ML20084E659

Ro:On 720320,while Reactor in Hot Shutdown,Msivs Tested for Closure & MSIV-1B Valve Found Closed Only Half Way.Cause Unknown.Valve Mfg Contacted for Recommendations to Prevent Recurrence

ML20084E659
Person / Time
Site:	Ginna
Issue date:	03/30/1972
From:	Amish K ROCHESTER GAS & ELECTRIC CORP.
To:	Morris P US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084E662	List: ML20084E659
References
NUDOCS 8304150232
Download: ML20084E659 (2)

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Dr. Peter A. Morris, Director Division of Reactor Licensing

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Subject:

I' allure of Main Steam Line Isolation Valve MSIV-1B to close 4 cigu'y R. E. Ginna Nuclear Power Plant Unit No.1 Docket 50-244

Dear Dr. Morris:

On March 20, 1972, while the reactor plant was in the hot shutdown condition, the main steam isolation valves were tested for closure.

While our Technical bpecifications require that these valves be tested only at each refueling, because of our concern and the prior committal of December 21, 1971 to do so, these valves are tested each time that the turbine generator is removed from service. It is pertinent to note that since July 1971 these valves have been tested ten times and with-out incident.

On this date (March 20) the MSIV-1A valve performed satisfactorily but the MSIV-1B valve was found to have closed only half way, thus fail-ing to meet the criteria of closure time of five seconds.

Additional operations of this valve were made and each time the amount of closing was increased. The packing glands were then loosened slightly and the valve then closed fully. It was then exercised several times with full closure within five seconds without further adjustment.

Immediate investigation did not reveal any known adjustment of the packing prior to the testing. Conservative calculations of the closing moment of the valve disc in this semi-closed position indicate that the "1 forces developed under flow conditions would be more than double the

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binding force that was indicated under this no-flow condition.

[E It is the opinion of the Plant Operations Review Committee and concurred d with by the Nuclear Safety Audit and Review Board that there is reason-

• h/ aole assurance that the valve would have performed its intended function.

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O PCCHC$TCn Gis /+HO Et.ECTRic CORP.

. O SHEET NO. 2 var March 30,1972 l To' Dr. Peter A. Morris K , f l ,

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In the interval between now and the planned refueling shutdown of April 15,1972 these valves will be exercised in the event of a secondary *

. plant shutdown as stated previously. .

The valve manufacturer and other plant supervisors have been contacted to determine their experience and their recommendations to prevent recurrence of this malfunction. We are confident that the failure of the valve was entirely due to the binding of the shaft in the packing gland-area. During the April 1972 shutdown, these valves will be disassembled

, for a planned inspection of the cover bolts and for a complete invest-igation of all moving and shaft contacting surfaces. ,

Very t ly yours, liR.L $,/)5 n L Keith W. Amish t

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