ML20042G815
| 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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.p 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
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1990.
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Very truly yours,
' I 6'on}7n A
Tony B. Owen Station Manager keb\\ REPORT.SP-xc:
Mr. S. D. Ebneter
'American Nuclear Insurers Regional Administrator, Region II
- c/o Dottie Sherman, ANI Library.
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U. S. Nuclear Regulator Commission The Exchange,: Suite.245.
101 Marietta Street, NW, Suite 2900.
'270 Farmington Avenue-Atlanta, GA 30323 lFarmington,. CT :.06032'
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'I M & M Nuclear Consultants Mr. K. Jabbour-i 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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9005160126 900508
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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
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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:
.1 strategic locations to observe panel,. controls, and engine functions.-
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 ~
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D during the start and run. In the same manner, observed start #2 was 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.
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The.'2L heim joint was original. equipment. It had been in servicef some 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.
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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
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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
I attributable to heim joints. Conversations-_with a. Senior. Design
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Engineer of Energy Services Group, Cooper-Industries informs us that
. l no failures have been reported concerning binding heim joints as the-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
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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.
The failure was caused by a particle (or particles) of grit that had j
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;
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- 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:
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In the upcoming outage, 2EOC3, tho'heim joints will receive 4
an inspection for freedom of movement and clearance.
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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
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. guidance ~ is formalized ' Duke may ask that It be reclassified :as 'an" invalid :
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,'
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.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 be counted as 7
valid demands-ornfailures when they can be-definitelyTattributedito 4
.any.of the following..
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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 J
-corrective maintenance or significant problem' diagnosis)"1
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