ML19208D305
| ML19208D305 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 09/24/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Nichols T SOUTH CAROLINA ELECTRIC & GAS CO. |
| References | |
| NUDOCS 7909280215 | |
| Download: ML19208D305 (1) | |
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[ EAR M4g UNITED STATES o,j 8
.g. gg'A NUCLEAR REGULATORY COMMISSION g
,a REGION II O
101 MARlETTA ST., N.W., SUITE 3100 4
o ATLANTA, GEORGIA 30303 SEP 2 41979 In Reply Refer To:
RII:JPO d&
South Carolina Electric and Gas Company Attn:
T. C. Nichols, Jr., Vice President Power Production and System Operations Poct Office Box 764 Columbia, South Carolina 29218 Gentlemen:
The enclosed IE Circ.lar 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, h
James P. O'Reilly Director
Enclosures:
1.
IE Circular No. 79-20 2.
List of IE Circulars Issued in the Last six months 1052 014 7909280*IQ
Y 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 SU12-11-AC WITH A 120V AC COIL Description of Circumstances:
During inspection of relays in the Engineered Safeguards Actuation System at Metropolitan Edison T'. 2e Mile Island Nuclear Station Unit #1, relay 62X2B/RCIA failed to drop out when Lhe coil was deenergized.
The failed 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 indi;ated that twenty-five (25) of the relays had detectable notches ranging from 0.001 to 0.003 inches 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 ensur, that the armature operating rod is not notched and is operating freely.
2.
Relays found with detectable notches on 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 information regarding this subject, contact the Director of the appropriate NRC Regional Office.
DUPLICATE DOCUMENT Entire .acument previously entered into system under:
1052 015
^"o N O W O W No. of pages:
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