PNO-IV-03-015, Columbia Generating Station, Technical Specification Required Shutdown to Exceed 72 Hours
| ML030640742 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 03/05/2003 |
| From: | William Jones NRC Region 4 |
| To: | |
| References | |
| PNO-IV-03-015 | |
| Download: ML030640742 (2) | |
March 5, 2003 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-IV-03-015 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 IV staff on this date.
Facility Columbia Generating Station Richland, Washington Docket: 50-397 License: NPF-21 Licensee Emergency Classification Notification of Unusual Event Alert Site Area Emergency General Emergency X Not Applicable
SUBJECT:
TECHNICAL SPECIFICATION REQUIRED SHUTDOWN TO EXCEED 72-HOURS DESCRIPTION:
On February 27, 2003, at approximately 5:45 p.m. (PST), Energy Northwest began a manual shutdown of Columbia Generating Station from 100 percent power. The shutdown was required by Technical Specification 3.8.1.F for an inoperable emergency diesel generator (12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to Mode 3 and 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> to Mode 4). The licensee had recently replaced two Division 1 emergency diesel generator bearings and was in the process of postmaintenance testing when they detected unexpected vibration signatures associated with the new bearings. Further, the vibration levels showed evidence of an increasing trend. The licensee determined that further testing and diagnosis was needed to support an operability decision. However, the additional testing and evaluation required additional time, beyond that already provided by an NRC Notice of Enforcement Discretion. The shutdown was completed on February 28 and the plant achieved Mode 4 operation later that day.
Energy Northwest had previously requested enforcement discretion from the requirements of Columbia Generating Station Technical Specification 3.8.1, A.C. Sources - Operating. Specifically, the licensee requested discretion from compliance with the completion time requirements of TS 3.8.1, Condition B.4, for the 11-day period beginning at 9 p.m. on February 16, 2003, and ending at 9 p.m. on February 27, 2003. Enforcement discretion was granted to allow replacement of a degraded generator bearing. As a precautionary measure, the licensee replaced both generator end bearings on the Division 1 tandem emergency diesel engines.
Following the plant shutdown, the licensee identified a preliminary cause for the bearing degradation.
An incorrectly installed insulated dowel pin created a short circuit that permitted circulating electrical currents to pass through the bearings. These types of circulating currents are a known cause of wear in generator bearings. The licensee has initiated actions to replace the bearings; however, those actions will extend the current forced shutdown beyond 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
The state of Washington will be informed.
The licensee has issued a press release. In addition, the plant shutdown and emergency diesel generator work is discussed in their newsletter, which is available to the public and media organizations.
Region IV received notification of this occurrence on February 27 through the NRC senior resident
inspector of the intended shutdown and notification on March 4 that the forced outage would extend beyond 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to repair the emergency diesel generator. Region IV has informed EDO/NRR/PA.
This information has been discussed with the licensee and is current as of March 4, 2003, at 5:15 p.m. (PST).
CONTACTS: William B. Jones, 817/860-8147