ML20084N861

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Telecopy Ro:On 750826,pressure Switches PS3-263-53A,53B & 53C Drifted Above Tech Spec Limit.Probably Caused by Inactivity Due to Refueling Outage
ML20084N861
Person / Time
Site: Dresden Constellation icon.png
Issue date: 08/28/1975
From: Stephenson B
COMMONWEALTH EDISON CO.
To: Rusche B
Office of Nuclear Reactor Regulation
Shared Package
ML20084N845 List:
References
NUDOCS 8306090097
Download: ML20084N861 (1)


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NRC DHDA WU INF0 MASTER l-011234C240 08/28/75 TLX"WU TFC WSH 030 TWX 7108240415 NRC BHDA SPLO30 WAD 037 (0949)(2-00 8125D240-001 )PD 08/2 8/7 5 0901 ICS IPMWAWF WSH SUSPECTED DUPLICATE: 2-007725E240 WAD 026 ICS IPMBNGZ CSP 8159424449 TDBN MORRIS IL 206 08-28 0830A CDT PMS DERNARD C RUSCHE, DIRECTOR DIRECTORATE OF LICENSING WUX US NUCLEAR REGULATORY COMMISSION WASHINGTON DC 20555 C

SUBJECT:

DPR-25, DRESDEN NUCLEAR POWER STATION, UNIT 3 THIS WILL

' CONFIRM A CONVERSATION WITH MR R KNOP OF YOUR OFFICE AT 1710 HOURS 8-26-75 CONCERNING INSTRUMENT DRIFT OF 1.

ISOLATION CONDENSOR SUSTAINED HIGH REACTOR PRESSURE SWITCHES PS3-263-53A,8&C TO A90VE THE TECH. SPEC. LIMIT OF LESS THAN OR E006L TO 1070 PS IG. PS3-263-53A WAS FOUND AT 1090PSIJ 538 AT 10 87PS I J 53C AT ll22 PSI. SWITCHES ARE :lELETRON TYPE AND DRIFT IS BELIEVED CAUSED

.8Y INACTIVITY CAUSED BY CURRENT REFUEL OUTAGE.

2. ADDITIONALLY, REACTOR PRESSURE ECCS INITIATION SWITCHES PS3-263-52A-1 AND SPA-2 WERE ALSO FOUND ABOVE TECH. SPEC LIMITS OF 300PSIG LESS THAN OR EQUAL TO P LESS THAN OR EQUAL TO 3 50PS IG. THE MELETRON SWITCHES WERE FOUND AT 365PS I (A-1) AND 366 PSI (A-2). THESE DRIFTS ALSO ARE BELIEVED TO BE CAUSED BY INACTIVITY.
3. MAIN STEAM LINE DRAIN ISOLATION VALVE M03-220-1, DURING MAINTENANCE, WAS FOUND WITH A FAILED OVERLOAD RELAY WHICH CAUSED MALOPERATION OF THE VALVE DURING TESTING. PRIMARY CONT AINMENT INTEGRITY MAY HAVE BEEN AFFECTED IN THE SINGLE FAILURE MODE WOULD HAVE AN ISOLATION DURING OPERATION OC, CURRED. ADDITIONAL INFORMATION WILL FOLLOW IN A TEN DAY REPORT.

B B STEPHENSON SUPERINTENDENT DRESDEN NUCLEAR POWER STATION COMMONWEALTH EDISON CO RR.! MORRIS ILLINOIS 60450 s

1046 EST I

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