Part 21 Report - 1999-392

 

 

ACCESSION #: 9909170178

FOXBORO

The Foxboro Company Foxboro, MA 02035-2099 United States of America

September 13, 1999

Mr. Bob Stransky United States Nuclear Regulatory Commission Event Assessment 1155 Rockville Heights Rockville, MD 02852	Telephone +1 508 543 8750 Facsimile +1 508 549 6750 Internet http://iom.invensys.com/UK/Pages/Foxboro.aspx/
SUBJECT:	Update to our notification to you at 02:30 PM September 03, 1999, Event # 36122

Dear Mr. Stransky,

On July 9, 1999, we reported a potential defect with N-2A0-L2C-R or N-2A0-L2C-R with ECEP 10273, Contact Output Isolator cards that contained N0152CK relays supplied by Potter & Brumfield (Event # 35906). The Potter & Brumfield relays were manufactured utilizing pure tin plated contact support arms. As a result, in low voltage low current applications, the growth of tin whiskers between adjacent metallic surfaces of the contact support arms could lead to the establishment of a resistive shunt path.

We recently reported (on 03 September 1999 Event # 36122) a potential defect with N-2A0-L2C-R or N-2A0-L2C-R with ECEP 10273, Contact Output Isolator cards that contain specific N0152CK relays. The subject relays, supplied by Communications Instruments Inc., were either manufactured utilizing a specific repair residual on the contact armature plate and/or supplied with substandard solder connections. As a result, the contacts on the relays supplied with Mylar repair residuals may not return to the normal deenergized position. The utilization of this repair residual would prevent the relay from functioning as designed. This potential defect was first reported to be limited to only those relays supplied by Communications Instruments Inc. which displayed a manufacturer's date code of 9834 to 9933.

EVENT # 36122 UPDATE:

Subsequent investigative analysis and an audit performed at the supplier's manufacturing facility, has determined that the utilization of Mylar repair residuals is present on relays displaying a manufacturer's date code of 9806 to 9933.

As we were investigating the Mylar problem, we identified another potential defect of substandard solder joints. Relays that were supplied with substandard (poorly wetted) solder joints could lead to cracked, or in extreme cases, intermittent solder connections. This potential defect could present itself as an intermittent connection to the common relay contact. Foxboro has determined that relays manufactured between 9801 and 9936 could display this potential defect.

Foxboro is taking immediate corrective action to rectify the situation and will notify all Nuclear Utilities that have purchased this product from Foxboro during the time period affected and provide replacement relays.

Sincerely, The Foxboro Company /s/ George Robert Johnson Director, Corporate Quality Assurance and Product Safety

SIEBE

A Siebe Group Company

 

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Representative Sample

September 13, 1999

((Title)) <(FirstName>> (<LastName)>

(<JobTitle))

<(Company))

<<Address1))

(<Address2)>

((City)>, ((State)> <(PostalCode))

>

Reference:	Your Purchase Order Number:	(<PurchaseOrderNo)>
		Foxboro Sales Order Number:	((SalesOrderNo>>
		Quantity:	((Quantity>)
		Model:	N-2A0-L20-R or 2A0-L2C-R Contact Output Isolator and/or N01 52CK spare relays.

Dear Customer,

In compliance with 10CFR Part 21 this letter is to inform you of a potential failure with N-2A0-L2C-R or 2A0-L2C-R Contact Output Isolator cards and/or N0152CK Ways purchased from The Foxboro Company as referenced above. The subject Contact Isolator cards may contain N0152CK relays supplied by Communications Instruments Inc. which may have been manufactured utilizing a specific repair residual on the contact armature plate and/or used improper solder techniques on specific lots. As a result, relays utilizing a Mylar repair residual have contacts that may not return to their normal de-energized position when the relay is de-energized (a condition known as contact hang-up). Relays with improper solder techniques could result in intermittent solder connections.

Extensive analysis performed on a number of relays confirmed that utilization of a Mylar repair residual prevented the return of the contact armature (and contacts) to the normally de-energized position when the relay coil was de-energized after an energization period of at least one hour. Further analysis performed by the supplier of the relay confirmed the presence of this type of repair residual as the root-cause for the relay failures. To date, this is the first confirmed instance of this failure mode (utilization of a Mylar repair residual) on the relays. The supplier has determined that during assembly of the relays, this unauthorized repair residual may have been utilized on 5 to 6% of the relays manufactured since manufacturing week 9806. Utilization of the repair residual has been halted by the manufacturer of the relay.

During extensive analysis of this issue, the Foxboro Company also detected improper solder techniques utilized by the supplier during their assembly process which could result in an intermittent connection on the common side of the relay contacts. Analysis performed by the supplier concludes that a lack of solder flux utilized on particular lots resulted in substandard (poorly wetted) solder connections between the escheon pins (from Octal base pins #5 & 6) and the solder eyelets of the relay support bracket. Such substandard solder connections could lead to cracked or in extreme cases, intermittent solder connections, Through an audit performed at the supplier's manufacturing facility, Foxboro determined that relays manufactured since manufacturing week 9801 could have this potential defect.

