AECM-85-0394, Special Rept 85-016/0:on 851106,diesel Generator Declared Inoperable Due to Overspeed.Caused by Insufficient Oil in Mechanical Governor.Damaged Components Repaired,Replaced or Accepted as Found.Administrative Controls Changed

Special Rept 85-016/0:on 851106,diesel Generator Declared Inoperable Due to Overspeed.Caused by Insufficient Oil in Mechanical Governor.Damaged Components Repaired,Replaced or Accepted as Found.Administrative Controls Changed

ML20138P275
Person / Time
Site:	Grand Gulf
Issue date:	12/06/1985
From:	Dale L MISSISSIPPI POWER & LIGHT CO.
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
85-016-0, 85-16, AECM-85-0394, AECM-85-394, R-851206, NUDOCS 8512260024
Download: ML20138P275 (2)

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g MISSISSIPPI POWER & LIGHT COMPANY Helping Build Mississippi P. O. B O X 164 0, J A C K S O N, MIS SIS SIP PI 39215-1S40 c.n December 6, 1985 cm r-r1 NUCLEAR LCENSING & $AFETY DEF ARTMENT c2 to U. S. Nuclear Regulatory Commission "U Region II N 101 Marietta St., N. W., Suite 2900 N

Atlanta, Georgia 30323 Cn Attention: Dr. J. Nelson Grace, Regional Administrator

SUBJECT:

Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 License No. NPF-29 Special Report 85-016/0 Diesel Generator 11 Failure AECM-85/0394 On November 6, 1985, at approximately 1500, Diesel Generator 11 was manually started for retest following preventive maintenance. After a successful start, the engine surged to over 600 RPM before it could be shutdown. The diesel generator was declared inoperable. Investigations and inspections were conducted to determine the cause and affect of the event.

It is concluded from the investigations that the overspeed was caused by insufficient oil in the mechanical governor. A governor coupling had been replaced and the governor oil changed just prior to the event.

The engine was dismantled to determine the extent of damage caused by the overspeed event. Cracking, heat marks, fretting, or scoring were exhibited on some components. The components were repaired, replaced or accepted as found. The details of the nonconformance and the disposition of each item are documented on plant Material Nonconformance Reports.

Corrective measures including changes to administrative controls to prevent recurrence are under evaluation and will be included in an update to this report. The diesel generator is expected to be restored to service by December 8, 1985.

Mississippi Power & Light Company (MP&L) described the damage repair effort and the root cause of the overspeed event to the NRC Staff in meetings held on November 14, 1985, and November 21, 1985. Preventive measures were discussed in these two meetings and will be discussed further in a meeting between MP&L and NRC Staff scheduled for December 13, 1985 in Atlanta, Georgia.

8512260024 DR 851206 ADOCK 05000416 PDR Member Middle South Utilities System h )2.k 70 J16AECM85112901 - 1 -

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AECM-85/0394 Page 2 The failure is considered an invalid failure pursuant to Position C.2.e(2) of Regulatory Guide 1.108. The unsuccessful completion of the start and load attempt is attributed to operating error (operation with insufficient oil in the mechanical governor). The current test interval remains at once per 31 days in conformance with the schedule of Regulatory Position C.2.d.

This report is submitted as an interim report. A final comprehensive report detailing action to prevent recurrence is expected to be submitted by January 31, 1986.

Yours truly, L. F. Dale Director

-EBS/SHH: bas cc: Mr. O. D. Kingsley, Jr.

Mr. T. H. Cloninger Mr. R. B. McGehee Mr. N. S. Reynolds Mr. H. L. Thomas.

Mr. R. C. Butcher Mr. James M. Taylor, Director Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Document Control Desk U. S. Nuclear Regulatory Commission Washington, D. C. 20555 I

J16AECM85112901 - 2

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