ML19323D333

Deficiency Rept SD 369/80-05 Re Cutler-Hammer Relay Contact Blocks W/Oversized Contact Compressions Springs.All Relays Equipped W/Type D26MF & D23MF Contact Blocks Having Date Codes 775,875,975 & 1075 Will Be Replaced

ML19323D333
Person / Time
Site:	McGuire
Issue date:	05/15/1980
From:	DUKE POWER CO.
To:
Shared Package
ML19323D330	List: ML19323D329 ML19323D333
References
NUDOCS 8005210444
Download: ML19323D333 (2)

Text

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MCGUIRE NUCLEAR STATION REPORT NO.- SD-369/80-05

_ REPORT DATE: May 15, 1980 FACillTY:

McGuire Nuclear Station - Unit i IDENTIFICATION OF DEFICIENCY:

Cutler-Hammer Relay Contact Blocks - Oversized Contact Compression Springs INITIAL REPORT:

On April 15, 1980, John Rausch, NRC Region II, Atlanta, Georgia was notified of the deficiency by J. R. Wells, T. C. McMeekin, J. E. Thomas and B. M. Rice of Duke Power Company, Charlotte, North Carolina.

SUPPLIER AND/OR COMPONEffT:

i The components identified as having the deficiency are Cutler-Hammer relay contact blocks Types 023MF, and D26MF with date codes of 775, 875, 975, and 1075.

The date manufacturing codes runs represent July, August, September, and October in 1975.

DESCRIPTION OF DEFICIENCY:

1 During testing of the McGuire Unit I diesel generator sequencer, a Cutler-designed. relay failed causing a safety-related circuit not to function as Hammer An investigation of the failure revealed that the relay coil operated properly; however, a malfunction did occur in the thi-d contact block of batch the relay.

labeled 975. The contact block in question was a Type 026MF from a Preliminary Indications were that the failure of the walls of the contact channel carrier. contacts to close resulted from the contact co taken apart and inspected. Seven other 026MF contact blocks were Of the seven, two contact blocks also from a batch labeled 975 exhibited binding characteristics similar to the failed block .

The other five blocks were from different batches and did not exhibit binding characteristics.

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Eight contact blocks (the failed block plus the other seven blocks inspected) were forwarded to Cutler-Hammer for evaluation. Cutler-Hammer subsequently confirmed that the malfunction was caused by the contact compression' spring binding on the channel carrier wall. The binding was determined by Cutler-Hammer to be caused by oversized contact compression springs. Cut l er-Hamme r has traced supplier.

the spring the oversized springs to a shipment received on July 23, 1975 from Some of the springs in this shipment were found to be slightly oversized according to manufacturing rpecifications. The oversized s, =

8005210 M ,

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-2 DESCRIPTION OF DEFICIENCY: (Con ' t. )

springs were determined to have been used in the manufacture of Type D26MF, D23MF, 1075. and 021MF contact block bearing the date code of 775, 875, 975, and

_ ANALYSIS OF SAFETY IMPLICATIONS:

The Cutler-Hanmer 026MF and D23MF contact blocks are used in various safety-related applications at McGuire. As stated previously, the failure mechanism 1

of 1s the contact blocks results in contacts potentially not closing when the relay energized.

Depending on the specific application of the relay, the failure of the contact ~ block could result in the loss of a safety function (s).

CORRECTIVE ACTION:

Approximately 218 Cutler-Hammer relays equipped with D26MF and 023MF contact blocks have been identified as installed in safety-related circuits on McGuire Unit 1. (Note that Type D21MF contact blocks are not used at McGuire).

These contact blocks will be inspected and all blocks with date codes 775, 875, 975, and 1075 will be replaced. This corrective action is schaduled for completion prior to McGuire Unit I fuel loading.

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