ML11242A083

Email from Susan Gardner to John Reynoso, Subject: FW: 3G003 Cracked Rotor Bar 0200 Status

ML11242A083
Person / Time
Site:	San Onofre
Issue date:	08/20/2008
From:	Gardner S Southern California Edison Co
To:	John Reynoso - No Known Affiliation, Office of Information Services
References
FOIA/PA-2011-0157
Download: ML11242A083 (4)

Text

- t John Reynoso From:

Sent: Wednesday, August 20, 2008 7:10 AM To: John Reynoso

Subject:

Fw: 3G003 Cracked Rotor Bar 0200 status Attachments: ATT00001; ATTOO002

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08/20/2008 02:31 AM cc Subject Re: 3G003 Cracked Rotor Bar 0200 statusl IJ11

-Notification 200106606 written to document crack in rotor bar.

-Vendor repi (b)(6) . iof ESI notified to supply personnel to change out generator with spare.

-Maintenance-planning notified to S-Uppo-rt inspection of both Unit 2 machines on 8/20. SRGF made notification.

-Operations in process of clearing U2 train A DG for work by 0600/8/20/08 to be followed imediately by an inspeciton of the U2 train B machine.

(b)(6) SSID sent home about midnight. Will be on call for inspecitons of U2 machines.

-N5 means of inspecting the U3 A train machine in time( two hours) to verify condition does not exist in this machine to i~...

avoid the..... ...........

need .....to shut down the unit. Twenty four hour clock runs until 2100 08/20/08. Shift manager working issue.

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.1 i(b)(6) SONGS/SCE/EIX (b)(6)

T 08/20/2008 12:56 AM Subject 3G003 Cracked Rotor BarLilnk To All, i-Tb) (6) 1 3G003 inspection was done today by) II(SSID) using a boroscope. During the visual inspection it was observed that there was a crack of the shorting ring of the damper winding on the rotor. This circuit carries the circulating current during the start up or change in loading of the EDG. The crack was observed to be adjacent to the weld overlap of the copper, and dislocated approximately 75% of the estimated 1/4" thickness of the material. It is not recommended to continue with the operation of the unit with this as found condition. The damper winding could not be considered reliable for service based on this finding. It is recommended that the generator in 3G003 be replaced.

2

Another indication was found in an adjacent location on the next pole which is just starting to separate, and not open Mike the first finding.

The other 3 EDG's have been inspected visually for general condition about 1 to 2 years ago. Similar rotor bar crack has not been observed in the other 3 EDGs. One of the other 3 EDGs (2G002 ?) was just inspected about 2 weeks ago. We cannot be certain that the other 3 EDGs have been inspected in detail at this location due to the foreign contaminated material that gathers in the ovelap between the two pieces of copper as joined. The other 3 EDGs have not been specifically inspected for this type of crack in this location in detail.

To comply with the Tech Spec requirement, we need to perform a common cause evaluation within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (by 21:00 8/20) to address the generic implication of this failure on the other EDGs. It appears at this time the other EDGs could be subjected to the same failure mechanism.

r I~b( SONGSISCEJEIX TO; 0811912008 10:11 PM cc 3

Subject 3G003 Cracked Conductor

All, Iniitial indications from the boroscope inspection of 3G003 generator is that we have a cracked conductor on the 3G003 generator windings.

Engineering is validating SSID findings and is contacting ESI ti come to SONGS and advise on the repair plan.

Regards,(b)(6)j 4