ML19317E101
| ML19317E101 | |
| Person / Time | |
|---|---|
| Site: | Oconee, Mcguire, McGuire  |
| Issue date: | 09/12/1977 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Parker W DUKE POWER CO. |
| References | |
| NUDOCS 7912130758 | |
| Download: ML19317E101 (2) | |
Text
o g.
AR "80 0,'o f
UNITED STATES
,7g NUCLEAR REGULATORY COMMISSION f
v, g
REGloN 11 f
- g 230 PEACHTREE STREET, N.W. SulTE 1217
" E o
ATLANTA, GEORGIA 30303 SEP 121977 N
In Reply Refer To:
RII:JPO 50-369, 50-370, 50-269, 50-270, 50-287 Duke Power Company Atta:
Mr. William O. Parker, Jr.
Vice President of Steam Production 422 South Church Street P. O. Box 2178 Charlotte, North Carolina 28242 Gentlemen:
Enclosed is IE Bulletin No. 77-02 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, f'&f
,g ames P. 7 Reilly 3
Director
Enclosure:
29121807b8 Q
Mr. M. D. McIntosh, Plant Manager McGuire Nuclear Station P. O. Box 488 Cornelius, North Carolina 20031 Mr. J. E. Smith, Station Manager Oconee Nuclear Plant P. O. Box 1175 j
Seneca, South Carolina 29678 4
t i
t I
l r
t l
l i
l 1
NUCLEAR REGULATORY COMMISSION
)77 0FFICE OF INSPECTION AND ENFORCD4FJr WASHINGTON D. C.
20555 IE Bulletin 77-02 Date: September 12, 1977 Page 1'of 2 DTENTIAL FAILURE MECHANISM IN CERTAIN WESTINGHOUSE (W) AR RELAYS
[TH LATCH ATTACHMENTS accription of Circumstances:
BSTINGHOUSE RECENTLY REPORTED THAT A NUMBER OF AR Relays, with a ntch attachment to provide a seal-in feature, have failed during te system check out of the Solid State Protection System (SSPS) at Nuclear Instrumentation Control Division in Hunt Valley, Maryland.
istinghouse has determined that contacts of these AR Relays can
- opsn of ter the relay coil is de-energized even though the latch
- chanism is engaged. Normal operation calls for the contacts to main closed so that under abnormal conditions Safeguards actions, tea initiated, go to completion.
e failure mechanism has been found to be caused by insufficient
,nufceturing tolerances which prevent full travel of the relay ntect assembly which is essential for proper relay operation, is rsduction of contact movement resulted from a design change da in the relay contact assembly in mid 1973 by the W Control oducts Division, Beaver, Pennsylvania.
In addition to the tole-ace problem, it was determined that excessive tightening of the ntret cartridge terminal screw may also contribute to the Ifunction of the contacts during relay operation where tolerances e marginal. AR Relays using latch attachments and produced prior mid 1973 are not a matter of concern in this issue.
p cnclosed W Technical Bulletin, NSD TB 77-10 was sent to all facted Westinghouse plants notifying them of the problem and of S corrective actions being taken. The technical bulletin
)3cribssindetailtheactiondevelopedbyWtocorrecttheidenti-pd probicm. The technical bulletin also provides specific Fing instructions to assure that design tolerances are not quead by excessive tightening of electrical terminals on the ay*
l hy QG 3 ;, <[
a COPY
- 2. Auxiliary Safeguards Cabinet: William McGuire #1 & #2 Byron #1 & #2 OHI #1 & #2 Braidwood #1 & #2 Joseph Farley #1 & #2 Beaver Valley #2 Almaraz #1 & #2 Angra #1 Virgil C. Summer D. C. Cook #2 Lemoniz #1 & #2 North Anna #1 & #2 C.
On all future applications of AR relays with latch attachments, use only the approved contact cartridge that will result from the resolu-tion of this problem. Once qualified, it will have a unique identification code.
D.
Upon installation of any contact cartridge, new or existing, or the changing of any wire terminations to any AR relay, the maximum torque applied to the terminal screws shall not exceed 10 inch-pounds.
5 Page 3 of 3 I
l l
l l
l i
i l
l l
l
COPY IE Bulletin 77-02 LISTING OF IE BULLETINS ISSUED IN 1977 Bulletin Subject First Date Issued Issued To No.
77-01 Pneumatic Time 4-29-77 All Holders of Delay Set Point Operating License Drift (OL) or Construc-tion Permit (CP) l 4
i l
t
- ~.
-...,