IR 05000269/2006016

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PROPRIETARY INFORMATIONDOCUMENT TRANSMITTED HEREWITH CONTAINS PROPRIETARYINFORMATION. WHEN SEPARATED FROM THE ENCLOSURE, THIS DOCUMENT ISDECONTROLLED.August 31, 2006EA-06-199 Duke Power Company, LLC d/b/a Duke Energy Carolinas, LLC (Duke)

ATTN:Mr. Bruce Site Vice President Oconee Nuclear Station7800 Rochester Highway Seneca, SC 29672

SUBJECT: OCONEE NUCLEAR STATION - NRC INSPECTION REPORT05000269/2006016, 05000270/2006016, AND 05000287/2006016;PRELIMINARY WHITE FINDING

Dear Mr. Hamilton:

On March 31, 2006, the U.S. Nuclear Regulatory Commission (NRC) completed a quarterlyintegrated inspection at your Oconee Nuclear Station. The inspection findings weredocumented in NRC Inspection Report 05000269/2006002, 05000270/2006002, and05000287/2006002, which was issued on April 28, 2006.Section 1R06b.(1) of that report identified Unresolved Item (URI) 05000269,270,287/2006002-01, which concerned a failure to maintain control of the standby shutdown facility (SSF) floodprotection barrier. Subsequent to further inspection, the performance deficiency was identified as a failure to effectively control maintenance activities, and therefore assess and manage the risk, associated with removing the CO2 access cover (a passive NRC committed floodprotection barrier as indicated on Oconee drawing O-310 K-22) in the south wall of the SSF to facilitate installation of temporary electrical power cables. It has been determined that thefailure to effectively control and perform a risk assessment for the aforementioned maintenance activity resulted in the following failures to manage risk:*The failure to expeditiously remove the temporary power cables from the SSF as soonas conditions permitted, and failure to reinstall the 6"x 10" CO2 supply access coverplate, a passive flood protection barrier, located in the Southwest corner of the SSFResponse Room.*The failure to post and maintain various plant equipment as protected equipment toensure the operability of the remaining safety-related equipment was not jeopardized. PROPRIETARY INFORMATIONDuke2DOCUMENT TRANSMITTED HEREWITH CONTAINS PROPRIETARYINFORMATION. WHEN SEPARATED FROM THE ENCLOSURE, THIS DOCUMENT ISDECONTROLLED.*The failure to effectively communicate the elevated risk associated with planned workactivities to station personnel to ensure changes in work scope or schedules were elevated to the appropriate personnel for review and assessment. Consequently, for almost two years (from August 13, 2003, to August 3, 2005) anuncompensated for and uncontrolled flowpath existed through the SSF wall, which could have rendered the SSF unable to perform its intended functions in the event of an external flood in excess of 4.6 feet (800.625 feet above msl).The staff performed a quantitative risk analysis to estimate the increase in risk from theperformance deficiency. The estimated change in core damage frequency was 3.3 E -6 per year. However, the staff recognized that probabilistic risk estimates for rare events do havelarge uncertainties and that use of a linear scaling factor for the reduced effective wall height (due to the hole) contains considerable uncertainties in itself. The staff used the best available information since probabilistic based flood distributions to determine the likelihood of floodlevels between the hole and wall height were not readily available to provide a more precise risk-based assessment. Given these modeling uncertainties and the need for a risk-informed decision (in lieu of risk-based), the staff also considered qualitative, deterministic information.

From a defense-in-depth perspective, the SSF would normally mitigate the hypothetical external flood scenario. If the SSF is unavailable, no other event mitigation systems would be availableto prevent core damage. Hence, defense-in-depth may not be preserved. Given both thequantitative and qualitative considerations, the staff has preliminarily determined that theperformance deficiency represents a finding that has low-to-moderate risk significance (White).

