RS-20-024, Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors: Difference between revisions

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{{#Wiki_filter:4300 Winfield Road Exelon Generation Warrenville, IL 60555 630 657 2000 Office RS-20-024                                                                                  10 CFR 50.46 March 9, 2020 U.S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, DC 20555-0001 LaSalle County Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-11 and NPF-18 NRC Docket Nos. 50-373 and 50-374
{{#Wiki_filter:}}
 
==Subject:==
Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station
 
==References:==
: 1. Letter from D. M. Gullatt (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station," dated March 7, 2019 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 the attached information to fulfill the annual reporting requirements for LaSalle County Station (LSCS), Units 1 and 2. The attachments describe the changes in accumulated peak cladding temperature (PCT) since the previous annual report submitted in Reference 1.
There are no regulatory commitments contained in this submittal. Should you have any questions concerning this letter, please contact Mr. Jason Taken at (630) 657-3660.
Respectfully, D i Murray Senior Manager - Licensing Exelon Generation Company, LLC Attachments:
: 1) LaSalle County Station, Units 1 and 2 - 10 CFR 50.46 Report
: 2) LaSalle County Station, Units 1 and 2 - 10 CFR 50.46 Report Assessment Notes
 
March 9, 2020 U.S . Nuclear Regulatory Commission Page 2 cc:    NRC Regional Administrator, Region Ill NRC Senior Resident Inspector, LaSalle County Station Illinois Emergency Management Agency - Division of Nuclear Safety
 
ATTACHMENT 1 LaSalle County Station, Units 1 and 2 10 CFR 50.46 Report PLANT NAME:                        LaSalle County Station (LSCS). Units 1 & 2 ECCS EVALUATION MODEL:            SAFER/PRIME LOCA REPORT REVISION DATE:              February 24. 2020 CURRENT OPERATING CYCLES: L1C19 and L2C18 ANALYSES OF RECORD
: 1) General Electric Hitachi (GEH) Calculation 0000-0121-8990-RO, "LaSalle County Station GNF2 ECCS-LOCA Evaluation," GEH Nuclear Energy, January 2012
: 2) GNF Document Number 002N3086.1, "Technical Evaluation to Support Introduction of GNF3 Lead Use Assemblies (LUAs) in LaSalle County Station, Unit 2," Global Nuclear Fuel, December 2014 Fuel Types:                                          GNF2. GNF3 LUAs Limiting Single Failure:                              High Pressure Core Spray Diesel Generator Failure Limiting Break Size & Location:                      Recirculation Pump Suction Line Break (0 .08 ft2 in small break)
Reference Peak Cladding Temperature (PCT):            GNF2: 1540°F GNF3 LUAs: 1550°F Page 1 of 2
 
ATTACHMENT 1 LaSalle County Station, Units 1 and 2 10 CFR 50.46 Report MARGIN ALLOCATION A. PR IOR LOCA MODEL ASSESSMENTS GNF2:              00F 1o CFR 50.46 Report dated March 7, 2012 (Note 1)
                                                                    ~PCT GNF3 LUA:      N/A 00F 1o CFR 50.46 Report dated March 7, 2013 (Note 2)
GNF2:      ~PCT GNF3 LUA:      N/A GNF2:      ~PCT    00F 10 CFR 50.46 Report dated March 7, 2014 (Note 3)
GNF3 LUA:      N/A GNF2:
1o CFR 50.46 Report dated March 6, 2015 (Note 4)
                                                                    ~PCT    -5°F GNF3 LUA:  ~PCT=    0°F GNF2:              00F 1o CFR 50.46 Report dated March 7, 2016 (Note 5)
                                                                    ~PCT GNF3 LUA:  ~PCT=    0°F 00F 1o CFR 50.46 Report dated March 7, 2017 (Note 6)
GNF2:      ~PCT GNF3 LUA:  ~PCT=    0°F GNF2:              00F 1o CFR 50.46 Report dated March 7, 2018 (Note 7)
                                                                    ~PCT GNF3 LUA:  ~PCT=    0°F GNF2:              00F 1o CFR 50.46 Report dated March 7, 2019 (Note 8)
                                                                    ~PCT GNF3 LUA:  ~PCT=    0°F GNF2:      1535°F Net PCT GNF3 LUA:  1550°F B. CURRENT LOCA MODEL ASSESSMENTS GNF2:    L~PCT      00F Total PCT Change from Current Assessments (Note 9)
GNF3 LUA: L ~PCT- 0°F GNF2:    L  l~PCTI  00F Cumulative PCT Change from Current Assessments GNF3 LUA: L  l~PCTI - 0°F GNF2:        1535°F Net PCT GNF3 LUA:  1550°F Page 2 of 2
 
