ML20084M738

AO 3-72-3:on 720814,during Routine Test,Diesel Generator Bus Breaker 3B 4kv Failed to Close Manually.Caused by Binding Positive Interlock Switch Rod.Rod Lubricated

ML20084M738
Person / Time
Site:	Turkey Point
Issue date:	08/18/1972
From:	Schmidt A FLORIDA POWER & LIGHT CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084M733	List: ML20084M738 ML20084M745
References
AO-3-72-3, NUDOCS 8306020310
Download: ML20084M738 (1)

Text

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} b L4 i> s [$3 FLORIDA POWER & LIGHT COMPANY Turkey Point Plant Mr. John F. O' Leary, Director August

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Division of Reactor Licensing /q U.S. Atomic Energy Commission g(

4 Washington, D. C. 20545 6 /

TURKEY POINT PLANT UNIT NO. 3 kg ABNORMAL OCCURRENCE No. 3-72-3 $* q.'"' Tk f MALFUNCTION OF DIESEL GENERATOR BREAKER g, ,

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Dear Mr. O' Leary:

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In accordance with Technical Specifications 6.6.2 a (1), and in amplification of the Company's preliminary telegram to Director, Region II, AEC, dated 8/15/72, this report is submitted.

At 3:52 PM, 8/14/72, during a routine test of the B diesel generator, in accordance with Technical Specifications 4.8.la, the 3B 4KV bus breaker (1200 Amp, G.E. type AM-4-16-360-lH, Serial 0204A8545-017) did not close manually.

A spare breaker was installed and the test satisfactorily completed at 4:13 PM.

The defective breaker was extensively examined and the problem was found to be a _ binding positive interlock switch rod. This rod normally actuates two auxiliary switches l'or charging and closing the breaker when the breaker is racked in.

Repeated tests showed the rod to be sticking erratically. The rod was lubricated and the breaker operated properly.

In order to prevent recurrence of this problem, lubrication of the positive interlock switch rod will be made a routine scheduled preventative maintenance item for this and similar breakers.

This problem was an abnormal occurrence in accordance with Technical ,

Specifications 1.13.4 because in a loss of power situation, the subject breaker g should close automatically to supply power to the 3B bus. This bus carries reactor j safety related equipment. However, reactor safety would not have been affected in l

g such a loss of power condition because the 3A, 4A, and 4B busses would have been powered through other breakers. Redundant safety related equipment, including three out of four safety injection pumps, powered from the 3A, 4A, and 4B busses

j would insure that reactor safety was maintained.

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Sincerely yours, 8Q 4.

as D. bcnmidt Director"of Power Resources d

ADS:jd cc: Mr. John Davis, Director Region II, Directorate of Regulatory Operation U.S. Atomic Energy Commission, p$ ,#

l Suite 218, 230 Peachtree Street, N.W.

Atlanta, Georgia PTP File

( 8306020310 721030 i

PDR ADOCK 05000250 COPY SENI' REGION --

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