ML19250C539
| ML19250C539 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 11/02/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| References | |
| NUDOCS 7911280061 | |
| Download: ML19250C539 (11) | |
Text
,
,5f "%c,'o,,
l'DQ UNITED STATES y,
y, ') w 3 g NUCLEAR REGULATORY COMMISSION
,, %,/. E REGION I O, 8 431 PARK AVENUE
'N KING OF PRUSSIA, PENNSYLVANIA 19406 o
Docket Nos. 50-245 NOV 0 21973 50-336 50-423 Northeast Nuclear Energy Company ATTN:
Mr. W. G. Counsil Vice President - Nuclear Engineering and Operations P. O. Box 270 Hartford, Connecticut 06101 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 er the actions required of you, please contact this office.
Sincerely, k*
AIC Boyce H. Grier
- Director
Enclosures:
1.
IE Bulletin No. 79-25 w/ attachments 2.
List of IE Bulletins Issued in the Last Six Months CONTACT:
S. O. Ebneter (215-337-5283) cc w/encis:
J. F. Opeka, Station Superintendent D. G. Diedrick, Manager of Quality Assurance J. R. Himmelwright, Licensing Safeguards Engineer K. W. Gray, Construction Quality Assurance Lead H. R. Nims, Director of Nuclear Projects 1406 238 7911280 06/ q
ENCLOSURE 1 UNITED STATES SSINS No.:
6820 NUCLEAR REGULATORY COMMISSION Accession No.:
OFFICE OF INSPECTION AND ENFORCEMENT 7908220139 WASHINGTON, D. C.
20555 IE Bulletin No. 79-25 Date:
November 2, 1979 Page 1 of 3 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 ene dized. 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 5069A;3G03, coil style 1259C71G19.
Upon discovery of the two stuck relays in the test program, 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 investigatic'1 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 ge % rated by normally energized coils causes a softening and resultant flow of apoxy adhesive used to attach the magnetic antistick disc to the top of the armature stop post.
When sufficient adhesive flows to the tcp 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 discolt, red 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 attached 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 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 tin house issued a Technical Bulletin NSD-TB-79-05 to Licensees.
attached for your information and u method for identifying relays with replacement of relays with insuffic DUPLICATE DOCUMENT 1406 279 document previ_ously entered into system under:
9%3&)l3q
^uO No. Of pages:
,/[