05000499/LER-2003-004, Regarding Standby Diesel Generator 22 Failure
| ML040420283 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 02/05/2004 |
| From: | Halpin E South Texas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NOC-AE-04001674 LER 03-004-00 | |
| Download: ML040420283 (9) | |
| Event date: | |
|---|---|
| Report date: | |
| 4992003004R00 - NRC Website | |
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'February 5, 2004 NOC-AE-04001674 1 OCFR50.73 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852 South Texas Project Unit 2 Docket No. STN 50-499 Licensee Event Report 2-03-004 Standby Diesel Generator 22 Failure Pursuant to 10CFR50.73, the South Texas Project submits the attached Unit 2 Licensee Event Report 2-03-004 regarding the failure of Standby Diesel Generator 22. This event did not have an adverse effect on the health and safety of the public.
Commitments are listed in the Corrective Actions section of the attached report.
If there are any questions on this submittal, please contact either P. L. Walker at (361) 972-8392 or me at (361) 972-7849.
E. D. Halpin Plant General Manager PLW Attachment: LER 2-03-004 LER 2-03-004 (DG 22).doc STI: 31692636
NOC-AE-04001674 Page 2 of 2 cc:
(paper copy)
(electronic copy)
Bruce S. Mallett Regional Administrator, Region IV U. S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, Texas 76011-8064 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852 Richard A. Ratliff Bureau of Radiation Control Texas Department of Health 1100 West 49t Street Austin, TX 78756-3189 Jeffrey Cruz U. S. Nuclear Regulatory Commission P. O. Box 289, Mail Code: MN116 Wadsworth, TX 77483 A. H. Gutterman, Esquire Morgan, Lewis & Bockius LLP L. D. Blaylock City Public Service David H. Jaffe U. S. Nuclear Regulatory Commission R. L. Balcom Texas Genco, LP A. Ramirez City of Austin C. A. Johnson AEP Texas Central Company Jon C. Wood Matthews & Branscomb C. M. Canady City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704 LER 2-03-004 (DG 22).doc
Abstract
On Tuesday, December 9, 2003, a monthly surveillance test was being performed on Standby Diesel Generator 22. Unit 2 was operating in Mode 1 at 100% power. At approximately 1038, Standby Diesel Generator 22 experienced a mechanical failure in which the position 9 Master Connecting Rod fractured.
This occurred approximately 18 minutes after the diesel generator was loaded to 100% during the surveillance. The failure caused significant peripheral damage to the cylinders, pistons, frame, control systems, lubrication system, crankshaft, and bearings on the engine, as well as the starting air system components located adjacent to the engine.
The root cause of the failure is microcracks that developed on the position 9 Master Connecting Rod during the manufacturing process. The microcracks later propagated due to high cycle fatigue until the master connecting rod failed.
Corrective actions include inspection of the master connecting rods of all Standby Diesel Generators to ensure that similar cracking had not occurred elsewhere.
This event resulted in no personnel injuries, no offsite radiological releases, and no damage to other safety-related equipment. Unit 2 continued to operate at 100% power after the event.
NRC FORM 366 (7-2001)
(If more space is required, use additional copies of SUMMARY OF THE EVENT, INCLUDING DATES AND APPROXIMATE TIMES On December 9, 2003, an operability test of Standby Diesel Generator 22 was performed in accordance with surveillance procedures. Standby Diesel Generator 22 was started at 0942 and initially loaded at 0947. The generator load was increased to 25% at 0950, 50% at 1000, 75% at 1010, and 100% at 1020. At 1038, the 9R master connecting rod and associated parts failed. The engine continued to run until the fuel racks were manually closed approximately six minutes later.
At the time of the engine failure, the Plant Operator monitoring the diesel locally was taking the first set of diesel logs as directed by the surveillance procedure. The Plant Operator was standing at the northwest corner of the engine recording the crankcase differential pressure reading when a loud noise came from the engine. The local Plant Operator immediately left the diesel engine area and returned to the local control panel area where multiple alarms were indicated. At the same time that the noise occurred, the Main Control Room received a diesel trouble alarm. The licensed operator in the Main Control Room observed indication of no electrical load and no engine oil pressure for Standby Diesel Generator 22. The Main Control Room Operator put the diesel control switch in Pull-To-Stop," but the engine continued to run.
The local Plant Operator notified the Main Control Room of the alarms, that no oil or jacket water pressure was indicated, and that the diesel was still running at approximately 600 rpm. The local Plant Operator was instructed by the Main Control Room to locally push the two emergency stop buttons.
The buttons were pushed immediately, but the diesel engine continued to run. A second licensed Operator left the Main Control Room and went to the Standby Diesel Generator 22 bay to aid in tripping the diesel engine locally. The local Plant Operator and he both tried the emergency stop push buttons, again with no response, and then went to the remote trip location for the air intake butterfly valve. The licensed Operator was unable to trip the air intake butterfly valve at the overspeed governor. Seeing some of the engine damage and significant amounts of smoke-like oil fumes in the area, the licensed Operator directed the local Plant Operator to leave the area for safety reasons. The local Plant Operator then went to the fuel oil storage tank room and closed the fuel isolation valve to the engine. The licensed Operator returned to the butterfly remote trip to try aqain to isolate it. At LER 2-03-004 (DG 22).doc
(If more space is required, use additional copies of (It more space Is required, use additional copies of (If more space Is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) (17)
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Piston Pin
- 13.
Bearing Shell, Top
- 2.
Oil Passage
- 14.
Dowel (2)
- 3.
Dowel (3)
- 15.
Rod Cap
- 4. Washer (4)
- 16.
Locknut (4)
.5. Bolt Lock (4)
- 17.
Stud (4)
- 6.
Pin Bolt (4)
- 18.
Bearing Shell Bottom
- 7.
Drake Nut (4) 19.
Art. Rod Pin
- 8.
Bolt Lock (2)
- 20.
Rod Pin Bolt
- 9.
Washer (2)
- 21.
Beaiing Cap (Nut
- 60.
Oil Passage.
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- 22.
Washer
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