ML17238A720: Difference between revisions
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| number = ML17238A720 | | number = ML17238A720 | ||
| issue date = 07/24/1972 | | issue date = 07/24/1972 | ||
| title = | | title = Letter Regarding Drift Beyond the Limit of Accuracy in the Calibration So Some of the Low Electro Hydraulic (EHC) Oil Pressure Scram Switches | ||
| author name = Worden W P | | author name = Worden W P | ||
| author affiliation = Commonwealth Edison Co | | author affiliation = Commonwealth Edison Co | ||
Revision as of 17:51, 1 February 2019
| ML17238A720 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 07/24/1972 |
| From: | Worden W P Commonwealth Edison Co |
| To: | Bloch E G US Atomic Energy Commission (AEC) |
| References | |
| Download: ML17238A720 (1) | |
Text
,;._;:-NNNN.¥ R B 9. 50-237 MSG NR. 5 4,3 G . TLXAO!l PC154 . *. 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 ..
U S ATOMIC COMM liJASHDC 20545
- BT SUBJECT DPR19 AND DPR 25 DRESDEN POWER UNITS 2 AND ,3.. . .. T iU S 1 iJI 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 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, INVOLVED TWO SWITCHES ON 2 AND ALL FOUR S\:JITCHES ON UNIT *3. THE SVITCHES, 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 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 S 1 1JITCl!ES SlW\)ED A TENDANCY TO DRIFT !JUT* NOT BEYOND THE LIMITS. IN ADDITION Tf.iE CALIBR/HION PlWCEDURE lr.'AS _REVIEWED AND 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 1 o'!ILL BE CALIBRATED NEXT MOMTlt RtHHER THAN JUST *FUNCTIONALLY CHECKED AS REQUIRED BY THE SPECIFICATION W P WORDEN SUPT *DRESDEN NUCLEAR STATION NNNNCOR25P EDT) .... : '
.. . 1215A EDT USAEC MQS GHIN -.... . . 40G8.( 1W'I
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