ML20086J197

Telecopy AO 74-33:on 741204,main Steam Line High Flow Switch DPIS-3-2-116C Failed to Trip During Surveillance Test.Caused by Slight Mechanical Binding.Face & Scale Removed from Instrumentation to Watch Linkage

ML20086J197
Person / Time
Site:	Peach Bottom
Issue date:	12/05/1974
From:	Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20086J196	List: ML20086J192 ML20086J197
References
AO-74-33, NUDOCS 8401230298
Download: ML20086J197 (1)

Text

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Pg.ADELPHIAELECTRICCOMPANY Kb" '

PeabpBottom Atomic Power Station (/g g, (tJ A L't M O b

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United States Atomic Energy Coeraission ;R Q Directorate of Regulatory Operatfons 631 Park Avenue

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King of Prussia, Pennsylvania 19406

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Subj ec t : Abnormal Occurrence 24-Ilour Notification CO M

Confireing V. T. Ullrich's phone conversation with Mr. Walt Baunack, A.E.C. Region 1 L

Regulatory Operations Office on December 5, 1974. {gf

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Reference:

License Number DPR-56 lechnical Specification

Reference:

Table 3.2.A J.Q um s Roport No.: 50-278-74-33 ME Report Date: December 5, 1974 lf; Occurrence Date: December 4, 1974 -

p, Fecility: Peach Botton Atomic Power Station Ty

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Delta, Pennsylvania 17314 t F.J Identification of Occurrence:

M 4"b; Failure of Main Steam Line High Flow Switch dPIS-3-2-116C to trip during a 4%

surveillance test. ].I; a

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Conditions Prior to Occurrence: g.,

Unit 3 at approximately 75% power. QA ,g Description of Occurrence: '""

During a routine surveillance test, dPIS-3-2-Ll6C failed to trip.

Designation of Apparent Cause of Occurrence Probably a clight mechanical binding. The Linding cleared during visual examination of the switch linkage.

Analysis of Occurrence:

There are no safety implications since its con:panion switch in a one-of-two-twice logic was operable and would have tripped at the prescribed setpoint.

4 Co r rec t ive Ac tion :

Following the failure to trip, the f ace and scale were removed from the instrument in order to watch the linkage during an operation to try to determine the type of f ailure. The switch was again tested and this tima and each succeeding time it worked properly. It was then reassembled, tested and continued to work successfull

.. Failure Data:

Previous occurrences on theos type switches have been reported as dPIS-2-2-119D on 9/7/ 7 3, 50-277-74-28, 50-277-74-48, and 50-278-74-20.

Very truly yours, WYW W. T. Ullrich, Superintendent Pach Bottom Atomic Power Station 8401230298 741205 i PDR ADOCK 05000278 S pop u v&h -: .jpR f- %.6 9 h., +.f;; "ky6 . : p * ; _s v. .+li + (Ngv

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