Text

Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors
	ML15296A127
Person / Time
Site:	Dresden
Issue date:	10/23/2015
From:	Simpson P; Exelon Generation Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	RS-15-265
	Download: ML15296A127 (8)
	v • d • e

4300 Winfield Road Warrenville. IL 60555 Exelon Generation(!, 630 657 2000 Office RS-15-265 10 CFR 50.46 October 23, 2015 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 25, 2014, through October 23, 2015.

There are no regulatory commitments contained in this letter. If there are any questions concerning this letter, please contact Mr. Mitchel A. Mathews at (630) 657-2819.

~R Patrick R. Simpson Manager - Licensing Attachments:

1. Dresden Nuclear Power Station Unit 2 - 10 CFR 50.46 Report (Westinghouse Fuel)

2. Dresden Nuclear Power Station Unit 3 - 10 CFR 50.46 Report (Westinghouse Fuel)

3. 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)

PLANT NAME: Dresden Nuclear Power Station, Unit 2 ECCS EVALUATION MODEL: USA5 REPORT REVISION DATE: 10/23/2015 CURRENT OPERATING CYCLE: 24 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,"

dated November 2004 Calculations: 1. OPTIMA2-TR021DR-LOCA, "Dresden 2 & 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 Double-Ended Guillotine Break in the Recirculation Pump Suction Line Reference Peak Cladding 2150°F Temperature (PCT)

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Attachment 1 Dresden Nuclear Power Station, Unit 2 10 CFR 50.46 Report (Westinghouse Fuel)

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= 18°F 10 CFR 50.46 report dated October 26, 2012 (See Note 4) ~PCT= 0°F 10 CFR 50.46 report dated October 25, 2013 (See Note 5) ~PCT= 0°F 10 CFR 50.46 report dated October 24, 2014 (See Note 6) ~PCT= 0°F Net PCT 2168°F

8. CURRENT LOCA MODEL ASSESSMENTS None (see Note 7) ~PCT= 0°F Total PCT change from current assessments l:~PCT = 0°F Cumulative PCT change from current assessments :Ll~PCTI = 0°F Net PCT 2168°F Page 2 of 2

Attachment 2 Dresden Nuclear Power Station, Unit 3 10 CFR 50.46 Report (Westinghouse Fuel)

PLANT NAME: Dresden Nuclear Power Station, Unit 3 ECCS EVALUATION MODEL: USA5 REPORT REVISION DATE: 10/23/2015 CURRENT OPERATING CYCLE: 24 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," dated November 2004 Calculations: 1. OPTIMA2-TR021 DR-LOCA, "Dresden 2 & 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 Double-Ended Guillotine Break in the Recirculation Pump Suction Line Reference Peak Cladding 2150°F Tern perature (PCT)

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Attachment 2 Dresden Nuclear Power Station, Unit 3 10 CFR 50.46 Report (Westinghouse Fuel)

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= 18°F 10 CFR 50.46 report dated October 26, 2012 (See Note 4) ~PCT= 0°F 10 CFR 50.46 report dated October 25, 2013 (See Note 5) ~PCT= 0°F 10 CFR 50.46 report dated October 24, 2014 (See Note 6) ~PCT= 0°F Net PCT 2168°F B. CURRENT LOCA MODEL ASSESSMENTS None; Discharge of fuel related to Notes 1 and 2 (See Note 7) ~PCT= 0°F Total PCT change from current assessments L:~PCT = 0°F Cumulative PCT change from current assessments L: I~PCT I = 0° F Net PCT 2168°F Page 2of2

Attachment 3 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 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 cl~dding 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 core 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 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 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, 201 O.]

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Attachment 3 Dresden Nuclear Power Station, Units 2 and 3 10 CFR 50.46 Report Assessment Notes

3. Prior LOCA Model Assessment 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. Gullatt (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 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-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 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.]

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Attachment 3 Dresden Nuclear Power Station, Units 2 and 3 10 CFR 50.46 Report Assessment Notes

6. Prior LOCA Model Assessment 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. Current LOCA Model Assessment 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 & 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.

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