ML20034G290
| ML20034G290 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 03/01/1993 |
| From: | Marsh W SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-REGGD-01.108, RTR-REGGD-1.108 GL-84-15, NUDOCS 9303090291 | |
| Download: ML20034G290 (3) | |
Text
s Southern California Edison Company P3 PARKER STREE T IRVINE. CALIF ORNI A 92718 March 1, 1993 WALT E R C. fAARSH T L t L pt eONF A!sS$1 ANl M AN AGE R (714)454 4403 NUCt.E AR 61E Ot.si. A TOHV AF F AiHS
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i U. S. Nuclear Regulatory Commission Document Control Desk Washington, D. C.
20555
Subject:
Docket Nos. 50-361 and 50-362 Diesel Generator Annual Report - 1992 San Onofre Nuclear Generating Station, Units 2 and 3 The purpose of this letter is to provide the Emergency Diesel Generator Annual Report for 1992.
The report is required by Technical Specifications 4.8.1.1.3 and 6.9.1 of Appendix A, Technical Specifications to Facility Licenses NPF-10 and NPF-15 for San Onofre Nuclear Generating Station, Units 2 and 3, respectively. The report, provided as Enclosure 1, includes the seven items requested in Regulatory Position C.3.b of Regulatory Guide (RG) 1.108 as revised by Generic Letter (GL) 84-15 for two invalid test failures that occurred in 1992.
If you require any additional information, please let me know.
Sincerely, 4/k V
Enclosures cc:
J. B. Martin (Regional Administrator, NRC Region V)
H. B. Fields, NRC Project Manager, San Onofre Units 2 and 3 C. W. Caldwell (NRC Senior Resident Inspector, Units 1, 2 and 3)
Institute of Nuclear Power Operations (INPO) 080117
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930309029t 9303o1 PDR ADOCK 05000361 g,
PDR R
Emergency Diesel Generator Report Southern California Edison Company San Onofre Nuclear Generating Station Units 2 and 3, Docket Nos. 50-361 and 50-362 Introduction i
The following infonr.ation is provided in accordance with Technical Specification Surveillance Requirement 4.8.1.1.3 and Regulatory Position C.3.b. of Regulatory Guide (RG) 1.108 as revised by Generic Letter (GL) 84-15.
RG 1.108 requested information on seven items for each valid or invalid test failure.
Event Date: March 2. 1992.
1.
This event was an invalid failure of the San Onofre Unit 3 Emergency Diesel Generator (EDG) 3G002.
2.
As this was an invalid failure, no additions were made to the failure statistics.
3.
EDG 3G002, tripped on Stator over temperature. The cause of the stator over temperature was found to be a failed RTD.
4.
The failed RTD was disconnected from circuitry.
This protective function is bypassed during emergency operations.
The five remaining RTD's provide adequate protection during non emergency operations.
5.
This failure occurred during a period of inoperability which was previously scheduled for maintenance activities.
6.
EDG 3G002 was in a 31 day testing mode during this time period.
7.
The surveillance test interval was in accordance with the schedule of Technical Specification Table 4.8-1.
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t Emergency Diesel Generator Report Southern California Edison Company San Onofre Nuclear Generating Station Units 2 and 3, Docket Nos. 50-361 and 50-362 Event Date: February 18. 1992.
1.
This event was an invalid failure of the San Onofre Unit 2 Emergency Diesel Generator (EDG) 2G003.
2.
As this was an invalid failure, no additions were made to the failure statistics.
3.
At the completion of the monthly surveillance run with the generator unloaded with the output circuit breaker open, speed and voltage oscillations were observed. The EDG was declared inoperable to determine of the cause of oscillations.
4.
The oscillations were caused by failure of the series boost assembly of the voltage regulator.
The failure of the series boost assembly occurred when one of the 220 KV circuit breakers was closed to backfeed the Unit 3 main transformer from the switchyard. The EDG, which was running in parallel with the 220 KV switchyard, attempted to pick up the instantaneous extra load caused by initial transformer current in-rush.
The voltage regulator response was an excessive spike to the series boost assembly.
This could not occur during emergency operations because the EDG is not operated in parallel with the 220 KV switchyard.
Procedural guidance has been implemented to preclude changing switchyard arrangements during EDG testing.
5.
This event resulted in the EDG being inoperable from 0355 on February 18,1992 until 0235 on February 19, 1992.
6.
EDG 2G003 was in a 7 day accelerated testing mode during this time period.
7.
The surveillance test interval was in accordance with the schedule of Technical Specification Table 4.8-1.
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