ML113060277

2010 Emergency Core Cooling System Annual 10 CFR 50.46 Report

ML113060277
Person / Time
Site:	San Onofre
Issue date:	11/01/2011
From:	St.Onge R Southern California Edison Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML113060277 (10)

Text

SOUTHERN CALIFORNIA Richard J. St. Onge EDISON Director, Nuclear Regulatory Affairs and Emergency Planning An EDISON INTERNATIONAL Compan y 10 CFR 50.46 November 1, 2011 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Wash ington, D. C. 20555

Subject:

Docket Nos. 50-361 and 50-362, 2010 Emergency Core Cooling System Annual 10 CFR 50.46 Report, San Onofre Nuclear Generating Station, Units 2 and 3

References:

Letter from R. J. St. Onge (SCE) to Document Control Desk (NRC) ,

dated December 15,2010,

Subject:

Docket Nos. 50-361 and 50-362, 2009 Emergency Core Cooling System, Annual 10 CFR 50.46 Report, San Onofre Nuclear Generating Station , Units 2 and 3

Dear Sir or Madam:

This letter transmits as Enclosures 1 and 2 the San Onofre Units 2 and 3 annual report for the 2010 calendar year required by paragraph (a)(3)(ii) of 10 CFR 50.46, "Acceptance criteria for emergency core cooling systems for light-water nuclear power reacto rs." This regulation requires Southern California Edison (SCE) to annually report to the NRC for San Onofre Units 2 and 3 the nature of each change to , or error discovered in, the Emergency Core Cooling System (ECCS) evaluation model , or in the application of this model that affects the temperature calculation and estimated effects of any such changes , errors , or appl ications on the limiting ECCS analysis. Any significant change or error is required to be reported to the NRC within 30 days.

The previous Emergency Core Cooling System Annual 10 CFR 50.46 Report was submitted to the NRC in the above Reference.

Enclosure 1 is a description of changes or errors in the Westinghouse evaluation models (EM) used in the San Onofre Nuclear Generating Station (SONGS) Units 2 and 3 ECCS performance analyses Enclosure 2 is a summary of the effect on Peak Clad Temperature (PCT) of the errors or changes in the Westinghouse evaluation models used in the SONGS Units 2 and 3 ECCS performance Analyses. While not limiting with regard to PCT, information for the Small Break Loss of Coolant Accident (LOCA) is also included in Enclosure 2 (in accordance with Supplement 1 to Information Notice 97-15).

SCE made no changes to the LOCA evaluation models.

P.O . Box 128 San Clemente, CA 92672

Document Control Desk November 1, 2011 Operating Cycle Information Unit 2 and Unit 3 operation for the current reporting period is outlined below.

Reporting Calendar Year 2010 Unit Cycle 15 Cycle 16 April 11, 2010

• 2 Ended prior to 2010 through December 31, 2010 January 1, 2010 3 Through Did not start in 2010 October 10,2010 **

• Unit 2 was in refueling outage the early part of 2010.

• • Unit 3 was in refueling outage the remainder of 2010.

2010 REPORTING PERIOD SONGS Units 2 and 3 Large Break LOCA Evaluation Model (EM)

The Large Break LOCA (LBLOCA) analysis used the 1999 evaluation mode for this reporting period.

The limiting Large Break LOCA PCT did not exceed the 10CFR50.46(b)(1) acceptance criterion of 2,200 of . This is documented in Enclosure 2 (Table 1).

There are no cumulative (sum of the absolute magnitudes of PCT changes) 1999 EM Large Break LOCA 10CFR 50.46 model changes or model errors. This is documented in Enclosure 2 (Table 2).

SONGS Units 2 and 3 Small Break LOCA Evaluation Model (EM)

The Small Break LOCA (SBLOCA) analysis used the Supplement 2 Model (S2M) Small Break LOCA evaluation model for this reporting period.

Document Control Desk November 1, 2011 The limiting Small Break LOCA PCT did not exceed the 10CFR50.46(b)(1) acceptance criterion of 2,200 of , and remained bounded by the large break LOCA PCT. This is documented in Enclosure 2 (Table 3).

There are no cumulative (sum of the absolute magnitudes of PCT changes) S2M Evaluation Model Small Break LOCA 10CFR50.46 model changes and model errors.

This is documented in Enclosure 2 (Table 4).

If you have any questions or need additional information on this subject, please contact Ms. L. T. Conklin at 949/368-9443.

Enclosures:

1. Description of Changes and Errors in the Westinghouse Evaluation Models used in the SONGS Units 2 and 3 ECCS Performance Analyses (Calendar Year 2010)

2. Summary of the Effect on PCT of the Errors or Changes in the Westinghouse Evaluation Models used in the SONGS Units 2 and 3 ECCS Performance Analyses (Calendar Year 2010) cc: E. E. Collins , Regional Administrator, NRC Region IV R. Hall , NRC Project Manager, San Onofre Units 2 and 3 G. G. Warnick, NRC Senior Resident Inspector, San Onofre Units 2 and 3

Enclosure 1 Description of Changes and Errors in the Westinghouse Evaluation Models Used in the SONGS Units 2 and 3 ECCS Performance Analyses (Calendar Year 2010)

(2 pages includ ing this page)

Enclosure 1, Page 1 of 2

1. 1999 EM Version of the Westinghouse Appendix K Large Break LOCA Evaluation Model for Combustion Engineering PWRs None .

