ML19210A235

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Abnormal Occurrence 75-21:on 750625,reactor Protection Sys Channel C Failed During Surveillance Test.Caused by Coolant Temp Trip Bistable Failure to Trip Due to Component Failure in Signal Converter
ML19210A235
Person / Time
Site: Three Mile Island Constellation icon.png
Issue date: 06/25/1975
From: Colitz J
METROPOLITAN EDISON CO.
To:
Shared Package
ML19210A232 List:
References
NUDOCS 7910240948
Download: ML19210A235 (1)


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,3 METROPOLITAN EDESON COMPANY sussroianvor centaat.rueucununescoarosanc.s POST OFFICE BOX 480 MIDDLETOWN.PENNSY;.VANIA 17057 TELEP HON E 717-9i84-4041

- June 25,1975 Mr. J. P. O'Pel11y, Director Directorate of Regulatory. Operations D* On th 3. < @" ' i,S ' o rlp n g. '

' d, SU Region 1 o ML 1 .o a 631 Park Avenue King of Prussia. Pennsylvania 19406 Operating License CPR-50 -

Docket 50-289 ,

Subject:

Abnormal Occurrence No. A0-75-21

Dear tir. O'Reilly:

This telegrara is to confim the telecon between Bert Davis (Region 1-tRO) and J. J. Colitz (Til! Unit 1 Superintendent) at 1700 beurs, June 25, 1975.

Violation of Technical Specification 2.3.1 in that the high reactor coolant teraperature trip bistable for Reactor Protection System Channel C failrd to trip during routine P.PS Surveillance Testing. Table 2.3-1(Page 2-9) of the Tecnnical Srccification requires that the bistable trip at a marimun tenperature of 619"F. ,

T^ne bistable failed to trip because .s carpenent failure in the signal .

converter prevented the trip signal from reaching the .bistabl,e.

The high temperature trip feature for the remaining three RPS channels was imediately checked and the bistables were found to trip within Technical Specification limits.

The def ective signal converter is currently under repair. Upon completion of repairs, the high temperature trip feature will be ccmpletely tested prior to returning APS Chcnnel C to service.

Very truly yours.

. . Coli z tinit 1 Superintendent TMI Nuclear Station '

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