ML19329E337
| ML19329E337 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 09/12/1977 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Howell S CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| NUDOCS 8006120647 | |
| Download: ML19329E337 (1) | |
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Dochoc Ilo. 50-329 Decket Ho. S0-330 h..310 Cont.umcra Poucr Company
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lir. Stephen :1. Ilovell l
Vice President s
j 1945 kant Par".all Rond Jackcou, III 49201 i
i Couticacn:
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Enclosed is IE Bulletin Jo. 77-02 which requires action by you with regard to your power reactor facility with cn operatin:t j
license or a construction pemit.
j Should you hria questiens regarding thio Bullestin or the actions j
required of you, pleaso coatect this office, f
Sincerely, l
I Jar.tos G. I:nppler l
Director Dsclosure: IE Dulletin 1;.
77-02 19tS DOCUMENT CONTAg3 i
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S POOR QUAUTY PAGES
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September 12, 1977 IE Bulletin No. 77-02
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l'OTENTIAL FAILURE MZCl! ANIS!! IN CERTAIM UESTINGHOUSE (W) AR RELAYS
', HITl! LATCl! ATTAC!!MENTS I
Description of Circumstances:
WestinghouserecentlyreportedthatanumberofARkolays,witha latch attachment to provide a sesi-in feature, have failed during j
the system chcch out of the Solid State Protection System (SSPS) at U Nuclear Instrumentation Control Division in Hunt Valley, !!aryland.
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Ucstinghouse has determined that contacts of these AR Relays can reopen after the relay coil is de-energized even though the latch nachanism is engaged. Normal operation calls for the contacts to remain closed ss that unde.r abnormal conditions Safeguards actions, once initiated, go to completion.
The failure mechanism has been fcund to be caused by insufficient 5
manufacturing tolerances which prevent full travel of the relay contact assembly which is essencial for proper relay operation.
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~~his reduction of contact movecent resulted from a design change
' made in the relay contact assembly in mid 1973 by the W Control
-s Pro'aucts Division, Beaver, Pennsylvcnia.
In addition to the tole-rance problem, it was determined that excessive tightening of the
<:ontact cartridge terminal screw may also contribute to the
- nalfunction of the contacts during relay operation where tolerances arc marginal. AR Relays using latch attachments and produced prior to mid 1973 are not a matter of concern in this issue.
The enclosed W Technical Bulletin, NSD TB 77-10 was sent to all 3
affected Ucstinghouse plants notifying them of the prob 1r.m and of the corrective actions being taken. The technical bulletin describes in detail the action developed by W to correct the identi-
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ficd proble'a.
The technical bulletin also provides specific viring instructions to ass'tre that design toleratices are not reduced by excessive tightening of electrical terminals on the
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relay.
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Coltember 12, 1977 lE Dulletin No. 77-02
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Action to Be Taken By Licenaces and Permit !!olders:
For all power reactor facilitics with an operating license or n construction perait:
(1/
Describe what action you have taken to determine whether thn relays of the type and vintage described in the enclosed W Bulletin are in use or planned for use in safety related cystems at your facility.
(2)
Describe what action you plan to take regarding replacement of any relays of the type and vintage described which are t
in use or planned for use in safety related systems. Further iastruction pertaining to replacement procedures can be oltainad from the W Nuclear Service Department in Monroeville, Pennsylvania.
(3)
Report to this office in writing within 45 days for facilitics with an operating license and within 60 days for facilities with a construction permit, the results of findings with regard to Item 1 or 2.
/.pproval o'f URC requirc=ents for reports concerning possible generic problems has been obtained from the U. S. General Accounting Office.
(GAO approval 3-180225 (R0072) expires 7/31/80).
Enclosures:
1.
Extract From W Technical Bulletin NSD-77-10 Entitled "AR Relays with
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Latch Attachment" 2.
