RS-16-054, Transmittal of 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors

Transmittal of 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors

ML16067A022
Person / Time
Site:	LaSalle
Issue date:	03/07/2016
From:	Gullott D Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RS-16-054
Download: ML16067A022 (9)

Text

1l lOL,W1 *c R,.ic W111c1 ville IL6L.'i'ir.

Exelon Generation RS-16-054 10 CFR 50.46 March 7, 2016 U. S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, DC 20555-0001 LaSalle County Station, Units 1 and 2 Facility Operating License Nos. NPF-11 and NPF-18 NRC Docket Nos. 50-373 and 50-374

Subject:

Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station

Reference:

Letter from D. M. Gullott (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 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 the referenced letter.

There are no regulatory commitments contained in this submittal. Should you have any questions concerning this letter, please contact Ms. Lisa A. Simpson at (630) 657-2815.

Respectfully, David M. Gullott Manager - Licensing Exelon Generation Company, LLC Attachments:

1) LaSalle County Station, Units 1 and 2 I 10 CFR 50.46 Report - GNF Fuel

2) LaSalle County Station, Unit 2 I 10 CFR 50.46 Report-AREVA NP Fuel

3) LaSalle County Station, Units 1 and 2 I 10 CFR 50.46 Report - Assessment Notes

March 7, 2016 U. S. Nuclear Regulatory Commission Page2 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 - GNF Fuel PLANT NAME: LaSalle County Station (LSCS). Units 1 & 2 ECCS EVALUATION MODEL: SAFER/PRIME LOCA REPORT REVISION DATE: March 7. 2016 CURRENT OPERATING CYCLE: L1C17* and L2C16 ANALYSIS OF RECORD Evaluation Model Methodology:

1) NEDE-23785-1-PA, Rev. 1, "GESTR-LOCA and SAFER Models for the Evaluation of the Loss-of-Coolant Accident (Volume Ill), SAFER/GESTR Application Methodology,"

October 1984.

2) "The PRIME Model for Analysis of Fuel Rod Thermal-Mechanical Performance,"

Technical Bases - NEDC-33256P-A, Qualification - NEDC-33257P-A, and Application Methodology- NEDC-33258P-A, September 2010.

3) NED0-33173 Supplement 4-A, "Implementation of PRIME Models and Data in Downstream Methods," September 2011.

Calculation:

1) NEDC-32258P, "LaSalle County Station Units 1 and 2 SAFER/GESTR-LOCA Loss-of-Coolant Accident Analysis," GE Nuclear Energy, October 1993.

2) GE Hitachi Calculation 0000-0121-8990-RO, "LaSalle County Station GNF2 ECCS-LOCA Evaluation," GE Hitachi Nuclear Energy, January 2012.

3) GNF Calculation 002N3086, "Technical Evaluation to Support Introduction of GNF3 Lead Use Assemblies (LUAs) in LaSalle County Station, Unit 2," Global Nuclear Fuel, November 2014.

Fuel: GNF2, GNF3 LUAs Limiting Single Failure: High Pressure Core Spray Diesel Generator Limiting Break Size and Location: 0.08 ft2 Recirculation Pump Suction Line Break Reference Peak Cladding Temperature (Pen: GNF2: 1540°F GNF3 LUAs: 1550°F

• LSCS, Unit 1, is currently in refueling outage, LSCS, Unit 1 Reload 16 (L 1R16). Expected startup date for LSCS, Unit 1, Cycle 17 (L 1C17) is March 9, 2016.

Page 1 of 2

ATTACHMENT 1 LaSalle County Station, Units 1 and 2 10 CFR 50.46 Report - GNF Fuel MARGIN ALLOCATION A. PRIOR LOSS-OF-COOLANT ACCIDENT (LOCA) MODEL ASSESSMENTS GNF2: L\PCT 0°F 10 CFR 50.46 report dated March 7, 2012 (Note 1)

GNF3 LUAs: N/A GNF2: L\PCT 0°F 10 CFR 50.46 report dated March 7, 2013 (Note 2)

GNF3 LUAs: N/A GNF2: L\PCT - 0°F 10 CFR 50.46 report dated March 7, 2014 (Note 3)

GNF3 LUAs: N/A GNF2: L\PCT -5°F 10 CFR 50.46 report dated March 6, 2015 (Note 4)

GNF3 LUAs: L\PCT = 0°F GNF2: 1535°F Net PCT GNF3 LUAs: 1550°F B. CURRENT LOCA MODEL ASSESSMENTS GNF2: L\PCT 0°F None (See Note 5)

