ML13316B176

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CFR 50.46 Annual Report
ML13316B176
Person / Time
Site: Limerick  Constellation icon.png
Issue date: 11/08/2013
From:
Exelon Generation Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML13316B176 (13)
v • d • e


Text

10 CFR 50.46 November 8, 2013 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Units 1 and 2 Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353 Subject 10 CFR 50.46 Annual Report

References:

1) Letter from M. D. Jesse (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "1 0 CFR 50.46 Annual Report,"

dated November 9, 2012

2) Letter from M.D. Jesse (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "1 0 CFR 50.46 30-Day Report,"

dated December 12, 2012 The purpose of this letter is to submit the 10 CFR 50.46 reporting information for Limerick Generating Station (LGS), Units 1 and 2. The most recent annual 10 CFR 50.46 Report for LGS, Units 1 and 2, (Reference 1) provided the cumulative Peak Cladding Temperature (PCT) errors for the most recent fuel designs through November 9, 2012.

Since the Reference 1 report was issued, one vendor notification of an Emergency Core Cooling System (ECCS) model error/change applicable to LGS, Units 1 and 2 has been issued (see Reference 2). Also, no ECCS-related changes or modifications have occurred at LGS, Units 1 and 2, that affect the assumptions of the ECCS analyses.

Three attachments are included with this letter that provide the current LGS, Units 1 and 2, 10 CFR 50.46 status. Attachments 1 and 2 ("Peak Cladding Temperature Rack-Up Sheef')

provide updated information regarding the PCT for the limiting Loss of Coolant Accident

Limerick Generating Station, Units 1 and 2 10 CFR 50.46 Annual Report November 8, 2013 Page 2 (LOCA) analysis evaluations for LGS, Units 1 and 2, respectively. Attachment 3, "Assessment Notes," contains a detailed description for each change or error reported.

If you have any questions, please contact Tom Loomis at 61 0-765-551 0.

Respectfully, James Barstow Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC Attachments:

1) Peak Cladding Temperature Rack-Up Sheet (Limerick Generating Station, Unit 1)
2) Peak Cladding Temperature Rack-Up Sheet (Limerick Generating Station, Unit 2)
3) Assessment Notes (Limerick Generating Station, Units 1 and 2) cc: USNRC Region I, Regional Administrator USNRC Senior Resident Inspector, LGS USNRC Project Manager, LGS R. R. Janati, Bureau of Radiation Protection

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 November 8, 2013 Peak Cladding Temperature Rack-Up Sheet Limerick Generating Station, Unit 1

Report of the Emergency Core Cooling System Evaluation Model Changes and Errors Assessments as of November 8, 2013 Attachment 1 Peak Cladding Temperature Rack-Up Sheet, LGS U1 Page 1 of 2 PLANT NAME: Limerick Unit 1 ECCS EVALUATION MODEL: SAFER/GESTR-LOCA REPORT REVISION DATE: 11/8/13 CURRENT OPERATING CYCLE: 1§ 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 BW R Loss-of-Coolant Analysis," October 1987.
3. NEDC-32950P, "Compilation of Improvements to GENE's SAFER ECCS-LOCA Evaluation Model," January 2000.
4. NEDC-23785-1-PA Rev. 1, The GESTR-LOCA and SAFER Models for the Evaluation of the Loss-Of-Coolant Accident Volume Ill, SAFER/GESTR Application Methodology,"

October 1984. (Jet Pump Plant- SAFER)

Calculations:

1. ..Limerick Generating Station, Units 1 and 2 SAFER/GESTR-LOCA Loss-of-Coolant Accident Analysis," NEDC-32170P, Rev. 2, May 1995.
2. "Limerick Generating Station Units 1 and 2 ECCS-LOCA Evaluation for GE14," GE-NE-J 11 03793-09-01 P, March 2001.
3. "Limerick Generating Station Units 1 and 2 GNF2 ECCS-LOCA Evaluation,"

0000-0111-9078-RO, February 2011.

