PNO-III-06-012, A: Kewaunee: Manual Reactor Shutdown Following Feedwater Pump Trip (Update)
| ML061370315 | |
| Person / Time | |
|---|---|
| Site: | Kewaunee  |
| Issue date: | 05/17/2006 |
| From: | Louden P NRC/RGN-III |
| To: | |
| References | |
| PNO-III-06-012A | |
| Download: ML061370315 (2) | |
May 17, 2006 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-III-06-012A This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region III staff on this date.
Facility Licensee Emergency Classification Kewaunee Notification of Unusual Event Dominion Energy Kewaunee, Inc. x Alert Docket: 50-305 Site Area Emergency License: DPR-43 General Emergency Not Applicable
SUBJECT:
MANUAL REACTOR SHUTDOWN FOLLOWING FEEDWATER PUMP TRIP (UPDATE)
DESCRIPTION:
On April 26, 2006, operators manually tripped the reactor when the A feedwater pump unexpectedly tripped. At the time, operators were reducing reactor power in preparation for a maintenance outage. Since the B feedwater pump was already shut down, the tripping of the operating pump should have caused a turbine trip followed by a reactor trip. When the turbine did not trip, operators took manual action to shut down the reactor, which tripped the turbine.
The licensee has determined that the cause of the trip of the A feedwater pump was a switch in the cubicle of the breaker for the B feedwater pump that had not repositioned properly. The licensee identified that the mispositioned switch was caused by an improperly adjusted mechanical linkage in the cubicle. The linkage was subsequently repaired.
The licensee examined other breaker cubicles and had to make only minor adjustments to linkages in some of the cubicles for nonsafety-related equipment. Procedures for maintenance of the cubicles will be revised to include specifications for linkage adjustments. NRC inspectors reviewed these planned corrective actions and found them appropriate.
An NRC Special Inspection Team reviewed the circumstances surrounding the event and the licensees evaluation of the cause. The inspection team agreed with the results of the evaluation and concluded that reactor operators responded appropriately to the unexpected trip of the A feedwater pump. The declaration of the Alert was also determined by the inspectors to have been appropriate. The results of the NRCs special inspection will be issued in an inspection report in about 45 days.
The licensee is making plans to restart the plant.
The State of Wisconsin will be informed. The information in this preliminary notification has been reviewed with licensee management.
This information is current as of 8:00 a.m. (CDT) on May 17, 2006.
CONTACT: Patrick Louden 630/829-9627