ENS 47112
ENS Event | |
|---|---|
16:00 Jun 16, 2011 | |
| Title | Part 21 - Emergency Diesel Generator Failed Air Start Motor |
| Event Description | The following information was received by facsimile:
COMPONENT: Air start motors with friction-clutch inertia drives (not pre-engagement type) Engine Systems Inc. (ESI) began a 10CFR21 evaluation on 06/16/11 upon receipt of a failed air start motor from Exelon - Clinton. According to information provided by Clinton Nuclear Plant, they experienced a slow start of an EDG during one of their surveillance runs. Subsequent troubleshooting revealed that one of the air start motors had failed. Specifically, it was found that the starter drive had failed which prevented the air start motor from applying full starting torque to the engine. The inspections performed by Clinton indicated the failed motor had what appeared to be excessive preload applied to the springs of the drive clutch which led to spring roll and fragmentation. Clinton had also supplied six remaining air start motors from their inventory to ESI for evaluation of the drive clutch torque setting. The air starters are Pow-R-Quik type LS-60-RH1 and LS-60-LH1 (where RH and LH designate right hand and left hand rotation respectively). The evaluation was concluded on 08/01/11 and determined the air motor failure to be a reportable defect as defined by 10CFR21. The starter drive failure was attributed to excessive torque adjustment of the clutch assembly. This overstressed the clutch disc plates which lead to eventual failure of the friction-clutch inertia drive assembly. Failure of the clutch drive renders the air start motor inoperative. Depending upon the configuration of the engine's starting system, an inoperative air start motor could cause excessive starting times or a start failure. Either scenario has the potential to prevent the emergency diesel generator from performing its safety related function. Clutch torque testing was performed on the six (6) starters returned from Clinton's inventory. [Results indicate inconsistent clutch settings]. The specified torque setting for the clutch drive is 275-300 ft-Ibs. Of the six starters tested, only one was within specification. Based on the test data obtained from the six (6) Clinton starters, all previous shipments of air motors with the friction-clutch inertia drive are suspect for having inconsistent clutch drive torque settings. Affected users of the air start motors that contain friction-clutch inertia drives include the following: Exelon-Clinton, Entergy-Indian Point 3 and PSE&G-Salem. Engine Systems, Inc Report Number: 10CFR21-0102, Rev. 0. |
| Where | |
|---|---|
| Engine Systems, Inc Rocky Mount, North Carolina (NRC Region 1) | |
| Organization: | Engine Systems, Inc |
| Reporting | |
| 10 CFR 21.21 | |
| Time - Person (Reporting Time:+1100.05 h45.835 days <br />6.548 weeks <br />1.507 months <br />) | |
| Opened: | Tom Horner 12:03 Aug 1, 2011 |
| NRC Officer: | Vince Klco |
| Last Updated: | Aug 1, 2011 |
| 47112 - NRC Website | |
Engine Systems, Inc with 10 CFR 21.21 | |
WEEKMONTHYEARENS 473472011-10-11T04:00:00011 October 2011 04:00:00
[Table view]10 CFR 21.21 Part 21 Notification - Emergency Diesel Generator Piston Delamination ENS 471122011-06-16T16:00:00016 June 2011 16:00:00 10 CFR 21.21 Part 21 - Emergency Diesel Generator Failed Air Start Motor 2011-06-16T16:00:00 | |