Fuels Analyzed in Calculations and in Operation: GE14 and GNF2 Limiting Fuel Type: GNF2 Limiting Single Failure (GE14/GNF2): Battery Failure Limiting Break Size and Location (GE14/GNF2): Double-Ended Guillotine in a Recirculation Suction Pipe Reference Peak Cladding Temperature (PCT) - GE14: 1670°F Reference Peak Cladding Temperature (PCT) - GNF2: 1880°F

Report of the Emergency Core Cooling System Evaluation Model Changes and Errors Assessments as of November 8, 2013 Attachment 1 Peak Cladding Temperature Rack-Up Sheet, LGS U1 Page 2 of 2 MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS 10 CFR 50.46 Report dated December 18, 2002 (See Note 1) GE14 ~PCT = 10aF 10 CFR 50.46 Report dated December 16, 2003 (See Note 2) GE14 ~PCT = -5aF 10 CFR 50.46 Report dated December 3, 2004 (See Note 3) GE14 ~PCT = oaF 10 CFR 50.46 Report dated December 1, 2005 (See Note 4) GE14 ~PCT = oaF 10 CFR 50.46 Report dated December 1, 2006 (See Note 5) GE14 ~PCT = oaF 10 CFR 50.46 Report dated November 30, 2007 (See Note 6) GE14 ~PCT =oaF 10 CFR 50.46 Report dated November 24, 2008 (See Note 7) GE14 ~PCT = oaF 10 CFR 50.46 Report dated November 24, 2009 (See Note 8) GE14 ~PCT =oaF 10 CFR 50.46 Report dated November 24, 2010 (See Note 9) GE14 ~PCT =oaF 10 CFR 50.46 Report dated November 23, 2011 (See Note 10) GE14 ~PCT = 50aF GNF2 ~PCT = 50aF 10 CFR 50.46 Report dated November 9, 2012 (See Note 11) GE14 ~PCT = oaF GNF2 ~PCT = oaF I 10 CFR 50.46 Report dated December 12, 2012 (See Note 12) GE14 ~PCT = 65aF GNF2 ~PCT = 45aF Net PCT {GE14} 1790°F Net PCT {GNF2} 1975°F B. CURRENT LOCA MODEL ASSESSMENTS None (See Note 13) GE14 ~PCT = ooF GNF2 ~PCT =oaF Total PCT change from current assessments (GE14) I~PCT =oaF Total PCT change from current assessments (GNF2) I~PCT =oaF Cumulative PCT change from current assessments (GE14) II~PCTI =OaF Cumulative PCT change from current assessments (GNF2) II~PCTI =OaF Net PCT {GE14} 1790°F Net PCT {GNF2} 1975°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 November 8, 2013 Peak Cladding Temperature Rack-Up Sheet Limerick Generating Station, Unit 2

Report of the Emergency Core Cooling System Evaluation Model Changes and Errors Assessments as of November 8, 2013 Attachment 2 Peak Cladding Temperature Rack-Up Sheet, LGS U2 Page 1 of 2 PLANT NAME: Limerick Unit 2 ECCS EVALUATION MODEL: SAFER/GESTR-LOCA REPORT REVISION DATE: 11/8/13 CURRENT OPERATING CYCLE: 13 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-32950P, "Compilation of Improvements to GENE's SAFER ECCS-LOCA Evaluation Model," January 2000.
4. NEDC-23785-1-PA Rev. 1, The GESTR-LOCA and SAFER Models for the Evaluation of the Loss-Of-Coolant Accident Volume Ill, SAFER/GESTR Application Methodology,"

October 1984. (Jet Pump Plant- SAFER)

Calculations:

1. "Limerick Generating Station, Units 1 and 2 SAFER/GESTR-LOCA Loss-of-Coolant Accident Analysis," NEDC-32170P, Rev. 2, May 1995.

2 ... Limerick Generating Station Units 1 and 2 ECCS-LOCA Evaluation for GE14, .. GE-NE-J 11 03793-09-01 P, March 2001.

3. "Limerick Generating Station Units 1 and 2 GNF2 ECCS-LOCA Evaluation,"

0000-0111-9078-RO, February 2011.

Fuels Analyzed in Calculations and in Operation: GE14 and GNF2 Limiting Fuel Type: GNF2 Limiting Single Failure (GE14/GNF2): Battery Failure Limiting Break Size and Location (GE14/GNF2): Double-Ended Guillotine in a Recirculation Suction Pipe Reference Peak Cladding Temperature (PCT) - GE14: 1670°F Reference Peak Cladding Temperature (PCT) - GNF2: 1880°F