GNF3 LUAs: L\PCT = 0°F GNF2: IL\PCT 0°F Total PCT change from current assessments GNF3 LUAs: IL\PCT = 0°F Cumulative PCT change from current assessments GNF2: L.IL\PCTI 0°F GNF3 LUAs: I L\PCT = 0°F GNF2: 1535°F Net PCT GNF3 LUAs: 1550°F Page 2 of 2

AITACHMENT2 LaSalle County Station, Unit 2 10 CFR 50.46 Report - AREVA NP Fuel PLANT NAME: LaSalle County Station (LSCS). Unit 2 ECCS EVALUATION MODEL: SAFER/PRIME LOCA REPORT REVISION DATE: March 7. 2016 CURRENT OPERATING CYCLES: L2C16 ANALYSIS OF RECORD Evaluation Model Methodology:

1) NEDE-23785-1-PA, Rev. 1, "GESTR-LOCA and SAFER Models for the Evaluation of the Loss-of-Coolant Accident (Volume Ill), SAFER/GESTR Application Methodology,"

October 1984.

2) "The PRIME Model for Analysis of Fuel Rod Thermal-Mechanical Performance,"

Technical Bases - NEDC-33256P-A, Qualification - NEDC-33257P-A, and Application Methodology- NEDC-33258P-A, September 2010.

3) NED0-33173 Supplement 4-A, "Implementation of PRIME Models and Data in Downstream Methods," September 2011.

Calculation:

1) NEDC-32258P, "LaSalle County Station Units 1 and 2 SAFER/GESTR-LOCA Loss-of-Coolant Accident Analysis," GE Nuclear Energy, October 1993.

2) GE Hitachi Calculation 0000-0142-8555-RO, "LaSalle County Station ECCS-LOCA Evaluation for ATRIUM-10 Fuel," GE Hitachi Nuclear Energy, April 2012.

Fuel: ATRIUM-10 Limiting Single Failure: High Pressure Core Spray Diesel Generator Limiting Break Size and Location: 0.08 ft2 Recirculation Pump Suction Line Break Reference Peak Cladding Temperature (PCT): 1460°F Page 1 of 2

ATTACHMENT 2 LaSalle County Station, Unit 2 10 CFR 50.46 Report - AREVA NP Fuel MARGIN ALLOCATION A. PRIOR LOSS-OF-COOLANT ACCIDENT (LOCA) MODEL ASSESSMENTS 10 CFR 50.46 report dated March 7, 2013 (Note 2) ~PCT= 0°F 10 CFR 50.46 report dated March 7, 2014 (Note 3) ~PCT= 0°F 10 CFR 50.46 report dated March 6, 2015 (Note 4) ~PCT= -5°F Net PCT 1455°F B. CURRENT LOCA MODEL ASSESSMENTS None (See Note 5) ~PCT= 0°F Total PCT chanoe from current assessments :E~PCT= 0°F Cumulative PCT chanoe from current assessments :El~PCTI = 0°F Net PCT 1455°F Page 2 of 2

ATTAC HM ENT 3 LaSalle County Station, Units 1 and 2 1o CFR 50.46 Report - Assessment Notes

1) Prior LOCA Model Assessment for AREVA NP Fuel and GNF Fuel 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.

The LOCA analysis of record for the ATRIUM-1 O fuel in LSCS, Units 1 and 2, for the 2012 reporting period was performed by AREVA. The AREVA analysis was replaced by the GEH analysis as discussed in Assessment Notes 2 and 3. The Assessment Notes for the AREVA analysis were removed from the LSCS 10 CFR 50.46 report starting in 2014.

[

Reference:

Letter from David M. Gullatt (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 Model Assessment for AREVA NP Fuel and GNF Fuel 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.

The referenced letter reported a new LOCA analysis of record for the ATRIUM-1 o fuel in LSCS, Units 1 and 2, was performed by GEH and implemented only at LSCS, Unit 2. The referenced letter reported that no ECCS related changes or modifications occurred at LSCS that affected the assumptions in the GEH LOCA analysis of record for the ATRIUM-10 fuel in LSCS, Unit 2.

The LOCA analysis of record for the ATRIUM-10 fuel in LSCS, Unit 1, for the 2013 reporting period was performed by AREVA. The AREVA analysis has been replaced by the GEH analysis as previously discussed and in Assessment Note 3. The Assessment Notes for the AREVA analysis were removed from the LSCS 10 CFR 50.46 report starting in 2014.

