ML19289C899

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Final Rept of Deficiency:Shaft Key & Spline Adapter of Basic in-flow Valves May Vibrate Loose & Fall Away,Leaving Valve Inoperable.Corrective Action:Stainless Steel Spacer to Be Inserted Against End of Valve Stem
ML19289C899
Person / Time
Site: Bellefonte  Tennessee Valley Authority icon.png
Issue date: 11/16/1978
From:
TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML110820267 List:
References
NUDOCS 7901260214
Download: ML19289C899 (2)


Text

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ENCLOSURE BELLEFONTE NUCLEAR PLANT NCR QEB 78-7 BIF BUTTERFLY VALVES DEFICIENT FINAL REPORT Description of Deficiency In a letter from Basic In Flow (BIF) to TVA dated October 17, 1978, BIF notified TVA of the possibility of an operating defect with BIF Butterfly valves when used in conjunction with Limitorque motor and manual operators and installed under certain installation conditions.

Both the shaft key that locks the operator spline adapter to the valve stem and the spline adapter may vibrate loose and fall along the valve stem away from the valve body disengaging the driving torque to the valve and rendering the valve inoperable. This problem will cost likely occur when the valve is installed in a horizontal pipe line with the valve shaft in the vertical plane and with the operator under the valve.

BIF has~ identified all possibly affected valves for use in Bellefonte.

The affected components are all manually operated, ASME Section III, Class C valves for use in the Component Cooling Water, Essential Rav Cooling Water, Waste Disposal and Spent Fuel Cooling systems.

Safety Implications Because of the number of valves affected (152 valves have beca identified by BIF), it is not possible to identify all Jmplications to safety. -

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d-IL:eever, the affected valves are safety grade components for use in safety related systems. Therefore, the potential exists for an unoperable valve to be unable to perform a safety function when required.

This could adverselv affect the safe operation of the plant.

Corrective Act' ions -

BIF has recommended the insertion of a stainless steel spacer, provided by BIF, against the end of the valve stem. This spacer will maintain proper orientation between the spline adapter, shaf t key, and valve stem and will prevent the spline adapter from vibrating loose from the valve stem. This corrective action is to be performed either at the site or at BIP before initial fuel load. This deficiency only affects BIF Butterfly valves with Limitorque operators on the Bellefonte contract.

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