ML17238A723

Regarding Failure of a Reactor Protection Limit Switch on Number 2 Turbine Control Valve on 7/7/1972

ML17238A723
Person / Time
Site:	Dresden
Issue date:	07/10/1972
From:	Worden W Commonwealth Edison Co
To:	Bloch E US Atomic Energy Commission (AEC)
References
Download: ML17238A723 (1)

Text

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TWX NR 51 7 I TLXA090 WAG028(1103) <1-005134C192002)PD 07/10/72 1100 R~~~.o' - tJJ.e py..

.ig~c I~~~L~~F J~~RRIS ILL IO 950A CDT ~~~,,r-Dat&d~ae.*:cy,*-

PMS EDWARD J BLOCH, ACTING DIRN, DLR DIRECTORATE OF LICENSING U. S. ATOMIC ENERGY COMM WASHDC SUBJECT DPR25 DRESQEN NUCLEAR POWER STATION UNIT 3. TRIS WILL CONFIRM CONVERSATION AT 0845 HOURS TRIS DATE WITH MR F MAURA OF YOUR OFFICE REGARDING FAILURE OF A REACTOR PROTECTION LIMIT SWITCH ON THE NUMBER 2 TURBINE CONTROL VALVE. AT 2320 HOURS ON 7-7-83, TEE TURBINE CONTROL VALVES ~ERE-INDIVIDUALLY CYCLED CLOSED AS PART OF THE

, ROUTINE TURBIN SURVEILLANCE PROCEDURE. THE REACTOR PROTECTION SYSTEM RELAYS ASSOCIATED WITH IRE' NUMBER 2 CONTROL VALVE DID NOT SWWNWEFIZE WREN THIS VALVE CLOSED. TRE OTHER THREE VALVES OPERATED SATISFACTORY THE.LOAD WAS *REDUCED TO 300 MWE BY 0103 ON 7-9-72.

INVESTIGATION OF TflE SWITCH SHOWED TRAT ONE OF TWO MOUNTING~

SCREWS HAD COME OUT. THIS PERMITTED TRE PLUNGER THAT OPERATED THE SWITCFI TO PUSH-'HIE SWITCH .AROUND THE REMAINING MOUNTING SCREW INSTEAD OF OPERATING THE SWitca.

THE MISSING SWITCH 0AS REPLACED AND THE OPERArION -OF THE SWITCH WAS_ TESTED SATISFACTORY ABOUT 1400 HOURS ON 7-8-72.

IRE LOAD WAS RETURNED TO 480 MWE AT 1440 HOURS.

W. P. WORDEN SUPT COMMONWEALTH EDISON DRESDEN NUCLEAR POWER STATION RRl MORRIS ILL.

I DPR25 3 0845 2 -2320 7-7-72 109P EDT JUL 10 1972

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