ML20086J485

AP 74-5:on 750910,emergency Shutdown Panel RCIC Static Inverter Tripped from Operation of Barometric Condenser Condensate Pump.Caused by Failure in Trip Circuitry of Inverter Unit.Inverter Unit Replaced

ML20086J485
Person / Time
Site:	Peach Bottom
Issue date:	09/20/1974
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086J487	List: ML20086J485 ML20086J490
References
AO-74-5, NUDOCS 8401240036
Download: ML20086J485 (2)

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PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET "['

PHILADELPHIA. PA.19101 g} p g% p-2isi 841-4ooo u.s. gg**' j

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September 20, 1974 Mr. A. Giambusso Deputy Director of Reactor Projects

. United States Atomic Energy Commission Directorate of Licensing Washington, DC 20545

Subject:

Abnormal Occurrence The following occurrence was reported to Mr. W. Baunack, A.E.C. Region 1 Regulatory Operations Office on September 11, 1974.

Written notification was made to Mr. James P. O'Reilly, Region 1 Regulatory Operations Office on September 11, 1974. In accordance with Section 6.7 2.A of the Technical Specifications, Appendix A of DPR-56 for Unit 3 Peach Bottom Atomic Power Station, the following report is being submitted to the Directorate of Licensing as an Abnormal Occurrence.

Reference:

License Number DPR-56, Amendment Number 1 Technical Specification 3 5 0 Report No.: 50-278-74-5 Report Date: September 20, 1974 Occurrence Date: September 10, 1974 Facility: Peach Bottom Atomic Power Station R. D. 1, Delta, Pennsylvania 17314 Identification of Occurrence:

Unit 3 Emergency Shutdown Panel RCIC static inverter tripping from operation of the Barometric Condenser Condensate Pump.

Conditions Prior to Occurrence:

The reactor was operating at approximately 22% power with the RCIC in test at the Emergency Shutdown Panc1.

8401240036 740920 PDR ADDCK 05000278 9860

" 2

.' COPY SENT REGION __

Mr. A. Giambusso .

Szptember 20, 1974 \ Page 2 .

s-Description of Occurrence:

During the test run of the RCIC from the Emergency Shutdown Panel, the static inverter feeding the RCIC flow controller at the Emer-gency Shutdown Panel tripped repeatedly upon automatic starting of the RCIC reset.

Barometric Condenser Condensate Pump. Each time, it was immediately Designation of Apparent Cause of Occurrence: ._

Investigation points to a failure in the trip circuitry of the particular inverter unit. i i

Analysis of Occurrence:

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At the time of the inverter trippings, all other Unit 3 Emer-gency Core Cooling Systems were operable. Due to this, and the short time intervals that the inverter was in a tripped condition, this occurrence has minimal safety significance.

Corrective Action:

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The inverter unit was replaced with a spare. A storage oscilloscope was installed to monitor inverter input and output during i the testing. This spare inverter did not trip throughout the remainder of the RCIC testing at the Emergency Shutdown Panel .

• The input filter network as outlined in A0-50-277-74-40 is ~

in progress, in that two'of six filters have been installed.

Failure Data:

Five other trippings of RCIC inverters have been reported as:

A0-50-277-74-14, 20, 37, 39, and 40.

Very truly yours,

/

f'tYL4 M. . Cooney f Ass t Gen' t Supe'rintendent Generation Division cc: Mr. J. P. O'Reilly Director, Region ! '

United States Atomic Energy Commission

' 631 Park Avenue King of Prus'sia, PA 19406 '"

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