[

Reference:

Letter from David M. Gullott (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.]

Page 1 of 3

ATTACHMENT 3 LaSalle County Station, Units 1 and 2 10 CFR 50.46 Report - Assessment Notes

3) Prior LOCA Model Assessment for AREVA NP Fuel and GNF Fuel 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 the GEH LOCA analysis of record for the ATRIUM-1 O fuel in LSCS, Units 1 and 2, was implemented at LSCS, Unit 1, as part of LSCS, Unit 1, Cycle 16 (L 1C16). The referenced letter reported no ECCS related changes or modifications occurred at LSCS that affected the assumptions in the GEH ATRIUM-10 LOCA analysis for the ATRIUM-10 fuel in LSCS, Units 1and2.

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. 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, 2014.]

4) Prior LOCA Model Assessment for AREVA NP Fuel and GNF Fuel 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, 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 and ATRIUM-1 O fuel. 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 and ATRIUM-10 fuel. The third notification addressed an error with the imposed minimum pressure differential (f1p) 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 and ATRIUM-10 fuel. 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 and ATRIUM-10 fuel.

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 ATRIUM-10 and 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. 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 6, 2015.]

Page 2 of 3

ATTACHMENT 3 LaSalle County Station, Units 1 and 2 1o CFR 50.46 Report - Assessment Notes

5) Current LOCA Model Assessment for AREVA NP Fuel and GNF Fuel Since the last annual report, no vendor notifications of ECCS model errors/changes applicable to the GNF2 fuel in LSCS, Units 1 and 2, have been issued. 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.

Additionally, no vendor notifications of ECCS model errors/changes applicable to the GNF3 and ATRIUM-10 fuels in LSCS, Unit 2, have been issued. No ECCS related changes or modifications occurred at LSCS, Unit 2, that affected the assumptions in the GEH GNF3 and ATRIUM-10 LOCA analysis of record for the GNF3 and ATRIUM-10 fuels in LSCS, Unit 2.

All ATRIUM-1 O fuel will be removed from LSCS, Unit 1, during the LSCS, Unit 1, Reload 16 outage (L 1R16) prior to startup of LSCS, Unit 1, Cycle 17 (L 1C17), expected on March 9, 2016. With the removal of ATRIUM-10 fuel from LSCS, Unit 1, a PCT assessment was not performed for the AREVA NP fuel for LSCS, Unit 1.

Page 3 of 3

1l lOL,W1 *c R,.ic W111c1 ville IL6L.'i'ir.

Exelon Generation RS-16-054 10 CFR 50.46 March 7, 2016 U. S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, DC 20555-0001 LaSalle County Station, Units 1 and 2 Facility Operating License Nos. NPF-11 and NPF-18 NRC Docket Nos. 50-373 and 50-374

Subject:

Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station

Reference:

Letter from D. M. Gullott (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 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 the referenced letter.

There are no regulatory commitments contained in this submittal. Should you have any questions concerning this letter, please contact Ms. Lisa A. Simpson at (630) 657-2815.

Respectfully, David M. Gullott Manager - Licensing Exelon Generation Company, LLC Attachments:

1) LaSalle County Station, Units 1 and 2 I 10 CFR 50.46 Report - GNF Fuel

2) LaSalle County Station, Unit 2 I 10 CFR 50.46 Report-AREVA NP Fuel

3) LaSalle County Station, Units 1 and 2 I 10 CFR 50.46 Report - Assessment Notes

March 7, 2016 U. S. Nuclear Regulatory Commission Page2 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 - GNF Fuel PLANT NAME: LaSalle County Station (LSCS). Units 1 & 2 ECCS EVALUATION MODEL: SAFER/PRIME LOCA REPORT REVISION DATE: March 7. 2016 CURRENT OPERATING CYCLE: L1C17* and L2C16 ANALYSIS OF RECORD Evaluation Model Methodology:

1) NEDE-23785-1-PA, Rev. 1, "GESTR-LOCA and SAFER Models for the Evaluation of the Loss-of-Coolant Accident (Volume Ill), SAFER/GESTR Application Methodology,"

October 1984.

2) "The PRIME Model for Analysis of Fuel Rod Thermal-Mechanical Performance,"

Technical Bases - NEDC-33256P-A, Qualification - NEDC-33257P-A, and Application Methodology- NEDC-33258P-A, September 2010.

3) NED0-33173 Supplement 4-A, "Implementation of PRIME Models and Data in Downstream Methods," September 2011.

