ML17252A971

Letter Reporting a 06/08/1973 Occurrence Relating to the Failure of the HPCI Steam Supply Valve 3-2301-3 to Open Completely - Dresden Unit 3

ML17252A971
Person / Time
Site:	Dresden
Issue date:	06/14/1973
From:	Worden W Commonwealth Edison Co
To:	Giambusso A US Atomic Energy Commission (AEC)
References
WPW Ltr. #458-73
Download: ML17252A971 (2)

Text

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• Commonw*

One First Nati

. h Edison Plaza, Chicago, Illinois

. ~dress Reply to: Post Office Box 767

- Chicago, Illinois 60690 50-249 WPW Ltr.11458-73 - Dresden Nuclear Power Station R. R. 111 Morris, Illinois 60450 June 14, 1973 Mr. A. Giambusso Deputy Director for Reactor Projects

. Directorate of Licensing U. s. Atomic Energy Commission Washington, D. C. 20545

SUBJECT:

LICENSE DPR-25, DRESDEN NUCLEAR POWER STATION, UNIT 113 SECTION 6.6.B.2 OF 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.l of the Technical Specifications. At the ti.ine the incident occurred, the reactor was in the "Run" mod,e 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. G.rier 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 inunediately correct the situation, and get the ~PCI 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 that time, the valve internals will be inspected to determine the cause for the stem bending.

I -

J.!

Mr. A. Giambusso

~-.

• June. 14, 1973 At present, the steam supply valve 3-2301-3 to the-HPCl.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. '

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 after 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 vabre disassembly and repair is completed.

Sincerely,

'd~i~~ . .

(/...-" W. P. Worden -

~ ""'Superintendent WPW:do