05000269/LER-2007-001, Re Dual Unit Trip from Jocassee Breaker Failure
| ML071140153 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/16/2007 |
| From: | Brandi Hamilton Duke Energy Corp |
| To: | Document Control Desk, Plant Licensing Branch III-2 |
| References | |
| LER 07-001-00 | |
| Download: ML071140153 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 2692007001R00 - NRC Website | |
text
P Duke GEnergy BRUCE H HAMILTON Vice President Oconee Nuclear Station Duke Energy Corporation ON01 VP / 7800 Rochester Highway Seneca, SC 29672 864 885 3487 864 885 4208 fax bhharnilton@duke-energy. corn April 16, 2007 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C.
20555
Subject:
Oconee Nuclear Station Docket Nos.
50-269,-270 Licensee Event Report 269/2007-01, Revision 0 Problem Investigation Process No.: 0-07-0940 and 0-07-0941 Gentlemen:
Pursuant to 10 CFR 50.73 Sections (a)(1) and (d), attached is Licensee Event Report 269/2007-01, Revision 0, regarding reactor trips at Oconee Nuclear Station Units 1 and 2 on February 15, 2007.
This report will be supplemented.
This report is being submitted in accordance with 10 CFR 50.73 (a)(2)(iv)(A).
This event is considered to be of no significancewith respect to the health and safety of the public.
Very truly yours, Bruce H.
Hamilton, Vice President Oconee Nuclear Site Attachment www. duke-energy. com
Document Control Desk Date: April 16, 2007 Page 2 cc:
Mr. William D.
Travers Administrator, Region II U.S. Nuclear Regulatory Commission 61 Forsyth Street, S.
W.,
Suite 23T85 Atlanta, GA 30303 Mr.
L.
N. Olshan Project Manager U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D.C.
20555 Mr.
D.
W. Rich NRC Senior Resident Inspector Oconee Nuclear Station INPO (Word File via E-mail)
Date: April 16, 2007 Page 3 bxc: ONS Site:
Document Control (Master File)*
PIP FILE*
Site PORC Members RGC MGR/B.G.
Davenport RGC: Commitment Index/J.E. Smith#
LER Book*#
WOE Mgr/S.
J.
Magee OPS-Procedures/D.B.
Coyle#
Work Control:D.V. Deatherage#
Site Engineering:
W.B. Edge#
T.A. Ledford#
K.R. Alter#
R.J. Freudenberger#
M. Bailey#
EPIX Cord/R.E. Harris GO:
NRIA/R.L. Gill
- ELL/EC050*
NGO/SAA:D.J. Herrick NGO/SA/S.B.
Thomas NGO Serv: R.G. Hull#
LEGAL/L.F. Vaughn*
CNS:
SA MGR/J.R. Ferguson, Jr.
MNS:
SA MGR/J.
A.
Kammer OPS Mgr/S.L. Bradshaw#
NSRB/E.B. Kulesa/EC05N*
C.M. Misenheimer#
RATES/S.L. Collis#
RGC MGR/R.D.
Hart RGC MGR/K.L.
Ashe Non-routine Recipients:
None Hardcopy - All others by E-Mail Distribution Copied By Request: -
All others by Directive (Revised 1-22-2007)
Abstract
On February 15, 2007 at 1654 hours0.0191 days <br />0.459 hours <br />0.00273 weeks <br />6.29347e-4 months <br />, a breaker failure occurred in the Jocassee Hydro Station switchyard, causing one phase to fault to ground.
The phase-to-ground fault was isolated at the Oconee 230 KV switchyard, but the resulting prolonged (less than 1 second) grid disturbance led to a trip of Oconee Units 1 and 2.
A wiring design error on the loss-of-excitation relays caused a generator lock-out, turbine trip, and bus transfer from normal to startup sources on Oconee Units 1 and 2.
Both reactors were subsequently tripped by the reactor coolant pump power monitors, which correctly sensed the voltage transient and resultant power sag.
Incorrect settings on the auxiliary switch fast contacts of the normal main feeder bus breakers caused a slow bus transfer of 4160 volt loads on Oconee Unit 1, leading to a loss of normal feedwater flow.
This necessitated cooldown to Mode 4, which was accomplished by procedure with emergency feedwater and atmospheric dump valves.
Unit 2 secondary systems performed as expected and cooldown of the unit to Mode 3 proceeded normally.
Appropriate post-trip reviews were performed and recovery actions completed per station procedures.
Unit 2 was returned to power operation on February 19, 2007 and Unit 1 returned to service on February 23, 2007.
This event is considered to have no significance with respect to the health and safety of the public.
NRC FORM 366 (7-2001)