ML20114C567
| ML20114C567 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 08/25/1992 |
| From: | Rosenblum R 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 9209020295 | |
| Download: ML20114C567 (7) | |
Text
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Southom Califamia Edison Company W F*AFWE R ST GRT ilh lfd, C AL IF OHNi A 92716 TL 94. f'tOGE Nat. tJtA T EL E P6DNE 47*414 % 4h0S (g A,nagn or PFh M DW Gbt M DM W MM August 25, 1992 U. S. Nuclear Regulatory Commissiot.
Document Control Desk Washington, D. C. 20555 -
Subject:
Docket Nos. 50-361 and 50 362 Diesel Generator Annual Report - 1991 San O.
9 Nuclear Generating Station, Units 2 and 3
-a The purpose of this letts t is to provi! the Emergency Diesci Generator Annual Report for 1991. The report is required by Tecnnical 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, includes the seven items requested in Regulatory Position C.3.b of Regulatory Guide (RG) 1.108 as revised by Generi: Letter (GL) 84-15 for the four valid and one invalid test failure that occurred in 1991.
Additionally, provided as Enclosure 2, is a corrected page 2 of the 1990 Diesel Generator Annual Report. A correction is provided to item 2 increasing the number of failures per 100 starts from two to three due to a data compilation error which occurred while the 1990 statistics were being prepared, e
If you require any additional information, please let me know.
Very indy yours,
/,/
f l'1 k%u->d Enclosures cc:
J. B. Martin (Regional Administrator, NRC Region V)
C W. Caldwell (NRC Senior Resident Inspector, Units 1,2 at.d 3)
Institute of Nuclear Power Operations (INPO) k l00
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6 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 The following information is provided in~accordance with Technical Un-scifice" ion Suiveillance Requirement 4.8.1.1.3 and s
Regulatory Pocitio C.3.b.~of Regulatory Guide (RG) 3 108 as revised: by Generic Letter' (GL) 84-15.
RG 1.108 requested
. inf ormation on: seven items for each valid or inva.' ; 3 test failure.
l Event Date: May 17',
1991.
1.
This event was considered a valid test failure of the San Onofre1 Unit 2 Emergency Diesel Generator (EDG) 2G003.
2.
This-was the second failure in the last 20 valid tests and t:1e-fourth 1 failure in the last 100 valid tests of 2G003.
(Reported as requested 17 GL 84-15.)
3.-
EDG~2G003,Jtripped on loss-of-exc3tation under full-load conditions.. Investigation revealed that the loss-of-excitation was due to a failed rheostat.
= 4.
JThe rheostat was--cleaned and 2G003 was successfully retested-for operability.
5.
This event resulted in the EDG being anoperab.'.e from'0242 on May17,,1992, until :2135 on May.17, 1991.
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15.
-EDG 2G003 was in a seven day accelerated testing mode during this-time period.
7.
The s'irveillance test' interval was in accordance with the
-schedule-of; Technical Specification Table 4.8-1.
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_ Emergency Diesel Generator Report Southern California 1 Edison Company San Onofre Nuclear. Generating Station Units 2 and 3,.Cocket Nos. 50-361 and 50-362 Event Date: June 17, 1991.
' 1.
This event was considered a valid test failure of the San Onofre Unit 2 Emergency Diesel Generator (EDG)-2G003, 2.
This was the second failure'in the last 20 valid tests and the fourth failure in the last 100 valid-tests of 2G003.
(Reported as requested in GL 84-15.)
3.
While-preparing:for handbarring 2G003 for a monthly tes" a
- few tablespoons of brown water came out when one of the. test-coc'ls was opened on engine number one.-
Further investigation found approximately-one pint of water in the cylinder caused by a leak-in the cylinder head gasket.
- 4.
_ The activity which lead 'co the discovery of water in-the cyfinder was the result of handbarring being performed prior to a= surveillance test in accordance with the manufacturer's prestart recommendaticas.
The corrective action was to replace the entire :ylinder assembly _ (power pack) with a new unit.
Root cause investigation revealed a dent _in the cylinder to.h md-gasket mating surface, which apparently had occurred _dur;*
manufacture.
This 1 dent had subsequently led to failure of one of the head gasket water' seals.
S.
This event resulted in the EDG-being inoperable from 2035 on 1991 until 1810-on June 19, 1991.
-June 17, 1
6.
-_EDG12G003-was in a seven day accelerated testing mode during thisstime period.-
- 7 TheLsurveillance test interval was in accordance with the schedule-of Technical 1 Specification Table 4.8-1.
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-Emergency Diesel Generator-Report Southern California Edison.Comnany San Onofre Nuclear Generating Station Units 2 and-3, Docket Nos. 50-361-and 50-362 Event Date: September 16,1991.-
1.
This event was considered a-valid-test failure of the San Onofre Unit 2 Emergency Diesel Generator (EDG) 2G003, 2,
This-was the third failure in the last 20 valid tests and
-theEfifth failure in the'last 100 valid tests of 2G003.
(Reported as requested in GL 84-15.)
3.
-During_a-1-hour _ weekly _ surveillance _run, EDG 2G003 was emergency stopped from the local panel at 2110 due to
-erratic operation.
A subsequent inepention of the engine 1
revealed damage to_the left bank camshaft and camshaft gear
-drive train.
The preliminary root cause is the combination of 5th order harmonic vibration, coupled with the presence of-short cam bolts in worn (widenedi holes in the rst j
camshaft bearing block.
The 5th order vibration caused.the outboard' bolt on the camshaft bearing block closest to the camshaft gear to vibrate completely out of the threaded-i portion of its bolt hole and the inboard bolt to vibrate partially out of-its' bolt hole.
