ML20072S704
| ML20072S704 | |
| Person / Time | |
|---|---|
| Site: | Zimmer |
| Issue date: | 03/28/1983 |
| 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, LOZ-83-0012, LOZ-83-12, NUDOCS 8304070303 | |
| Download: ML20072S704 (2) | |
Text
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f y'* m THE CINCINNATI GAS & ELECTRIC COMPANY sW CINCINNATt, OHIO 4520t March 28, 1983 LOZ-83-0012 ca.soaGMANN SENIOR VICE PRESIDENT.
Docket No. 50-358 U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen-Ellyn, IL 60137 Attention:
Mr. J.G. Keppler Regional Administrator Gentlemen:
RE:
WM. H.
ZIMMER NUCLEAR POWER STATION - UNIT 1 10CFR50. 55 (e) - ITEM E FAILURE OF BROWN BOVERI (ITE) SOLID STATE TRIP DEVICES W.O. 57300, JOB E-5590, FILE 956C, E-42 This letter constitutes an interim report concerning the subject condition initially reported to the NRC on March 7, 1983 as a potentially reportable deficiency under the requirements of 10CFR50.55(e).
Brown Boveri (formerly ITE Imperial) 480 volt circuit breakers are used in the essential 480 volt sub-stations at Zimmer.
These breakers are supplied with solid state trip units which are used as-power and overload sensors to trip the breakers.
A capacitor in the power supply circuit has been subject to failure by long term degradation.
This damage is caused by halogenated compounds (cleaning solvents) attacking the aluminum in the capacitor as explained in the Brown Boveri letter to Mr. V. Stello, Jr., dated December 10, 1982.
During the degradation period nuisance trips can occur which would cause the loss of an essential function.
The ultimate failure mode of the capacitor is an open circuit.
At this point the trip unit will not respond to overcurrent conditions, thus failing to trip the breaker.
The manufacturer has determined that this deficiency is limited to trip units manufactured prior to August 17, 1976.
These units are identified by serial numbers below 28,300.
A B304070303L83'0328 PDR ADOCK 05000358 APR S
PDR D7j
Mr. J.G. Keppict Regional Administrator March 28, 1983 LOZ-83-0012 Page 2 review of the circuit breakers at this facility identified fifty-seven.(57) of the subject units.
The corrective action for this deficiency is to replace the capacitor or replace the entire trip unit.
However, due to the NRC November 12, 1982 " Order to Show Cause and Order Immediately Suspending Construction", this work cannot-be accomplished.
A Construction Work Authorization Request (CWAR) will be prepared to obtain approval to perform the proposed corrective actions.
Completion of the required corrective actions is contingent upon the NRC's approval of the CWAR.
A follow-up report will be submitted by June 1, 1983.
We trust the above will be found acceptable as an interim report under 10CFR50.55 (e).
Very truly yours, THE CINCINNATI GAS & ELECTRIC COMPANY
~
By E.A. BORGMANN SENIOR VICE PRESIDENT RNT/WPC/bcf cc:
NRC Office of Inspection & Enforcement Washington, D.C.
20555 NRC Senior Resident Inspector Attn:
W.F. Christianson l
NRC Zimmer Project Inspector l
Region III l
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