ML20086B169

Ro:On 701207,emergency Diesel Generator a Started & High Vibration Immediately Apparent.Caused by Damage to Stator Windings.Stator Field Coils Being Replaced.Complete Investigation Underway by Fairbanks-Morse Co

ML20086B169
Person / Time
Site:	Robinson
Issue date:	12/16/1970
From:	Utley E CAROLINA POWER & LIGHT CO.
To:	Morris P US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086B171	List: ML20086B169 ML20086B182
References
NUDOCS 8311170087
Download: ML20086B169 (2)

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-Carolina Power & Light Company Raleigh, North Carolina 27602 December 16, 1970 s

Dr. Peter A. Morris c Division of Reactor Licensing U. S. Atomic Energy Commission Washington, D. C. 20545 RE: FACILITY LICENSE NO. DPR-23 DOCKET NO. 50-261

Dear Dr. Morris:

In accordance with Section 6.6.2 of the H. B. Robinson Unit No. 2 Technical Specifications, the Company reports a failure of the generator of emergency diesel generator "A". The reactor was in a cold-shutdown condition at the time.

Sequence of Events A test program had been initiated on December 4,1970, to verify start reliability of the diesel engines with a safety injection signal. Once every eight hours a safety injection signal was manually initiated and the starting of the diesels monitored. This program was followed until approximately 1:26 PM, December 7, 1970 when the '

diesels were started and high vibration was immediately apparent on Y generator "A". Vibrometer readings indicated 7.0 mils on the exhaust end (horizontal) of the diesel and 18.5 mils on the generator end bearing (horizontal).

An inspection of the generator indicated th'at a rotor pole cap including attached balancing weights had been thrown clear of the j rotor and had caused damage to the stator windings.  !

Corrective Action -

A complete set of stator field coils on generator "A" are being replaced.

/2M9 d A complete investigation of the cause of the failure is in

[k progress under the direction of a Fairbanks-Morse Company representative.

In addition to repairs to generator "A", a thorough inspection of generator "B" is in progress to insure that a similar f ailure does -

not occur on that machine. (

8311170087 701216 M

PDR S ADOCK 05000261 i PDR COPY SENT REGION )

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Dr. Peter A. Morris December 16, 1970 The reactor will not be made critical until repairs to generator "A" have been completed and both diesel generators have been tested. It is estimated that both diesels will be in service by December 22, 1970.

Yours very truly,

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f'. EE. ' Utley 3 Manager Generation & System Operations h3B/lef cc: Mr. J. A.' Jones

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