To date, there have been no field failures experienced on either of these two issues.

The Foxboro Company is recommending that each customer inspect for, and replace, N0152CK relays manufactured by Communications Instruments Inc which display manufacturer's date codes between 9801 and 9936, with Replacement relays provided by The Foxboro Company. The date code is indicative of the year of manufacture first, followed by the calendar week of the indicated year.

Inspection for those relays supplied by Communications Instruments Inc. will require removal of the N-2A0-L2C-R and/or 2A0-L2C-R cards from the nest. Visual inspection of the relay package allows identification of the suspect relays. The side of the relay is stamped with the Communications Instruments Inc name and logo, the Communications Instruments Inc part number 41JO-500G-BSL, and the manufacturer's date code. If the relay has a manufacturer's date code marking beginning with and including 9801 through 9936, it should be removed and replaced with one supplied by Foxboro Company.

Replacement N0152CK relays may be obtained by contacting the Foxboro Response Center at 1-888-Foxboro (1-888-369-2676). You may also feel free to contact the Foxboro Response Center if you have any questions regarding this notification.

The U.S. Nuclear Regulatory Commission has been informed of this potential defect. The Foxboro Company sincerely regrets any inconvenience this potential defect may cause you and trusts that our actions will completely resolve this matter to your satisfaction.

Best regards, The Foxboro Company George Robert Johnson Director, Corporate Quality Assurance and Product Safety

 

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09/13/1999

U.S. Nuclear Regulatory Commission Operations Center Event Report

Page 1

General Information or Other (PAR)			Event #	36122
Rep Org:	FOXBORO COMPANY		Notification Date/Time:	09/03/1999 14:00 (EDT)
Supplier:	FOXBORO COMPANY		Event Date/Time:	09/03/1999 (EDT)
			Last Modification:	09/13/1999
Region:	1		Docket #:
City:	FOXBORO		Agreement State:	Yes
County:			License#:
State:	MA
NRC Notified by:	GEORGE JOHNSON		Notifications:	VERN HODGE (FAX) NRR
HQ Ops Officer:	WILLIAM POERTNER			TAD MARSH NRR
Emergency Class:	NON EMERGENCY
10 CFR Section:	21.21 UNSPECIFIED PARAGRAPH

DEFECTIVE RELAYS PROVIDED TO FOXBORO BY VENDOR

Foxboro Co., has identified a potential failure with N-2A0-L2C-R and/or 2A0-L2C-R Contact Output Isolator cards. The subject cards may contain N01 52CK relays supplied by Communications Instruments Inc. which may have been manufactured utilizing a repair residual on the contact armature plate, As a result, relays utilizing this repair residual have contacts that may not return to their normal de-energized position when the relay is de-energized (a condition known as contact hang-up).

Extensive analysis performed on a number of relays confirmed that utilization of this repair residual prevented the return of the contact armature (and contacts) to the normally de-energized position when the relay coil was deenergized after an energization period of at least one hour. Further analysis performed by the supplier of the relay confirmed the presence of this repair residual as the root cause for the relay failures. The supplier has determined that during assembly of the relays, this unauthorized repair procedure may have been utilized on 5 to 6 percent of the relays manufactured since manufacturing week 9834. Utilization of the repair residual has been halted by the manufacturer of the relay.

***Update on 09/13/99 at 1325 ET by George Johnson taken by MacKinnon***

"Subsequent investigate analysis and an audit performed at the supplier's manufacturing facility, has determined that the utilization of Mylar repair residuals is present is present on relays displaying a manufacturers date code of 9806 to 9933.

"As we were investigating the Mylar problem, we identified another potential defect of substandard solder joints. Relays that were supplied with substandard (poorly wetted) solder joints could lead to cracked, or in extreme cases, intermittent solder connections. This potential defect could present itself as an intermittent connection to the common relay contact. Foxboro has determined that relays manufactured between 9801 and 9936 could display this potential defect.

"Foxboro is taking immediate corrective action to rectify the situation and will notify all Nuclear Utilities that have purchased this product from Foxboro during the time period affected and provide replacement relays"

 

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09/13/1999

U.S.Nuclear Regulatory Commission Operations Center Event Report

Page 1

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General Information or Other (PAR)

Event # 36122

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FOXBORO

The Foxboro Company
Foxboro, MA U.S.A. 02035-2099
Telephone: 508-543-8750
Telex: MCI-6817660
Fax: (508) 549-4458

Date ......	13 September, 1999..........	From....	George R. Johnson.......
To ..	Mr.Bob Stransky............	Signed.................................
Fax No. .301-816-5151	This telefax consists of...4 pages--including this page

MESSAGE

Mr. Stransky,

Per my telephone conversation earlier today with the Operations Center, following is the second notification regarding the N0152CK relays, The additional problem found is detailed.

Also following is a sample of the customer notification letter.

An Invensys Company

 

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