Part 21 Report - 1999-351
ACCESSION #: 9907150121
Foxboro
The Foxboro Company
Foxboro, MA 02035-2099
United States of America
Telephone +1 508 543 8750
Facsimile +1 508 549 6750
Internet http://iom.invensys.com/UK/Pages/Foxboro.aspx/
July 9, 1999
Mr. Bob Stransky
United States Nuclear Regulatory Commission
Event Assessment
1155 Rockville Heights
Rockville, MD 02852
SUBJECT: Our notification to you at 10:00 AM July 9, 1999
Dear Mr. Stransky,
In accordance with 10CFR21 this letter is to inform you that Foxboro Co. has identified a potential defect with N-2A0-L2C-R or N-2A0-L2C-R with ECEP 10273, Contact Output Isolator cards that may contain specific N0152CK or C0147SS relays. These relays, supplied by Potter & Brumfield, 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 can lead to the establishment of a resistive shunt path. This shunt path would prevent the relay from functioning as designed. This potential defect is limited to only those relays supplied by Potter & Brumfield manufactured from 1 December 1981 to 31 December 1993.
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 George Robert Johnson Director, Corporate Quality Assurance and Product Safety |
SIEBE
A Siebe Group Company
07/09/1999 | U.S. Nuclear Regulatory Commission Operations Center Event Report | Page 1 |
General Information or Other (PAR) | | Event # | 35906 |
Rep Org: | FOXBORO COMPANY | Notification Date / Time: | 07/09/1999 |
| | | 10:35 (EDT) |
Supplier: | FOXBORO COMPANY | Event Date / Time: | 07/09/1999 (EDT) |
| | Last Modification: | 07/09/1999 |
Region: | 1 | Docket #: | |
City: | FOXBORO | Agreement State: | Yes |
County: | | License #: | |
State: | MA | | |
NRC Notified by: | G. ROBERT JOHNSON | Notifications: | VERN HODGE NRR |
HQ Ops Officer: | BOB STRANSKY | | |
Emergency Class: | NON EMERGENCY | | |
10 CFR Section: | 21.21 UNSPECIFIED PARAGRAPH |
| DEFECTIVE RELAYS PROVIDED TO FOXBORO BY VENDOR |
"Foxboro Co. has identified a potential defect with N-2A0-L2C-R or N-2A0-L2C-R with ECEP 10273, Contact Output Isolator cards that may contain specific NO152CK or CO147SS relays. These relays, supplied by Potter & Brumfield, 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 can lead to the establishment of a resistive shunt path. This shunt path would prevent the relay from functioning as designed. This potential defect is limited to only those relays supplied by Potter & Brumfield manufactured from 1 December 1981 to 31 December 1993.
"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."
The representative reported that two failed relays were identified after being returned by a foreign reactor facility.
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