ML20212F968
| ML20212F968 | |
| Person / Time | |
|---|---|
| Issue date: | 09/28/1999 |
| From: | Hodge V NRC |
| To: | Johnson G FOXBORO CORP. |
| References | |
| REF-PT21-99 NUDOCS 9909290037 | |
| Download: ML20212F968 (3) | |
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1 September 28,1999 George Robert Johnson Director, Corporate Quality Assurance and Product Safety l The Foxboro Company
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Foxboro MA 02035-2099 On Wednesday, September 22,1999, your staff participated in a telephone conference call with our staff at the Nuclear Regulatory Commission (NRC) conceming your 10 CFR Part 21 notifications of potential defects with NO152CK and CO147SS relays supplied by Potter & ,
Brumfield, Inc., or by Communications Instruments, Inc. We arranged to draft a morning report, ;
to be issued on the NRC website, for your review and comment. That draft is attached. We will '
also make this draft available to the public in the NRC Public Documents Room.
au Vern Hodge Nuclear Regulatory Commission Telephone: (301)415-1861 Email: cvh@nrc. gov i
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PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION SEPTEMBER XX,1999 Tue 28 Sep 991054 Licensee / Facility: Notification:
Part 21 Database MR Number: H-99-xxxx l Foxboro Date: 09/xx/99
Subject:
Part 21 - Update on contact output isolator relays Discussion:
VENDOR: Foxboro PT21 FILE NO: 99-35-0,99-29-0 DATES OF DOCUMENTS: 07/09/99 ACCESSION NUMBER:
09/03/99 09/13/99 SOURCE DOCUMENT: EN 35906 REVIEWER: REXB, V. Hodge EN 36122 EN 36122 update On July 9, September 3, and September 13,1999, the vendor, Foxboro, reported several potential defects in relays contained in contact output isolator cards.
The July 9,1999, report involved the cards, described below, using relays manufactured by Potter & Brumfield (MR H-99-0078). The tin-plated contact support arms could develop leakage paths between adjacent metallic surfaces because of growth of tin whiskers. In telephone discussions, Foxboro provided additional information.
Between December 1,1981, and December 31,1993, Potter & Brumfield manufactured these relays with pure tin plated contact support arms instead of wetted tin plated contact arms.
During the service life, in a low voltage, low current application, whisker-type growth was observed in the region of the contact plates. The whisker-type growth could result in the inadvertent failure of the relays. Potter & Brumfield discontinued manufacturing these relays after 1993.
Foxboro sent notification letters to its customers, referencing purchase order number, sales order number, quantity, and contact output isolator model number. Foxboro stated that it would provide replacement relays manufactured during the affected period.
The September 3,1999, report involved these same cards but using relays manufactured by Communications Instruments (MR H-99-0080]. Repair residual material on the contact armature plate could result in relay failure, in telephone discussions, Foxboro provided
, additionalinformation.
I The relays were to be assembled using non-adhesive Mylar insulation held in place by rivets.
During the initial assembly, this insulation was inadvertently torn away from the rivets. '
During rework of the relays, the torn-away insulation was replaced with a piece of adhesive- ;
based Mylar insulation. Foxboro later found that the adhesive migrated from the Mylar to the !
upper coil region of the relay, captured, and held the relay contacts in the energized condition I even after the coil was deenergized.
On September 13,1999, Foxboro updated the September 3,1999, report. Concerning this problem with adhesive Mylar insulation, Foxboro determined that affected relays display a manufacturer's date code in the range 9806 to 9933.
An additional problem was found involving these same cards using the same Communications Instruments relays. In an affected relay, poor solder joint connections may exist between external pins 5 and 6 and the internal copper base-plate. Foxboro determined that affected relays display a manufacturer's date code in the range 9801 to 9936.
Foxboro sent notification letters to its customers, referencing purchase order number, sales order number, quantity, and contact output isolator model number. Foxboro stated that it would provide replacement relays manufactured during the periods affected.
The affected relays are described as follows:
Foxboro Designation NO152CK Potter & Brumfield Designation R10-T0154-3 Communications Instruments Designation 41JO-500G-BSL Action single-pole, double-throw Installation N-A0-L2C-R contact output isolator card Foxboro Designation CO147SS Potter & Brumfield Designation R10-T0346-1 Communications Instruments Designation 42JO-500G-SIL Action double-pole, double-throw Installation N-AO-L2C-R with Nuclear Engineering Change Existing Product (NECEP) 10273 contact output isolator card Typical applications of these isolator cards include reactor protection systems, reactor control systems, balance of plant systems such as main condenser indication and feedwater control, and anticipated-transient-without-scram systems.