United States Nuclear Regulatory Commission - Protecting People and the Environment

ASCO
50 Hanover Road, Florham Park, NJ 07932 A Constant Flow Of Ideas
Tel: 973-966-2000 • Fax: 973-966-2628 • www.ascovalve.com

December 21, 2001

Documents Control Desk
United States Nuclear Regulatory Commission
Washington, DC 20555

SUBJECT: Potential Manufacturing Problem With Certain Limit Switch Assemblies Used in ASCO General Controls Hydramotor® Actuators.

Gentlemen:

We enclose information relating to certain Limit Switch assemblies used in ASCO General Controls Hydramotor® Actuators. As you will see from the enclosed materials, there is the possibility of a manufacturing deficiency with certain of these assemblies, which may affect the operation of the Hydramotor® actuators. ASCO was alerted to this problem upon examination of a limit switch, recently returned to ASCO, which had failed during post installation tests at the Palo Verde Nuclear Power Station. This condition may result in the failure of the actuator piston to retract when the Hydramotor® is powered. A complete list of any potentially affected actuators, along with their purchasers, is being assembled and will be forwarded to you when complete.

ASCO does not have adequate knowledge of the actual installation and operating conditions of these actuators to determine whether their malfunction could create a "substantial safety hazard" as defined in 10CFR21.3. We are likewise unable to conduct the evaluation necessary to make such a determination. Nevertheless, we furnish this information to keep you apprised of our investigation.

Our investigation of this potential problem is continuing. We are in the process of identifying purchasers of limit switch kits, controller kits, and complete actuators in which these assemblies may be used. We will notify these purchasers as soon as possible.

Should you wish to discuss this further, or obtain any additional information, please let us know. Should any additional information become available we will forward it to you.

Very truly yours,
ASCO Valve, Inc.

Clark Hale
President ASCO Valve - Domestic

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Enclosure

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