Headquarters Daily Report
AUGUST 10, 2000
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PRIORITY ATTENTION REQUIRED MORNING REPORT - HEADQUARTERS AUGUST 10, 2000
Licensee/Facility: Notification:
Part 21 Database MR Number: H-00-0048
Abb Automation Date: 08/10/00
Allentown,Pennsylvania
Subject: Part 21 - Defective Siemens Output Interface Relays for ABB Type
27N, 87B, 81, 47H, and 50D Protective Relays
Discussion:
VENDOR: ABB Automation PT21 FILE NO: mm-18-0
DATE OF DOCUMENT: 08/02/00 ACCESSION NUMBER:
SOURCE DOCUMENT: LETTER REVIEWER: REXB, D. Skeen
ABB Automation Incorporated (ABB), located in Allentown, Pennsylvania,
notified the NRC that a piece part (small double pole, double throw
output relay) on some of ABB's protective relay assemblies was defective.
The ABB protective relays employ a solid state electronic sensing unit in
combination with an electro-mechanical output relay to provide the
interface with external control circuitry. The output interface relay
(part number RTE24048) is made by Siemens. The defect is the epoxy seal
on the underside of the relay housing. The Siemens relay is intended to
be a sealed unit, such that when ABB performs the wave soldering and
washing process during assembly of the protective relay unit, no water is
introduced into the internals of the Siemens relay. However, ABB
discovered that 19 of 67 relays failed during testing.
ABB contacted Siemens and found that there was a problem with the epoxy
seals on relays with a date code prior to the 10th week of 2000. The
Siemens relays were manufactured in Austria using a one-step epoxy
sealant. Two possible failure mechanisms were identified: (1) an
insufficient amount of epoxy may have been applied, and (2) the
ultraviolet light method of curing the epoxy may not be effective in
assuring a complete seal during the wave solder and washing process.
Water intrusion into the Siemens relay can result in (1) corrosion of the
armature, causing it to stick and hold the normally open contacts in the
closed position, or (2) the contacts may become corroded and experience
either intermittent contact or no contact operation.
ABB has identified all customers who procured the protective relay units
as 1E nuclear safety-related equipment. The plants affected are Oyster
Creek Nuclear Station, Peach Bottom Atomic Power Station, Limerick
Generating Station, and Perry Nuclear Power Plant. ABB has informed these
customers of the defective Siemens relays and recommended that the ABB
protective relay units be returned to the Allentown, Pennsylvania
facility for replacement of the Siemens relays with those of another
approved manufacturer. In addition, ABB has issued a Product Advisory
Recall letter to customers who may have received the affected product for
non-safety applications.
Contacts: Steve Alexander, NRR Dave Skeen, NRR
301-415-2995 301-415-1174
HEADQUARTERS MORNING REPORT PAGE 2 AUGUST 10, 2000
MR Number: H-00-0048 (cont.)
Email: sda@nrc.gov Email: dls@nrc.gov
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