ML20114C567

Forwards Emergency Diesel Generator Annual Rept for 1991,per TSs 4.8.1.1.3 & 6.9.1.Rept Includes Seven Items Requested in Regulatory Position C.3.b of Reg Guide 1.108 as Revised by GL 84-15.Corrected Page 2 of 1990 DG Annual Rept Also Encl

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 (g A,nagn or 47*414 % 4h0S 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 Enclosure 1, 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 e occurred while the 1990 statistics were being prepared, 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

g9k%5N $8Sh j R

6 Enclosure 1 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 s Technical Un-scifice" ion Suiveillance Requirement 4.8.1.1.3 and 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

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s May17,,1992, until :2135 on May.17, 1991. -

5. 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

-June 17, 1991 1 until 1810-on June 19, 1991.

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 i

-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 l 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 bearings of oil. R i

- 4. = Corrective- action for 2G003: included reworking and repairing 1 all damage. The -short bolt probler, has been corrected by l the installation of correct length bolts and tae'_ worn hole- l 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

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a Refueling outage-during this perata and routine refueling 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 had not previously noted any failures of this type; 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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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_ ~,

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-emergency 1 supply: fans failed to start during. subsequent

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 e satisfactorily. A' revision to the procedure will indicate 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.

p - 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 ?

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-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:

This/ failure-involved a valid test of-the San Onofre Unit 2

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- 1.

Emergency Diesel' Generator (EDG) 2G003. ~

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

_ 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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