Information Notice 1979-03, Limitorque Valve Geared Limit Switch Lubricant

Limitorque Valve Geared Limit Switch Lubricant

ML031180114
Person / Time
Site:	05000000
Issue date:	02/09/1979
From:	NRC/IE
To:
References
IN-79-003, NUDOCS 7902150358
Download: ML031180114 (2)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 February 9, 1979 IE Information Notice No. 79-03

Description of Circumstances

At Commonwealth Edison reactors excessive failure rates of the Limitorque

valve geared limit switches were being experienced. Investigation

revealed that the failure mode was a drying out and hardening of the

Beacon 325 lubricant. Once hardening takes place, the brass gears

within the limit switch become immobile and destroy themselves when an

attempt is made to operate tfie valve.

The Limitorque Corporation has recommended Mobilgrease 28 as a replacement

grease for switch applications where the temperature exceeds 140 degrees

Fahrenheit. Tests conducted by Mobil and Limitorque Corporation indicate

that Mobilgrease 28, in addition to having a superior temperature

rating, will satisfy the same environmental conditions and meet the same

qualification parameters as Beacon 325.

All licensee and construction permit holders should consider conducting

a review to determine if Beacon 325 lubricant is being used in geared

limit switches in environments conducive to drying out and subsequent

hardening of the lubricant.

If conditions are found to be conducive to failures, consideration

should be given to replacing the grease with a more suitable grease.

This information is provided as an early notification of a possibly

significant matter. It is expected that recipients will review the

information for possible applicability to their facilities. No specific

action or response is requested at this time. If further NRC evalua- tions so indicate, an IE Circular or Bulletin will be issued to recom- mend or request specific licensee actions. If you have questions

regarding this matter, please contact the Director of the appropriate

NRC Regional Office. I0

IE Information Notice No. 79-03 February 9, 1979 LISTING OF IE INFORMATION NOTICES

ISSUED IN 1979 Information Subject Date Issued To

Notice No. Issued

79-01 Bergen-Paterson Hydraulic 2/2/79 All power reactor

Shock and Sway Arrestor facilities with an

OL or a CP

79-02 Attempted Extortion - 2/2/79 All Fuel Facilities

Low Enriched Uranium