ML060310459
| ML060310459 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 02/10/2006 |
| From: | Pickett D Plant Licensing Branch III-2 |
| To: | Singer K Tennessee Valley Authority |
| Pickett , NRR/DLPM, 415-1364 | |
| Shared Package | |
| ML060310495 | List: |
| References | |
| IR 327-2004-010 | |
| Download: ML060310459 (3) | |
Text
February 10, 2006 Mr. Karl W. Singer Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801
SUBJECT:
SEQUOYAH NUCLEAR PLANT, UNIT 1 - TRANSMITTAL OF FINAL ACCIDENT SEQUENCE PRECURSOR ANALYSES REPORT, IR 327-2004-010
Dear Mr. Singer:
Enclosed for your use and information is a copy of the Nuclear Regulatory Commission (NRC)
Final Accident Sequence Precursor Report, IR 327-2004-010, for the Sequoyah Nuclear Plant, Unit 1.
NRC Inspection Report 50-327/2004-004 dated October 25, 2004, described an event where Residual Heat Removal Pump 1A failed to start during a surveillance test. The failure was caused by the pump breaker due to binding of the Siemens breaker mechanism operated cell slide assembly (a wear out failure mode). This event was analyzed as a WHITE event by a Phase 3 significant determination process (SDP) analysis in the fall of 2004. In Winter 2004, a significant revision to the simplified plant analysis risk (SPAR) model and the associated equipment reliability data was published. The accident sequence precursor (ASP) analysis used the same condition analysis approach as the SDP and the newer SPAR model, which resulted in a change in core damage probability that is a factor of about 3 lower than the SDP.
The difference between the ASP and SDP analyses is the result of ongoing improvements to the SPAR model.
If you have any questions about the analysis, please contact Gary DeMoss of the NRCs Office of Research at 301-415-6225.
Sincerely,
/RA/
Douglas V. Pickett, Senior Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-327
Enclosure:
Final Accident Sequence Precursor Report cc w/enclosure: See next page
ML060310459 NRR-106 OFFICE LPL2-2/PM LPL2-2/LA D:RES LPL2-2/BC NAME DPickett RSola CAder MMarshall DATE 02/03/06 02/03/06 signed by memo dated 1/27/06 02/10/06
Mr. Karl W. Singer SEQUOYAH NUCLEAR PLANT Tennessee Valley Authority cc:
Mr. Ashok S. Bhatnagar, Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Larry S. Bryant, Vice President Nuclear Engineering & Technical Services Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Robert J. Beecken, Vice President Nuclear Support Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Randy Douet Site Vice President Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37384-2000 General Counsel Tennessee Valley Authority ET 11A 400 West Summit Hill Drive Knoxville, TN 37902 Mr. John C. Fornicola, Manager Nuclear Assurance and Licensing Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Glenn W. Morris, Manager Corporate Nuclear Licensing and Industry Affairs Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. Paul L. Pace, Manager Licensing and Industry Affairs ATTN: Mr. James D. Smith Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37384-2000 Mr. David A. Kulisek, Plant Manager Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37384-2000 Senior Resident Inspector Sequoyah Nuclear Plant U.S. Nuclear Regulatory Commission 2600 Igou Ferry Road Soddy Daisy, TN 37379 Mr. Lawrence E. Nanney, Director Division of Radiological Health Dept. of Environment & Conservation Third Floor, L and C Annex 401 Church Street Nashville, TN 37243-1532 County Mayor Hamilton County Courthouse Chattanooga, TN 37402-2801 Ms. Ann P. Harris 341 Swing Loop Road Rockwood, Tennessee 37854