ATTACHMENT 2 LaSalle County Station, Units 1 and 2 10 CFR 50.46 Report Assessment Notes ASSESSMENT NOTES
: 1. Prior LOCA Assessment The referenced letter provided the annual 10 CFR 50.46 report for LSCS, Units 1 and 2, for the 2012 reporting period. The referenced letter reported the introduction of GNF2 fuel into the LSCS, Unit 1 core . A new LOCA analysis of record for GNF2 fuel was performed by GE Hitachi Nuclear Energy (GEH). No Emergency Core Cooling System (ECCS) related changes or modifications occurred at LSCS that affected the assumptions in the GEH GNF2 LOCA analysis.
[
 
==Reference:==
Letter from David M. Gullett (Exelon Generation Company, LLC) to U.S.
Nuclear Regulatory Commission, "Plant Specific ECCS Evaluation Changes -10 CFR 50.46 Report," dated March 7, 2012]
: 2. Prior LOCA Assessment The referenced letter provided the annual 10 CFR 50.46 report for LSCS, Units 1 and 2, for the 2013 reporting period. The referenced letter reported the introduction of GNF2 fuel into the LSCS , Unit 2 core. The referenced letter also reported no vendor notifications of ECCS model errors/changes applicable to the GNF2 fuel in LSCS, Units 1 and 2, and reported that no ECCS related changes or modifications occurred at LSCS that affected the assumptions in the GEH GNF2 LOCA analysis for the GNF2 fuel in LSCS , Units 1 and 2.
[
 
==Reference:==
Letter from David M. Gullett (Exelon Generation Company, LLC) to U.S.
Nuclear Regulatory Commission, "Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station,"
dated March 7, 2013]
: 3. Prior LOCA Assessment The referenced letter provided the annual 10 CFR 50.46 report for LSCS, Units 1 and 2, for the 2014 reporting period. The referenced letter reported no vendor notifications of ECCS model errors/changes applicable to the GNF2 fuel in LSCS, Units 1 and 2, and reported that no ECCS related changes or modifications occurred at LSCS that affected the assumptions in the GEH GNF2 LOCA analysis for the GNF2 fuel in LSCS, Units 1 and 2.
[
 
==Reference:==
Letter from David M. Gullett (Exelon Generation Company, LLC) to U.S.
Nuclear Regulatory Commission, "Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station,"
dated March 7, 2014]
: 4. Prior LOCA Assessment The referenced letter provided the annual 10 CFR 50.46 report for LSCS, Units 1 and 2, for the 2015 reporting period. The referenced letter reported four vendor notifications, Page 1 of 4
 
ATTACHMENT 2 LaSalle County Station, Units 1 and 2 10 CFR 50.46 Report Assessment Notes Notifications 2014-01 through 2014-04, of ECCS model error/changes. The first notification addressed several code maintenance changes to the SAFER04A model, which resulted in a PCT change of 0°F for GNF2. The second notification corrected a logic error, which affects the ECCS flow credited as reaching the core. Correction of this error resulted in a 0°F PCT change for GNF2. The third notification addressed an error with the imposed minimum pressure differential (.6.p) for droplet flow above a two-phase level in the core. This error can offer an inappropriate steam cooling benefit above the core two phase level. Correction of this error resulted in a PCT change of -10°F for GNF2. The fourth notification addressed an incorrect pressure head representation when defining the counter current flow limitation (CCFL). Correction of this error resulted in a +5°F PCT change for GNF2.
The referenced letter also reported that no ECCS related changes or modifications occurred at LSCS that affected the assumptions in the GEH LOCA analysis for the GNF2 fuel in LSCS , Units 1 and 2.
Four (4) GNF3 Lead Use Assemblies (LUAs) were loaded into LSCS, Unit 2, during the LSCS, Unit 2 Reload 15 outage (L2R15). Notifications 2014-01through2014-04 were included in the determination of the licensing basis PCT for the GNF3 LUAs.
[
 
