IR 05000413/2007012

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March 21, 2007

Duke Power Company LLC d/b/a Duke Energy Carolinas, LLC ATTN:Mr. J. R. MorrisSite Vice President Catawba Site4800 Concord Road York, SC 29745-9635

SUBJECT: CATAWBA NUCLEAR STATION - NRC FINAL SIGNIFICANCEDETERMINATION AND CLOSURE OF UNRESOLVED ITEM - REPORT 05000413/2007012 AND 05000414/2006012

Dear Mr. Morris:

On December 6, 2006, the U.S. Nuclear Regulatory Commission (NRC) completed a SpecialInspection at your Catawba Nuclear Station Units 1 and 2 related to flooding vulnerabilities of the turbine building and some safety-related areas. The results of this inspection were documented in NRC Special Inspection Report 05000413/2006010 and 05000414/2006010.

This report contained Unresolved Item 05000413,414/2006010-01. This unresolved item was opened to re-quantify the risk for a Green non-cited violation (NCV05000413,414/2006004-02) issued on October 26, 2006. This NCV documented your failure to maintain appropriate design control to ensure that below-grade electrical conduits were properly sealed to prevent water intrusion into areas of the plant containing safety-related equipment.

The NRC Special Inspection identified that additional flooding vulnerabilities were present from April 6, 2005 to May 22, 2006, and determined that a requantification of the station risk was appropriate.The NRC staff has completed requantification of the station risk for this issue and determinedthat the change to core damage frequency that resulted from the additional water ingress paths was less than 1E-6 (Green) because of the low frequency of rainfall events with the potential to flood the susceptible areas. Therefore, the risk significance of this issue, which was dispositioned as Green NCV 05000413/2006004-02, 05000414/2006004-02, will not change. Thank you for your assistance in this matter. If you have any questions concerning this matter,please contact me at (404) 562-4647.

DPC2In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and itsenclosure will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of NRC's document system (ADAMS). ADAMS is accessible from the NRC Web site at www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).

Sincerely,/RA/ James H. Moorman, III, Chief Reactor Projects Branch 1 Division of Reactor ProjectsDocket Nos.:50-413, 50-414License Nos.:NPF-35, NPF-52cc: (See page 3)

DPC2In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and itsenclosure will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of NRC's document system (ADAMS). ADAMS is accessible from the NRC Web site at www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).

Sincerely,/RA/ James H. Moorman, III, Chief Reactor Projects Branch 1 Division of Reactor ProjectsDocket Nos.:50-413, 50-414License Nos.:NPF-35, NPF-52cc: (See page 3)X PUBLICLY AVAILABLE G NON-PUBLICLY AVAILABLEG SENSITIVE X NON-SENSITIVEADAMS: X YesACCESSION NUMBER:_________________________OFFICERII:DRPRII:DRPSIGNATURERHB /RA/JHM /RA/NAMERBernhardJMoormanDATE03/21/200703/21/2007 E-MAIL COPY? YESNO YESNO YESNO YESNO YESNO YESNO YESNO OFFICIAL RECORD COPY DOCUMENT NAME: C:\FileNet\ML070800461.wpd DPC3cc:Randy D. Hart Regulatory Compliance Manager Duke Power Company LLC d/b/a/Duke Energy Carolinas, LLC Electronic Mail DistributionLisa F. VaughnAssociate General Counsel and Managing Attorney Duke Energy Corporation 526 South Church Street-EC 07H Charlotte, NC 28202Kathryn B. NolanSenior Counsel Duke Energy Corporation 526 South Church Street-EC 07H Charlotte, NC 28202David A. RepkaWinston & Strawn LLP Electronic Mail DistributionNorth Carolina MPA-1Electronic Mail DistributionHenry J. Porter, Asst. DirectorDiv. of Radioactive Waste Mgmt.

S. C. Department of Health and Environmental Control Electronic Mail DistributionR. Mike GandyDivision of Radioactive Waste Mgmt.

S. C. Department of Health and Environmental Control Electronic Mail DistributionElizabeth McMahonAssistant Attorney General S. C. Attorney General's Office Electronic Mail DistributionVanessa QuinnFederal Emergency Management Agency Electronic Mail DistributionNorth Carolina Electric Membership Corporation Electronic Mail DistributionPeggy ForceAssistant Attorney General N. C. Department of Justice Electronic Mail DistributionCounty Manager of York County, SCElectronic Mail DistributionPiedmont Municipal Power AgencyElectronic Mail DistributionR. L. Gill, Jr., ManagerNuclear Regulatory Issues and Industry Affairs Duke Power Company LLC d/b/a Duke Energy Carolinas, LLC 526 S. Church Street Charlotte, NC 28201-0006Distribution: (See page 4)

DPC4Letter to J. from James Moorman, III dated March 21, 2007

SUBJECT: CATAWBA NUCLEAR STATION - NRC FINAL SIGNIFICANCEDETERMINATION AND CLOSURE OF UNRESOLVED ITEM - REPORT 05000413/2007012 AND 05000414/2006012Distribution:J. Stang, NRRC. Evans, RII EICS L. Slack, RII EICS RIDSNRRDIRS OE Mail PUBLIC