear power reactors," report for Dresden Nuclear Power Station (DNPS), Units 2 and 3. The letter updated the vessel leakage between the lower shroud and the downcomer. Westinghouse evaluated this change and demonstrated that all 10 CFR 50.46 criteria were satisfied. This evaluation resulted in maximum peak cladding temperature (PCT) impact due to the change in vessel leakage of 2°F for Optima2 fuel with the licensing basis PCT of 2152°F.
This PCT impact will remain in effect until the maximum average planar linear heat generation rate (MAPLHGR) limits for all bundles in future DNPS, Unit 2 and Unit 3 cores are evaluated for this change. The MAPLHGR limits for all bundles in the DNPS, Unit 2 were evaluated for this change for Cycle 24 and this penalty no longer applies for DNPS, Unit 2. Additionally, the MAPLHGR limits for all bundles in the DNPS, Unit 3 were evaluated for this change for Cycle 24 and this penalty no longer applies for DNPS, Unit 3.
[
Reference:
Letter from Timothy Hanley (SVPLTR: No. 09-0052, Exelon Generation Company, LLC (EGC)) to NRC, "Plant Specific ECCS Evaluation Changes - 10 CFR 50.46 Report," dated October 30, 2009]
- 2. Prior LOCA Model Assessment (2010)
The referenced letter provided the annual 10 CFR 50.46 report for DNPS, Units 2 and 3.
The letter reported the replacement of core spray lower sectional piping in DNPS, Unit 2 during DNPS, Unit 2 Refueling Outage No. 21. Westinghouse evaluated the core spray leakage due to this modification and concluded that the PCT impact was 0°F. The letter also identified a change in input for modeling bypass hole flow coefficient in the Westinghouse LOCA analysis. The impact on PCT due to this change was determined by Westinghouse to be 12°F. Westinghouse established a MAPLHGR limit for the fresh bundles to accommodate the change. For 10 CFR 50.46 reporting purposes, the PCT impact is conservatively applied to all bundle types in the core including the fresh bundles. This PCT update will remain in effect until the MAPLHGR limits for all bundles in future Dresden, Unit 2 and Unit 3 cores are evaluated for the change in bypass hole flow coefficient. The MAPLHGR limits for all bundles in the DNPS, Unit 2 were evaluated for this change for Cycle 24 and this penalty no longer applies for DNPS, Unit 2. Additionally, the MAPLHGR limits for all bundles in the DNPS, Unit 3 core were evaluated for this change for Cycle 24 and this penalty no longer applies for DNPS, Unit 3.
[
Reference:
Letter from Jeffrey Hansen (RS-10-191, EGC) to NRC, "Plant Specific ECCS Evaluation Changes - 10 CFR 50.46 Report," dated October 29, 2010]
Page 1 of 5
Attachment 6 Dresden Nuclear Power Station, Units 2 and 3 10 CFR 50.46 Report Assessment Notes
- 3. Prior LOCA Model Assessment (2011)
The referenced letter provided the annual 10 CFR 50.46 report for DNPS, Units 2 and 3.
The letter reported errors in the current Westinghouse Dresden LOCA analysis associated with the use of incorrect R-factors. The impact due to this change was determined to be 18°F in PCT update. For 10 CFR 50.46 reporting purposes, the PCT update is conservatively applied to all bundle types including the fresh bundles. This PCT update will remain in effect only until the MAPLHGR limits for all bundles in future DNPS, Unit 2 and Unit 3 cores are evaluated with the correct R-factors.
[
Reference:
Letter from David M. Gullott (RS-11-171, EGC) to NRC, "Plant Specific ECCS Evaluation Changes - 10 CFR 50.46 Report," dated October 28, 2011]
- 4. Prior LOCA Model Assessment (2012)
The referenced letter provided the annual 10 CFR 50.46 report for DNPS, Units 2 and 3.
The letter reported no changes, error corrections, or enhancements in the current Westinghouse Dresden LOCA analysis; therefore the delta is 0oF in PCT update.
