ML20011F597
| ML20011F597 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley, Browns Ferry, Perry, Fermi, Sequoyah, 05000000, Marble Hill |
| Issue date: | 02/22/1990 |
| From: | Kaiser A ABB ATOM, INC. (FORMERLY ASEA ATOM, INC.) |
| To: | Berlinger C Office of Nuclear Reactor Regulation |
| References | |
| REF-PT21-90 NUDOCS 9003070020 | |
| Download: ML20011F597 (3) | |
Text
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Mbert F. Kaiser
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ASEA BROWN BOVEFil February 22, 1990 Mr. Carl Berlinger. Branch Chief Office of Generic Communications U.S. Nuclear Regulatory Commission Washington. D.C.
20555
Subject:
10CFR Part 21 Report ABB 27/59 Relay Catalog Series 211L Gentlement-An ABB 27/59 Relay (Catalog No. 211L1175) was returned by CEI Perry Nuclear Station for evaluation. Examination has revealed that six (6) solder connections, where 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 R41 on the circuit board.
- The printed wiring patterns uses pads of only 1/8 inch diameter at these locations. The heat is dissipated in the wire wound resistors and is conducted through the leads of the resistors to these pads. It is also radiated from the body of the resistor to the board below. This thermal stress has caused the bond of the printed wiring pattern to the glass epoxy circuit board to show discoloration and the pads have lifted from the surface of the board. This jeopardizes the integrity of the connections. No actual failure has occurred. however should the connection fail, the relay would not operate properly. The likely failure tuode for Catalog Number 211Lil75. would be to go into an "Undervoltage" condition.
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 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 ABB that they are evaluating their procedures for alternatives to circuit board or relay replacement.
The newer model relays have substantially larger pads and higher wattage rating resietors to lower the operating temperature, and avoid the conditions-listed previously.
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These 211L relays are used in ether 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 higher set point accuracy, and therefore will not have this condition.
9003070020 900222 I
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ABB Power Dist@uton ine Telephone:
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i Mr. Carl Berlinger U.S. Nuclear Regulatory Commission February 22, 1990 Page 2 1
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.
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Detroit Edison (Termi) and Duquesne Light (Beaver Valley) should contact ABB I
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 applications.
Also, the relays may be identified as "1TE" 27/59 rather than ABB 27/59.
Copies of this report are being sent to the nuclear stations listed in Appendix "A".
dc.-.4.(n A. F. Kaiser, President ABB Power Distribution Inc.
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ol APPENDIX "A" Company Station Aty Relay S.O.
Switchgear S.O.
t CEI Perry 48 33-51959 (211L1175)
Detroit Edison Fermi 12 34-31322 O-(211LO275)
Duquesne Light Beaver 2
34-34310 (211LO275)
Valley 2
34-34717 PSI Marble Hill 12 34-39971 33-52213 (211L1175)
'2 34-39902 33-52213 P
TVA Browns Ferry )3 34-38625 (211L0175)
TVA Sequoyah 12 34-42905 (211LO175) l l
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