ML20097A430
| ML20097A430 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 01/29/1996 |
| From: | Tulon T COMMONWEALTH EDISON CO. |
| To: | NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BW-96-0012, BW-96-12, NUDOCS 9602060026 | |
| Download: ML20097A430 (2) | |
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Commonwealth Edison Comp.tny Ilraidw ood Generating $tation
' Route *l, Ilox H i Ilicaceville. IL GH07%19
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Tel 81045&2801 January 29,1996 BW/96-0012 Office ofNuclear Reactor Relatina 4
U.S. Nuclear Relatary Comminion Wmakingna. D.C. 20555-0001 Attaanna Document Control Desk
Subject:
Braidwood Station Unit 2 Train A Diesel Generator Failure i
Docket No. STN 50-456 i
Reference.
NUREG-1276, Technical Specifications, Braidwood Station, Unit Nos. I and 2
Dear Sir:
Specification 4.8.1.1.3 of above reference requires that all diesel generator failures, valid or non-valid, be reported to the Nuclear Regulatory Cnmmi== ion pursuant to Specification 6.9.2 of above reference.
'Ibe enclosure addresses a valid failure of the Braidwood Unit 2, Train A (2A) Diesel Generator (DG). W valid failure occurred on 12/28/95 during performance of the Technical Specification required monthly operability surveillance. h criteria to determme validrmvalid tests and failures are in accordance with Regulatory Guide 1.108, Section C.2.e.
Please direct any questions regardmg this submittal to Doug Huston, Braidwood Station Regulatory Assurance, (815)458-2801, extension 2511.
- Truly,
/A
. J. Tulon tation Manager Braidwood Station TJT/DIVdla 9602060026 960129 -
PDR ADOCK 05000456 Enclosure S
PDR cc:
Mr. H.J. Miller, Regional Admmistrator Senior Resident inspector, Braidwood R. Assa,NRR B. Clayton, Region III A
g 00 H. Pontious, NLA T1(
05Cr60 D. Gustar on, Systems Engineering A !!nicom Company
BRAIDWOOD DIESEL GENERATOR FAILURE REPORT 1
'Ihc 2A DG was taken out of service at 0519 hours0.00601 days <br />0.144 hours <br />8.581349e-4 weeks <br />1.974795e-4 months <br /> on December 28,1995, for preplannad maintmance. Work performed included the replacement of four control relays, fuel filter /stramer replacement and ia=aac+iaa of both govemor drive assemblies for proper lube oil flow. Following l
completion of this maintmance work, the 2A DG was started for peta.wecc of 2BwOS 8.1.1.2.a-1, Unit Two 2A Diesel Generator Operability Monthly (Staggered) and Semi-Annual i
(Staggered) Surveillance. 'Ihe time from 2A DG start to attaining rated speed and voltage was measured by Operations perso d at 10.28 sec. Systems Fmginaarmg personnel timed the tagine start at 8.28 =arnads. Per survedlance 2BwOS 8.1.1.2.a-1, the allowable start time is 10 eacand.
I F-ding the surveillance acceptance entena constituted a failure of the 2A DG.
i At 1650 the 2A DG was restarted for a troubleshooting run. System F=p==irig perenanal momtored the engme during the start attempt. 'Ihe 2A DG started and ranchad rated speed and voltage in a time of 7.27 nacande with no problems noted by Systems Engiaaaring 'Ihe 2A DG i
was subsequently started for performance of the operability survallance. 'Ihc time from 2A DO I
start to =*=iaiag rated speed and voltage was measured by Operations persci d at 7.38 seconds i
Root cause of the event is believed to be a timing error on the part of Operations personnel. Listed below are facts that support this:
'Ihere has been no history of slow start problems on the 2A DG Review of start time trendmg data shows start times consistently less than 8 sec.
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i Systems F=giaaaring perso d timed the engine start at 8.28 seconds
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The work performed on the 2A DG would not have had any impact on the start time of the DG.
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'Ihe troubla<hnating start and the operability surveillance start were less than 8 seconds, and l
no equipment problems could be found by Systems Engineering.
After successfully completing the troubWhaatia: runs and the Tech Spec operability surveillance run, the 2A DG was declared operable at 2149 on December 28,1995. 'Ihc 2A DG was unavailable for a total of 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> and 30 minutes.
'Ihis failure was conservatively considered valid hac=nea it occured during the monthly operability run. Regulatory Guide 1.108, Section C.2.e. allows a failure to be considered invalid if the failure "can definitely be attributed to operating error." In this case, an operator tuning error is suspected, but the demand will conservatively be classified a valid failure.
There have not been similar valid failures of this nature on the other DG at Braidwood Station.
'Ihis failure of the 2A DG has been determmed to be a valid failure in accordance with Regulatory Guide 1.108, Section C.2.e. The 2A DG remains on a monthly test firquency.
As of January 23,1996, the 2A DG has had one valid failure in the last 100 valid Braidwood Unit 2 demands.
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