Calculation:

1) NEDC-32258P, "LaSalle County Station Units 1 and 2 SAFER/GESTR-LOCA Loss-of-Coolant Accident Analysis," GE Nuclear Energy, October 1993.

2) GE Hitachi Calculation 0000-0121-8990-RO, "LaSalle County Station GNF2 ECCS-LOCA Evaluation," GE Hitachi Nuclear Energy, January 2012.

3) GNF Calculation 002N3086, "Technical Evaluation to Support Introduction of GNF3 Lead Use Assemblies (LUAs) in LaSalle County Station, Unit 2," Global Nuclear Fuel, November 2014.

Fuel: GNF2, GNF3 LUAs Limiting Single Failure: High Pressure Core Spray Diesel Generator Limiting Break Size and Location: 0.08 ft2 Recirculation Pump Suction Line Break Reference Peak Cladding Temperature (Pen: GNF2: 1540°F GNF3 LUAs: 1550°F

• LSCS, Unit 1, is currently in refueling outage, LSCS, Unit 1 Reload 16 (L 1R16). Expected startup date for LSCS, Unit 1, Cycle 17 (L 1C17) is March 9, 2016.

Page 1 of 2

ATTACHMENT 1 LaSalle County Station, Units 1 and 2 10 CFR 50.46 Report - GNF Fuel MARGIN ALLOCATION A. PRIOR LOSS-OF-COOLANT ACCIDENT (LOCA) MODEL ASSESSMENTS GNF2: L\PCT 0°F 10 CFR 50.46 report dated March 7, 2012 (Note 1)

GNF3 LUAs: N/A GNF2: L\PCT 0°F 10 CFR 50.46 report dated March 7, 2013 (Note 2)

GNF3 LUAs: N/A GNF2: L\PCT - 0°F 10 CFR 50.46 report dated March 7, 2014 (Note 3)

GNF3 LUAs: N/A GNF2: L\PCT -5°F 10 CFR 50.46 report dated March 6, 2015 (Note 4)

GNF3 LUAs: L\PCT = 0°F GNF2: 1535°F Net PCT GNF3 LUAs: 1550°F B. CURRENT LOCA MODEL ASSESSMENTS GNF2: L\PCT 0°F None (See Note 5)

GNF3 LUAs: L\PCT = 0°F GNF2: IL\PCT 0°F Total PCT change from current assessments GNF3 LUAs: IL\PCT = 0°F Cumulative PCT change from current assessments GNF2: L.IL\PCTI 0°F GNF3 LUAs: I L\PCT = 0°F GNF2: 1535°F Net PCT GNF3 LUAs: 1550°F Page 2 of 2

AITACHMENT2 LaSalle County Station, Unit 2 10 CFR 50.46 Report - AREVA NP Fuel PLANT NAME: LaSalle County Station (LSCS). Unit 2 ECCS EVALUATION MODEL: SAFER/PRIME LOCA REPORT REVISION DATE: March 7. 2016 CURRENT OPERATING CYCLES: L2C16 ANALYSIS OF RECORD Evaluation Model Methodology:

1) NEDE-23785-1-PA, Rev. 1, "GESTR-LOCA and SAFER Models for the Evaluation of the Loss-of-Coolant Accident (Volume Ill), SAFER/GESTR Application Methodology,"

October 1984.

2) "The PRIME Model for Analysis of Fuel Rod Thermal-Mechanical Performance,"

Technical Bases - NEDC-33256P-A, Qualification - NEDC-33257P-A, and Application Methodology- NEDC-33258P-A, September 2010.

3) NED0-33173 Supplement 4-A, "Implementation of PRIME Models and Data in Downstream Methods," September 2011.

Calculation:

1) NEDC-32258P, "LaSalle County Station Units 1 and 2 SAFER/GESTR-LOCA Loss-of-Coolant Accident Analysis," GE Nuclear Energy, October 1993.

2) GE Hitachi Calculation 0000-0142-8555-RO, "LaSalle County Station ECCS-LOCA Evaluation for ATRIUM-10 Fuel," GE Hitachi Nuclear Energy, April 2012.

