ML20084S144

Ro:On 730407 While Performing LPCI Logic Testing,Motor Operated Valve 3-1501-22B Stopped in Mid Position.Caused by Bent Valve Stem.Valve Opened & Second Isolation Valve Line Closed

ML20084S144
Person / Time
Site:	Dresden
Issue date:	05/04/1973
From:	Worden W COMMONWEALTH EDISON CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084S139	List: ML20084S136 ML20084S144
References
354-73, NUDOCS 8306160181
Download: ML20084S144 (2)

Text

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O - - . . O 50-249 Commonwealth Edison Company ONE FIRST NATIONAL PLAZA

• C H I C A G O.. ILLINOIS Address Reply f.:

POST OFFICE SOX 767

• C H I C A G O, ILLINOl$ 60490 WPU Ltr.d354-73 Dresden Nuclear Power Station R. R. #1 Morris, Illinois 60450 cu Hay 4, 1973 S'

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'I MAY7 1973>!D Mr. A. Giambusso .,

q Deputy Director for Reactor Projects g c:a.n, j Directorate of Licensing ,8ygjg ,

U. S. Atomic Energy Commission Washington, D. C. 20545 b g /gf

SUBJECT:

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

( F f SECTION 6.6.C.1 0F THE TECllNICAL SPECIFICATIONS,

Dear Mr. Giambusso:

This is to report a condition relating to the operation of Unit #3 in which, on April 7,1973, at 1115 hours0.0129 days <br />0.31 hours <br />0.00184 weeks <br />4.242575e-4 months <br />, while performing low pressure

[r j" coolant injection (LPCI) logic testing it was noted that motor operated 3

, valve 3-1501-22B was stopped in the mid position. At the time of the failure, p0 the unit was shutdown for refueling.

[AI PROBLEM AND INVESTIGATION While performing low pressure coolant injection logic testing, l motor operated valve 3-1501-22B was found stopped in mid travel. Prior to LPCI logic testing, M.0. 3-1501-22B was operable. M.O. 3-1501-22B is one of two LPCI injection valves in the line and is normally closed.

l Af ter repeated attempts to close the valve from the control room, the thermal overload tripped. Attempts to move the valve with the manual

handwheel also proved unsuccessful.

The subsequent inspection revealed the valve stem to be b.ut. f The l

bent stem caused binding of the valve which resulted in high motor current l and subsequent motor overload trip due to the repeated attempts to close the l valve. Prior to the failure, the valve had been cycled several times during logic testing. '

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Mr. A. Gicmbusso May 4, 1973 H.O. 3-1501-22B was opened and M.0. 3-1501-21B, a normally opened valve in the injection line, was closed. By opening M.O.. 3-1501-22B and using IL O. 3-1501-21B as the isolation valve, the LPCI system remains in service. On a LPCI initiation signal, both M.0. 3-1501-22B and !!.0. 3-1501-21B may receive an open signal. Therefore, the failure of this valve is not considered to present any hazard to the public health and safety since the LPCI system was not degraded.

CORRECTIVE ACTION Valve M.0, 3-1501-22B was opened and the second isolation valve in the line was closed.

At this time, the cause of the valve stem deformation is not known.

The valve inspection and repair is presently in progress. A followup report identifying the failure mode will be issued by June 13, 1973.

Sincerely, D. it u W. P. Worden Superintendent WPU:do 4

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