Information Notice No. 79-03, Limitorque Valve Geared Limit Switch Lubricant
IN79003
February 6, 1979
MEMORANDUM FOR: B. H. Grier, Director, Region I
J. P. O'Reilly, Director, Region II
J. G. Keppler, Director, Region III
K. V. Seyfrit, Director, Region IV
R. H. Engelken, Director, Region V
FROM: N. C. Moseley, Director, ROI:IE
SUBJECT: Information Notice No. 79-03, LIMITORQUE VALVE GEARED
LIMIT SWITCH LUBRICANT
The subject Information Notice is transmitted for issuance on February 9,
1979. The Information Notice should be issued to all power reactor
facilities with an operating license or a construction permit. Also enclosed
is a draft copy of the transmittal letter for this purpose.
The subject document was changed to an Information Notice from the proposed
draft Circular transmitted to you for comment. The change was made in
response to contents on the proposed Circular. No inspection followup is
necessary since this issuance is for information only.
Norman C. Moseley, Director
Division of Reactor Operations
Inspection
Office of Inspection and Enforcement
Enclosures:
1. Information Notice No. 79-03
2. Draft Transmittal Letter
CONTACT:
C. J. DeBevec, IE
49-28180
.
(Draft letter to all power reactor facilities with an operating license or a
construction permit)
Information Notice No. 79-03
Addressee:
This Information Notice 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 evaluations so
indicate, an IE Circular or Bulletin will be issued to recommend or request
specific licensee actions. If you have questions regarding the matter,
please contact the Director of the appropriate NRC Regional Office.
Signature
(Regional Director)
Enclosures:
1. Information Notice No. 79-03
2. List of IE Information Notices
Issued in 1979
.
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
February 9, 1979
Information Notice No. 79-03
LIMITORQUE VALVE GEARED LIMIT SWITCH LUBRICANT
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 the 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 evaluations so
indicate, an IE Circular or Bulletin will be issued to recommend or request
specific licensee actions. If you have questions regarding this matter,
please contact the Director of the appropriate NRC Regional Office.
Enclosure:
List of IE Information Notices
Issued in 1979
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