NOC-AE-02001441, 10CFR50.46 Thirty Day Report of Significant ECCS Model Changes

10CFR50.46 Thirty Day Report of Significant ECCS Model Changes

ML023570351
Person / Time
Site:	South Texas
Issue date:	12/17/2002
From:	Leazar D South Texas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NOC-AE-02001441
Download: ML023570351 (4)

Text

Nuclear Operating Company South Tc.sPmftctEkck Generatin StaUon PCaBr289 ldsiworh, TeCW 77483

• December 17, 2002 NOC-AE-02001441 File No.: G25 10CFR50.46 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852 South Texas Project Units 1 & 2 Docket Nos. STN 50-498, STN 50-499 10CFR50.46 Thirty-Day Report of Significant ECCS Model Changes

References:

1) Letter from D. A. Leazar to NRC Document Control Desk, "10CFR50.46 Annual Report of ECCS Model Revisions and 30 Day Report of Significant ECCS Model Changes," dated December 13,2000 (NOC-AE-000980)

2) Letter from D. A. Leazar to NRC Document Control Desk, "10CFR50.46 Annual Report of ECCS Model Revisions," dated January 9, 2002 (NOC-AE-02001233)

Pursuant to 10CFR50.46(a)(3)(ii), the South Texas Project (STP) is submitting this thirty-day-'

report of significant Emergency Core Cooling System (ECCS) changes for the STP Unit 2 Small Break Loss of Coolant Accident (LOCA) evaluation model.

In 2000, Westinghouse re-performed the A94 steam generator Small Break LOCA analysis to address errors discovered in the NOTRUMP code (Reference 1). The reanalysis, which has been tracked as an evaluation for Unit 1 since 2000, also included final "as-built" data for the Unit 1 A94 steam generators, a Westinghouse IMP database correction, and explicit modeling of annular blankets.

Concurrent with the completion of the Unit 2 steam generator replacement project, the STP Nuclear Operating Company is implementing the year 2000 Small Break LOCA reanalysis as the analysis of record for Units 1 and 2. With the implementation of the year 2000 Small Break LOCA reanalysis as the common Unit 1 / Unit 2 analysis of record, the Unit 1 Small Break LOCA Peak Clad Temperature (PCT) remains unchanged at 1578*F while the Unit 2 Small Break LOCA PCT decreases from 1951'F (Reference 2) to 1578°F. Since absolute value of the Unit 2 PCT change exceeds 50TF, the change is considered significant, in accordance with 10 CFR 50.46. No schedule for reanalysis is proposed since the Unit 2 Small Break LOCA PCT change is the result of a complete reanalysis and the PCT remains below the 10 CFR 50.46 limit of 2200'F. Attachment 1 provides the current Small Break LOCA ECCS analysis PCT rack-ups.

0O/QUAITFYAND -LICENSING/nl/nrc-ap/misc-02/02001441 (50 46 letter) doc ST131533900

NOC-AE-02001441 Page 2 If you should have any questions concerning this matter, please contact Mr. Safdar Hafeez at (361) 972-8906 or me at (361) 972-7795.

fry D.A. Leazar Director Nuclear Fuel and Analysis jmw/kaw Attachments: Small Break LOCA PCT Rack-ups OJQUALITY_ANDLICENSING/nllnrc-ap/inisc-02/02001441 (50.46 letter) doc ST131533900

NOC-AE-02001441 Page 3 cc:

(paper copy) (electronic copy)

Ellis W. Merschoff A. H. Gutterman, Esquire Regional Administrator, Region IV Morgan, Lewis & Bockius LLP U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 M. T. HardtlW. C. Gunst Arlington, Texas 76011-8064 City Public Service U. S. Nuclear Regulatory Commission Mohan C. Thadani Attention: Document Control Desk U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike R. L. Balcom Rockville, MD 20852 Texas Genco, LP Richard A. Ratliff A. Ramirez Bureau of Radiation Control City of Austin Texas Department of Health 1100 West 49th Street C. A. Johnson Austin, TX 78756-3189 AEP - Central Power and Light Company Cornelius F. O'Keefe Jon C. Wood U. S. Nuclear Regulatory Commission Matthews & Branscomb P. O. Box 289, Mail Code: MN16 Wadsworth, TX 77483 C. M. Canady City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704 OIQUALITY_AND_UICENSING/nllnrc-ap/misc-02102001441 (50 46 letter) doc STI 31533900

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NOC-AE-02001441 Page 4 ATTACHMENT 1 Small Break LOCA PCT Rack-ups Unit 1 Small Break LOCA:

Unit 1 Small Break LOCA PCT (Reference 2) 1578 OF Unit 2 Small Break LOCA:

2001 Year End Unit 2 Small Break LOCA PCT (Reference 2) 1951 OF Adoption of A94 steam generator Small Break LOCA analysis -373 OF Revised Unit 2 Small Break LOCA PCT 1578 OF 0 /QUAL1TY AND_LICENSING/nl/nrc-ap/mise-02/02001441 (50 46 letter) doc STi:31533900