The finding does not represent a current safety concern because the temporary electrical power cables have been removed and the CO2 access cover reinstalled.As inferred above, the finding reflects two apparent violations (AVs) associated with removingthe CO2 access cover in the south wall of the SSF to facilitate installation of temporary electricalpower: (1) failure to provide adequate procedures to control maintenance activities that could affect safety-related equipment, as required by Technical Specification 5.4.1 and Regulatory Guide 1.33, Section 9.a.; and (2) failure to assess and manage the increase in risk from external floods, as required by 10 CFR 50.65(a)(4), Requirements for monitoring the Effectiveness of Maintenance at Nuclear Power Plants. These apparent violations (respectively identified as AV 05000269,270,287/2006016-01: Inadequate Procedural Controls OverMaintenance Activities Affecting the SSF Flood Protection Barrier and AV 05000269,270,287/

2006016-02: Failure to Assess and Manage Risk Associated with Breaching the SSF Flood Protection Barrier) are being considered for escalated enforcement action in accordance with the NRC Enforcement Policy. Accordingly, for administrative purposes, URI 05000269,270,287/2006002-01 is considered closed. The current Enforcement Policy is included on the Nuclear Regulatory Commission's website at http://www.nrc.gov/reading-rm/adams.html.In accordance with Inspection Manual Chapter (IMC) 0609, we intend to complete ourevaluation using the best available information and issue our final determination of safety significance within 90 days of the date of this letter. The significance determination process PROPRIETARY INFORMATIONDuke3DOCUMENT TRANSMITTED HEREWITH CONTAINS PROPRIETARYINFORMATION. WHEN SEPARATED FROM THE ENCLOSURE, THIS DOCUMENT ISDECONTROLLED.encourages an open dialogue between the staff and the licensee; however, the dialogue shouldnot impact the timeliness of the staff's final determination. Before we make a final decision on this matter, we are providing you an opportunity to: (1) present to the NRC your perspectives onthe facts and assumptions, used by the NRC to arrive at the finding and its significance, at aRegulatory Conference or (2) submit your position on the finding to the NRC in writing. If yourequest a Regulatory Conference, it should be held within 30 days of the receipt of this letter and we encourage you to submit supporting documentation at least 1 week prior to the conference in an effort to make the conference more efficient and effective. If a Regulatory Conference is held, it will be open for public observation. The NRC will also issue a pressrelease to announce the conference. If you decide to submit only a written response, such a submittal should be sent to the NRC within 30 days of the receipt of this letter. Please contact Mr. Mike Ernstes at (404) 562-4540 within 10 business days of the date of yourreceipt of this letter to notify the NRC of your intentions. If we have not heard from you within10 days, we will continue with our significance determination and enforcement decisions andyou will be advised by separate correspondence of the results of our deliberations on thismatter. Since the NRC has not made a final determination in this matter, a Notice of Violation is notbeing issued at this time. In addition, please be advised that the number and characterization of the apparent violations may change as a result of further NRC review. In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter (withoutenclosure) and your response (if any) will be available electronically for public inspection in theNRC Public Document Room or from the Publicly Available Records (PARS) component ofNRC's document system (ADAMS). ADAMS is accessible from the NRC web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).

Sincerely,/RA/Charles Casto, DirectorDivision of Reactor Projects Docket Nos.: 50-269, 50-270, 50-287License Nos.: DPR-38, DPR-47, DPR-55

Enclosure:

SDP Phase 3 Summary ( PROPRIETARY INFORMATION) cc w/encl. (See page 4) PROPRIETARY INFORMATIONDuke3DOCUMENT TRANSMITTED HEREWITH CONTAINS PROPRIETARYINFORMATION. WHEN SEPARATED FROM THE ENCLOSURE, THIS DOCUMENT ISDECONTROLLED.encourages an open dialogue between the staff and the licensee; however, the dialogue shouldnot impact the timeliness of the staff's final determination. Before we make a final decision on this matter, we are providing you an opportunity to: (1) present to the NRC your perspectives onthe facts and assumptions, used by the NRC to arrive at the finding and its significance, at aRegulatory Conference or (2) submit your position on the finding to the NRC in writing. If yourequest a Regulatory Conference, it should be held within 30 days of the receipt of this letter and we encourage you to submit supporting documentation at least 1 week prior to the conference in an effort to make the conference more efficient and effective. If a Regulatory Conference is held, it will be open for public observation. The NRC will also issue a pressrelease to announce the conference. If you decide to submit only a written response, such a submittal should be sent to the NRC within 30 days of the receipt of this letter. Please contact Mr. Mike Ernstes at (404) 562-4540 within 10 business days of the date of yourreceipt of this letter to notify the NRC of your intentions. If we have not heard from you within10 days, we will continue with our significance determination and enforcement decisions andyou will be advised by separate correspondence of the results of our deliberations on thismatter. Since the NRC has not made a final determination in this matter, a Notice of Violation is notbeing issued at this time. In addition, please be advised that the number and characterization of the apparent violations may change as a result of further NRC review. In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter (withoutenclosure) and your response (if any) will be available electronically for public inspection in theNRC Public Document Room or from the Publicly Available Records (PARS) component ofNRC's document system (ADAMS). ADAMS is accessible from the NRC web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).

Sincerely,/RA/Charles Casto, DirectorDivision of Reactor Projects Docket Nos.: 50-269, 50-270, 50-287License Nos.: DPR-38, DPR-47, DPR-55

Enclosure:

SDP Phase 3 Summary ( PROPRIETARY INFORMATION) cc w/encl. (See page 4)PUBLIC DOCUMENT (circle one): YES ADAMS: ML062480170 OFFICERII:DRPRII:DRSEICSSIGNATUREMEE /RA/SDR /RA/CFE /RA/NAMEMErnstesWRogersCEvansDATE08/23/200608/23/200608/24/2006 E-MAIL COPY? YESNO YESNO YESNO YESNO YESNO YESNO YESNO OFFICIAL RECORD COPY DOCUMENT NAME: E:\Filenet\ML062480170.wpd PROPRIETARY INFORMATIONDuke4DOCUMENT TRANSMITTED HEREWITH CONTAINS PROPRIETARYINFORMATION. WHEN SEPARATED FROM THE ENCLOSURE, THIS DOCUMENT ISDECONTROLLED.cc w/encl.:Compliance Manager (ONS)

Duke Energy Corporation Electronic Mail Distributioncc w/o encl.:Lisa Vaughn Legal Department (PB05E)

Duke Energy Corporation 422 South Church Street Charlotte, NC 28242Anne CottinghamWinston and Strawn Electronic Mail DistributionMel Fry, DirectorDivision of Radiation Protection N. C. Department of Environmental Health & Natural Resources Electronic Mail DistributionHenry J. Porter, Assistant DirectorDiv. of 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 DistributionCounty Supervisor of Oconee County 415 S. Pine Street Walhalla, SC 29691-2145Lyle Graber, LISNUS Corporation Electronic Mail DistributionManagerNuclear Regulatory Licensing Duke Energy Corporation 526 S. Church Street Charlotte, NC 28201-0006Peggy ForceAssistant Attorney General N. C. Department of Justice Electronic Mail DistributionDistribution w/encl. (See page 5) PROPRIETARY INFORMATIONDuke5DOCUMENT TRANSMITTED HEREWITH CONTAINS PROPRIETARYINFORMATION. WHEN SEPARATED FROM THE ENCLOSURE, THIS DOCUMENT ISDECONTROLLED.Letter to Bruce from Charles Casto dated August 31, 2006

SUBJECT: OCONEE NUCLEAR STATION - NRC INSPECTION REPORT05000269/2006016, 05000270/2006016, AND 05000287/2006016;PRELIMINARY WHITE FINDINGDistribution w/o encl.:L. Olshan, NRR OEMAIL OEWEB C. Evans RIDSNRRDIPMLIPB PUBLIC