ML19312C428
| ML19312C428 | |
| Person / Time | |
|---|---|
| Site: | Oconee, Mcguire, Catawba, McGuire  |
| Issue date: | 08/18/1976 |
| From: | Moseley N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Owen W DUKE POWER CO. |
| References | |
| NUDOCS 7912130952 | |
| Download: ML19312C428 (1) | |
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The enclosed Circular, 76-02 is foruarded to you for infornation and action.
This is the second issue of an enpanded systen for co=unica-tion from the Office of Inspection and Enforeccient to cpplicants and licensees, to supplement the issuance of IE Bulletins.
Bulletins have bcea, and uill continue to be liuited to subjects considered to be of appropriate significance to require prompt response.
Circulars uill cover subjects of lesser significance, itztediacy or for uhich a lon;cr response time appc.ars appropriate.
Future IE Circulars may be addressed to any class of ::RC licencees, and nay or cay not require respcase.
Sincerel'/,
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N. C. Ibseley b'tiq Regional Director
Enclosure:
August 18, 1976 IE Circular No. 76-02 RELAY FAILURES-WESTINGHOUSE BF (ac) AND BFD (de) RELAY,
DESCRIPTION OF CIRCDiSTANCES:
DURING TESTING OF Westinghouse BFD relays, the Point B ach nuclear power plant experienced malfunctior., with two relays in the reactor trip system. The malfunctions were caused by the pin that connects the plunger to the operating head rubbing against the contact block.
Although the coils were fully energized the relay contacts remained in the deenergized position.
A similar malfunction occurred in one of a set of relays undergoing accelerated aging tests at the Westing-house Beaver facility.
The malfunction relating to pin misalignment may be common to both BF (ac) and BFD (de) relays. Portions of a Westinghouse service letter containing information about these relays are attached to this circular.
Further instructions regarding this relay problem can be obtained from Westinghouse Nuclear Service Division, Pittsburgh, Pennsylvania 15230.
ACTION TO BE TAKEN BY LICENSEES A*iD PERIIIT HOLDERS:
The following actions should be taken with respect to all Westinghouse BF (ac) and BFD (de) relays in safety related systems:
1.
Describe the action taken or that you plan to take to verify that normally energized relays in safety related systems are in fact 3perable and that the relay contacts are in the energized position.
2.
Describe the action taken or that you plan to take to verify that normally deenergized relays in safety related systems operate properly when energized and that the relay contacts are in the energized position.
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Reports for facilities with operating licenses should be submitted within 60 days after receipt of this circular, and reports for facilities with construction permits should be submitted within 90 days after receipt of this circular. Your report should include the date when the above actions were or will be completed.
Reports should be submitted to the Director of the NRC Regional Office and a copy should be forwarded to the NRC Of fice of Inspection and Enforcement, Division of Reactor Inspection Programs, Washington, D. C.
20555.
Approval of MRC requirements for reports concerning possible generic problems has been obtained under 44 U.S.C 3152 from the U. S. General Accounting Office.
(GA0 Approval B180255 (R0072), expires 7/31/77)
ATTACHMENT:
Extract from Westinghouse Service Letter:
BF (ac) AND BFD (de) RELAYS
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EXTRACT FR0!! WESTINGHOUSE SERVICE LETTER:
B & BFD RELAYS DURING TIIE TESTING OF CERTAIN Westinghouse BFD relays at an operating nuclear power plant, two relays in the reactor trip system were found to have malfunctions.
Although the coils were fully energized, the relay contacts remained in the deenergized position.
It was determined that, in both cases, the pin that connects the plunger to the operating head was rubbing against the contact block.
This rubbing action resulted in friction that impeded the plunger movement when the relay coil was energized thereby preventing contact movement.
The malfunctioning relays were i==ediately replaced. When dissassembled it was found that the relays would operate normally when the pin was centered in the plunger.
COINCIDENTLY, Westinghous2 (Beaver) the relay manufacturer, experienced a similar malfunction in one of a set of similar relays which are currently undergoing accelerated aging tests.
Westinghouse (Beaver) and Westinghouse (NES) are currently investigating this situation in detail as it appl.ies to both BF (ac) and BFD (de) models. Consideration is being given to various means by which the pin could be held captive, thereby precluding archer pin misalignment, if such a co-te of action becomes necessary.
RECO:CIENDED ACTION Visually inspect normally energized relays to verify that such relays are in fact picked up.
Observe the performance of normally deenergized relays during normal periodic testing.
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