ML20086K570

AO 75-1:On 750113,setpoint Shift Found on Low Condenser Vacuum Reactor Protection Sys Trip PS-2-5-11C & 11d.Caused by Setpoint shift.Out-of-tolerance Pressure Switches Recalibr

ML20086K570
Person / Time
Site:	Peach Bottom
Issue date:	01/23/1975
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A Office of Nuclear Reactor Regulation
References
AO-75-1, NUDOCS 8401270272
Download: ML20086K570 (2)

Text

,

O O PHILADELPHIA ELECTRIC COMPANY <

b 2301 MARKET STREET PHILADELPHI A. PA.19101 1215)841 4000 ,

January 23, 1975

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Mr. A. Giambusso 9

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Deputy Director of Reactor Projects [5  ;'! , \[.^b United States Atomic Energy Commission / **1 %  ;{/f'I YL Directorate of Licensing.

Washington, D.C. 20545

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Dear.Mr. Giambusso:

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Subject:

Abnormal Occurrence /

The following occurrence was reported to Mr. Bert Davis, A.E.C. Region I Regulatory Operations Office on January 14, 1975.

Written notification'was made to Mr. James P. O'Reilly, Region I pagnlatory Onorations Office on Januarv 14 1975. In accordance with_Section;6i.7.2.A of the Technical Specifications, Appendix A of DPR-44 for Unit 2 Peach Bottom Atomic Power Station', the following report is being submitted to the Directorate of Licensing as an Abnormal Occurrence.

Reference:

License Number DPR-44 Technical Specification

Reference:

Table 3.1.1 Report No.: 50-277-75-1 Report Date: January 23, 1975 Occurrence Date: January 13, 1975 Facility: Peach Bot tom Atomic Power Station R.D. 1. Delta, Pennsylvania 17314 Identification of Occurrence:

~

Setpoint shift on PS-2-5-llc and llD, low condenser vacuum RPS trips.

Condition Prior to Occurrence:

Unit 2 operating at' 100% power.

8401270272 750123 h,12 gDRADOCK 05000277 PDR

'Mr. A. Giambusso January. 23, 1975 () f Page 2 s .

Description of Occurrence:

During routine instrument _ surveillance' testing, PS-2-5-llc was' found to trip at 22.77 inches Hg and PS-2-5-llD was found to trip at 22.33 inches Hg. The Technical. Specification limit is greater than or. equal to 23 inches Hg. ,

Designation of Apparent Cause of Occurrence:

Setpoint shift.

Analysis of Occurrence: ,,

The contacts on these devices are part of a one-out-of-two twice RPS logic scheme. Because-all switches were functional (the A&B switches were tested immediately and found to function within the Technical Specification limits), and the minor setpoint shifts were not.in the same logic path, the safety implications of this occurrence are minimal.

Corrective Action:

Inc out-or-tolerance pressure dwildaes wurs iumediatcly recalibrated to within the allowable limits of the Technical Specifications and checked for proper calibration per the applicable surveillance tests. The other two devices monitoring the same

_ parameter were immediately tested and found to be satisfactory i

^

in both function and setpoint.

Failure Data:

Setpoint shifts on this type device in this service have

.been reported previously as AO-50-277-74-1, AO-50-277-74-19, AO 277-74-35, AO-50-277-74-43 and AO-50-278-74-24.

Very truly yours, mys \ p .

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lf[. ,

M. J. Cdoney [ /

Ass't Gen'l Superintendent /

Generation Division

, cc: J. P. O'Reilly rector, Region I caited States Atomic Energy Commission

^ 631. Par.k Avenue King of Prussia, PA 19406 L' ? __.J