ML20084U069

Ro:On 720801,during Monthly Surveillance Testing of Isolation Condenser Steam Line High Flow Isolation,Inboard Isolation Valve MO-3-1301-1 Failed to Close.Caused by Heatup of Motor Due to Repeated Operations

ML20084U069
Person / Time
Site:	Dresden
Issue date:	08/10/1972
From:	Worden W COMMONWEALTH EDISON CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084U071	List: ML20084U069 ML20084U075
References
NUDOCS 8306270042
Download: ML20084U069 (2)

Text

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Cornmonwealth Edison Company l 72 WEST ADAMS STREET

• C HIC A G 3 ILLINOIS

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POST OfPICE 80% 767

• C H I C A G O, titlHO 15 60690 Dresden Nuclear Power Station e R. R. #1  ! ~~ Q.

Morris, Illinois 60450 j ,

August 10, 1972  ;, -

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.m Mr. A. Giambusso 197gA,

,1g :N j h/,;M Deputy Director for Itcactor Projects \ ~

Directorate of Licensing ,

U. S. Atomic Energy Con: mission 5: 3, fj

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Washington, D. C. 20545

SUBJECT:

LICENSE DPR-25, DRESDEN NUCLEAR POWER STATION, UNIT #3, SECTION 6.6.B.2 0F TILE TECHNICAL SPECIFICATIONS.

Dear Mr. Giambusso:

This is to report a condition relating to the operation of the station, in uhich, during monthly surveillance testing of the Isolation Condenser " steam line high flow" isolation, the inboard isolation valve MO-3-1301-1 failed to close, thus rendering the Isolation Condenser "stcam line high flow" isolation protection inoperable, contrary to the requirements of Section 3.2.A of the Technical Specifications.

PROBLEM AND INVESTIGATION Isolation condenser " steam line high flow" surveillance was being conducted'on August 1, 1972. The surveillance procedure results in numerous valve operations as the " steam line high flow" sensors are tripped. As valve M0-3-1301-1 was operated for the third time, the motor thermal overload protection tripped during valve closure.

The valve operator is designed for single cycle cperation; that is, a periodic single opening or closure, as required. Hence, the valve operator motor is designed with a fif teen minute r.crvice factor.

Upon investigation, it was determined that during the surveil-lance testing, the repeated valve operation in a short period of time resulted in a continuous "heatup" of the motor and consequently, a trip '

of the thermal overload protection. Following cooldown.of the overloads, the valve was cycled satisfactorily.

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B306270042 720010 PDR ACOCK 05000249 S PDR

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Hr. A. Giambuss( y! (}

(y Auguet 10, 1972

.. s Because operation of the valve, when required, would be limited to single cycle operation, the valve is considered operable and would function as designed when required to do so.

CORRECTIVE ACTION The surveillance procedure will be modified to eliminate repeated valve operations in a short time period,. and thus eliminate " nuisance" trips such as that herein reported.

. . Dmcb W. P. Worden Superintendent WpW:do

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