ML20084T780

Telecopy Ro:On 720909,setpoint on Two Electro Hydraulic Control Low Oil Pressure Scram Switches Found Below Tech Spec Limits & on 720910,control Valve 4 Failed to Indicate Half Scram When Fast Closed.All Switches Adjusted

ML20084T780
Person / Time
Site:	Dresden
Issue date:	09/12/1972
From:	Worden W COMMONWEALTH EDISON CO.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20084T764	List: ML20084T760 ML20084T780
References
NUDOCS 8306240103
Download: ML20084T780 (1)

Text

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a 1211P ES SEP 12 7 DEA 471 KA183 K VEB118 ." D" 'E MORRIS ILL 11352P CDT y 'i '

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BOYCE GRIER,DIR OF COMPLIANCE REGION .3 US ATOMIC ENERGY.0055ff[S_SION 799 ROOSEVELT RD CLEN ELLYN ILL 60ib7 -

"c# d SUPJECT8 DPR-25 DRESDEN NUCLEAR POWER ST g ,Uf [r h fj THIS WILL CONFIRM A C0!NERSATION WITH MR H :BANdE--C. GM pELIGL AT 114 _

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5 HOURS THIS DATE CONCERNING TWO SEPA _ gyer -

ATE INCIDENTS ON UNIT 3.

ON 9-9-72 VHILE MAKING A CALLAbATION ON EHC LOU OIL PRESSURE SCRAM SU ITCHES, THE SET POINT ON TWO SWITCHES WAS FOUND BELOW THE 900 PSIG TEC g

HNICJL SPECIFICATION LIMITS. PS-LS-1 HAD DRIFTED DOWN TO A SET POINT 0 F 895 PSIG. PS-LS-4 HAD DD f"TED DOWN TO A SET POINT OF 818PSIG.

PS-LS-1 MAS A HISTORY OF h : TING SET POINT WHILE PS-LS-4 IS A NEW MO DEL SWITCH WITH A SUPOSIDL) J. EATER ACCURACY. THE SET POINT ON ALL SUI TCHES HAS BEEN INCREASED TO 935PSIG. IN ADDITION A CALLABRATION CHECK t WILL BE MADE ON PS-LS-4 ON A WEEKLY BASIS UNTIL THIS PROBLEM OF EXCESS 8,.isos cuan i

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IVE SET POINT DRIFT CAN BE CORR'ECTED.

THE SECOND INCIDENT OCCURED ON 9-10-72 AT 0300 HOURS. LTILE CONDUCTING TURBINE WEEKLY CHECKS NUMBER 4 CONTROL VALVE FAILED TO INNICIATE A HA 15 SCRAM WHEN IT WAS FAST CLOSED. FUSE #590-725H WAS PULLED TO ACCUATE A HALF SCRAM UNTIL REPAIRS COULD BE COMPLETEDM MAINTENANCE CHECKED THE FAST ACTING SOLINOID ON #4 CONTROL VALVE AND F OUND IT LIMIT SWITCH WAS LOOSE. THE LIMIT SWITCH WAS ADJUSTED TIGHTENE D AND #4 CONTROL VALVE WAS TESTED SATISFACTORILY. ALL LIMIT SWITCHES WERE INSPECTED AND TIGHTENED. IN THE FUTURE DOUBLE NUTS WILL BE USED 0 N THE MOUNTING SCREWS WHICH SHOULD PREVENT THIS TYPE OF INCIDENT FROM

( REACCURING W P WORDEN SUPT DRESDEN NUCLEAR POWER STATION.

l DPR-25 3 1145 3 9-9-72 EHC 900 PSIG PS-LS-1 895PSIG PS-LS-4 81SPSIG P

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S-LS- 1 PS-LS-4 935PSIC PS-LS-4 9-10-72 0300 #590-725H #4 #4 (1005A). ,

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