Fuel: ATRIUM-10 Limiting Single Failure: High Pressure Core Spray Diesel Generator Limiting Break Size and Location: 0.08 ft2 Recirculation Pump Suction Line Break Reference Peak Cladding Temperature (PCT): 1460°F Page 1 of 2

ATTACHMENT 2 LaSalle County Station, Unit 2 10 CFR 50.46 Report - AREVA NP Fuel MARGIN ALLOCATION A. PRIOR LOSS-OF-COOLANT ACCIDENT (LOCA) MODEL ASSESSMENTS 10 CFR 50.46 report dated March 7, 2013 (Note 2) ~PCT= 0°F 10 CFR 50.46 report dated March 7, 2014 (Note 3) ~PCT= 0°F 10 CFR 50.46 report dated March 6, 2015 (Note 4) ~PCT= -5°F Net PCT 1455°F B. CURRENT LOCA MODEL ASSESSMENTS None (See Note 5) ~PCT= 0°F Total PCT chanoe from current assessments :E~PCT= 0°F Cumulative PCT chanoe from current assessments :El~PCTI = 0°F Net PCT 1455°F Page 2 of 2

ATTAC HM ENT 3 LaSalle County Station, Units 1 and 2 1o CFR 50.46 Report - Assessment Notes

1) Prior LOCA Model Assessment for AREVA NP Fuel and GNF Fuel 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.

The LOCA analysis of record for the ATRIUM-1 O fuel in LSCS, Units 1 and 2, for the 2012 reporting period was performed by AREVA. The AREVA analysis was replaced by the GEH analysis as discussed in Assessment Notes 2 and 3. The Assessment Notes for the AREVA analysis were removed from the LSCS 10 CFR 50.46 report starting in 2014.

[

Reference:

Letter from David M. Gullatt (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 Model Assessment for AREVA NP Fuel and GNF Fuel 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.

The referenced letter reported a new LOCA analysis of record for the ATRIUM-1 o fuel in LSCS, Units 1 and 2, was performed by GEH and implemented only at LSCS, Unit 2. The referenced letter reported that no ECCS related changes or modifications occurred at LSCS that affected the assumptions in the GEH LOCA analysis of record for the ATRIUM-10 fuel in LSCS, Unit 2.

The LOCA analysis of record for the ATRIUM-10 fuel in LSCS, Unit 1, for the 2013 reporting period was performed by AREVA. The AREVA analysis has been replaced by the GEH analysis as previously discussed and in Assessment Note 3. The Assessment Notes for the AREVA analysis were removed from the LSCS 10 CFR 50.46 report starting in 2014.

[

Reference:

Letter from David M. Gullott (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.]

Page 1 of 3

ATTACHMENT 3 LaSalle County Station, Units 1 and 2 10 CFR 50.46 Report - Assessment Notes

3) Prior LOCA Model Assessment for AREVA NP Fuel and GNF Fuel 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 the GEH LOCA analysis of record for the ATRIUM-1 O fuel in LSCS, Units 1 and 2, was implemented at LSCS, Unit 1, as part of LSCS, Unit 1, Cycle 16 (L 1C16). The referenced letter reported no ECCS related changes or modifications occurred at LSCS that affected the assumptions in the GEH ATRIUM-10 LOCA analysis for the ATRIUM-10 fuel in LSCS, Units 1and2.

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. 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, 2014.]

4) Prior LOCA Model Assessment for AREVA NP Fuel and GNF Fuel 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, 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 and ATRIUM-1 O fuel. 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 and ATRIUM-10 fuel. The third notification addressed an error with the imposed minimum pressure differential (f1p) 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 and ATRIUM-10 fuel. 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 and ATRIUM-10 fuel.

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 ATRIUM-10 and 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. 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 6, 2015.]

Page 2 of 3

ATTACHMENT 3 LaSalle County Station, Units 1 and 2 1o CFR 50.46 Report - Assessment Notes

5) Current LOCA Model Assessment for AREVA NP Fuel and GNF Fuel Since the last annual report, no vendor notifications of ECCS model errors/changes applicable to the GNF2 fuel in LSCS, Units 1 and 2, have been issued. 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.

Additionally, no vendor notifications of ECCS model errors/changes applicable to the GNF3 and ATRIUM-10 fuels in LSCS, Unit 2, have been issued. No ECCS related changes or modifications occurred at LSCS, Unit 2, that affected the assumptions in the GEH GNF3 and ATRIUM-10 LOCA analysis of record for the GNF3 and ATRIUM-10 fuels in LSCS, Unit 2.

All ATRIUM-1 O fuel will be removed from LSCS, Unit 1, during the LSCS, Unit 1, Reload 16 outage (L 1R16) prior to startup of LSCS, Unit 1, Cycle 17 (L 1C17), expected on March 9, 2016. With the removal of ATRIUM-10 fuel from LSCS, Unit 1, a PCT assessment was not performed for the AREVA NP fuel for LSCS, Unit 1.

Page 3 of 3