ML20086L194

AO 74-20:on 740410,momentary Trip of RCIC Inverter in Emergency Shutdown Panel Occurred.Cause Under Investigation. Inverter Replaced

ML20086L194
Person / Time
Site:	Peach Bottom
Issue date:	04/20/1974
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
References
AO-74-20, NUDOCS 8402070455
Download: ML20086L194 (2)

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( % p April 20, 1974 %g Mr. A. Giambusso Deputy Director of Reactor Projects United States Atomic Energy Conmission Directorate of Licensing Washington, DC 20545

Subject:

Abnormal Occurrence The following occurrence was reported to Mr. R. A. Feil, A.E.C.

Region I Regulatory Operations Office on April 11, 1974. Written noti-fication was made to Mr. James P. O'Reilly, Region I Regulatory Operations Office on April 11, 1974. In accordance with Section 6.7 2.A of the Technical <pa r-i f i c a t i en t , p.ppendi;; f, cf OP,7 ';8; f c;- U,,; - 2 .N osi, Guiivm Atomic Power Station, the following report is being submitted to the Directorate of Licensing as an Abnormal Occurrence.

Reference:

License Number DPR-44, Amendment Number 1 Technical Specification 3 5.D.1 Report No.: 50-277-74-20 Report Date: April 20, 1974 Occurrence Date: April 10, 1974 Facility: Peach Bottom Atomic Power Station R.D. #1, Delta, Pennsylvania 17314 Identification of Occurrence:

Momentary trip of RCIC Inverter in the Emergency Shutdown Panel.

Conditions Prior to Occurrence:

Reactor was critical at about 3% power.

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April 20, 1974 Pcga 2 Description of Occurrence:

During the manual trip of a reactor feedwater turbine, the RCIC inverter located on the emergency shutdown control panel tripped.

This condition was annunciated in the control room, The tripped in-verter was immediately identified and successfully reset.

Designation of Apparent Cause of Occurrence:

Cause of TOPAZ inverter trippings is still under investigation.

Tripping appears to be associated with possible voltage spikes on the D.C. system.

Analysis of Occurrence:

Since A.C. power from the normal RCIC inverter was never in-terrupted, the operability of the RCIC system was not affected. Since the tripped invertcr could be reset immediately, RCIC operability from the emergency shutdown panel was only out of service for a few minutes.

t Corrective Action:

The inverter installed in the emergency shutdown panel was replaced with a spare unit. The unit which experienced the trippings was bench-tested and found to be satisfactory. Further investigation utilizing high speed recording equipment is presently being undertaken.

The Philadelphia Electric Company Electrical Engineering Department has been requested to investigate this matter and recommend a long term corrective action.

Failure Data:

One other tripping of the RCIC inverter has been reported as A0-50-277-74-14.

Very truly yours, 11 r,

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M. J.' Cooney A Ass't Gen't Superintendent Generation Division cc

Mr. J. P. O'Reilly Director, Region i United States Atomic Energy Commission 631 Park Avenue King of Prussia, PA 19406

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