[
Reference:
Letter from Patrick R. Simpson (RS-12-192, EGC) to NRC, "Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors for Dresden Nuclear Power Station, Units 2 and 3," dated October 26, 2012]
- 5. Prior LOCA Model Assessment (2013)
The referenced letter provided the annual 10 CFR 50.46 report for DNPS, Units 2 and 3.
The letter reported no changes, error corrections, or enhancements in the current Westinghouse Dresden LOCA analysis; therefore the delta is 0°F in PCT update.
[
Reference:
Letter from Patrick R. Simpson (RS-13-250, EGC) to NRC, "Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors for Dresden Nuclear Power Station, Units 2 and 3," dated October 25, 2013]
Page 2 of 5
Attachment 6 Dresden Nuclear Power Station, Units 2 and 3 10 CFR 50.46 Report Assessment Notes
- 6. Prior LOCA Model Assessment (2014)
Updated LOCA/MAPLHGR analyses were performed for DNPS, Unit 2 in support of operating Cycle 24. These analyses maintained the calculated PCT at 2150°F and accounted for the changes to the vessel leakage and bypass hole coefficient. Therefore, the penalties in Notes 1 and 2 no longer apply for DNPS, Unit 2. The penalty for incorrect R-factors in Note 3 remains applicable resulting in a net PCT of 2168°F for DNPS, Unit 2.
No changes, error corrections, or enhancements have been reported for the current DNPS, Unit 3 LOCA analysis. No ECCS-related changes or modifications have occurred at DNPS, Unit 3 that affect the assumptions in the DNPS LOCA analysis of record.
[
Reference:
Letter from Patrick R. Simpson (RS-14-296, EGC) to NRC, "Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors for Dresden Nuclear Power Station, Units 2 and 3," dated October 24, 2014]
- 7. Prior LOCA Model Assessment (2015)
Updated LOCA/MAPLHGR analyses were performed for DNPS, Unit 3 in support of Operating Cycle 24. These analyses for DNPS, Unit 3 maintained the calculated PCT at 2150°F and accounted for the changes to the vessel leakage and bypass hole coefficient. Therefore, the previous penalties of 2°F in Note 1 and 12°F in Note 2 above no longer apply for DNPS, Unit 3. The penalties in Attachment 2 listed for Notes 1 and 2 for DNPS, Unit 3 were changed to 0°F. The penalty for incorrect R-factors in Note 3 remains applicable resulting in a net PCT of 2168°F for DNPS, Unit 3.
No changes, error corrections, or enhancements have been reported for the current DNPS, Units 2 and 3 LOCA analyses. No ECCS-related changes or modifications have occurred at DNPS, Units 2 and 3 that affect the assumptions in the DNPS LOCA analysis of record.
[
Reference:
Letter from Patrick R. Simpson (RS-15-265, EGC) to NRC, "Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors for Dresden Nuclear Power Station, Units 2 and 3," dated October 23, 2015]
Page 3 of 5
Attachment 6 Dresden Nuclear Power Station, Units 2 and 3 10 CFR 50.46 Report Assessment Notes
- 8. Prior LOCA Model Assessment (2016)
The new USA6 LOCA Evaluation Model and calculation has been implemented for DNPS, Unit 2 for all fresh fuel starting with Cycle 25. This evaluation model and calculation supplement the existing Evaluation Model and calculation. This model reports a limiting PCT of 2150°F and has no additional PCT impacts or estimates as seen in Attachment 2.
Additionally, updated LOCA/MAPLHGR analyses were performed for DNPS, Unit 2 in support of operating Cycle 25. These analyses for DNPS, Unit 2 maintained the calculated PCT at 2150°F and accounted for the incorrect R-factors. Therefore, the previous penalty of 18°F in Note 3 no longer applies for DNPS, Unit 2. The penalty in Attachment 1 listed for Note 3 for DNPS, Unit 2 was changed to 0°F. The penalty for DNPS, Unit 3 in Attachment 3 related to Note 3 remains.
