05000331/FIN-2008005-03
From kanterella
Jump to navigation
Jump to search
Finding | |
|---|---|
| Title | Root Cause Evaluation 1078, B EDG Output Breaker Trip |
| Description | Operators received a spurious B EDG overspeed alarm on February 13, 2008. The engine overspeed alarm occurred while the engine was shutdown and was coincident with an operator performing the shiftly overspeed trip lever reset check. Subsequently, spurious B EDG overspeed alarms were received on February 21, March 17, 19, 22, and 24, 2008. Initial troubleshooting efforts by engineering personnel determined that the spurious overspeed alarms were the result of degraded capacitors on the annunciator alarm circuit cards. Several Corrective Work Orders (CWOs) were generated to replace the suspect alarm circuit cards. On March 25, maintenance personnel replaced one of the suspect annunciator alarm cards. The remaining CWOs could not be worked because the licensee did not have spare annunciator cards in stock. Post-maintenance inspections of the removed card identified a bad capacitor on the card. The licensee continued to monitor the B EDG following the maintenance. No additional spurious overspeed alarms were documented until June 26, 2008. Further troubleshooting efforts by the licensee continued to focus on the potential degraded annunciator alarm cards. On July 14, 2008, maintenance personnel replaced the annunciator alarm card that had been previously replaced in March. Analysis of the removed annunciator card did not identify any degraded capacitors. Engineering personnel continued to believe that the issue was due to degraded capacitors that were in the remaining annunciator alarm cards, and several CAPs written for additional spurious overspeed alarms received in July, August, and September, were closed to the open CWOs to replace the remaining annunciator alarm cards once replacement parts were received. While performing a TS required surveillance run of the B EDG on November 2, 2008, operators received an engine overspeed alarm. The EDG continued to run at its rated speed and carry an electrical load. The initial overspeed alarm cleared, and then multiple overspeed alarms were received over the next several minutes. After approximately 30 to 50 overspeed alarms were received and cleared, the output breaker unexpectedly tripped open. The B EDG never reached an actual overspeed condition and the engine continued to run unloaded after the breaker tripped open. Operations personnel declared the B EDG inoperable, shut down the EDG, and aborted the surveillance test. The licensee entered their failure investigation process to troubleshoot, identify, and repair the cause of the B EDG output breaker tripping open. On November 5, 2008, the B EDG was repaired and the EDG was declared operable. RCE 1078 was initiated to determine the root cause of the B EDG output breaker trip. Revision 0 of RCE 1078 was completed on December 12, 2008. After review by the sites Management Review Committee, the licensee proceeded to revise RCE 1078 to incorporate managements comments. As of the end of the inspection period, the licensee had not yet approved revision 1 to RCE 1078. Therefore, this issue is being tracked as a URI (URI 05000331/2008005-03) pending inspector review of the final approved revision of RCE 1078 |
| Site: | Duane Arnold  |
|---|---|
| Report | IR 05000331/2008005 Section 4OA2 |
| Date counted | Dec 31, 2008 (2008Q4) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | K Riemer R Orlikowski R Baker L Haeg T Go R Russell B Cushman C Scott M Audraind Mcneild Reeser J Neurauter J Tapp K Riemer R Baker R Orlikowski R Russell R Winter T God Passehlk Riemer N Shah R Baker R Orlikowski |
| INPO aspect | |
| ' | |
Finding - Duane Arnold - IR 05000331/2008005 | ||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Finding List (Duane Arnold) @ 2008Q4
Self-Identified List (Duane Arnold)
| ||||||||||||||||||||||||||||||||||||||||||||||||||