ML20084S086

Ro:On 730608 While Conducting Valve Operability Checks on HPCI Sys,Valve 3-2301-3 Failed to Open Completely.Caused by Bent Stem.Valve Manually Opened.New Stem Ordered & Will Be Installed During Next Outage

ML20084S086
Person / Time
Site:	Dresden
Issue date:	06/14/1973
From:	Worden W COMMONWEALTH EDISON CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084S074	List: ML20084S070 ML20084S086 ML20084S091 ML20084S094
References
458-73, NUDOCS 8306160142
Download: ML20084S086 (2)

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crith Edis::n Plaza. Chicago, Illinois Address Reply to: Post Office Box 767

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Chicago. !!!inois 60690 50.249 WFW Ltr.#458-73 Dresden Nuclear Power Station R. R. #1 Morris, Illinois 60450 June 14, 1973

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Mr. A. Giambusso h,g, \ \

Deputy Director for Reactor Projects Directorate of Licensing y-p g1, y

U. S. Atomic Energy Co= mission s Washington, D. C. 20545 9 @ (' , , ', /, [4

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SUBJECT:

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

SECTION 6.6.B.2 0F THE TECHNICAL SPECIFICATIONS.

Dear Mr. Giambusso:

This is to report a condition relating to the operation of the unit in which on June 8, 1973, at 10:00 hours the high pressure coolant injection steam supply valve failed to open completely. HPCI steam supply valve 3-2301-3 was found to open to about mid position which would derate the HPCI system, and be in noncompliance with section 3.5.C.1 of the Technical Specifications. At the time the incident occurred, the reactor was in the "Run" mode and at near rated conditions. This incident was reported to Region III by telephone to Mr. F. Maura on June 8, 1973, at 1650 hours0.0191 days <br />0.458 hours <br />0.00273 weeks <br />6.27825e-4 months <br /> and by telegraph to Mr. B. Grier at 1730 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.58265e-4 months <br />.

PROBLEM AND INVESTIGATION

Reference:

P&ID M-374 On June 8, 1973 while conducting valve operability checks on the HPCI system, valve 3-2301-3 failed to open completely. With the valve in the mid position, the HPCI system was declared inoperable.

An investigation into the problem revealed that the reason the valve would open only part way was because the stem was bent. To imediately correct the situation, and get the HPCI system operable, the valve was manually opened.

Once the HPCI system was operable, attempts were made to straighten the stem. When repeated attempts failed, it was decided to order a new stem and replace it during the next unit outage. In order to replace the valve stem, it will be necessary to completely disassemble the valve. At tha t time ,

the valve internals will be inspected to determine the cause for the stem s, bending.

O 9 PDR

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( Juna 14, 1973 Mr. A. Giambusso At present, the steam supply valve 3-2301-3 to the HPCI turbine has a bent stem and is in the open position. The 3-2301-4 and 5 HPCI valves are also open and are operable. Due to the above valve line up, the HPCI system will function as designed and is therefore operable.

I Had a loss of coolant accident occurred while the 3-2301-3 valve was partially open, there would have been some injection by the HPCI system.

However, had the coolant injected by the system not been enough to cope with the situation, then the Auto Blowdown System would have operated. Operation of Auto Blowdown would have decreased reactor pressure to a low enough value.

to allow LPCI and core spray systems to function.

CORRECTIVE ACTION The immediate corrective action was to open the 3-2301-3 valve manually allowing the HPCI system to be declared operable at 1545 hours0.0179 days <br />0.429 hours <br />0.00255 weeks <br />5.878725e-4 months <br />.

Final corrective action will be determined af ter the valve has been completely disassembled and inspected. Future corrective action will be based on the outcome of that inspection. The result of the inspection will be reported after the valve disassembly and repair is completed.

Sincerely,

.$No W. P. Worden

' Superintendent WPW:do

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