ML093280856
| ML093280856 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 11/21/2009 |
| From: | St.Onge R Southern California Edison Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML093280856 (11) | |
Text
SOUTHERN CALIFORNIA Richard 1. St. Onge V 1 EDISON Director Nuclear Regulatory Affairs An EDISON INTERNATIONAL Company 10 CFR 50.46 November 21, 2009 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555
Subject:
Docket Nos. 50-361 and 50-362 2008 Emergency Core Cooling System Annual 10 CFR 50.46 Report San Onofre Nuclear Generating Station, Units 2 and 3
Reference:
Letter from A. E. Scherer (SCE) to Document Control Desk (NRC),
dated December 16, 2008,
Subject:
Docket Nos. 50-361 and 50-362, 2007 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 2008 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 reactors." This regulation requires Southern California Edison (SCE) to report annually 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 applications 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. is a description of changes and errors in the Westinghouse evaluation models (EM) used in the San Onofre Nuclear Generating Station (SONGS) Units 2 and 3 ECCS performance analyses. is a summary of the effect on Peak Clad Temperature (PCT) of the errors and changes in the Westinghouse evaluation models used in the SONGS Units 2 and 3 ECCS Performance Analyses. While not limiting with regard to PCT, detailed information for the Small Break Loss of Coolant Accident (LOCA) is also included in (in accordance with Supplement 1 to Information Notice 97-15).
P.O. Box 128 San Clemente, CA 92674 mzK
Document Control Desk November 21, 2009 SCE made no changes to the LOCA evaluation models.
Operating Cycle Information Unit 2 and Unit 3 operation for the current reporting period is outlined below.
Unit Year Cycle 14 Cycle 15 January 19, 2008 2
2008 through December 31, 2008 January 1, 2008 December 18, 2008 3
2008 through through October 12, 2008 December 31, 2008 Unit 2 operated only under Cycle 15 in 2008, hence, no input for this entry.
Unit 2 was in refueling outage prior to January 19, 2008 2008 REPORTING PERIOD SONGS Units 2 and 3 Larqe Break LOCA Evaluation Model (EM)
The Large Break LOCA (LBLOCA) analysis used the 1999 evaluation model for this reporting period.
The limiting Large Break LOCA PCT did not exceed the 10 CFR 50.46(b)(1) acceptance criterion of 2,200 'F. 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 10 CFR 50.46 model changes and model errors. This is documented in Enclosure 2 (Table 2).
Document Control Desk
-3 November 21, 2009 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.
The limiting Small Break LOCA PCT did not exceed the 10 CFR 50.46(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 10 CFR 50.46 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. Linda T. Conklin at 949/368-9443.
Sincerely,
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 2008)
- 2.
Summary of the Effect on PCT of the Errors and Changes in the Westinghouse Evaluation Models used in the SONGS Units 2 and 3 ECCS Performance Analyses (Calendar Year 2008) 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 Description of Changes and Errors in the Westinghouse Evaluation Models used in the SONGS Units 2 and 3 ECCS Performance Analyses (Calendar Year 2008)
(3 pages including this page), Page 1 of 3
- 1.
1999 EM Version of the Westinghouse Appendix K Large Break LOCA Evaluation Model for Combustion Engineering PWRs IMPLEMENTATION OF OPTIONAL MODELS FOR A MIXED CORE ANALYSIS AND DEFORMED GRID COOLABILITY ANALYSIS (Discretionary Change)
Background
The Appendix K EGGS Performance Analysis for LBLOCA for CE plants is performed with the 1999 Evaluation Model (1999 EM).
A new User-Controlled Interface (UCI) parameter (mixed core) is added to the UCI File Parameter List to facilitate the selection of optional model features for use in performing a non-licensing mixed core analysis. The mixed core analysis is used to analyze the effects of co-resident, thermal-hydraulically dissimilar, fuel assembly design types. This new UCI option is not intended for licensing applications of the 1999 EM, which must use a uniform core representation of one fuel assembly type for conformance to the 1999 EM licensed methodology. As required by the NRC in Limitations and Conditions for WCAP-1 6500, the Core Reference Report for the Implementation of the CE 16x1 6 Next Generation Fuel (NGF) assembly design, mixed core effects must be dispositioned. The mixed core UCI file parameter is designed to automate base deck input vector changes needed to perform analyses to disposition transition core configurations.
Also, a new UCI parameter (deformed grid) is added to the UCI File Parameter List to facilitate the selection of optional model features for use in performing a non-licensing Deformed Grid Coolability Analysis (DGCA) as part of the Seismic/LOCA fuel design qualification process. This new UCI option is not intended for licensing application of the 1999 EM, which is constrained by NRC imposed limitations/constraints to applications for ECCS Performance Analysis only. However, the DGCA analysis is permissible under NUREG 0800, SRP 4.2, Appendix A, Section D, where cases of deformed grids are acceptable for fuel assembly designs provided an ECCS Performance analysis confirms that 10 CFR 50.46 peak clad temperature and maximum local cladding oxidation criteria are satisfied with the assumption of maximum credible grid deformation.
