PNO-III-87-020, on 870204,lubricating Oil & Fuel Leaks Detected During 24 H Test Run of Emergency Diesel Generator. Caused by Interference Between Cross Head & Cross Head Guide.Steps to Ensure Correct Clearance Being Taken

PNO-III-87-020:on 870204,lubricating Oil & Fuel Leaks Detected During 24 H Test Run of Emergency Diesel Generator. Caused by Interference Between Cross Head & Cross Head Guide.Steps to Ensure Correct Clearance Being Taken

ML20210T158
Person / Time
Site:	Braidwood
Issue date:	02/06/1987
From:	Little W, Tongue T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-87-020, PNO-III-87-20, NUDOCS 8702180086
Download: ML20210T158 (2)

PRELIMINARY' NOTIFICATION OF EVENT ~0R UNUSUAL' OCCURRENCE--PNO-III-87-20=Dat2 February 6 1987-

~ v This preliminary no'tification constitutes EARLYjnotice of events of POSSIBLE safety-Or public interest significance.- The-information-is as initially received without Ab n verification or evaluation, and is basically all that is known'by the Region III staff on this date.

\D Facility: Comonwealth Edison Company Licensee Emergency Classification:

Braidwood Units 1 and 2 Notification of an Unusual-Event Braceville, IL '60407 Alert Site Area Emergency Docket Nos. 50-456; 50-457 General Emergency _

x Not' Applicable

Subject:

EMERGENCY DIESEL GENERATOR FAILURE

~

During a 24-hour test run of the 2A emergency diesel generator on February 4,1987, lubricating. oil.and fuel oil leaks were detected. The test was halted. An_ inspection of_ _.

the diesel internals showed damage to the rocker arms in five of the 20 cylinders. The diesel is manufactured by Cooper-Bessemer. [Similar damage occurred in an identical diesel

~

generator at Byron Unit 1 on February 17, 1986, and that damage was attributed to cylinder head misalignment. (

Reference:

PNO-III-86-14)]

The licensee's preliminary findings are that there was no cylinder head misalignment in the Braidwood 2A diesel. Examination of the damaged cylinder indicates that there was inter-ference between the cross head and the cross head guide which led to the failure. A review of the inspection records for diesel generators 2A, IA and IB reveal that the clearance between the cross head and its guide was less for 2A than for IA and~18, which.have operated satisfactorily. The outside surface of the cross head for the damaged 2A cylinder shows evidence of interference between the cross head and its guide. The clearances between the:

cross head and its guide in the damaged 2A cylinders were at.the low end of the standard clearance of 0.002 to 0.004 inches, while the clearances in the 1A and 18 diesels which have optrated successfully were 0.004 and 0.003 inches respectively. The. corrective action being taken by the licensee is to make sure that the clearance'between the cross head and-its guide is greater then 0 A02 inches but equal.to or less than 0.006 inches as recommended by Cooper-Bessemer. A fourth diesel generator is being examined.

Unit 1 has completed fuel loading and is in Mode 5 (cold shutdown) awaiting authorization j for initial criticality. The 2A diesel generator is required to be capable of being jmanuallystartedandcrosstiedtoBus141inorderforUnit1toenterMode3(hotstandby).-  ;

4 j The resident inspectors are monitoring the licensee's investigation and repair of the diesel damage.

The State of Illinois will be notified.

!This information is current as of 8 a.m. February 9, 1987. I

! CONTACT: T. Tongue { . Little l

, FTS 388-5543 FTS 388-5578 l l

l I 8702180086 870206 '

L f $ 11f-87-020 PDR l

DISTRIBUTION:

H St." - ED0 NRR E/W 'Willsta Mail: ADM:DMB Chairman Zech PA IE NMSS D0T:Trans only Cosm. Roberts - ELD OIA RES Comm. Asselstine AEOD NRC Ops Ctr /J,*39/

Com. Bernthal Comm. Carr SP //.~.2 h Regional Offices ACRS SECY CA INP0 /.2 ~M3 - NSAC /197

PDR RIII Resident/2/sd Licensee: Offig/ (Corp. Office - Reactor Lic. Only)

Region III-Rev. November 1986 i

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