ML20010F404
| ML20010F404 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 08/28/1981 |
| From: | Crouse R TOLEDO EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 1-213, IEB-79-27, NUDOCS 8109100142 | |
| Download: ML20010F404 (2) | |
Text
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TOLEDO
%se EDISON Docket No. 50-346 Rowo P. Cnoust Vw_e lhes. dent
% war License No. NPF-3 m9,as3m Serial No. 1-213 e
g August 28, 1981 g
SEP 0 91981 >.g 9
Mr. James G. Keppler h/
Regional Director, Region III Office of Inspection and Enforcement
/
U.S. Nuc}.ar Regulatory Commission 4
799 Rossevelt Road Glen Ellyn, Illinois 60:37
Dear Mr. Keppler:
This letter is to correct an error mcde in Toledo Edison Company response letter (Serial No. 1-116, dated March 3, 1980) to IE Bulletin 79-27, dated November 30, 1979 (Log No. 1-280) as applicable to the Davis-Besse Nuclear Power Station Unit 1.
In our response letter to you, we stated on page two under our response for Item la for Non-Class I-E "AC Uninterruptable Instrument Distribution Panels" (Item C) "a loss of power to the bus would result from a failure of the inverter which would alarm on r.he station annunciator and the station computer". This is not an accurate statement. On June 24, 1981, an event occurred at Davis-Besse Unit 1 that caused a loss of power to the YAU bus (see LER 81-037). This loss of the YAU bus caused the loss of all power to the station annunciator, except for a redundant horn feed from YBU.
It also caused a partial loss of power to the station computer. This resulted in a total loss of all alarms to the operator to inform him that a loss of power on YAU had occurred.
We are presently installing an automatic transfer scheme to allow the station annunciator to be fed from either YAU or YBU buses. We are presently awaiting parts to complete this work in the near future.
Toledo Edison Company has tentative plans to replace the present Bailey 855 computer in the 1982 refueling outage with a new computer system that will have a redundant computing capability if either YAU or YBU is 5s o i
THE TOLEDO EDISON COMPANY EDISON PLAZA 300 MADISON AVENUE TOLEDO. OHIO 43652 8109100142 810828 BEP'.
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, lost. We are also tentatively planning to replace the station computer's multiplexers during the 1983/1984 refueling outage. When replacement is completed computer alarms will be provided where required upon the loss of either YAU or YBU.
Very truly yours,
/./ C44 RPC/RLW/FM Jh a/3-4 cc:
DB-1 NRC Resident Inspector DB-1 NRR Project Manager