ML110950367
| ML110950367 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 03/23/2011 |
| From: | Dunn R South Texas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NOC-AE-11002644 | |
| Download: ML110950367 (2) | |
Text
Nuclear Operating Company South Texas Project Electric Generating Station PO. Box 289 Wadsworth. Tews 77483 March 23, 2011 NOC-AE-1 1002644 File No.: G25 10 CFR 50.46 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 South Texas Project Units 1 & 2 Docket Nos. STN 50-498, STN 50-499 10 CFR 50.46 Annual Report of ECCS Model Revisions
Reference:
David A. Leazar to NRC Document Control Desk, "10 CFR 50.46 Annual Report of ECCS Model Revisions,"
dated March 17, 2010 (NOC-AE-1 0002537) (ML100880110)
Pursuant to 10 CFR 50.46(a)(3)(ii), STP Nuclear Operating Company submits this report to address revisions to the accepted Emergency Core Cooling System evaluation model at South Texas Project (STP) Units 1 and 2.
Westinghouse Technical Bulletin TB-10-5, "Indicated Higher than Actual Average Temperature Rod Control Uncertainties," addresses a safety concern in which positive instrument uncertainty was not used in large and small break Loss of Coolant Accident (LOCA) analyses.
Not including positive instrument uncertainty in calculations (i.e., indicated temperature is higher than the actual temperature) is potentially non-conservative for LOCA analyses. However, this discrepancy has a negligible impact on STP for existing large and small break LOCA analysis results. The estimated peak clad temperature impact is 0°F.
STP Unit 1 and Unit 2 large and small break LOCA peak clad temperatures have not changed since submittal of the referenced report.
There are no commitments in this submittal.
If there are any questions, please contact either Mr. Philip L. Walker at (361) 972-8392 or me at (361) 972-7743.
Roland Dunn
- Manager, Nuclear Fuels & Analysis PLW STI: 32828772
NOC-AE-1 1002644 Page 2 of 2 cc:
(paper copy)
(electronic copy)
Regional Administrator, Region IV U. S. Nuclear Regulatory Commission 612 East Lamar Blvd., Suite 400 Arlington, Texas 76011-8064 Mohan C. Thadani Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint North (MS 8 B1A) 11555 Rockville Pike Rockville, MD 20852 Senior Resident Inspector U. S. Nuclear Regulatory Commission P. 0. Box 289, Mail Code: MN116 Wadsworth, TX 77483 C. M. Canady City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704 John Ragan Catherine Callaway Jim von Suskil NRG South Texas LP A. H. Gutterman, Esquire Morgan, Lewis & Bockius LLP Mohan C. Thadani U. S. Nuclear Regulatory Commission Kevin Polio Richard Pena E. Alarcon City Public Service C. Mele City of Austin Peter Nemeth Crain Caton & James, P.C.
Richard A. Ratliff Texas Department of State Health Services Alice Rogers Texas Department of State Health Services