ML17238A720
| ML17238A720 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 07/24/1972 |
| From: | Worden W Commonwealth Edison Co |
| To: | Bloch E US Atomic Energy Commission (AEC) |
| References | |
| Download: ML17238A720 (1) | |
Text
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- . SSF234 EAWA Q NND166 CCH 206NN305166)PD W U TELEX JOL ORIBP EDt0?/24/72 ZCZC 002 NA PDF TDJL MORR IS ILL 24 *42op CDT ED'r/ARD G BLOCH-ACTING DIR DIRECTORATE-OF LICENCY
.. **~egula.t,orY U S ATOMIC COMM liJASHDC 20545
- BT SUBJECT DPR19 AND DPR 25 DRESDEN
~UCLEAR POWER SlATIO~
UNITS 2 AND,3..
T iU S 1iJI LL C 0 NF I RM C 0 NV ER SAT I O N AT I 5 :,<, 0 !': 0 UR S T E I S DATE
~!ITH MR
):{ D!\\MPE OF YOUR OFF I CE REGARD I NG DR I FT BEYOND T!*(E LIMIT OF INSTRUMENT ACCVHACY,° IN TnE CALIBRATION SO SOME OF THE LOl.*1 ELECTRO HYDR/'!ULIC CONTROL CE/'.!C) OIL PRESSURE SCR-AM
$'.)ITCHES, BUT RESULTED IN SET POI NT BEYOND THOSE ALLO\\-!ED IN SECT I 0 N :~
- DURING ROUTINE CALIBRATION JULY 15 1972 THE SWITCHES WERE FOUND SET AT VALUES AANGING FROM q66PSIG TO P85PSIG COMPARED TO LIMIT TO 900 PSIG DECREASING, ~ND INVOLVED TWO SWITCHES ON 2 AND ALL FOUR S\\:JITCHES ON UNIT *3. THE SVITCHES, B~.RKSD.~LE MODEL TC9622-3 '*VERE H1Mt:DIATELY RECf\\LIBRtHED ANO fiN INVESTIGATION Wf\\S REGLIN T0.DETERM1NE THE CAUSE OF THE DRIFT.
INSPECTION OF THE Sv!ITCi-! INTERNAL HEVL~LED NO APPARANT A RMORf*JAL n* I ES. A REV I E'.1 OF A CAL I RRA fI_ON HI ST ORY OF TJ1ESE S11JITCl!ES SlW\\)ED A TENDANCY TO DRIFT !JUT* NOT BEYOND THE LIMITS. IN ADDITION Tf.iE CALIBR/HION PlWCEDURE lr.'AS
_REVIEWED AND FOU~D TO BE SATISFACTORY.
TJlf. CAUSE OF T:ns LARGE SET POINT c::fl\\NGE IS UNEXPLAfNED AND BECAUSE OF TRE PAST TENDENCY OF TUESE S\\ITCHES to DRIFT.SOME\\-!.HAT, urEY 1o'!ILL BE CALIBRATED NEXT MOMTlt RtHHER THAN JUST *FUNCTIONALLY CHECKED AS REQUIRED BY THE TEC~NICAL SPECIFICATION W P WORDEN SUPT *DRESDEN NUCLEAR STATION NNNNCOR25P EDT)
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1215A EDT USAEC MQS GHIN
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