No changes, error corrections, or enhancements have been reported for the current DNPS, Units 2 and 3 LOCA analysis. No ECCS-related changes or modifications have occurred at DNPS, Unit 2 and 3 that affect the assumptions in the DNPS LOCA analysis of record.
[
Reference:
Letter from Patrick R. Simpson (RS-16-206, EGC) to NRC, "Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors for Dresden Nuclear Power Station, Units 2 and 3," dated October 21, 2016]
- 9. Prior LOCA Model Assessment (2017)
The new Framatome EXEM BWR-2000 Evaluation Model and calculation has been implemented for DNPS Unit 3 for the fresh fuel of ATRIUM 10XM loaded into the Cycle 25. This model reported a licensing basis PCT of 2125°F.
Additionally, updated LOCA/MAPLHGR analyses were performed for DNPS, Unit 3 for the Westinghouse fuel first introduced in Cycles 23 and 24. These analyses for DNPS, Unit 3 maintained the calculated PCT at 2150°F and accounted for the incorrect R-factors. All other Westinghouse fuel from before cycle 23 that was impacted by the R-factor error within Unit 3 has been discharged. Therefore, the previous penalty of 18°F in Note 3 no longer applies for DNPS, Unit 3. The penalty in Attachment 3 listed for Note 3 for DNPS, Unit 3 was changed to 0°F.
No changes, error corrections, or enhancements have been reported for the current DNPS, Units 2 and 3 LOCA analysis. No ECCS-related changes or modifications have occurred at DNPS, Unit 2 and 3 that affect the assumptions in the DNPS LOCA analysis of record.
[
Reference:
Letter from Patrick R. Simpson (RS-17-136, EGC) to NRC, "Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors for Dresden Nuclear Power Station, Units 2 and 3," dated October 20, 2017]
Page 4 of 5
Attachment 6 Dresden Nuclear Power Station, Units 2 and 3 10 CFR 50.46 Report Assessment Notes
- 10. Prior LOCA Model Assessment (2018)
The new Framatome EXEM BWR-2000 Evaluation Model and calculation has been implemented for DNPS Unit 2 for the fresh fuel of ATRIUM 10XM loaded into the Cycle 26 core. This model reports a limiting PCT of 2125°F. Subsequently, based on a review of design drawings, Framatome identified a PCT impact of 10°F for errors related to recirculation piping differences and a PCT impact of 4°F for errors due to updated steam dryer geometry, for a total PCT impact of 14°F, applicable to both Unit 2 and Unit-3 LOCA analyses.
No changes, error corrections, or enhancements have been reported for the current Westinghouse DNPS, Units 2 and 3 LOCA analysis. No ECCS-related changes or modifications have occurred at DNPS, Unit 2 and 3 that affect the assumptions in the DNPS LOCA analyses by Westinghouse and Framatome.
[
Reference:
Letter from Patrick R. Simpson (RS-18-132, EGC) to NRC, "Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors for Dresden Nuclear Power Station, Units 2 and 3," dated October 19, 2018.]
- 11. Current LOCA Model Assessment No changes, error corrections, or enhancements have been reported for the current Westinghouse DNPS, Units 2 and 3 LOCA analyses. No ECCS-related changes or modifications have occurred at DNPS, Unit 2 and 3 that affect the assumptions in the DNPS LOCA analyses by Westinghouse and Framatome.
There are two new changes, error corrections or enhancements in the Framatome EXEM BWR-2000 Evaluation Model for DNPS Units 2 and 3. First, an incorrect power was used in break spectrum HUXY calculation, which resulted in a 0°F PCT impact.
Second, a LOCA automation code incorrectly calculated a planar power heatup analysis, resulting in a PCT impact of +41°F.
No ECCS-related changes or modifications occurred at DNPS, Units 2 and 3 that affected the assumptions to any of the LOCA Analyses of Record (AORs).
Page 5 of 5