ML19254F827
| ML19254F827 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 11/02/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Mary Johnson SOUTH CAROLINA ELECTRIC & GAS CO. |
| References | |
| NUDOCS 7911190122 | |
| Download: ML19254F827 (2) | |
Text
[b
!( ), (,g NUCLEAR REGULATORY COMMISSION
'o, UNITED STATES
[d %SM 3
h'j, [
101 MARIETTA ST., N.W., SUITE 3100 e
REGION 11 0,
b/
ATLANTA, GEORGIA 30303 o
NOV 2 1979 In Reply Refer To:
RII:JPO 50-395 South Carolina Electric and Gas Company Attn:
M. C. Johnson, Vice President Special Services and Purchasing Post Office Box 764 Columbia, South Carolina 29218 Gentlemen:
Enclosed is IE Bulletin No. 79-25 which requires action by you with regard to your power reactor facility (ies) with an operating license or a construction permit.
Should you have questions regarding this Bulletin or the actions required of you, please contact this office.
Sincerely,
'x y
JamesP.O'ReillhI Director
Enclosures:
1.
IE Bulletin No. 79-25 w/ enclosures 2.
List of IE Bulletins Issued in the Last Six Months 1345 215 7911190 / D Q
NOV L' 197S South Carolina Electric and Gas Company
- cc w/ encl:
T. B. Corners, Jr.
Conners,. Moore and Corber 1747 Pennsylvania Avenue, N.W.
Washington, D.C.
20006 A. A. Smith Quality Assurance Post Office Box 8 Jenkinsville, South Caroliaa 29065 O. S. Bradham, Manager
. Nuclear Operations Post Office Boy 8 Jenkinsville, South Carolina 29065
}lkb j
UNITED STATES SSINS No.:
6820 NUCLEAR REGULATORY COMMISSION Accession No.:
OFFICE OF INSPECTION AND ENFORCEMENT 7908220139 WASHINGTON, D. C.
20555 November 2, 1979 IE Bulletin No. 79-25 FAILURES OF WESTINGHOUSE BFD RELAYS IN SAFETY-RELATED SYSTEMS Description of Circumstances:
While conducting response time tests on Westinghouse BFD relays at the H. B.
Robinson facility, two relays were found to be stuck in the energized position with the coil de-energized. The twenty relays being tested were installed spares and provided no safety-related or operational function.
The subject relay is identified as a Westinghouse Electric Corporation type BFD, style 5069A95G03, coil style 1259C71G19.
Upon discovery of the two stuck relays in the test pro-gram, the licensee conducted response tests on similar relays installed in the Reactor Protection System. During this additional testing a reactor trip relay was found to be stuck in the energized position.
Detailed investigation of the problem by the licensee's staff indicated that the armature was sticking to the armature stop post. This condition is apparently created when heat generated by normally energized coils causes a softening and resultant flow of epoxy adhesive used to attach the magnetic antistick disc to the top of the armature stop post.
When sufficient adhesive flows to the top of the armature stop, the armature becomes bonded to the stop post, resulting in the relay sticking in the energized position.
The epoxy adhesive had also discolored to a dark brown as opposed to clear in new relays.
After reviewing this problem, Westinghouse issued a service letter dated December 6, 1978. A copy of this letter is enclosed for your information and appropriate use. Westinghouse recommended replacing affected relays with a relay identified as NBFD, style 5072A49, coil style 1271C50G01, 125/130 Volt DC i 10 percent.
During installation and testing of the new NBFD relays identified by Westinghouse, H. B. Robinson determined that some of the new style relays exhibited marginal or unsatisfactory armature overtravel.
An investigation of the problem by Westinghouse indicated that the insufficient overtravel was limited to eight and twelve pole models of the NBFD relays. Westinghouse issued a Technical Bulletin NSD-TB-79-05 to Licensees. A copy of this Technical Bulletin is also enclosed for your information and use. Westinghouse recommended a testing method for identifying relays with insufficient overtravel and alsa recommended replace-ment of relays with insufficient overtravel.
Action to be Taken by Licensees:
For all power reactor facilities DUR ICATE DOCUMENT] }f} }j [
1.
Determine whether or not th used or planned for use in Type BFD, style 46E735 entered into system under:
c.
Type BFD, s yle 50 2A4 ANO No. of pages: