ML20085K164

Ro:On 731028,diesel Generator Failed to Start When Given Start Signal from Control Room.Probably Caused by Foreign Matl Interfering W/Proper Operation of Starting Air Solenoid.Maint Procedure Revised

ML20085K164
Person / Time
Site:	Dresden
Issue date:	11/06/1973
From:	Worden W COMMONWEALTH EDISON CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085K167	List: ML20085K164 ML20085K170
References
826-73, NUDOCS 8310200243
Download: ML20085K164 (2)

Text

. Ce nwealth Edison p

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Address Rep!y to: Post Ofhce Box 767 Ch:cago. Ilhnois 60690 WPW Ltr.#826-73 Dresden Nuclear Power Station R. R. 91 i

Morris, Illinois 60450 .,

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Mr. A. Giambusso 'k q/: . O ' bI Deputy Director for Reactor Projects  %. h Directorate of Licensing kd

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1 U. S. Atomic Energy Commission Washington, D. C. 20545 Y4 /

L SUBJECI: LICENSE DPR-25, DRESDEN NUCLEAR POWER STATION, UNIT 43 1 SECTION 6.6.B.? O? THE TECHNICAL SPECIFICATIONS.

FAILU3E OF UNIT 03 DIESEL GENZRATOR AIR STARTING SYSTEM

Reference:

Notification of Region III of AEC Regulatory Operations Telephone: Mr. F. Maura, 1120 hours0.013 days <br />0.311 hours <br />0.00185 weeks <br />4.2616e-4 months <br /> on October 29, 1973.

Telegram: Mr. J. Keppler, 1140 hours0.0132 days <br />0.317 hours <br />0.00188 weeks <br />4.3377e-4 months <br /> on October 29, 1973.

Dear Mr. Giambusso:

This letter is to report a condition relating to the operation of.

the unit at cbcut 0010 hcars ca October 2G, 1973. At this time, the Unit 43 diesel generator failed to start when given a start signal from the control room.

PROBLEM When the deviation occurred, the Unit #3 mode switch was locked in shutdown for inspection of the Bergen-Paterson hydraulic shock suppressors.

At 0910 hours0.0105 days <br />0.253 hours <br />0.0015 weeks <br />3.46255e-4 months <br /> on October 28, 1973, the operator gave the Unit #3 diesel generator a start signal from the control room, in preparation for planned-transformer deluge testing. The diesel generator failed to start because sufficient starting air was not icmediately available to rotate the starting ,

motors. The shift foreman, who was standing near the diesel generator at the time of the deviation, vibrated the starting air lines and the diesel O*#5 g

started and operated satisfactorily.~ The Unit 02/3 diesel generator was # f started and loaded to verify its operability, b ve *7 INVESTICATION '

l It is believed that the deviation was caused by a small piece of l foreign material interfering with the proper operation of the starting air l solenoid. When the shift foreman vibrated the starting air lines, the blockage was dislodged and discharged from the system through the starting i air motor discharge, p p sw $

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, , - j. .Mr. A. Giacbus so Novembar 6, 1973 The Instrument Maintenance Department checked the operation of the starting air high 6 p alsrm and found it to operate satisfactorily.

The starting notor solenoid was tested several times by the Maintenance Department and operated ,,roperly each time. In addition, the Maintenance Department rc=oved, cleaned and replaced the main air valve. The "B" starting air filter, which was in service at the time of the deviation, was taken out of service and inspected. Inspection of the starting raotor solenoid, the nain air valve, and the starting air filter revealed nothing which could have caused the deviation.

CORRECTIVE ACTIONS The diesel generator periodic maintenance and inspection procedure was reviewed for adequacy. In light cf this review, the procedure was changed to require conthly disassembly, inspection and cleaning of the starting air solenoid.

EVALUATIONS This deviation resulted in no reduction in the margin of safety as defined in the basis for any Technical Specification, because the reactor node switch was locked in shutdown and the Unit 2/3 diesel generator was operable. The safety of the plant and the public was not jeopardized in any way. The operator cc=pleted the correct inmediate action by verifying operability of the Unit 2/3 diesel generator.

The corrective action previously described should reduce the probability of recurrence of a deviation of this type. The consequences of this deviation have no effect on the startup and subsequent operation of Unit #3.

Sincercly, .

u3.9.h60 W. P. Worden Superintendent WFW:do I