2. S2M Version of the Westinghouse Appendix K Small Break LOCA Evaluation Model for Combustion Engineering PWRs None.

Enclosure 1, Page 2 of 2

Enclosure 2 Summary of the Effect on PCT of the Errors or Changes in the Westinghouse Evaluation Models Used in the SONGS Units 2 and 3 ECCS Performance Analyses (Calendar Year 2010)

(5 pages including this page)

Enclosu re 2, Page 1 of 5

2010 REPORTING PERIOD LOSS OF COOLANT ACCIDENT (LOCA) MARGIN

SUMMARY

SAN ONOFRE NUCLEAR GENERATING STATION UNITS 2 AND 3 Large Break LOCA Table 1 provides a time line of the items which could affect the Large Break LOCA (LBLOCA) peak cladding temperature (PCT) for this reporting period . The LBLOCA 10 CFR 50.46 PCT limit of 2,200°F was not exceeded .

Table 1 Limiting Large Break LOCA PCT Unit2 Unit 3 Limiting Large Break LOCA PCT End 0'2009 2,170 °F 2,170 of Changes in PCT during 2010 due to:

a) Model changes or Model errors (1999 EM)

• Cycle 15

• o of

• Cycle 16 o OF **

b) Cycle Dependent Input Changes

• Cycle 15

• o of

• Cycle 16 4 of **

Limiting Large Break LOCA PCT End 0'2010 2,174°F 2,170 of

• Unit 2 operated only under Cycle 16 in 2010 , hence no input for this entry.

• • Unit 3 operated only under Cycle 15 in 2010 , hence no input for this entry.

Enclosu re 2, Page 2 of 5

The cumulative effect of the 10 CFR 50.46 model changes and model errors for the Large Break LOCA 1999 Evaluation Model are shown in Table 2.

Table 2 Cumulative Large Break LOCA 10 CFR 50.46 Model Changes and Model Errors r ILl PCTI (1) t2 IUnit31

[;J Cumulative LBLOCA 10 CFR 50.46 Model Changes and Model Errors Prior to 2010 o of Changes in LBLOCA PCT due to Model Changes and Model Errors During 2010

• Cycle 15 ** o of

• Cycle 16 o of **

Cumulative LBLOCA 10 CFR 50.46 Model Changes and Model Errors End 0'2010 o of O°F

• Unit 2 operated only under Cycle 16 in 2010, hence no input for this entry.

• • Unit 3 operated only under Cycle 15 in 2010 , hence no input for this entry.

Enclosure 2, Page 3 of 5 (1) Sum of the absolute magnitude of the 10 CFR 50.46 model changes and model errors.

Small Break LOCA Table 3 provides a time line of the items which could affect the Small Break LOCA (SBLOCA) peak cladding temperature (PCT) for this reporting period. The SBLOCA 10 CFR 50.46 PCT limit of 2200 of was not exceeded, and the SBLOCA PCT rema ined bounded by the LBLOCA PCT.

Table 3 Limiting Small Break LOCA PCT Unit2 Unit 3 Limiting Small Break LOCA PCT End 0'2009 2,077 of 2,077 of Changes in PCT during 2010 due to:

a) Model changes or Model errors

• Cycle 15

• Cycle 16

°of °of

b) Cycle Dependent Input Changes

• Cycle 15

• Cycle 16

°of °of

Limiting Small Break LOCA PCT End 0'2010 2,077 of 2,077 of

• Unit 2 operated only under Cycle 16 in 2010 , hence no input for this entry.

• • Unit 3 operated only under Cycle 15 in 2010, hence no input for this entry.

Enclosure 2, Page 4 of 5

The cumulative 10 CFR 50.46 model changes and model errors for the Small Break LOCA S2M Evaluation Model are shown in Table 4.

Table 4 Cumulative Small Break LOCA 10 CFR 50.46 Model Changes and Model Errors r 1L1 PCTI (2)

Unit2 Unit3 Cumulative SBLOCA 10 CFR 50.46 Model Changes and Model Errors Prior to 2010 o of o of Changes in SBLOCA PCT due to Model Changes and Model Errors During 2010

• Cycle 15

• o of

• Cycle 16 o of **

Cumu lative SBLOCA 10 CFR 50.46 Model Changes and Model Errors End of 2010 o of o of

• Unit 2 opera ted only under Cycle 16 in 2010 , hence no input for this entry.

• • Unit 3 operated only under Cycle 15 in 2010 , hence no input for this entry.

Enclosure 2, Page 5 of 5 (2) Sum of the absolute magnitude of the 10 CFR 50.46 model changes and model errors .