TXX-6796, Interim Deficiency Rept CP-87-88 Re Certian 6.9 Kv Switchgear Control Circuits Which Appear to Produce Excessive Voltage Drop.Initially Reported on 870903.Addl Calculations Being Performed.Next Rept by 880115
| ML20235V976 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 10/05/1987 |
| From: | Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| CP-87-88, TXX-6796, NUDOCS 8710150433 | |
| Download: ML20235V976 (1) | |
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- 10CFR50.5S(e)
Ref 7t#ELECTR/C October 5, 1987 William G. Counsil i
Executwe Vice President U.; S. Nuclear Regulatory Commission Attn: ' Document Control Desk.
Washington,-D. C, 20555-
SUBJECT:
COMANC'I PEAK STEAM ELECTRIC STATION (CPSES)
D002T NOS. 50-445 AND 50-446 6.9 KV CONTROL CIRCUIT V0LTAGE DROPS Sf!AR; CP-87-88 (INTERIM REPORT)
Gentlemen:
Or, Septemoer 3,1987, we verbally notified your Mr. H. S. Phillips of a L
deficiency involving certain 6.9 kV switchgear control circuits which appear i
to produce an excessive voltage drop.
These conditions were observed during the design validation program. This is an interim report of a potentially reportable item under the provisions of 10CFR50.55(e).
Specific' ally, a previous calculation (1V-16) identified 16 control circuits for the 6.9 kV switchgear in which the voltage drop through the control cables produces a voltage at the device being controlled which is lower than the minimum voltage rating of the device.
This undervoltage condition could cause a malfunction of the Class 1E equipment by preventing control circuits from operating properly.
Additional calculations are being performed to substantiate this condition and to determine the extent of the deficiency. Completion of those calculations is required to assess the im)act of this condition on the safe operations of the plant and to determine tie deportability of this issue under the provisions of 10CFR50.55(e).
Our next report on this issue will be submitted no later than January 15, 1988.
8710150433 B71005
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4 W. G. Counsil WJH:tgj c-Mr. R. D. Martin, Region IV Resident Inspectors, CPSES (3) c
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