ML19208D302
| ML19208D302 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 09/24/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Stampley N MISSISSIPPI POWER & LIGHT CO. |
| References | |
| NUDOCS 7909280213 | |
| Download: ML19208D302 (2) | |
Text
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NUCLEAR REGULATORY COMMISSION c,
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101 MARIETTA ST N.W tutTE 3100 kk '
o ATLANTA. GEORGIA 30303 SEP 2 41979 In Reply Refer To:
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Mississippi Power and Light Company Attn:
N. L. Stampley Vice President of Production P. O. Box 1640 Jackson, Mississippi 39205 Gentlemen:
The enclosed IE Circular No. 79-20, is forwarded to you for information.
No written response is required. Should you have any questions related to your understanding of this matter, please contact this office.
Sincerely,
_._ w JLmes P. O'Reilly Director
Enclosures:
1.
IE Circular No. 79-20 2.
List of IE Circulars Iss2ed in the Last six months
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SEP 2 41979 Mississippi Power and Light Company.
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C. K. McCoy Plant Manager Post Office Box 756 Port Gibson, Mississippi 39150
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Accession No.: 7908220118 SSINS No.: 6830 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C.
20555 September 24, 1979 IE Circular No. 79-20 FAILURE OF GTE SYLVANIA RELAY TYPE PM BULLETIN 7305, CATALOG 5U12-11-AC WITH A 120'/ AC COIL Description of Circumstances:
During inspection of relays in the Engineered Safeguards Actuation System at Metropolitan Edison Three Mile Island Nuclear Station Unit ('
relay 62X2B/RCIA failed to drop out when the coil was deenergized. The faileu relay would not prevent component starting but would have reduced the 2 of 3 coincidence logic to 2 of 2, affecting Decay Heat Closed Cooling Pump A and Nuclear Services Closed Cooling Pump A or B.
The cause for failure was attributed to a notch in the armature operating rod. The notch occurs where the rod vibrates against the magnet assembly due to coil hum. A review of the history of this component indicates that similar relays failed during 1977 through 1979 at least one of which was attributed to notching. An inspection of forty-eight (48) relays by this licensee indicated that twenty-five (25) of the relays had detectable notches ranging from 0.001 to 0.003 inchts deep.
Recommended Actions for Licensees' Consideration:
1.
Ensure that all GTE Sylvania Relays Type PM Bulletin 7305, with a 120V AC Coil used in or affecting the operation of safety-related equipment are examined to ensure that the armature operating rod is not notched and is operating freely.
2.
Relays found with detectable notches or the operating rod should be corrected.
If correction cannot be accomplished then administrative controls should be initiated to assure demonstrated operation until the relay condition is corrected.
No written response to this Circular is required < If you require additional informction regarding this subject, contact the Director of the appropriate NRC Regional Office.
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