ML19329E379
| ML19329E379 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 06/13/1978 |
| From: | Howell S CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | |
| Shared Package | |
| ML19329E376 | List: |
| References | |
| NUDOCS 8006120693 | |
| Download: ML19329E379 (3) | |
Text
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MAY31378 Docket No. 50-329 Docket No. 50-330 Consumers Power Company ATTN: Mr. Stephen H. Howell Vice President 1945 West Parnall Road Jackson, MI 49201 Centlemen:
Enclosed is IE Bulletin No. 78-06 which requires action by you with regard to your power reactor facilities 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, James C. Keppler Director
Enclosures:
1.
List of IE Bulletins Issued in 1978 cc w/encls:
/CentralFiles TrilS DOCUMENT CONTAINS Director, NRR/DPM P00R QUAUTY PAGES Director, NRR/ DOR PDR Local PDR NSIC TIC Ronald Callen, Michigan Public Service Commission Dr. Wayne E. North h '2 Myron M. Cherry, Chicago C4 or rice >
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as NRC Form 318A (R3II) (5-76) NRCM 02040
- U. S. GOVERNMENT PRINTING OFFICE: 1978-253-818 sooh en g p Q
O U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT REGION III May 31, 1978 l
II Bulletin No. 78-06 DEFECTIVE CUILER-HAMMER, TYPE M RELAYS WITH DC COILS Description of Circumstances:
The Duke Power Company recently reported that during a serzas of tests of the Emergency Power Switching Logic System at Oconee Nuclear Station, four relays in the standby buses il and #2 voltage sensing circuitry were found to be inoperable. The relays are identified as Cutler-Hammer Type M DC Relays, Catalog No. D23 MRD. This finding prompted the licensee to perform another test of the Emergency Power Switching Logic during which one additional relay of the same type and model as identified above also failed. To date, twelve failures of this DC relay type have occurred at Oconee Nuclear Station.
The manufacturer determined that cause for failure was loss of are gap in the coil clearing contact where the nor=al mode of operation is to have the coil continuously energized. The purpose of this contact is to interrupt the inrush current to the pickup coil winding in order to prevent winding burn out. The loss of are gap in the clearing contact
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was caused by an abnormal amount of heat induced shrinkage of molded magnet carriers which are used in subject relays manufactured between 1971 and July of 1976. /ccording to Cutler-Hamer, the loss of are gap affects the performance of only the type M relays with DC coils since relays with AC coils do not use the coil clearing contact feature.
The attached Cutler-Hammer Notification of Potential Product Tailure was sent to all dis'tributors of type M relays with DC coils with instructions to notify end users of the potential problems. The notification identifies the problem and provides their recommended corrective action.
Action To Be Taken By Licenses:
Tor all power reactor facilities with an operating license or construction h
permit:
((D 1.
Determine whether Cutler-Hammer Type M Relays with a DC coil are A
used or planned to be used in safety-related systems at your
,v fy facility (ies).
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IE Bulletin No. 78-06 May 31, 1978 2.
If such relays are used or planned for use in safety-related systems describe what corrective actions you have taken or plan to take to assure proper relay operation.
3.
Facilities having an operating license should report in writing within 45 days and facilities with construction permir. within 60 days, the results of action taken or planned with regard to Itecs 1 and 2 above. Your written reply should also include the date when such actions were or will be completed.
Reports should be submitted to the Director of the appropriate NRC Regional Office and a copy should be forwarded to the U. S. Nuclear Regulatory Co==ission, Office of Inspection and Enforcement, Division of Reactor Operations Inspection, k*ashington D.C.
20555.
Approval by GAO, B180225 (R0072); elearance expires 7/31/80. Approval was given under a blanket clearance specifically for identified generic problems.
Attachments:
Cutler-Hammar Notification f
6 6
4 e
e e
O
,n
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A IE Bulletin No. 78-06 May 31, 1978 LISTING OF BULLETINS ISSUED IN 1978 Bulletin Subject Date Issued Issued To No.
78-01 Flam=able Contact -
1/16/78 All Power Reactor Arm Retainers in G.I.
Facilities with an CR120A Relays OL or CP 78-02 Terminal Block 1/30/78 All Power Reactor Qualification Facilities with an Operating License (OL) or Construction Permit (CP) 78-03 Potential Explosive 2/8/78 All BWR Power Bas Mixture Accumula-Reactor Tacilities tions Associated with with an Operating BWR Offgas System License (OL) or Operations Construction Permit (CP) 78-04 Environmental Quali-2/21/78 All Power Reactor fication of Certain
.7acilities with an Stem Mounted Limit Operating License Switches Inside (OL) or Construction Reactor Containment Permit (CP).
78-05 Malfunctioning of 4/14/78 All Power Reactor Circuit Breaker Facilities with an Auxiliary Contact Operating License Mechanism-General (OL) or Construction 1
Model CR105%
Permit (CP).
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Inclosure Page'1 of 1 I
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c MA2 GRAM You may have purchased for resale, some of the type M relays with d-c coils described below. If you have, please take action to notify your customers of a potential mode of failure.
NOTIFICATION OF POTElEIAL PRODUCT 7AILURE Some Cutler-Hammer type M relays with d-c coils produced from 1971 thru July of 1976, that are used in circuits where the normal u de of opera-tion is to have the coil continuously energized, may eventually fail due to loss of are gap in the coil clearing pole. This loss of are gap is primarily caused by an abnormal amount of heat-induced shrinkage in some of the molded magnet carriers. If the relay is used in this circuit where the coil is continuously energized, the heat from the coil may cause the magnet carrier to shrink to a point where the are gap in the coil clearing pole becomes too small to break the inrush current of the pickup coil winding, causing the coil to overheat acd burn out. In some cases, the damage from the coil burning out may result in tne re. lay being stuck in the CN (energized) position, thus preventing it from l
dropping out when power is removed from the coil.
1 If you are aware of any applications where this relay is used in a continuously energized mode and where a f ailure as described above may result in a hazard, have that relay removed and replace it with a current Cutler-Hammer D26MRD type M d-c relay.
Cutler-Hammer type M relays can be identified by the front nameplate, and those with d-c coils can be further identified by looking for the wire from pickup winding of the coil that connects to the coil clearing pole. This wire protrudes from the coil molding on the opposite side as the normal coil terminals.
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The date code indicating when the relay was produced is stamped in white ink on the lower deck molding either in the center just above the coil terminals or on the leg of the lower deck molding adjacent l
to the coil terminals. The date code consists of either the month and year (example 6-75) or the month and year followed by an inspector 2
j number which may be 2 or 4 digits (example 12717121 which is December 1971).
4 If you need additional infomtion, please contact the writer at Area Code 414 442-7800, Ext. 2438.
1 John H. Braunig Product Marketing Engineer Logic Device Marketing Cutler-Hammer Inc.
Milwaukee, Wisconsin 53216 d
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