ML20042D840

Supplement to 900105 Special Rept Re Inoperability of Diesel Fire Pump Due to Failure in Right Angle Gear Drive. Broken Studs Replaced W/Cap Screws Per Vendor Recommendations & Preventive Maint Activity Added

ML20042D840
Person / Time
Site:	Davis Besse
Issue date:	03/30/1990
From:	Storz L TOLEDO EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BB90-00483, BB90-483, NP39-89-01, NP39-89-1, NUDOCS 9004100218
Download: ML20042D840 (1)

Text

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4 DocFet iJo. 50-346 y,0'lgyg(AAvt Nut tot t Do. osio 4at42 0331 Licente lio. IJi'F-3 IP39-89-01, Rev. 1 March 30,1990 BB90-00483 United States fluelear Regulatory Commission Document Contrel Desk Vashington, D. C. 20555 Gentlemen:

Subjects rollovup to the Special Report of the Diesel Fire Pump Being Inoperable on January 5,1990. Toledo Edison submitted a Specin1 Report of the Diesel Fire Pump (DTP) being inoperable. It was inoperable due to a failure in the right angle gear drive. The studs that he16 the hub f rom the horizontal drive shaft to a gear in the right angle gear drive broke. That letter indicated the studs vould be sent off-site for analysis. This letter provides the results.

The conclusion reached is that the stud failure was caused by the loss of preload due to the starting and stopping of the pump numerous times over many years. The loss of the preload changed the stresses on the studs, resulting in their fatigue fallute.

As noted in the previous letter, the broken studs vere replaced with cap screvs per the vendor's current recommendations. Toledo Edison is now adding a preventive maintenance activity to periodically check the cap screv preload.

This vould ensure the proper preload vhich vill maintain the cap screvs under the desired tensile stress conditions and pre: vent failure.

Very truly yours.

s L. T. Store Plant Manager JCS/pli ,

cci A. B. Davis Regional Administrator l Region III P. Byron DB-1 14RC Resident Inspector

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