ML20002A136
| ML20002A136 | |
| Person / Time | |
|---|---|
| Site: | 05000000 |
| Issue date: | 03/20/1981 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| IEIN-81-08, IEIN-81-8, NUDOCS 8011040272 | |
| Download: ML20002A136 (1) | |
Text
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SSINS No.: 6835 Accession No.:
8011040272 IN 81-08 UNITED STATES' NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT March 20, 1981 IE INFORMATION NOTICE NO. 81-08:
REPETITIVE FAILURES OF LIMITORQUE OPERATOR SMB-4 MOTOR-TO-SHAFT KEY Description of Circumstances:
During normal. surveillance testing of motor-operated valves at the Cooper Nuclear Station, it was discovered that the RHR "B" loop suppression pool cooling inboard throttle valve would not operate.
The valve did not operate because the key between the motor pinion gear and the motor shaf t had failed.
The operator for'the valve has been identified as being Limitorque model SMB-4.
Analysis,0f the failed key revealed that a standard type 1010 steel key had been installed instead of the required special type 4140 steel key.
1 Further review of the problem established that similar failures with motor-to-shaft keys had also taken place at the Pilgrim, Hatch, and Fitzpatrick nuclear power facilities.
Limitorque Company has performed an evaluation of the problem, and they have concluded that the problem is confined to operators having a torque rating in excess of 100 ft/lb.
The standard type 1010 steel possesses adequate strength to accommodate motor operators having a torque rating that is less than 100 ft/lb.
Recommended ' Action for Holders of Operating Licenses and Construction Permits:
It is recommended that licensees having Limitorque Operator SMB-4 installed in their facilities verify that the special type 4140 steel keys have beers used.
This can be easily accomplished by performing a hardness check of the motor-to-shaft keys during the next scheduled surveillance testing.
No written response to this information notice is required.
If you need additional information with regard to this subject, please contact the Director of the appropriate NRC Regional Office.
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Attachment:
Recently issued IE Information Notices t
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Attachment IN 81-08 March 20, 1981 RECENTLY ISSUED IE INFORMATION NOTICES Information Date of Notice No.
Subject Issue Issued to 81-07 Potential Problem with 3/16/81 All power reactor Water-Soluble Purge Dam facilities with an Materials Used During OL or CP Inert Gas Welding 81-06 Failure of ITE Model 3/11/81 All power reactor K-600 Circuit Breaker facilities with an OL or CP 81-05 Degraded DC System at 3/13/81 All power reactor Palisades facilities with an OL or CP 81-04 Cracking in Main Steam
./27/81 All power reactor Lines facilities with an OL 81-03 Checklist for Licensees 2/12/81 All power reactor Making Notifications of facilities with an Significant Events in OL 6
Accordance with 10 CFR 50.72 81-02 Transportation of 1/23/81 All Radiography Radiography Devices licensees 81-01 Possible Failures of 1/16/81 All power reactor General Electric Type facilities with an HFA Relays OL or CP.
80 45 Potential Failure of 12/17/80 All PWR facilities B'VR Backup Manual Scram with an OL or LP Capability 80-44 Actuation of ECCS in the 12/16/80 All PWR facilities Recirculation Mode While with an OL or CP in Hot Shutdown OL = Operating Licenses CP = Construction Permits
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