RA-15-040, Submittal of 10 CFR 50.46 Annual Report

Submittal of 10 CFR 50.46 Annual Report

ML15140A442
Person / Time
Site:	Oyster Creek
Issue date:	05/19/2015
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RA-15-040
Download: ML15140A442 (7)

Text

Exelon Generation ~, 200 Exelon Way Kennett Square. PA 19348 www.exeloncorp.com 10 CFR 50.46 RA-15-040 May 19, 2015 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Oyster Creek Nuclear Generating Station Renewed Facility Operating License No. DPR-16 NRC Docket No. 50-219

Subject:

1O CFR 50.46 Annual Report

Reference:

Letter from James Barstow, Exelon Generation Company, LLC, to U.S.

Nuclear Regulatory Commission, "10 CFR 50.46 Annual Report," dated May 20,2014 The purpose of this letter is to transmit the annual 1O CFR 50.46 reporting information for Oyster Creek Nuclear Generating Station (OCNGS). The previous annual 50.46 report for OCNGS submitted on May 20, 2014 (Reference) provided the cumulative Peak Cladding Temperature (PCT) errors for the most recent fuel designs.

Since the referenced annual report was issued, no vendor notifications of Emergency Core Cooling System (ECCS) model errors/changes that are applicable to OCNGS have been issued. Also, no EGGS-related changes or modifications have occurred at OCNGS that affect the assumptions of the ECCS analyses.

A new Loss of Coolant Accident (LOCA) analysis for OCNGS was performed to provide Maximum Average Planar Linear Heat Generation Rates (MAPLHGRs) for Cycle 25 operation which started in October 2014. New MAPLHGRs were generated for all GNF2 bundles in the reactor using SAFER/CORCUPRIME method with updated LOCA analysis inputs for the Cycle 25 reload. A new target Peak Cladding Temperature (PCT) of 2175°F was used to calculate improved MAPLHGR for GNF2 fuel in Cycle 25 whereas a target PCT of 2150°F was used to confirm MAPLHGR for twice-burned GE11 fuel same as previous cycle.

U.S. Nuclear Regulatory Commission Oyster Creek 1O CFR 50.46 Annual Report May 19, 2015 Page 2 Two attachments are included with this letter that provide the current OCNGS 1O CFR 50.46 status. Attachment 1, "Peak Cladding Temperature Rack-Up Sheet," provides information regarding the PCT for the limiting large break Loss of Coolant Accident (LOCA) analysis evaluations for OCNGS. Attachment 2, "Assessment Notes," contains a detailed description for each change or error reported.

There are no commitments contained in this letter. If you have any questions, please contact Richard Gropp at 610-765-5557.

Respecttu~ OI""> ~

James Barstow Director, Licensing & Regulatory Affairs Exelon Generation Company, LLC Attachments: 1) Peak Cladding Temperature Rack-Up Sheet

2) Assessment Notes cc: USNRC Administrator, Region I USNRC Senior Project Manager, OCNGS USNRC Senior Resident Inspector, OCNGS

ATTACHMENT 1 10 CFR 50.46 "Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors" Report of the Emergency Core Cooling System Evaluation Model Changes and Errors Assessments as of May 19, 2015 Peak Cladding Temperature Rack-Up Sheet Oyster Creek Nuclear Generating Station

Report of the Emergency Core Cooling System Evaluation Model Changes and Errors Assessments as of May 19, 2015 Attachment 1 Peak Cladding Temperature Rack-Up Sheet, OCNGS Page 1 of 2 PLANT NAME: Oyster Creek Nuclear Generation Station (OCNGS)

ECCS EVALUATION MODEL: SAFER/CORCUGESTR-LOCA (GE11)

SAFER/CORCUPRIME (GNF2)

REPORT REVISION DATE: 05/19/2015 CURRENT OPERATING CYCLE: 25 ANALYSIS OF RECORD Evaluation Model:

1. NEDC-23785-1-PA Rev. 1, "The GESTR-LOCA and SAFER Models for the Evaluation of the Loss-Of-Coolant Accident Volume II, SAFER - Long Term Inventory Model for BWR Loss-Of-Coolant Analysis," October 1984.

2. NEDC-30996P-A, "SAFER Model for Evaluation of Loss-of-Coolant Accidents for Jet Pump and Non-jet Pump Plants, Volume I, SAFER - Long Term Inventory Model for BWR Loss-of-Coolant Analysis," October 1987.

3. NEDC-30996P-A, "SAFER Model for Evaluation of Loss-of-Coolant Accidents for Jet Pump and Non-jet Pump Plants, Volume II, SAFER Application Methodology for Non-jet Pump Plants," October 1987 (Non-jet Pump Plant - SAFER/CORCL).