Report of the Emergency Core Cooling System Evaluation Model Changes and Errors Assessments as of November 8, 2013 Attachment 2 Peak Cladding Temperature Rack-Up Sheet, LGS U2 Page 2 of 2 MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS 10 CFR 50.46 Report dated December 18, 2002 (See Note 1) GE14 L\PCT = 1ooF 10 CFR 50.46 Report dated December 16, 2003 (See Note 2) GE14 L\PCT = -5°F 10 CFR 50.46 Report dated December 3, 2004 (See Note 3) GE14 L\PCT = ooF 10 CFR 50.46 Report dated December 1, 2005 (See Note 4) GE14 L\PCT = ooF 10 CFR 50.46 Report dated December 1, 2006 (See Note 5) GE14 L\PCT = ooF 10 CFR 50.46 Report dated November 30, 2007 (See Note 6) GE14 L\PCT = ooF 10 CFR 50.46 Report dated November 24, 2008 (See Note 7) GE14 L\PCT = ooF 10 CFR 50.46 Report dated November 24, 2009 (See Note 8) GE14 L\PCT = ooF 10 CFR 50.46 Report dated November 24, 2010 (See Note 9) GE14 L\PCT = ooF 10 CFR 50.46 Report dated November 23, 2011 (See Note 10) GE14 L\PCT = 50°F GNF2 L\PCT = 50°F 10 CFR 50.46 Report dated November 9, 2012 (See Note 11) GE14 L\PCT = ooF GNF2 L\PCT = ooF 10 CFR 50.46 Report dated December 12, 2012 (See Note 12) GE14 L\PCT = 65°F GNF2 L\PCT = 45°F Net PCT (GE14} 1790°F Net PCT (GNF2} 1975°F B. CURRENT LOCA MODEL ASSESSMENTS None (See Note 13) GE14 L\PCT = ooF GNF2 L\PCT = ooF Total PCT change from current assessments (GE14) l:L\PCT = ooF Total PCT change from current assessments (GNF2) l:L\PCT = ooF Cumulative PCT change from current assessments (GE14) 2: IL\PCT I = oo F Cumulative PCT change from current assessments (GNF2) 2: IL\PCT I = ooF Net PCT (GE14} 1790°F Net PCT (GNF2} 1975°F

Attachment 3 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 Assessment Notes Limerick Generating Station, Units 1 and 2

Report of the Emergency Core Cooling System Evaluation Model Changes and Errors Assessments as of November 8, 2013 Attachment 3 Assessment Notes LGS, U1 and U2 Page 1 of 4

1. Prior LOCA Assessment The referenced letter provided an annual 50.46 report for Units 1 and 2. This letter reported GE LOCA errors related to a SAFER core spray sparger elevation error and a SAFER bulk water level error. The PCT impact for the new errors was determined to be 15°F and -5°F, respectively, for GE14 fuel. The total PCT impact of these errors was determined to be 1ooF for GE14 fuel.

[

Reference:

Letter from Michael P. Gallagher (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "1 0 CFR 50.46 Reporting Requirements," dated December 18, 2002.]

2. Prior LOCA Assessment The referenced letter provided an annual 50.46 report for Units 1 and 2. This letter reported aGE LOCA error related to a SAFER LeveiNolume Table error. The PCT impact for the new error was determined to be -5°F for GE14 fuel.

[

Reference:

Letter from Michael P. Gallagher (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "1 0 CFR 50.46 Reporting Requirements," dated December 16, 2003.]

3. Prior LOCA Assessment The referenced letter provided an annual 50.46 report for Units 1 and 2. This letter reported GE LOCA errors related to a GESTR file interpolation error, a SAFER computer platform change, a WEVOL S1 volume error, a SAFER separator pressure drop error and a new heat source. The PCT impact for the new errors was determined to be ooF for each error. The total PCT impact of these errors on GE14 fuel was determined to be 0°F.

[

Reference:

Letter from Michael P. Gallagher (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "1 0 CFR 50.46 Annual Report," dated December 3, 2004.]

4. Prior LOCA Assessment The referenced letter provided an annual 50.46 report for Units 1 and 2. There were no errors reported for the 2005 reporting period.

[

Reference:

Letter from Pamela B. Cowan (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "1 0 CFR 50.46 Annual Report," dated December 1, 2005.]

5. Prior LOCA Assessment The referenced letter provided an annual 50.46 report for Units 1 and 2. This letter reported a newly discovered sensitivity to the assumed axial power shape for small break LOCA cases. This sensitivity may result in higher calculated PCT values for top-peaked

Report of the Emergency Core Cooling System Evaluation Model Changes and Errors Assessments as of November 8, 2013 Attachment 3 Assessment Notes LGS, U1 and U2 Page 2 of 4 axial power shapes. Due to this sensitivity, the calculated small break PCT for Limerick was higher than the previously calculated value. However, the Licensing Basis PCT (based on large break) remained the same. Therefore the PCT impact of the new power shape sensitivity was determined to be ooF for GE14 fuel.

