RS-15-074, Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors

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Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors
ML15065A067
Person / Time
Site: LaSalle  Constellation icon.png
Issue date: 03/06/2015
From: Gullott D
Exelon Generation Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
RS-15-074
Download: ML15065A067 (10)
v • d • e


Text

AMIN, 4300 Winfieid Road Warrenviiie, IL 60555 x 'ion Generation 630 657 2000 Office RS-15-074 10 CFR 50.46 March 6, 2015 U. S. Nuclear Regulatory Commission ATTN: 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 7, 2014 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 / 10 CFR 50.46 Report GNF Fuel
2) LaSalle County Station, Units 1 and 2/ 10 CFR 50.46 Report AREVA NP Fuel
3) LaSalle County Station, Units 1 and 2/ 10 CFR 50.46 Report Assessment Notes

March 6,2015 U. S. Nuclear Regulatory Commission Page 2 cc: NRC Regional Administrator, Region III 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 6, 2015 CURRENT OPERATING CYCLE: L1C16 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 III), 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) NEDO-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 (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 GNF Fuel MARGIN ALLOCATION A. PRIOR LOSS-OF-COOLANT ACCIDENT (LOCA) MODEL ASSESSMENTS GNF2: APCT = 0°F 10 CFR 50.46 report dated March 7, 2012 (Note 1)

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

GNF3 LUAs: N/A GNF2: APCT = 0°F 10 CFR 50.46 report dated March 7, 2014 (Note 3)

GNF3 LUAs: N/A GNF2: 1540°F Net PCT GNF3 LUAs: N/A B. CURRENT LOCA MODEL ASSESSMENTS GNF2: APCT = 0°F Notification 2014-01 (See Note 4)

GNF3 LUAs: N/A GNF2: APCT = 0°F Notification 2014-02 (See Note 4)

GNF3 LUAs: N/A GNF2: APCT = -10°F Notification 2014-03 (See Note 4)

GNF3 LUAs: N/A GNF2: APCT = +5°F Notification 2014-04 (See Note 4)

GNF3 LUAs: N/A GNF2: ZAPCT = -5°F Total PCT change from current assessments GNF3 LUAs: ZAPCT = 0°F GNF2: Z I APCTI= 15°F Cumulative PCT change from current assessments GNF3 LUAs: EI APCT I = 0°F GNF2: 1535°F Net PCT GNF3 LUAs: 1550°F Page 2 of 2

ATTACHMENT 2 LaSalle County Station, Units 1 and 2 10 CFR 50.46 Report AREVA NP Fuel PLANT NAME: LaSalle County Station (LSCS), Units l& 2 ECCS EVALUATION MODEL: SAFER/PRIME LOCA REPORT REVISION DATE: March 6.2015 CURRENT OPERATING CYCLES: L1C16 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 III), 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) NEDO-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, Units 1 and 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) APCT = 0°F 10 CFR 50.46 report dated March 7, 2014 (Note 3) APCT = 0°F Net PCT 1460°F B. CURRENT LOCA MODEL ASSESSMENTS Notification 2014-01 (See Note 4) APCT = 0°F Notification 2014-02 (See Note 4) APCT = 0°F Notification 2014-03 (See Note 4) APCT = -10°F Notification 2014-04 (See Note 4) APCT = +5°F Total PCT change from current assessments EAPCT = -5°F Cumulative PCT change from current assessments I I APCTI= 15°F Net PCT 1455°F Page 2 of 2

ATTACHMENT 3 LaSalle County Station, Units 1 and 2 10 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 had occurred at LSCS that affected the assumptions in the GEH GNF2 LOCA analysis.

The LOCA analysis of record for the ATRIUM-10 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 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. Gullott (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-10 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 was replaced by the GEH analysis as previously discussed and in Note 3. The assessments 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, 2013.1 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 ARE VA 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-10 fuel in LSCS, Units 1 and 2, was implemented at LSCS, Unit 1, as part of L1C16. 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 1 and 2.

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. 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, 2014.]

4) Current LOCA Model Assessment for AREVA NP Fuel and GNF Fuel Since the last annual report (see Note 3), four vendor notifications were received:

The first notification (Reference 1) addresses several accumulated updates to the SAFERO4A model. These code maintenance changes result in a PCT change of 0°F for GNF2 and ATRIUM-10 fuel.

The second notification (Reference 2) corrected a logic error that has been isolated, occurring with an indication that the expected system mass diverges from the calculated actual mass. This error affects the ECCS flow credited as reaching the core. Correction of this error results in a 0°F PCT change for GNF2 and ATRIUM-10 fuel.

The third notification (Reference 3) addresses an error with the imposed minimum pressure differential (4) 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. To correct this error, an explicit core Ap calculation is applied without regard to droplet condition resulting in a PCT change of -10°F for GNF2 and ATRIUM-10 fuel.

The fourth notification (Reference 4) addresses an incorrect pressure head representation when defining the counter current flow limitation (CCFL). Correction of this error results in a +5°F PCT change for GNF2 and ATRIUM-10 fuel.

Page 2 of 3

ATTACHMENT 3 LaSalle County Station, Units 1 and 2 10 CFR 50.46 Report Assessment Notes No ECCS related changes or modifications have occurred at LSCS that affect the assumptions in the GEH LOCA analyses 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 spring 2015 refueling outage (L2R15). Reference 5 supports the introduction of the GNF3 LUAs and includes the licensing basis PCT. Notifications 2014-01 through 2014-04 (References 1 4) were included in the determination of the licensing basis PCT for the GNF3 LUAs in Reference 5.

[Reference 1: Letter from GE Hitachi Nuclear Energy (GEH) to Exelon Generation Company, LLC, "10 CFR 50.46 Notification Letter 2014-01, LaSalle County Station (Unit 1 & 2)," dated May 21, 2014.]

[Reference 2: Letter from GE Hitachi Nuclear Energy (GEH) to Exelon Generation Company, LLC, "10 CFR 50.46 Notification Letter 2014-02, LaSalle County Station (Unit 1 & 2)," dated May 21, 2014.]

[Reference 3: Letter from GE Hitachi Nuclear Energy (GEH) to Exelon Generation Company, LLC, "10 CFR 50.46 Notification Letter 2014-03, LaSalle County Station (Unit 1 & 2)," dated May 21, 2014.]

[Reference 4: Letter from GE Hitachi Nuclear Energy (GEH) to Exelon Generation Company, LLC, "10 CFR 50.46 Notification Letter 2014-04, LaSalle County Station (Unit 1 & 2)," dated May 21, 2014.]

[Reference 5: GNF Evaluation 002N3086.1 Rev. 0, "Technical Evaluation to Support Introduction of GNF3 Lead Use Assemblies (LUAs) in LaSalle County Station, Unit 2,"

December 2014.]

Page 3 of 3

Bcc:

NRR Project Manager LaSalle County Station Exelon Document Control Desk - Licensing Site Vice President LaSalle County Station Director Licensing and Regulatory Affairs (Midwest)

Manager Licensing, LaSalle County Station Regulatory Assurance Manager LaSalle County Station Commitment Tracking Coordinator Midwest Gary Benes LaSalle County Station Larry Blunk LaSalle County Station John Massari -- Cantera Kristin McCoskey Cantera Joshua Shea LaSalle County Station Stephen T. Shields LaSalle County Station Lisa A. Simpson Cantera

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