05000425/LER-2006-003, Regarding Unit 2 Reactor Coolant Pump 4 Tripped, Resulting in an Automatic Reactor Trip
| ML063000222 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 10/26/2006 |
| From: | Grissette D Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-06-2468 LER 06-003-00 | |
| Download: ML063000222 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| 4252006003R00 - NRC Website | |
text
Don E. Grissette Vice President Southern Nuclear Operating Company, Inc.
40 lnverness Center Parkway Post Office Box 1295 Birmingham. Alabama 35201 Tel 205.992.6474 Fax 205.992.0341 October 26, 2006 Docket No.:
50-425 SOUTHERN A COMPANY Energy to Serve Your World" U. S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, D. C. 20555-0001 Vogtle Electric Generating Plant - Unit 2 Licensee Event Report 2-2006-003 Unit 2 Reactor Coolant Pump No. 4 Tripped Resulting in an Automatic Reactor Trip Ladies and Gentlemen:
In accordance with the requirements of 10 CFR 50.73, Southern Nuclear Operating Company hereby submits a Vogtle Electric Generating Plant licensee event report for a condition that was determined to be reportable on August 27, 2006.
Sincerely, Don E. Grissette Enclosure: LER 2-2006-003 cc:
Southern Nuclear Overating Company Mr. J. T. Gasser, Executive Vice President Mr. T. E. Tynan, General Manager - Plant Vogtle RType: CVC7000 U. S. Nuclear Regulatory Commission Dr. W. D. Travers, Regional Administrator Mr. R. E. Martin, NRR Project Manager - Vogtle Mr. G. J. McCoy, Senior Resident Inspector - Vogtle
Enclosure Vogtle Electric Generating Plant - Unit 2 Licensee Event Report 2-2006-003 Unit 2 Reactor Coolant Pump No. 4 Tripped Resulting in an Automatic Reactor Trip
Reported lessons learned are incorporated into the licensing process ack to industry. Send comments regarding burden estimate to the LICENSEE EVENT REPORT (LER)
(See reverse for required number of Unit 2 Reactor Coolant Pump #4 tripped, resulting in an automatic reactor trip
- 10. POWER LEVEL On August 27,2006, at 063 1 EDT, Unit 2 experienced an automatic reactor trip from 100% power. The Loop 4 Reactor Coolant Pump (RCP) tripped and the Reactor Protection System (RPS) actuated on "Reactor Coolant System Low Flow." The post-trip investigation revealed that, inside the RCP motor junction box, a degraded current transformer (CT) wire was in contact with a degraded surge arrestor cable shield. The degraded CT wire was grounded in the CT wiring junction box, creating a ground path that resulted in a fault in the RCP #4 motor junction box that caused the pump to trip.
Investigation determined that the cause of this event was an inadequate design change package.
Contributing causes were inadequate procedures, work instructions, and installation practices. Prior to restart, the Loop 4 RCP junction box CT wiring and CTs were replaced as well as the surge arrestor wiring and the differential protective relay in the feeder breaker cubicle for RCP #4.
(1-2001)
LICENSEE EVENT REPORT (LER)
Vogtle Electric Generating Plant - Unit 2 05000-425
- 17. NARRATIVE (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A)
- 1. FACILITY NAME Vogtle Electric Generating Plant - Unit 2
- 4) The appropriate corporate design procedures, plant design procedures, and plant maintenance procedures will be revised. Training will be provided to the appropriate personnel on voltage stress effects and spacing criteria for 4.1 6KV, 13.8KV and 25KV enclosures. Estimated completion date for procedure revisions is 1211 5/06. Estimated completion date for training is 4/15/07.
- 5) The technical inaccuracies in the design change package for adding the surge protection to 13.8KV and 4.16KV motors will be corrected. Estimated completion is 1211 5/06.
- 2. DOCKET 05000-425
G. ADDITIONAL INFORMATION
- 1) Failed Components:
None
- 6. LER NUMBER YEAR SEQUENTIAL REVISION NUMBER NUMBER 2006 1-003 -1 00
- 2) Previous Similar Events:
None
- 3. PAGE 40F
- 3) Energy Industry Identification System Codes:
- C FORM 366A (1 -2001)