ML20086K571

AO 74-57:on 741218,setpoint of HPCI Steam Line High Flow Switch DPIS-2-23-76 Found Outside Tech Spec Limits.Caused by Setpoint Shift.Switch Adjusted & Checked for Proper Calibr

ML20086K571
Person / Time
Site:	Peach Bottom
Issue date:	12/28/1974
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
References
AO-74-57, NUDOCS 8401270280
Download: ML20086K571 (2)

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,' PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET PHILADELPHIA. PA.19101

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December 28, 1974 00

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Mr. A. Giambusso Of w ' "40 Deputy Director of Reactor Projects Uni ted States Atomic Energy Commission dYr!,k ^* .

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Directorate of Licensing ',> ' ,'

Washington,- D.C. 20545 .

Subject:

Abnormal Occurrence The following occurrence was reported to Mr. Walt Baunack, A.E.C. Region.'1, Regulatory Operations Of fice on December 19, 1974.

Wri tten notification was made to Mr. James P. O'Reilly, Region 1 Regulatory Operations Office on Deceaber 19, 1974. In accordance wi th Section 6.7.2.A of the Technical Speci fications Appendix A of' DPR h4 for Unit 2 Peach Bottom Atomic Power Station, the following report is being submi tted to the Di rectorate of Licensing as an

. Abnormal Occurrence.

Reference:

License Number DPR-44 Technical Speci fica tion

Reference:

Table 3.2.B Report No.: 50-277-74-57

-Report Date

December 28, 1974 Occurrence Date: December 18, 1974 l Facility: Peach Bottom Atomic Power Station

! Delta, Pennsylvania 17314 i - Identi fi ca tion of Occurrence:

!- Setpoint of HPCI steam line high flow switch, dPIS-2-23-76, l outside of Technical Specification limits.

i i Condi tions Prior to Occurrence:

The reactor was at 100% power. p ,j Description of Occurrence: P

[. During a routine instrument calibration surveillance test the I

- setpoint of. one of the HPCI steam line high flow sensors, dPIS-2-23-76, was found to have drif ted outside the limits allowed by the Technical

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Speci fi ca ti ons. The prescribed setpoint for this device is icss than i or equal to 225 in. H 20. The device was found to trip at 230.5 in. H 20.

8401270280 74122'O COPY SENT REGION [_

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Mr. A. Giambusso '

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December 28, 1974 Page 2 .

Designation of Apparent Cause of Occurrence:

Setpoint shi f t wi thin the accuracy of the instrument.

Analysis of Occurrence:

The safety inplications are minimal since the setpoint shi f t was very small and the companion redundant switch was tested and found to trip within the Technical Specification limits.

Corrective Action:

The swi tch was adjusted and checked for proper calibration in accordance with the applicable surveillance test. The companion swi tch was tested satisfactorily. Further investigation revealed that the susceptibility of the instrument to setpoint shi f t was aggravated by a factory adjustment which allowed the swi tch actuating arm to operate very close to the knee of the actuation cam.

Since thi s problem has been noted on similar devices, veri fi-cation of the proper setting of this factory adjustment is scheduled compatibic with the surveillance testing schedule.

Failure Data:

One previous failure of thi s swi tch was reported as A0-50-277-74-41.

Very truly yours, 1

y s M. J. Cooney Asst. Gen 1. Supt.

Generation Division cc: Mr. J. P. O'Rei lly Di rector, Region 1 United States Atomic Energy Commission 631 Park Avenue King of Prussia, PA 19406

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