[

Reference:

Letter from David P. Helker (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "1 0 CFR 50.46 Annual Report," dated December 1, 2006.]

6. Prior LOCA Assessment The referenced letter provided an annual 50.46 report for Units 1 and 2. There were no errors reported for the 2007 reporting period.

[

Reference:

Letter from David P. Helker (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "1 0 CFR 50.46 Annual Report," dated November 30, 2007.]

7. Prior LOCA Assessment The referenced letter provided an annual 50.46 report for Units 1 and 2. There were no errors reported for the 2008 reporting period.

[

Reference:

Letter from David P. Helker (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "1 0 CFR 50.46 Annual Report," dated November 24, 2008.]

8. Prior LOCA Assessment The referenced letter provided an annual 50.46 report for Units 1 and 2. There were no errors reported for the 2009 reporting period.

[

Reference:

Letter from David P. Helker (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "1 0 CFR 50.46 Annual Report," dated November 24, 2009.]

9. Prior LOCA Assessment The referenced letter provided an annual 50.46 report for Units 1 and 2. There were no errors reported for the 2010 reporting period.

[

Reference:

Letter from David P. Helker (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "1 0 CFR 50.46 Annual Report," dated November 24, 2010.]

Report of the Emergency Core Cooling System Evaluation Model Changes and Errors Assessments as of November 8, 2013 Attachment 3 Assessment Notes LGS, U1 and U2 Page 3 of 4

10. Prior LOCA Assessment The referenced letter provided an annual 50.46 report for Units 1 and 2. The referenced letter discussed the introduction of the GNF2 fuel design to the Limerick Unit 2 core. The assessment notes above (Notes 1-9) are not applicable to GNF2 fuel. Subsequent to the referenced letter, the GNF2 fuel design was introduced to the Unit 1 core and the errors discussed in this note also apply to Unit 1 (See Note 11 ).

Also discussed in the referenced letter are two vendor notifications of Emergency Core Cooling System (ECCS) model error/changes for GE14 and GNF2 fuel applicable to Limerick. The errors/changes are summarized below.

The first error involved the way input coefficients were used to direct the deposition of gamma radiation energy produced by the fuel. Correction of this error resulted in a PCT increase of 45°F for both the GE14 fuel and GNF2 fuel.

The second error involved the contribution of heat from gamma ray absorption by the channel. The gamma ray absorption by the channel was found to have been minimized.

Correction of this error resulted in a PCT increase of 5°F for both the GE14 fuel and GNF2 fuel.

[

Reference:

Letter from Michael D. Jesse (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "1 0 CFR 50.46 Annual Report," dated November 23, 2011.]

11 . Prior LOCA Assessment The referenced letter provided an annual 50.46 report for Units 1 and 2. There were no errors reported for the 2012 reporting period.

GNF2 fuel was introduced into the Unit 1 core during Reload 14 (Cycle 15) outage. The ECCS model error/changes discussed in Note 10 were applied to Unit 1 as Prior LOCA Model Assessments.

[

Reference:

Letter from Michael D. Jesse (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "1 0 CFR 50.46 Annual Report," dated November 9, 2012.]

12. Prior LOCA Assessment The referenced letter provided an annual 50.46 report for Units 1 and 2. To address inaccuracies in fuel pellet thermal conductivity as a function of exposure, commonly referred to as thermal conductivity degradation (TCD), GEH replaced the GESTR-LOCA model with a newer model, PRIME. The most dominant effect impacting PCT is from the way the PRIME fuel properties treat thermal conductivity, which results in a higher fuel stored energy. The PCT impact identified in the referenced letter reflects the difference between the existing GESTR analysis PCT and a conservatively postulated PCT if the analysis was performed with the PRIME model. The ECCS-LOCA analysis methodology

Report of the Emergency Core Cooling System Evaluation Model Changes and Errors Assessments as of November 8, 2013 Attachment 3 Assessment Notes LGS, U1 and U2 Page 4 of 4 remains GESTR based and will not be PRIME based until the ECCS-LOCA analysis is re-performed using PRIME.

[

Reference:

Letter from Michael D. Jesse (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "1 0 CFR 50.46 30-Day Report," dated December 12, 2012.]

13. Current LOCA Assessment No vendor notifications of Emergency Core Cooling System (ECCS) model errors/changes applicable to Limerick have been issued since the last 10 CFR 50.46 30-Day Report (see Note 12). No ECCS related changes or modifications have occurred at Limerick that affect the assumptions in the Limerick Generating Station LOCA analysis of record.
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