ML20085J894

Ao:On 740522,main Steam Line Drain Valve 3-220-2 Failed to Operate Correctly.Caused by Burned Armature Windings in Valve Motor.Motor Replaced

ML20085J894
Person / Time
Site:	Dresden
Issue date:	06/21/1974
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085J895	List: ML20085J894 ML20085J898
References
453-74, NUDOCS 8310190179
Download: ML20085J894 (2)

Text

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$ g 'tal Plaza. Chicago, Illinois j One First (

Address RephWPost Office Box 767 Chicago. filinois 60090 BBS Ltr.f453-74 Dresden Nuclear Power Station 4

! Mor is Illinois 60450 [

June 21,1974 g'/s

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. l N I. / y 4 k Mr. J. F. O' Leary, Director

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U. S. Atomic Energy Commission g ofp" ', [/> ,:

y$) -C N. ,,b Washington, D. C. 20545 K i '.' .

SUBJECT:

_ LICENSE DPR-25, DRESDEN NUCLEAR POWER STATION, UNIT #3. REPORT j

OF ABNORMAL OCCURRENCE PER SECTION 6.6.B.10F THE TECHNICAL j SPECIFICATIO"S.

FAILURE OF MSIN STEAM LINE DRAIN VALVE 3-220-2.

Reference:

Notification of Region III of AEC Regulatory Operations Telephone: Mr. F. Maura, 1315 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />5.003575e-4 months <br /> on June 17, 1974 Telegram: Mr. J. Keppler,1610 hours0.0186 days <br />0.447 hours <br />0.00266 weeks <br />6.12605e-4 months <br /> on June 17, 1974

Dear Mr. O' Leary:

This letter is to report a condition relating to the operation of the '? nit at about 0400 hourn on May 22 I c73 At that ti= , the. a,,i,1y i

Lat.kn L n=alu steam line crain valve .s-220-2 tripped repeatedly. This selfunction is contrary to section 3.7.D.1 of the Technical Specifications which requires that all isolation valves listed in Table 3.7.1 be opera-l tional during power operations.

PROBLEM

' On May 22,1974 main steam line drain valve 3-220-2 failed to operate correctly.- While closing the- valve in order to perform local leak rate testing, the supply breaker tripped repeatedly. Several breaker resets were required before the valve could be fully closed. At the time of the occurrence, the reactor mode switch was in the '" Refuel" position, with thermal power at zero megawatts.

INVESTIGATION i

' An investigation into the.cause of the breaker trip revealed that the problem was associated with the valve motor. The motor was-then.

removed.and-inspected. . The inspection revealed the armature wiridings wera burnt and shorted. ,

8310190179 740621 vt I~ '

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q Mr. J. F.,0' Leary Junn 21, 1974 CORRECTIVE ACTION The imediate corrective action taken was to reset the breaker and attempt operation until the valve reached the fully closed position.

Additional corrective action was taken af ter it was determined that the valve motor was faulty. To correct the condition and to return the valve to service, a replacement motor was installed. The failed teotor was then sent out to be repaired. Since this is the first failure of this type in regarda to this valve, the corrective action taken et this time is considered satisfactory.

EVALUATION The failure of the 3-220-2 valve to operate properly did not place the safety of the plant or public in jeopardy. At the time of the occurrence, the unit was in the refuel mode and thermal power was aero.

Also at the time the 3-220-2 valve failed open, the upstream isolation valve 3-220-1 was operable. In addition, all safety systems were operabic at the time of the failure.

Sincerely,

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fa // o /_ J l /Y 'l % !(fi bBl.B.,Stephenso,yp~h' n.

Superintendent BBS:TEL:da i

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