==Reference:==
Letter from David M. Gullett (Exelon Generation Company, LLC) to U.S.
Nuclear Regulatory Commission, "Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station ,"
dated March 6, 2015]
: 5. Prior LOCA Assessment The referenced letter provided the annual 10 CFR 50.46 report for LSCS, Units 1 and 2, for the 2016 reporting period . The referenced letter reported no vendor notifications of ECCS model errors/changes applicable to the GNF2 fuel in LSCS, Units 1 and 2, and reported that no ECCS related changes or modifications occurred at LSCS that affected the assumptions in the GEH GNF2 LOCA analysis of record for the GNF2 fuel in LSCS, Units 1 and 2.
The referenced letter reported no vendor notifications of ECCS model errors/changes applicable to the GNF3 fuel in LSCS, Unit 2, and that no ECCS related changes or modifications occurred at LSCS , Unit 2, that affected the assumptions in the GEH GNF3 LOCA analysis of record for the GNF3 fuel in LSCS, Unit 2. All ATRIUM-10 fuel was removed from LSCS, Unit 1 during the LSCS, Unit 1 Reload 16 (L 1R16) outage prior to startup of LSCS , Unit 1 Cycle 17(L1C17).
[
 
==Reference:==
Letter from David M. Gullett (Exelon Generation Company, LLC) to U.S.
Nuclear Regulatory Commission, "Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station,"
dated March 7, 2016]
Page 2 of 4
 
ATTACHMENT 2 LaSalle County Station, Units 1 and 2 10 CFR 50.46 Report Assessment Notes
: 6. Prior LOCA Assessment The referenced letter provided the annual 10 CFR 50.46 report for LSCS, Units 1 and 2, for the 2017 reporting period. The referenced letter reported no vendor notification of the ECCS model errors/changes applicable to the GNF2 or GNF3 fuel in LSCS, Units 1 and 2 and reported that no ECCS related changes or modifications occurred at LSCS that affected the assumptions in the GEH LOCA analyses for GNF2 or GNF3 fuel at LSCS ,
Units 1 and 2.
The letter also noted that all ATRIUM-10 fuel was removed from LSCS, Unit 2 prior to the start of LSCS, Unit 2 Cycle 17 (L2C17).
[
 
==Reference:==
Letter from David M. Gullett (Exelon Generation Company, LLC) to U.S.
Nuclear Regulatory Commission, "Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station,"
dated March 7, 2017]
: 7. Prior LOCA Assessment The referenced letter provided the annual 10 CFR 50.46 report for LSCS, Units 1 and 2, for the 2018 reporting period. The referenced letter reported two vendor notifications were produced, 2017-01 and 2017-02. Notification 2017-01 describes corrections made to the GNF2 lower tie plate modeling and Notification 2017-02 describes corrections made to the fuel rod upper plenum thermal model. Neither of these corrections resulted in a change in PCT for either GNF2 or GNF3.
[
 
==Reference:==
Letter from David M. Gullett (Exelon Generation Company, LLC) to U.S.
Nuclear Regulatory Commission, "Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station,"
dated March 7, 2018]
: 8. Prior LOCA Assessment The referenced letter provided the annual 10 CFR 50.46 report for LSCS, Units 1 and 2, for the 2019 reporting period. The referenced letter reported no vendor notifications of the ECCS model errors/changes applicable to the GNF2 or GNF3 fuel in LSCS, Units 1 and 2 and reported that no ECCS related changes or modifications occurred at LSCS that affected the assumptions in the GEH LOCA analyses for GNF2 or GNF3 fuel at LSCS , Units 1 and 2.
[
 
==Reference:==
Letter from David M. Gullett (Exelon Generation Company, LLC) to U.S.
Nuclear Regulatory Commission, "Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station,"
dated March 7, 2019]
: 9. Current LOCA Assessment Since the last annual 10 CFR 50.46 report, one vendor notification of ECCS model errors/changes applicable to the GNF2 fuel in LSCS , Units 1 and 2 and the GNF3 LUAs Page 3 of 4
 
ATTACHMENT 2 LaSalle County Station, Units 1 and 2 10 CFR 50.46 Report Assessment Notes in LSCS, Unit 2 has been issued. The driving differential pressure for the lower limit for the control rod guide tube to control rod driving housing interface backward leakage path was found to be incorrect in SAFER. A SAFER version correcting this error was executed on representative plants and confirmed the software code and error had no impact on the plant ECCS LOCA evaluations, and reported a 0° F impact of PCT.
No ECCS related changes or modifications occurred at LSCS that affected the assumptions in the GEH GNF2 LOCA analysis of record for the GNF2 fuel in LSCS ,
Units 1 and 2. No ECCS related changes or modifications occurred at LSCS, Unit 2, that affected the assumptions in the GEH GNF3 LOCA analysis of record for the GNF3 fuel in LSCS, Unit 2.
Page 4 of 4}}

Revision as of 04:10, 29 March 2020

Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors
ML20069F791
Person / Time
Site: LaSalle  Constellation icon.png
Issue date: 03/09/2020
From: Demetrius Murray
Exelon Generation Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
RS-20-024
Download: ML20069F791 (8)
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