ML20147C174

Special Rept 87-015:on 871211,failure of Emergency Diesel Generator a Occurred Due to Excessive Leakage.Caused by Cracked Lube Oil Line Fitting.Fitting Replaced & Retested for Leakage.Cause of Cracking Not Determined

ML20147C174
Person / Time
Site:	Wolf Creek
Issue date:	01/08/1988
From:	Withers B WOLF CREEK NUCLEAR OPERATING CORP.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
87-015, 87-15, WM-88-0004, WM-88-4, NUDOCS 8801190100
Download: ML20147C174 (2)

Text

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,o WOLF CREEKNUCLEAR OPERATING CORPORATION Bart D. Withers NA ome., January 8, 1988 VM 88-0004 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington D. C. 20555 St ojec t : Docket No. 50-482: Special Report 87-015 Gentlemen:

The attached Special Report is being submitted pursuant to Technical Specifications 4.8.1.1 3 and 6.9.2. This report concerns a failure of E:nergency Diesel Generator "A" which occurred when a cracked lube oil line fitting caused excessive leakage and forced the diesel generator to be shut down.

If you have any questions concerning this matter, please contact me or Mr. O. L.

Maynard of my staff.

Very truly yours,

-uA Bart D. Withers

. President and Chief Executive Officer BIM/llk Attachment oc B. L. Bartlett (NRC), w/a P. V. O'Connor (NRC), 2 w/a R. D. Martin (NRC), w/a l

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, January 8, 1988 WDEF OtEEK GENERATIfU SMTICM TDCIAL REPORP 87-015 DIESEL GENERA'IOR 'A' FAIUJRE On Decenber 11, 1987, a failure of Emergency Diesel Generator (D/G) 'A' occurred when a cracked lube oil line fitting caused excessive leakage ard forced the D/G to be shut dcun. This Special Report is being subnitted l

pursuant Technical Specifications 4.8.1.1.3 and 6.9.2.

Se D/G was approximately 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> into the yearly 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> run when the lube oil line leak was reported by Operations personnel. Maintenance was notified to try and tighten the fitting. tJpon tightening, the fitting began leaking worse. Control Recru personnel were noti Fial ard the D/G was secured at approximately 1246 CST until the fitting could be replaced. The screw type fitting was on a 1/4 inch continuous vent line on top of the lube oil ,

filter tank. We fitting was replaced and retested for leakage r satisfactorily at approximately 1610 CETF on December 12. The fitting was found to be cracked. The cause of the cracking could not be detennined.

Other similar connections cn the 'A' and 'B' D/Gs were inspected. No cracking was found on any similar fittings.

The shut &wn was initiated due to a conditicn that could ultimately have i resulted in D/G damage or failure by causing excessive lube oil to lea'? frcan the D/G. This event is therefore considered to be a valid test ard failure in accordance with Regulatory Position C.2.e.(6) of Regulatory Guide 1.108, Revisicn 1.

! As of January 5,1988, there have been forty-six (46) valid successful tests of D/G 'A'. This is the secarrl valid failure of D/G 'A' in the last 20 valid tests and therefore increases the testing frequency to once per seven days as required by Technical Specification Table 4.8-1. The previous valid failure occurred on Decenber 1,1986, and is reported in Special Report 86-011. The December 1 failure was causal by a failure of the Synchro Start Electric Speed Switch.

Mille the engine was out of service for fitting replacement, further investigation of a previous mechanical gwernor problem was conducted. It was decided to replace the entire mechanical governor. his replacement and the subsequent replacement fai.lal mechanically. Both failed gwernors were j sent to the vendor for repair and further investigation of the problems.

} These probleus did not result in any D/G valid failures. Upcn canpleticn of the investigation, a suplement to this report will be issued.

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