ML20086J180

AO 74-30:on 741125,relay 14A-K9B in Lpci/Core Spray Low Reactor Pressure Permissive Logic Failed to Makeup Consistently.Caused by Dirty & Slightly Misaligned Relay Contacts.Contacts Burnished & Realigned

ML20086J180
Person / Time
Site:	Peach Bottom
Issue date:	12/05/1974
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086J183	List: ML20086J180 ML20086J187 ML20086J188
References
AO-74-30, NUDOCS 8401230278
Download: ML20086J180 (2)

Text

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i O O PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET PHILADELPHIA. PA.19101 1215) 841-400o December 5, 1974 . ' c .,

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Mr. A. Giambusso Y .A 3 0'

Deputy Director of Reactor Projects [  ;

United States Atomic Energy Conmission 'y <]5 . 6',

Directorate of Licensing Washingten, DC 20545 .u<k.t , 9.*. ;.^A,

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Dear Mr. Giambusso:

QA Subj,ect : Abnormal Occurrence y-..

The following occurrence was reported to Mr. Walt Baunack, A.E.C. Region i Regulatory Operations Office on November 26, 1974.

Written notification was made to Mr. James P. O'Reilly, Region i Regu-latory Operations Office on November 26, 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 f ollowing report is being submitted to the Directorate of Licensing as an Abnormal Occurrence.

Reference:

License Number DPR-56 Technical Specification Reference Table 3 2.B Report No.: 50-278-74-30 Report Date: December 5, 1974

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Occurrence Date: November 25, 1974 7

Facility: Peach Bottom Atomic Power Station

, R.D. 1, Delta, Pennsylvania 17314 Identification of O'ccurrences

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FaildFe of rel'ay 14A-K9B in thc[LPCI/Co're' Sp. ay low reactor..

pressure permissive logic to make-up consistently.

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Conditions Prier to Occurrence: ..

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Unit 3 operating at f3 pcwcr.

Description of Occurrence:

During a routine instrument surveillance test .on PS-3-3'528, -i its relay (14A-K98) to the LPCI/ Core: Spray low reactor pressure per-missive logic f ailed -to makeup consistently..

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Mr. A. Giambusso

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Designation of Apparent Cause of Occurrence:

Dirty and slightly misaligned relay ccatacts.

' Analysi s of Occurrence:

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Because this switch / relay combination operates in a one-out-of-two-twice logic, the failure of any one of the four devices will not render the logic inoperable. Therefore, the safety implications of this single f ailure are minimal.

Corrective Action:

Investigation revealed that a slight contact misalignment coupled with dirty contacts led to the inconsistent relay contact makeup. The contacts were burnished and realigned and the relay oper-Review of ation again checked several times with no further f ailures.

previously reported relay cont'act problems (see be l ow) indicates that the four reported f ailures have occurred on three dif ferent types of relays. Therefore, no generic problem is believed to exist.

Failure Data:

Previous relay contact problems were reported as Abnormai occurrence 50-277-74-5, 50-277-74-9, and 50-277-74-50.

Very truly yours,

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M. J., ooney ,)

Ass't Gen't Superintendent' Generation Division cc: Mr. J. P. O'Reilly Director, Region 1 1 United States Atomic Energy Commission .

631 Park Avenue King.of Prussia, PA 19406

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