05000413/LER-2006-001, Regarding Loss of Offsite Power Event Resulted in Reactor Trip of Both Catawba Units from 100% Power
| ML062080038 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 07/19/2006 |
| From: | Jamil D Duke Energy Corp, Duke Power Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 06-001-00 | |
| Download: ML062080038 (14) | |
| Event date: | |
|---|---|
| Report date: | |
| 4132006001R00 - NRC Website | |
text
P Duke W Energy D.M. JAMIL Vice President Catawba Nuclear Station 4800 Concord Rd. / CNOI VP York, SC 29745-9635 803 831 4251 803 831 3221 fax July 19, 2006 U.S. Nuclear Regulatory Commission Attention:
Document Control Desk Washington, D.C. 20555
Subject:
Duke Power Company LLC d/b/a Duke Energy Carolinas, LLC (Duke)
Catawba Nuclear Station, Units 1 and 2 Docket Nos. 50-413 and 50-414 Licensee Event Report 413/06-001 Attached is Licensee Event Report 413/06-001 titled "Loss of Offsite Power Event Resulted in Reactor Trip of Both Catawba Units from 100% Power."
There are no regulatory commitments contained in this letter or its attachment.
This event is considered to be of no significance with respect to the health and safety of the public.
If there are any questions on this report, please contact L.J. Rudy at (803) 831-3084.
Sincerely, D.M.
Jamil Attachment 1J E,2,-Z, www. duke-energy, com
Document Control Desk Page 2 July 19, 2006 xc (with attachment):
W.D. Travers Regional Administrator, Region II U.S. Nuclear Regulatory Commission 61 Forsyth Street, S.W.,
Suite 23T85 Atlanta, GA 30303 J.F. Stang, Jr. (addressee only)
NRC Senior Project Manager U.S. Nuclear Regulatory Commission Mail Stop 8-H4A 11555 Rockville Pike Rockville, MD 20852-2738 E.F. Guthrie NRC Senior Resident Inspector Catawba Nuclear Station INPO Records Center 700 Galleria Place
- Atlanta, GA 30339-5957 Marsh & McLennan, Inc.
K.W.
Gannaway 100 N. Tryon Street Charlotte, NC 28202
Abstract
On 05/20/06, at 1401 hours0.0162 days <br />0.389 hours <br />0.00232 weeks <br />5.330805e-4 months <br />, both Catawba units tripped automatically from 100% power following a Loss of Offsite Power (LOOP) event.
The event began when a fault occurred internal to a current transformer associated with one of the switchyard power circuit breakers.
A second current transformer failure, along with the actuation of differential relaying associated with both switchyard busses, cleared both busses and separated the units from the grid.
A Notification of Unusual Event (NOUE) was declared at 1414 hours0.0164 days <br />0.393 hours <br />0.00234 weeks <br />5.38027e-4 months <br />.
The Emergency Response Organization was electively activated.
Both emergency diesel generators on each unit started automatically and supplied their required blackout and essential loads as designed.
All three auxiliary feedwater pumps on each unit started automatically and fed the steam generators as designed.
Decay heat was removed via natural circulation of the reactor coolant system, with steam relief through the steam generator power operated relief valves.
Both units were stabilized in Mode 3 with cooldown activities in progress.
Offsite power was restored to all 6900V busses on both units by 05/20/06 at 2041 hours0.0236 days <br />0.567 hours <br />0.00337 weeks <br />7.766005e-4 months <br />.
The NOUE was subsequently terminated on 05/21/06 at 0140 hours0.00162 days <br />0.0389 hours <br />2.314815e-4 weeks <br />5.327e-5 months <br />.
The root cause analysis for this event determined that in 1981, certain switchyard relay tap setting changes were not implemented at Catawba.
Power Delivery documentation was subsequently erroneously updated to indicate that the changes had been made.
Corrective actions for this event will include developing an enhanced process to ensure correct configuration management for the Catawba protective relay settings.
The health and safety of the public were not adversely affected by this event.
NRC FORM 366 (6-2004)
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