ML20042G815

Special Rept:On 900411,valid Failure of Diesel Generator 2B Occurred.Caused by Fuel Pump 2L Sticking.Helm Joints Will Be Inspected for Freedom of Movement & Clearance & Possibility of Using More Efficient Filters Will Be Evaluated

ML20042G815
Person / Time
Site:	Catawba
Issue date:	05/08/1990
From:	Owen T DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9005160126
Download: ML20042G815 (4)

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> Duke Ibutt Company . - (803) 831 3 000

• . ~ ':Catwrt>a Nuclear Station .

PO Bas 256; Clawr, S C 29710 :

^ DUKEPOWER May 8, 1990-Document. Control' Desk U S. Nuclear Regulatory Commission Washington, D. C. 20555

Subject:

Catawba Nuclear Station Docket'No. 50-414 Special. Report - Unit 2.

PIR-2-C90-0130;rIIR-C90-039 Gentlemen:

pursuant.to' Technical Specifications 6.9.2 and 4.8.1.1.3 please find attached a. 1 Special Report'concerning-Unit 2' Diesel Generator 2B Valid Failure on April 11,l .]

1990. j l

Very truly yours, _

' I Tony B. Owen 6'on}7n A Station Manager keb\ REPORT.SP-xc: Mr. S. D. Ebneter 'American Nuclear Insurers Regional Administrator, Region II :c/o Dottie Sherman, ANI Library.

p. U. S. Nuclear Regulator Commission The Exchange,: Suite.245.

101 Marietta Street, NW, Suite 2900. '270 Farmington Avenue- -;

Atlanta, GA 30323 lFarmington,. CT :.06032' -d

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M & M Nuclear Consultants Mr. K. Jabbour-1221 Avenues of-the Americas- -U..S. Nuclear' Regulatory Commission New York,-NY 10020' Office of. Nuclear Reactor Regulation Washington,: D. C.

20555--

INPO Records Centor~ r Suite 1500 . .

Mr. W. T. Orders q 1100LCircle 75 Parkway NRC Resident Inspector Atlanta, GA 30339 Catawba Nuclear Station-l i

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'SPECIAL REPORT CATAWBA NUCLEAR STATION.

DIESEL GENERATOR 2B VALID FAILURE DURING-MONTHLY OPERABILITY TESTING OF ENGINE PROBLEM INVESTIGATION REPORT SERIAL No. 2-C90-0130 INCIDENT INVESTIGATION REPORT C90-039-2 A valid failure (start # 573) of Diesel Generator (D/G)128 occurred'on-April 11,.1990 at'0159 hours0.00184 days <br />0.0442 hours <br />2.628968e-4 weeks <br />6.04995e-5 months <br />. The failure occurred in the start attempt for the normal. monthly. operability performance test' , _ .

(PT/2/A/4350/02B).-D/G 2B was on-a monthly operability. test schedule.

at the time of this valid failure. There has been 1 valid failure in-the past 20 valid starts and 3 valid failures in the past'100 valid starts for D/G 2B.. l Following the initial 1 failure, Instrument, Electrical, and Mechanical 4 craft along with Engineering personnel looked to determine'theicause ]

of.the D/G not starting. Thoro-were no obvious' problems.' indicated or observed that1would'have prevented a. successful start' After review of-the findings and further' discussion with1the operators, the decision to restart the D/G to troubleshoot was made. Personnel'were placed at: .

strategic locations to observe panel,. controls, and engine functions.- 1 The D/G was auto started..The D/G started. It started in-the normal time of 6.2 seconds. No abnormal' indications were seen or reported ~ i D

during the start and run. In the same manner, observed start #2 was

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conducted'as a key start, with the same satisfactory ~results.

After the two successful normal' starts, the following were inspected;

-Fuel filters Fuel strainers Fuel rack _ linkages from governor to the fuel pungs for alignment j All fuel rack linkages for free movement j s

2L fuel pump was found sticking. The heim joint was removedLand the l injection pump was verified to have smooth and non-sticking movement.

l The.'2L heim joint was original. equipment. It had been in servicef some i ten years and had seen more than 670 hours0.00775 days <br />0.186 hours <br />0.00111 weeks <br />2.54935e-4 months <br /> of service. A new heim . )

joint, from spares, was. adjusted to the. replaced joint length and 1 installed. The pump and'new heim joint. assembly was-then rechbcked to verify movement to be smooth and non-sticking.