Affected Evaluation Model(s)
Non-Licensing Applications using the Appendix K LBLOCA Evaluation Model, 1999 EM Estimated Effect This process improvement is for non-licensing applications. Therefore, this change has no impact on the licensed methodology for the 1999 EM and does not conflict with the SER limitation/constraints imposed on the methodology by NRC for licensing applications. For licensing applications, there is no impact on PCT for 10 CFR 50.46 reporting purposes since these changes are intended only for use in non-licensing calculations., Page 2 of 3
UPDATE TO THE OXIDATION MODEL USER-CONTROL PARAMETER OPTION TO PERFORM EMBRITTLEMENT ANALYSIS (Discretionary Change)
Background
An update to the Oxidation Model UCI parameter (oxidation model) has been added to activate the calculation of the new NRC Embrittlement Model as described in the NRC's Research Information Letter (RIL) 0801. RIL 0801 is the NRC's announcement to the industry of planned regulatory modifications to the cladding embrittlement criteria of 10 CFR 50.46. The details of the ECCS Acceptance Criteria change have not been finalized by the NRC, but the essential elements of NRC's planned change are known.
The purpose of this update to the STRIKIN-II computer code is to modify the code logic to implement the preliminary capabilities that are necessary to calculate the new embrittlement model. This update to the Oxidation Model UCI parameter is a non-licensing option that is added to the 1999 EM to facilitate scoping studies and various advanced model calculations.
Affected Evaluation Model(s)
Non-Licensing Applications using the Appendix K LBLOCA Evaluation Model, 1999 EM Estimated Effect This process improvement is for non-licensing applications. Therefore, this change has no impact on the licensed methodology for the 1999 EM and does not conflict with the SER limitation/constraints imposed on the methodology by NRC for licensing applications. For licensing applications, there is no impact on PCT for 10 CFR 50.46 reporting purposes since these changes are intended only for use in non-licensing calculations.
- 2.
S2M Version of the Westinghouse Appendix K Small Break LOCA Evaluation Model for Combustion Engineering PWRs None., Page 3 of 3 Summary of the Effect on PCT of the Errors and Changes in the Westinghouse Evaluation Models used in the SONGS Units 2 and 3 ECCS Performance Analyses (Calendar Year 2008)
(5 pages including this page), Page 1 of 5
2008 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 clad 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 Unit 2 Unit 3 Limiting Large Break LOCA PCT End of 2007 2,170 OF 2,170 OF Changes in PCT during 2008 due to:
a) Model changes and Model errors (1999 EM)
" Cycle 14 0 OF
" Cycle 15 0 OF 0 OF b) Cycle Dependent Input Changes
" Cycle 14 0 OF
" Cycle 15 0 OF 0 OF Limiting Large Break LOCA PCT End of 2008 2,170 OF 2,170 OF
- Unit 2 operated only under Cycle 15 in 2008, hence, no input for this entry., 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 2:IA PCTI
- Unit 2 1Unit3 Cumulative LBLOCA 10 CFR 50.46 Model Changes and Model Errors Prior to 2008 0 OF 0 OF Changes in LBLOCA PCT due to Model Changes and Model Errors During 2008
" Cycle 14 0 F
" Cycle 15 0 OF 0 OF Cumulative LBLOCA 10 CFR 50.46 Model Changes and Model Errors End of 2008 0 OF 0 OF Sum of the absolute magnitude of the 10 CFR 50.46 model changes and model errors.
Unit 2 operated only under Cycle 15 in 2008, hence, no input for this entry., Page 3 of 5
Small Break LOCA Table 3 provides a time line of the items which could affect the Small Break LOCA (SBLOCA) peak clad temperature (PCT) for this reporting period. The SBLOCA 10 CFR 50.46 PCT limit of 2200 OF was not exceeded, and the SBLOCA PCT remained bounded by the LBLOCA PCT.
Table 3 Limiting Small Break LOCA PCT Unit 2 Unit 3 Unit 2 Unit 3 Limiting Small Break LOCA PCT End of 2007 2,077 OF 2,077 OF Changes in PCT during 2008 due to:
a) Model changes and Model errors
" Cycle 14 0 F
" Cycle 15 0 OF 0 OF b) Cycle Dependent Input Changes
" Cycle 14 0 F
" Cycle 15 0 OF 0 OF Limiting Small Break LOCA PCT End of 2008 2,077 OF 2,077 OF Unit 2 operated only under Cycle 15 in 2008, hence, no input for this entry., 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 E IA PCTI
- I Unit2 IUnit3 Cumulative SBLOCA 10 CFR 50.46 Model Changes and Model Errors Prior to 2008 0 OF 0 OF Changes in SBLOCA PCT due to Model Changes and Model Errors During 2008
- Cycle 14 0 OF Cycle 15 0 OF 0 OF Cumulative SBLOCA 10 CFR 50.46 Model Changes and Model Errors End of 2008 0 OF 0 OF Sum of the absolute magnitude of the 10 CFR 50.46 model changes and model errors.
Unit 2 operated only under Cycle 15 in 2008, hence, no input for this entry., Page 5 of 5