4. NEDC-32950P, "Compilation of Improvements to GENE's SAFER ECCS-LOCA Evaluation Model," January 2000 Calculations:

1. GE-NE-0000-0001-7486-01 P, "Oyster Creek Generating Station Loss-of-Coolant Accident Evaluation for GE11, "GE Nuclear Energy, dated July 2002.

2. Report 0000-0098-3503-R2, "Oyster Creek Generating Station GNF2 ECCS-LOCA Evaluation," GEH Nuclear Energy, dated November 2010

3. Report OOON3005-SRLR Rev 1, "Supplemental Reload Licensing Report for Oyster Creek Reload 25 Cycle 25," dated September 2014 Fuel: GE11, GNF2 Limiting Fuel Type: GNF2 Limiting Single Failure: ADS Valve Limiting Break Size and Location: 4.66 ft 2 Double-Ended Guillotine (DEG) in a Recirculation Discharge Pipe Reference Peak Cladding Temperature (PCT) for GE11 Fuel: 2150°F Reference Peak Cladding Temperature (PCT) for GNF2 Fuel: 2175°F

Report of the Emergency Core Cooling System Evaluation Model Changes and Errors Assessments as of May 19, 2015 Attachment 1 Peak Cladding Temperature Rack-Up Sheet, OCNGS Page 2 of 2 MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS 1O CFR 50.46 Report dated August 27, 2015 (See Note 1) GE11: ~PCT= +15°F GNF2: ~PCT= N/A (New Analysis)

NET PCT (GE11/GNF2) GE11: 2165°F GNF2: 2175°F B. CURRENT LOCA MODEL ASSESSMENTS Cycle 25 Reload LOCA Analyses (See Note 2) GE11: ~PCT= 0°F GNF2: ~PCT= 0°F Total PCT Change from Current Assessments GE11: L~PCT = 0°F GNF2: L~PCT = 0°F Cumulative PCT Change from Current Assessments GE11: Ll~PCTI = 0°F GNF2: Ll~PCTI = 0°F NET PCT GE11: 2165°F GNF2: 2175°F

ATTACHMENT 2 10 CFR 50.46 "Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors" Report of the Emergency Core Cooling System Evaluation Model Changes and Errors Assessments as of May 19, 2015 Assessment Notes Oyster Creek Nuclear Generating Station

Report of the Emergency Core Cooling System Evaluation Model Changes and Errors Assessments as of May 19, 2015 Attachment 2 Assessment Notes, OCNGS Page 1 of 1

1) Prior LOCA Assessment The previous LOCA assessment provides the PCT impact of error notifications (2014-01, 2014-02, 2014-03, and 2014-04) for the fuel residing in the Oyster Creek reactor.

Error 2014-01 addresses several code maintenance updates to the SAFER04A model with accumulated PCT change of + 10°F. Error 2014-02 corrected a logic error in the calculated system mass with a PCT change of -30°F. Error 2014-03 corrected an error with the imposed minimum pressure differential (flp) for droplet flow above a two-phase level in the core with a PCT change of+ 15°F. Error 2014-04 corrected the pressure head representation when defining the counter current flow limitation (CCFL) with PCT change of +20°F. The net PCT impact of these errors as previously reported was+ 15°F.

[

Reference:

RA-14-072, Letter from James Barstow (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "10 CFR 50.46 30-Day Report," dated August 27, 2014.]

2) Current LOCA Model Assessment A new LOCA analysis for Oyster Creek was performed to provide MAPLHGRs for Cycle 25 operation which started in October 2014. New MAPLHGRs were generated for all GNF2 bundles in the reactor using SAFER/CORCUPRIME method with updated LOCA Analysis inputs for the Cycle 25 reload. A new target PCT of 2175°F was used to calculate improved MAPLHGR for GNF2 fuel in Cycle 25 whereas a target PCT of 2150 F was used to confirm MAPLHGR for GE11 fuel to be the same as previous cycle. The new LOCA analysis for GNF2 fuel accounts for all previous reported error notifications, including: 2014-01, 2014-02, 2014-03, and 2014-04. As such, the previous LOCA model assessment no longer applies to GNF2.

However, for GE11 fuel the LOCA assessment due to the previous error notifications and their associated PCT assessment remain applicable. Since the issuance of the referenced report for Cycle 25 operation no new vendor notifications of Emergency Core Cooling System (ECCS) model error/changes has been reported.

[

Reference:

OOON3005-SRLR, Rev 1, "Supplemental Reload Licensing Report for Oyster Creek Reload 25 Cycle 25," September 2014.]