List of IE Bulletins issued in 1977
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COPY (Extracted from W Technical Bulletin NSD TB 77-10)
Subject:
AR RELNIS WIT!! LATCII ATTACIIME: TIS Number:
NSD-TB-77-10 System (s):
Solid State Protection System (SSPS) and Auxiliary Safeguards Cabinets (ASC)
Date:
July 21, 1977 Affected Plants: See following S.O.(s) 385 BACIGROUND INFORMATION Uestinghouse has recently experienced an increase in the number of g
failures of AR Relays with latch attachments during the SSPS system chech-out at the supplier's (WHICD) shop. Discussions with WNICD e
_7 and W Control Products Division (AR Relay supplier) on this subject
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,,- identified that a design change was made in the contact cartridge assembly which may have compromised the operability and reliability o
of the AR relay with latch attachment assembly. This change was implemented in mid 1973 at W Control Products Division.
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Specifically, the design change reduced the thickness of'the moveabic hontact button which, in turn, reduced contact overtravel.
In addi-tion, it was also determined that overtightening of tha contact cartridge terminal screw, which also acts as the cartridge holding screw, may deform the stationary contact assembly, further reducing contact overtravel. Once the relay is de-energized, the latch plunger back-travels to engage its mechanical stop.
It is this action whidi al, lows the contacts to relax a distance approaching or exceeding that of the contact overtravel. The end effect is that on AR relays with latch attachments, contact continuity could be lost after the actuation coil has been de-energized even though the latch mechanism is working properly.
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/7 COPY The above denign change was moda in mid 1970 and suspect relays can ha identified by boch:
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Manufactures code date - (located on underside of relay base which can be viewed only by removing the relay). Decode as follous: S-1, W-2, I-3, T=4, C=5, !!=6, G=7, E=8, A=9, R=0 (Example - CGI=7/73) 2.
Removing each contact cartridge: The moveable contact area vill be round add-on button (A square, integral moveable assembly is the good pre-change style).
PIC0m! ENDED ACTION A.
The following plants are to notify WUSD if they have replaced any original equipment relays with latches, or have added any relays
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with latches that have been identified as being made af ter 6/73 (HGI) and have the round, add-on contact button. Should any doubt exist as to this status, all AR relays with latches must be identified per the method above. Operating plants may postpone this action until a reasonable opportunity exists (i.e. shutdown),
since this design deficiency is detectable during periodic safe-guards testing.
In any event, replace =ent parts will be made available as soon as they are qualified.
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- 1. Solid State Protection System: OHI #1 Salem #1 & #2 North Anna #1 & #2 Ringhals #2 l
D.C. Cook #1 3 #2 Sequoyah #1 & #2 Joseph Farley #1 Beaver Valley #1
- 2. Auxiliary Safeguards Cabinct:
D.C. Cook #1 l
Beaver Valley #1 B.
The following plants will have contact cartridges available to them by the latter part of 1977 as replacements for all AR relays with latch attachments. Therefore, no custcmer action is required at this time.
1.
Solid State Protection System: William McGuire #1 & #2 Braidwood #1 & #2 OHI #2 Ringhals #3 & #4 Joseph Farley #2 Beaver Valley #2 l Watts Bar #1 & li2 Marble Hill #1 & i l Almaraz #1 & #2 M111 stone =#3 Virgil C. Summer KRSK0 Lemoni: #1 Catawba #1 & #2 ASCO #1 Co:mnanche Peak 11 Byron #1 & #2 l
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- 2. Auxiliary Safeguards Cabinet: William McGuire #1 & #2 Byron #1 & #2 OHI #1 & #2 Braidwood #1 & :!2 Joseph Farley #1 6 #2 Beaver Valley #2 Almaraz #1 & #2 Angra #1 Virgil C. Sun:mer D. C. Cook #2 l
Lemoniz #1 & J2 North Anna #1 4 #:'
1 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 4
identification code.
D.
Upon installation of any contact ccrtridge, 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.
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I LISTING OF IE BULLETINS 4
ISSUED IN 1977 Bu11ctin Subject First Date Issued Issued To no.
7-01 Pneumatic Time 4-29-77 All JIolders of
' Delay Set Point OperatinS License Drift (OL) or Construc-tiqn Perrit (CP)
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