ML20214J818

From kanterella
Jump to navigation Jump to search
Forwards Battelle 860831 Final Rept on Metallurgical Investigation of Various Defects on Surfaces of Diesel Engine aluminum-tin Bearings.Response to Battelle Recommendations to Minimize Bearing Conditions Provided
ML20214J818
Person / Time
Site: Fermi DTE Energy icon.png
Issue date: 11/21/1986
From: Agosti F
DETROIT EDISON CO.
To: Adensam E
Office of Nuclear Reactor Regulation
Shared Package
ML20214J820 List:
References
VP-86-0160, VP-86-160, NUDOCS 8612010482
Download: ML20214J818 (3)


Text

>

d -. D F,ank E. Agosti thco President Nuclear Operations Detroite re nu 6400 North Dixre Highway Edl Newport. Michigan 48166 osai ssim Nuclear operations November 21, 1986 VP-86-0160 Office of Nuclear Reactor Regulation Ms. Elinor G. Adensam, Director Project Directorate No. 3 Division of EUR Licensing U. S. Nuclear Regulatory Commission Washington, D. C. 20555

Dear Ms. Adensam:

Reference:

1) Fermi 2 NRC Docket No. 50-341 NRC License No. NPF-43
2) Detroit Edison Letter, VP-86-0025,

" Revision of Emergency Diesel Generator Crankshaft Dearing Reliability Demonstration Test Program", dated Match 8, 1906.

Subject:

Independent Investigation of EDG Bearing Defects Reference 2) documented Detroit Edison's actions to address the Emergency Diesel Generator (EDG) bearing failures and anomalies discovered in late 1985. One action was for Detroit Edison to obtain an independent investigation of various bearing surface defects d isc over ed . Attached, please find a report prepared by Battelle documentin; the results of their investigation of these defectc. Please note that the introduction to the report discusses some surveillance test procedures that are no longer applicable to the Fermi 2 EDGs.

These procedures were indeed followed previously, but have since been discontinued . This information was provided to Battelle to better characterize the operational conditions the bearing samples actually experienced. In the report, Battelle n akes three recommendations to minimize the majority of the bearing surface conditions. Each recommendation and Detroit

  • Edison's response follow:

3 Recommendation: 1) Improve the method used to remove

  • lapping compound from the journal surfaces end the general cleanup procedures.

\

90 B612010482 861121 Y

EDR ADOCK 05000341 3 PDR

I-r i a Ms. Elinor G. Adensam November 21, 1986 VP-86-0160 Page 2 Response: 1) According to current vendor hearing maintenance procedures, when bearing surfaces are reconditioned , lapping cocoound is used initially in the journal surface reconditioning process. Once the journal surface is reconditioned, the used lapping compound is removed. Bearing conditioner, containing lapping compound, is applied to new bearings which are installed. The engine is then reassemblec . To minimize the amount of lapping compcund remaining on bearings following rework, both the lapping compound removal procedure and the procedure. requiring the application of bearing conditioner would need modification.

This recommendation involves a modification to vendor maintenance procedures. Detroit Edison provided a copy of the Battelle report to the EDG vendor on October 20, 1986, and requested their consideration of this r ecommend a tion . Detroit Edison will comply with the vendor's response to this cecommendation.

Recommendation 2) Consider the use of steel-backed trimetal bearings with a babbit overlay to replace the solid aluminum alloy bearings.

Response 2) Use of steel-backed trimetal bearings with a babbit overlay has been considered and discucced with the EDG vendor. This recommendation involves a modification to the design of the EDGs. Detroit Edison provided a copy of the Battelle report to the EDG vendor on October 20, 1986, and requested their consideration of this recommend a t ion . Detroit Edison will comply with the vendor's response to this recommendation.

Recommendation 3) !!aintain a continuous recirculating, pressurincd lubrication system to prevent corrosion in stagnant areas of the bearings and to annure adequate lubrication dur ing r ap id start-ups of the diesel engine.

s ,

Ms. Elinor G. Adensam November 21, 1986 VP-86-0160 Page 3 Response 3) Detroit Edison complies with this recommendation as much as feasible within the constraints of the opposed piston engine design. This design prevents supply of a continuous, recirculating , pressurized lubrication to the upper crankline.

The Fermi 2 EDGs are currently operatea monthly. This monthly operation assures regular operation of the lubrication system which minimizes the possibility of corrosion in stagnant areas of the bearings. Also, Detroit Edison pro-lubricates the bearings prior to every planned start.

Should you have any questions regarding the above information, please contact R. Woolley at (313) 586-4211.

Sincerely, N >c 4 Attachment cc:  !!r. J. J. Stefano Mr. W. G. Rogers Mr. G. C. Wright USNEC Document Control Desk Uashington, D. C. 20535

.