ML20040D369
| ML20040D369 | |
| Person / Time | |
|---|---|
| Site: | Zimmer |
| Issue date: | 01/18/1982 |
| From: | Borgmann E CINCINNATI GAS & ELECTRIC CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, QA-1593, NUDOCS 8202010227 | |
| Download: ML20040D369 (2) | |
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' THE' CINCINNATI GAS & ELECTRIC COMPANY sW clNCINNATI. OHIO 452ol January 18, 1982 QA-1593 E. A. BORGMAN N stN80R WCE PRESIDENT f)g (
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U. S. Nuclear Regulatory Commission p
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2egion III
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799 Roosevelt Road Glen Ellyn, Illinois 60137' y n egg, 7,
EMcwaw;p Attention:
Mr. James G. Keppler 6
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Director h
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RE:
WM. H. ZIMMER NUCLEAR POWER STATION UNIT I 10CFR50.55(e) ITEM E-17, UNDERSIZED WIRING UTILIZED IN 480V MOTOR CONTROL CENTERS, W.O.
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- 57300, JOB E-5590 - FILE NO. NRC-7 Gentlemen:
This letter constitutes an interim report of the subject deficiency which was initially reported to Mr. W. F. Christianson of the NRC on December 7,'1981, as potentially reportable under 10CFR50.55(e).
As reported.in our initial notification, the deficiency it:volved undersized wiring utilized in 480V Motor Control Centers.
The wiring from the bus stab to the line side of the circuit breakers was found to be undersfi:ed for the design ampacity. As a result, wiring conducting currents in excess of design capacity could overheat allowing insulation to melt off thus enabling the potential for a short circuit. This could result in the loss of the system component and possibly the entire motor control center.
The deficiency, were it to remain uncorrected, could adversely affect the safe operations of the plant. This condition is considered to be reportable under 10CFR50.55(e).
The identified deficiency is not a manufacturer's design or construction defect, but rather a result of plant design changes. Circuit breakers were changed from a smaller to a larger ampere rating, however, the wire from the circuit breaker to the bus stab was not changed to a compatible size.
We are currently identifying circuit breakers that have been uprated as a result of design changes. The bus stab wiring to the circuit breaker will be checked to assure that the wire is of the proper size specified by the manufac-turer. When a discrepancy is identified the stab wiring will be replaced.
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y-Mr. James G. Keppler, Director Region III January 18, 1982 - QA-1593~
Page 2 In addition, corrective action has been taken to assure that properly sized wire is installed when additional molded case circuit breakers are replaced due to design changes. A review of the design change control process is being per-formed to determine if the potential for other deficiencies exists.
Our next interim report will be submitted by March 8, 1982. This report will address the results of our investigation and inform'you of the progress or schedule for upgrading the wire size.
We trust that this letter will fulfill the requirements of an interim report under 10CFR50.55(e).
Very truly yours, THE CINCINNATI' GAS & ELECTRIC COMPANY
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E. A. BORGMANN SENIOR VICE PRESIDENT MAP:ec cc: NRC Resident Site Inspector Attn:
W. F. Christianson-NRC Office of Inspection & Enforcement Washington, D. C. 20555