The loose-bolts allowed the bearing cap to lift resulting in a low resistance flow path j
for camshaft lube oil which starved the downstream camshaft R
bearings of oil.
i
- 4.
= Corrective-action for 2G003: included reworking and repairing 1
all damage.
The -short bolt probler, has been corrected by the installation of correct length bolts and tae'_ worn hole-problem has been corrected by the installation of helicoils, j
=The 5th-order harmonic vibration problem has been corrected by the installation of a previously planned coupling modification.
l S.
Tnis event caused'the diesel to remain inoperable from September 16, 1991 until October 19, 1991 when the
-Preliminary Root Cause Analysis war, issued.
SONGS 2 was in a Refueling outage-during this perata and routine refueling
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F surveillances1were also performed on the EDG'during this period of inoperability.
6.
EDGL2G003Lwas in a seven day accelerated-testing mode during this time period.
' 7.
-The surveillance test interval was in accordance with the
, schedule tf Technical Specification Table 4.8-1.
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Emergency Dieev1 Genarator_ Report U
Southern California Edison 1
_ San Onofre Nuclear Generating Station Units 2 and 3,1 Docket Nos. 50-161 and 50-3e2 Event Date:' November 4,
- 1991, l '.
This event was cunsidered a valid test failure of the San Onofre Unit 2-Emergency _ Diesel Generator'(EDG) 2G003'.
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2.
This was^the first. failure'in the last 20 valid tests and the sixth-failure in-the-last 100 valid-ter e of-2G003.
(Reported as requested in GL 84-15.)-
3.
-EDG:2G003 tripped at the completion of the one hour weekly _
l test run due to the failure of the electronic engine
- governor.
14.
The4:lectronic governor was_ replaced with a new unit and tue EDG was successfully retested.for operability.
A roct cause-analysis-of the'electrcnic mtdule failure was-performed by the-vcndor<(Woodward Governor).
A potentiometer in the
-governar-unit was.found to be intermittent.
This was considered 1to be a1 unique' failure as the investigating engineerf ad not previously noted any failures of this type; h
therefore,'no' additional. action is.being taken.
5.
- ThisLevent: resulted in the EDG being inoperable-from 2332 on November 4,J1991 until 2318.on November +, 1991.
c-
-6.
-EDG 2G003 was inLa seven day accelerated testing mode during
'thisl time. period.
7.
.The surveillance test interval wastin accordance with the p
schedulelof. Technical Specification Table 4.8-1.
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a 6.
Emergency-Diesel. Generator Report
_Scuthern California Edison Company
= San Cnofre Nuclear Generating Station Units 2 and 3, Docket Nos. 50-361 and 50-362.
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Event Date:' December 3;.1991.
hx
- 1..
This event:was considered an. invalid test failure of the San Onofra Unit 2 Emergency Diesel Generator'(EDG) 2G003.
2.
As-this was an invalid - test failure, no additions were mado
-to the failure statistics.
- 3;
'Following repairs to a failed power supply on the alarm
,panelufor the.EDG11ocal control panel,.the diesel build.ing_
~,
-emergency 1 supply: fans failed to start during. subsequent
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- operability. testing.
The fan circuit breakers had-not been realigned during1EDG return to service procedures.
4.
The radiator fan breakers were closed and EDG 2G003 retested satisfactorily.
A' revision to the procedure will indicate e
that the radiator fan breakers should_be tagged opened when
'the DC' control _ power is tagged opened.
The_ responsible-
-:1
-individuals 1were counseled on the requirements for manipulating; safety related equipment. LAn Operating Division: Experience Report-(2-90-22) has been prepared in response to this-' event.
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5.-
This failure becurred during'a period of inoperability b
- previously schedul'ed-~for maintenance ar:tivities-.
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.6.
.EDG 2G003.was_in a seven day accelerateditesting mode during.
this time period.
' 7.
Tre surveillance test interval was in accordance with the schedule of_ Technical Specification: Table-4.8-1.
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Enclosure ?
3
-Emergency Diesel Generator-Report
- Southern California Edison Company San Onofre Nuclear' Generating Station
- Units 2 and 3,-Locket Nos. 50-361 and 50-362 Event _Date: January 25, 1990 The following information is provided in accordance with-Technical Specification Surveillance Requirement 4.8a1.1.3 and Regulatory-Position C.3.bfof.' Regulatory Guide (RG) 1.108'as revised byJGeneric Letter (GL).84-15.
RG.I.100 requested ~the following seven; items for each valid or invalid test failure:
- 1.
This/ failure-involved a valid test of-the San Onofre Unit 2
~
Emergency Diesel' Generator (EDG) 2G003.
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1F. -
-Thia was.the first; failure in the last-20 valid tests and the third failure in_the last 100 valid tests of 2G003.
-(Reported as requested in GL 84-15.)
3.
During post 1 maintenance testing, EDG 2G003 tripped on loss-of-excitation'under full-load conditions. Investigation
' revealed that the loss-of-excitation was due.to loose automatic voltage regulator _l fuse clips.
4.
The? automatic voltage regulator fuse > clips were~ cleaned and tightened _to1 provide positive _ contact-and 2G003 was successfullypretested for_ operability.. Future; plant
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_ equipment = operator training will include proper fuse manipslations to preven'irecurrence, t
s 15 -.
This failure occurred during;a period of_inoperability.
previously scheduled for maintenance activities.
6.
.The -surve'lllance test interval remained at 31 days.
7.
The surveillanceLtest-interval was-in accordance'with the-schedule of Technica] Specification Table 4;8-1.
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