1 The force required to move the' complete fuel. rack:was checked and,was d found to be consistent with previous-tests of thisland the other unit  :{

2 engine. Then as an~added measure, the fuel rail-bearings were. . l lubricated even though they were scheduled for the-following month.

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.J After completing the above maintenance activities, personnel were strategically placed and the D/G started uneventfully. Following, the operability test wasTsatisfactorily performed and the D/G declared operable.

1 Cencurrently with the above inspection activities, MES contacted WW j Gallman, General Office, to inform and request assistance in -4 researching for other failures-involving sticking fuel racks d attributable to heim joints. Conversations-_with a. Senior. Design .

I Engineer of Energy Services Group, Cooper-Industries informs us that )

no failures have been reported concerning binding heim joints as the-

.l source of failure. This was borne out in conversations with two -l neighboring utilities, in-that;they had not, nor had they heard of a similar failure mechanism.  !

Physically, a bound heim joint will prevent'the fuel racks;from.  !

opening, effecting the start, however it will not prevent the D/G'from "

i shutting down. All heim joints are checked for free movement each outage. All joints were satisfactory at the last inspection. i Detailed inspection of the bound ball and retainer showed that the ball retainer had a pinch mark. The pinch mark was approximately-one quarter inch long and caused a-slight protrusion of metal, about an eighth inch long by one sixty-fourth inch wide...The. pinched area

]j probably caused some slight closure of the normal ball to housing l clearance at the pinch site. The pinch by itself was not aLproblem.

j The failure was caused by a particle (or particles) of grit that had gotten into the joint and in time worked around and collected at the l reduced clearance area to ultimately cause binding and prevent the. :j fuel racks from opening.

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To verify that no-other problem had caused the failure to-start, the I diesel generator was allowed .to sit for_ a week, then with personnel l strategically placed, satisfactority tested again.

This valid failure is considered an isolated incident--in that; ]

• No other failures were caused by this' mechanism-l

• All information'and evidence evalua'ted indicates less.than .

sterile housekeeping conditions coupled with an insignificantly (by itself) damaged heim joint housing and-time to concentrate 3 the dust caused the' failure of 2B diesel generator to~ start.

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.Near future activities to. prevent this condition from again causing a failure are: q

1. In the upcoming outage, 2EOC3, tho'heim joints will receive 4 an inspection for freedom of movement and clearance.  ;

2. The ventilation system will be evaluated to determine if  :

more efficient filters can be used to reduce dust introduction'into the diesel generator rooms and not j adversely impact current ventilation design considerations.

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Finally,~although-existingidocuments used to: classify Diesel ~ Generator testing

Adentify.this as a valid 1 failure,-new draft: guidance indicates thatteventsiof 9- s *

> this sort in .theLfuture.may: not classify this ~ as a f valid failure. As:this 4

. guidance ~ is formalized ' Duke may ask that It be reclassified :as 'an" invalid :

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failure' consistent with'the guidelines-and technical bases of:

1.'- NSAC-198'(The Reliabilit'y of, Emergency Diesel Generators!at;U.S.

-Nuclear' Power plants); .

2. INPO-(Institute of-Nuclear power ~ Operations),'and _

3. .NUMARC (Nuclear. Management.and Resources Council), and specifically,' i

4. .NUMARC 87-00-(Guidelines and. Technical Bases.for NUMARC Initiatives' AddressingLStation Blackoutfat Light Water Reactors) Revision 1, ,j Dated April-6,'1990, AppendixL-D',Eand page 4; EXCEPTIONS;J i

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" Unsuccessful attempts'to start or load-run should~not 7

be counted as .

valid demands-ornfailures when they can be-definitelyTattributedito 4

, .any.of the following..

-l "o. component malfunctions'or operating errors.that,did.not^ h' prevent the emergency generator frem being' restarted and brought to load :within a few minutes (i.e. , without .

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, -corrective maintenance or significant problem' diagnosis)"1

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