ML17272A440

Deficiency Rept:Possible Failure of Basic Inflow Butterfly Valves W/Limitorque Motor & Manual Operators.Valve May Become Inoperable Due to Vibration.All 19 Valves Are Being Repaired Per Manufacturer'S Recommendation

ML17272A440
Person / Time
Site:	Columbia
Issue date:	04/30/1979
From:	WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
Shared Package
ML17272A439	List: ML17272A438 ML17272A440
References
10CFR-050.55E, 10CFR-50.55E, GO2-79-80, NUDOCS 7905090073
Download: ML17272A440 (2)

Text

Attachment REPORTABLE CIENCY AND CORRECTIVE ACTION G02-79-80 April 30, 1979 Possible failure of BIF (Basic In Flow) butterfly valves with Limitorque motor. and manual operators.

Nature of Deficienc:

An operating defect, may exist on Limitorque motor and manual operators used in conjunction with BIF butterfly valves. The shaft key that locks the opera-tor spline adaptor to the valve stem and the spline adaptor may vibrate loose,

,disengaging the driving torque to the valve, rendering the valve inoperable.

The manufacturer has identi fied that this problem will most 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. However, the manufac-turer has also concluded that the same problem may occur regardless of operator position.

Safet Im lications:

There were 19 valves supplied of which 17 are utilized in safety related applications. There are 14 valves employed in the Standby Gas Treatment System (SGTS), and 3 in Standby Service Water System (SW).

Failure of the valves in the SGTS system, in the manner described by the manu-facturer; would cause loss of the redundant SGTS system. In turn, the negative pressure within the secondary containment system would be lost as well as the redundant filters. This would result in an unacceptable dose to the public in the event of a LOCA.

Failure of the valves in the Standby Service Water System (SW), in the manner descri bed by the manufacturer, would result in the loss of the redundant Standby Service Water System. Loss of the SW system, utilized for cooling for normal reactor shutdown, and post:-LOCA', would result in the loss of safety related equipment required to function during shutdown and post-LOCA.

Corrective Action:

All 19 valves are being repaired in accordance with the recommended fix of the manufacturer as follows:

a) Depressurize pipe line and close valve (where appropriate).

b) Remove operator from valve assembly making note of its mounting position.

c) Position spline adaptor flush with the end of the valve stem.

Position shaft key slightly below (1/16") the face of the spline adaptor.

d) Lock spline adaptor in place with set screw supplied by BIF.

e) Utilizing a center punch, stake the edges of the spline adaptor and the valve shaft around the end of the keyway to prevent the key from slipping past the flush position.

Re-install operator in original positions

'F 905 0 gp pqg

~ i':" () i,'j ~~

'>'