ML20086K487

Telecopy AO 75-9:on 750125,setpoint of APRM C Inoperable Trip Circuit Found Less Conservative than Allowed by Tech Specs.Caused by Accidential Gain Change to Circuit.Trip Unit Recalibr

ML20086K487
Person / Time
Site:	Peach Bottom
Issue date:	01/27/1975
From:	Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20086K477	List: ML20086K475 ML20086K487
References
AO-75-9, NUDOCS 8401270143
Download: ML20086K487 (1)

Text

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, , . ; u . v., s -- rm -um mm -m -v 4 Feach Botton Atonic Pavor Statino A.,. v % V . k h e.Y,. p y .<

Delta, Pennsylvanfm V 17314 U

. J:nurry 27, 1975 Mrs James P. O'Reilly, Director United States Atomic EnerCy Commission Directorate of Ragulatory Operations 631 Park Avenuo King of Prucaia, Pennsylvania 19406 subj ect: Abnore.nl Occurrence 24-Hour Notification Confirming W. T. U11 rich's phone conversation with Mr. Robert Carlson, A.E.C.

Region 1 Regulatory operations Office on January 25, 1975.

References L cenno Number DPR-44 Technical Specification References Table 3.1.1 note 11 Repore 16.: 50-277-75-9 Report Dator January 25, 1975 h.. , '

Occurrence Dates Janunry 24, 1975 IpM ', , j Yacility: . Pench Lotton Atomic Power Station ,s R.D. 1, Delta, Pennsylvania 17314 g% N' 2."< W '

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Identification of Occurrencet  ; ,.1j Setpoint of APRM "C" inop trip circuit Ices councrvative than 'o 'Nv_cd.' b

• the .

Teclutien1 Specifications.

Conditions Prior to occurrences Unit 2 at 65% power.

Dancription of Occurrence:

During a routine curvexAiance cent of the IJidi uyui.e.a. i.h inor Mp csts.sint 6 the LPRM count cire.uit van found out of the allowable tolerance on one APRH channol.

Dcoignation of Apparent Cause of Occurrenec:

Apparent accidental gain change to this circuit during APRM gain correction for l startup. ,

1 l Asullycin of Occurrences l The APRM inop signal natinfactorily produced a scram and a rod withdrawal block.

The actpoint error is of rainical nnfety nignificance because only one LPRM in tha APRH channel vau bypnsued or inoperable at the time. This trip to en cicctronic enforcement of an administrative limit that uns being complied with.

Corrective Action:

The biotable trip device was checked to ennure that the only probica pao the accidental setpoint chan30. The trip unit una then recalibrated to be u. ore conocrvative than the Toch Spec liuit. This was checked in accordance with the

- applicabic nurveilinnce tout and the APRM una returned to nervice.

Failure Datat ,

I Previous, APRH inop sotpoint chift reported as 50-270-74-3.

truly yours, s0 M<

W Vor 54 W. T. Ullrich, Superintendent Peach Dotton Atocic Power Station 8401270143 750204 PDR ADOCK 05000277 7 S PDR ggyy gyp pygygg -