ML20086J201

AO 74-27:on 741121,main Steam Relief Valve RV3-71J Operated Unexpectedly.Caused by Ground on Control Cable to Relief Valve J Manual Actuation Solenoid.Leads Lifted to Manual Actuation Solenoid

ML20086J201
Person / Time
Site:	Peach Bottom
Issue date:	12/01/1974
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086J203	List: ML20086J201 ML20086J204
References
AO-74-27, NUDOCS 8401230307
Download: ML20086J201 (2)

Text

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PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET ' .

PHILADELPHI A. PA.19101 \ N a2isi e414ooo b December 1, 1974 t

Mr. A. Giambusso Deputy Director of Reactor Projects Uni ted States Atomic Energy Commission Directorate of Licensing Washington, D.C. 20545

Subject:

Abnormal Occurrence The following occurrence was reported to Mr. Walt Baunack, l A.E.C. Region 1 Regulatory Operations Office on November 21, 1974.

Written notification was made to Mr. James P. O'Reilly, Region 1 Regulatory Operations Office on November 22, 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 Technical Speci fication Reference 3.6.D.1 Report No.: 50-278-74-27 Report Date: December 1, 1974.

Occurrence Date: November 21, 1974 Facility: Peach Bottom Atomic Power Station R.D. 1, Delta, Pennsylvania 17314 Identification of Occurrence:

Unexpected operation of Main Steam Relief Valve RV3-71J.

Conditions Prior to Occurrence:

Uni t 3 at approximately 35% power.

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j 8401230307 741201 PDR ADOCK 05000278 i S 1QQQ4 t

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COPY SENT REGION - *1

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Mr. Gicmbusso

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Occembsr 1, 1974 ('T v'

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Description of Occurrence:

At approximately 35% power with stable plant conditions, the "J" relief valve opened and closed dropping plant electrical load by dbout 70 MW. This occurred twice within a few minutes.

Designation of Apparent Cause of Occurrence:

Ground on the control cable to the "J" relief valve manual actuation solenoid.

Analysis of Occurrence:

Because this valve is not part of the Automatic Depressurization System and because the failure and subsequent li f ting of leads affected only the capability of manually operating the relief valve from the control room, the safety implications are minimal.

Corrective Action:

Investigation showed that one side of the relief valve manual actuation solenoid was solidly grounded and that there was a concurrent intermittent ground on the d.c. system supplying control power to this valve. This combination of grounds was responsible for the unexpected operation of the relief valve solenoid. The leads were lif ted to the manual actuation solenoid, removing only the manuel actuation capability The ground will be further investigated and corrected when practical.

Failure Data:

. No previous failures of this type.

Very truly yours,

, },l' g.n .a l / M.'J. Cooney Ass't Gen 51 Superintendent Genera tion Division l

cc: Mr. J. P. O'Reilly

- Di rector, Region i United States Atomic Energy Commission 631 Park Avenue King of Prussia, PA' 19406 t

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