ML20086J065

AO 75-6:on 740121,RSCS 30% Rated Power Interlock PS-3-3-250A Failed.Caused by Minor Leakage from Bourbon Tube Resulting in Buildup of Moisture in Switch Case.Switch Assembly Replaced,Calibr & Checked

ML20086J065
Person / Time
Site:	Peach Bottom
Issue date:	01/31/1975
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A Office of Nuclear Reactor Regulation
Shared Package
ML20086J066	List: ML20086J065 ML20086J068
References
AO-75-6, NUDOCS 8401230087
Download: ML20086J065 (2)

Text

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. PHILADELPHIA ELECTRIC COMPANY

S 2301 MARKET STREET ~~'

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t:J PHILADELPHIA. PA.19101 ,

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i2is 841-4ooo x . . .. b MY January 31, 1975 Mr. A. Giambusso Director, Division of Reactor Licensing Office of Nuclear Reactor Regulations U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Dear Mr. Giambusso

Subject:

Abnormal Occurrence The following occurrence was reported to Mr. Tom Shedlowsky, N'.R.C. Region 1 Office of Inspection and Enforcement on January 22, 1975 Written notification was made to Mr. James P. O'Reilly, Region 1 Of fice nf Inenact na aad Eaforca eat en J=ne=ry 22, 8975 i

In eccerdenca 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 l

being subm.tted to the Directorate of Reactor Licensing as an Abnormal Occurrence:

Reference:

License Number DPR-56 Technical Specification

Reference:

3 3 8 3.a Report No.: 50-278-75-6 Report Date: January 31, 1975 Occurrence Date: January 21, 1975 Facility: Peach Bottom Atomic Power Station R.D. 1, Delta, Pennsylvania 17314 j Identification of Occurrence:

Failure of PS-3-3-250A, RSCS 3DX rated power interlock.

Conditions Prior to Occurrence:

Unit 3 shutdwn.

5oy-2l3 *f 8401230087 750131 PDR ADOCK 05000278 S PDR .1180, COPY SElff REGION _

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V Mr. A. Giambusso e January 31~,1975 Page 2 -

Description of-Occurrence:

During a routine instrunent surveillance test, PS-3-3-250A was found to have suffered corrosion damage which rendered it inoper ab le.

The corrosion resulted from a buildup of mois ture in the switch housing.

Designation of Apparent Cause of Occurrence:

Minor leakage from the bourdon tube resulting in a building of mois ture in the switch case.

Analysis of Occurrence:

Because either the PS-250A or PS-250B switch serves independently to arm the RSCS below 30% rated power, the failure of only one of these switches has minimal safety implications.

Corrective Action:

The entire switch assembly was replaced in kind, calibrated, and checked in accordance with the applicabic surveillance test.

Failure Data:

None previous.

Very truly yours,

,,f [ /  % 'J - a

/ .f) I jfD th,M, h,'

M. J . C oon e~y l' /

Ass' t Gen' t Superintendent j Generation Division cc: Mr. J. P. O'Reilly Director Office of Inspection and Enforcement l _

Region 1 United States Nuclear Regulatory Coanission 631 Park Avenue '

King of Prussia, PA 19406 l

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