ML20086K359

AO 74-41:on 740919,setpoint of HPCI Steam Line High Flow Sensor Found Outside Tech Spec Limits.Caused by Setpoint Drift.Device Recalibr & Returned to Svc

ML20086K359
Person / Time
Site:	Peach Bottom
Issue date:	09/29/1974
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086K364	List: ML20086K359 ML20086K366
References
AO-74-41, NUDOCS 8401270043
Download: ML20086K359 (2)

Text

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PHILADELPHIA ELECTRIC COlviPANY

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4 2301 MARKET STREET Q, , q. 1 y,3

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PHILADELPHIA, PA.19101 . ..

g gg9 Septmber 29,197h

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Mr. A. Giarbusso Deputy Director of Reactor Projects United States Ato:aic Energy Cwnission Dircetorate.of Licensing

. Washington, D.C. 20$h5

Dear Mr. Giambusso:

Sub;iect: Abno'nnal Occurrence i

The fo31oiring occurrence was reported to Mr. Walt Baunack, A.E.C. Region 1 Regulatory Operations Offico on Septmber 20,197h.

Written notification uus made to Mr. Jones P. O'Reilly Region 1 Regulatory Operations Office on Scptonbcr 20,197h. In acconlance with Section 6.7 2.A of the Tcchnical Specifications, Appendix A of DPR-hh for Unit 2 Peach Bottom tA cmic Power Station, the folloulng report is being submitted to t'le Directorate of Licensing as an L Abnonaal Occurrence.

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Reference:

, License Number DPR-hh, Anmdment No.1

! Technical Specification 3 2.B Report No.: 50-277-7h-h1 j Report Date: Ecptmber 29,197h

! Occurrcnen Date: September 19,197h Peach Botton Atatic Power Statica 5'acility.

R.D. //1, Delta, Pennsylvania 1731h Identification of Occurronec:

Sctpoint of HPCI stean line high flow sensor outside of Technical Specification 1$ nits.

Conditions Prior to Gecurrence:

The reactor was at 80% power.

Descrintion of Occurrenec: ,

During a routine instninent' calibration curveil]ance test, the setpoint of one of the HPCI stcavi line high flo): cennors, 5PIS-?-23-76 A~k .c a M-was found to have driftcd outside tcic li. nits al] owed by the Tcchnical l

j 8401270043 740929 y' Or^ 'M gDRADOCK 05000277 COPY SENT REGION -

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,e Mr. A. Giambusso n n 1

,Septcr.iber 29,1() " U Page 2 Specifications. The prescribed actpoint for this device is less then or equal to 225 inches !!20. The device was found to trip at 231 inches H2 0.

Designation of Annarent Cause of Occurrence:

A careful cramination of the subject m7 itch revealed no evi-dance of binding or other mechanical malfunction. The suitch tripped consistently at 231 inches H 20. This setpoint failure is attributed to setpoint drift caly.

Analysis of Occurrence:

The HPCI steam line high flow isolation signal circuitry is nrranged in a one cut of two configuration. A high flow signal from either of the two differential pressure devices is sufficient to cause an isolation of the HPCI stcam supply. Due to the small msgnitude of the setpoint shift and the fact that the device was functional, this occurrence has a mininal effect on plant strety.

_ Corrective Action:

The subject device was innediately recalibrated to within acceptable limits and returned to service. The calibration of the companion switch was checked and found to be satisfactory.

Failure Dnta:

No previous failures of this type of device in this service.

Very truly yours, b' ,y I' . . ooney Ass t Gen'l Supe ntendent Generation Division ec: J. P. O' Reilly Director, Region 1 U. S. Atomic Energy Commission i 631 Park Avenue

! King of Pniscin, PA 19h06 l .