ML20011F194

Part 21 Rept Re ABB 27/59 Relay Catalog Series 211L.Solder Connections to Printed Wiring Runs on Bottom of Circuit Board Deteriorated Due to Thermal Stress.No Actual Failure Occurred & Relays to Be Changed at Next Outage

ML20011F194
Person / Time
Site:	Beaver Valley, Browns Ferry, Perry, Fermi, Sequoyah, 05000000
Issue date:	02/22/1990
From:	Kaiser A ASEA BROWN BOVERI, INC.
To:	Berlinger C Office of Nuclear Reactor Regulation
References
REF-PT21-90-030-000 PT21-90-030-000, NUDOCS 9003020075
Download: ML20011F194 (3)

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ft ASEA BROWN BOVERI L

iFebruary:22."1990 Mr. Carl Berlinger, Branch Chief office of Generic Communications s

.U.S.: Nuclear Regulatory Commission Washington,-D.C.- 20555

Subject:

- 10CFR Part'21 Report s

'ABB 27/59 Relay.

Catalog Series 211L a

~Gentlement-1An.ABB'27/59' Relay (Catalog No. 211Lil75) was returned by CEI Perry Nuclear Station ~for evaluation. Examination has revealed that six (6) solder connections,1where the leads from three (3) wire wound 3 watt resistors connect to the printed wiring runs on the bottom of the circuit board.:have

. deteriorated due.to thermal stress. The resistors are-designated R38, R39 and:

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R41' on the circuit' board.-

'The printed wiring patternt'uses pads of only 1/8 inch diameter at these-locations.: The heat is dissipated in the wire wound resistors and:isi L

conducted tiirough the leads of. the resistors to these pads. It is-also

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radiated from the body of the-resistor to the board below.. This thermal n

j stress has: caused the bond.of-the printed: wiring pattern to the glass epoxy

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. circuit' board to: show discoloration -and the pads have 1if ted f rom the surf ace

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of the board. This#jeopardizesithe integrity of the connections. No actual l

. failure has occurred, however should the connection fail,:the; relay would not*

~ operate properly. The likely failure mode for Catalog Number 211L1175, would o

be.tofgo into an "Undervoltage" condition.

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-ABB proposed to CEI.to furnish an interim circuit board with provisions for-

' adequate heat; dissipation. These boards'could be changed out'one at a time L

since-the plant is in operation.

It was also proposed that these relays be-

. changed out at the'next outage with different model relays. CEI has advised

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' ABB: that, they are' evaluating their procedures for alternatives to circuit, y

board or relay replacement.

j The' newer model relays have substantially larger pads-and higher wattage

rating' resistors to lower the operating temperature, and avoid the conditions '

f s listed-previously.

'These 211L relays are used in other nuclear stations and are listed in Appendix "A".

It is believed that the relays installed at.the TVA Browns Ferry!and-Sequoyah plants were replaced with the ABB 27N relay to obtain a f

higher set point accuracy, and therefore 'will not have this condition.

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I 9003020075 90022 e

PDR ADOCK 05000 59 E

A PDC.

h ABB Power Distribution Inc.

AB8 Powet oistreuhon inc.

Telephone.

Telefax.

201 Hekman Drive 407 323 8220 407 322 8934 Po. Box 1978 Sanford, FL 327721978

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._Mr. Carl Berlinger U.S. Nuclear Regulatory Commission February 22,.1990 Page 2 The: relays in the switchgear at PSI Marble Hill (cancelled) may have been resold to other plants or users. ABB has no knowledge of their current location.

Detroit Edison (Fermi) cnd Duquesne Light (beaver Valley) should contact ABB

= for recommended corrective action depending upon the application of these relays -

The quantity of relays listed in Appendix "A" includes the total number of relays at.each location. Not all are used in Safety Related app 12 cations.

I Also, the relays may be identified as "1TE" 27/59 rather than ABB 27/59.

J Copies of this report are being sent to the nuclear, stations listed in Appendix "A".

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' A. F. Kaiser, Presiden't ABB. power Distribution Inc.

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APPENDIX "A" il.

Company Station

-SUj(

Relay S.O.

Switchgear S.0, CEI Perry 48 33-51959 (211L1175)

Detroit Edison Fe rmi

'12 34-31322 (211LO275)-

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.Duquesne Light ~

Beaver 2

34-34310

(211LO275)

Valley 2

34-34717 Y

PSI Marble Hill 12 34-39971 33-52213

'(211Lil75) 12 34-39902 33-52213 f

TVA Browns Ferry 13 34-38625 L(211LO175)

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TVA

'Sequoyah

.12 34-42905 (211L0175) i l

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