ML20137L851
| ML20137L851 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 01/09/1986 |
| From: | Alexich M INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| AEP:NRC:0678R, AEP:NRC:678R, NUDOCS 8601280111 | |
| Download: ML20137L851 (1) | |
Text
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INDIANA & MICHIGAN ELECTRIC COMPANY P.O. BOX 16631 COLUMBUS, OHIO 43216 PRIO2f Ty gy: TIM
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Donald C. Cook Nuclear Plant Unit No. 2 d
7 Docket No. 50-316 License No. DPR-74 CONTAINMENT AREA RADIATION MONITOR Mr. James G.
Keppler, Regional Director U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137
Dear Mr. Keppler:
This information is being transmitted to you in accordance with our letter AEP:NRC:0678N, dated August 8, 1985.
Unit 2 Containment high-range area radiation monitor VRA-2310 failed at 10:50 a.m. on November 21, 1985. The monitor was serviced and restored to operable status on December 11, 1985. On December 12, 1985 the same type of failure occurred on VRA-2310.
The monitor was restored to operable status on January 2, 1986 following recalibration.
It should be noted that throughout these periods of inoperability, the other containment high-range area radiation monitor in Unit 2, VRA-2410, was available for use in the event of an accident.
The cause of these failures was determined to be associated with the calibration of the analog-to-digital (a/d) converter board. The uncertainties allowed for in the calibration did not sufficiently account for the inherent drift in the a/d board. The revised calibration encompasses the values of the drift which caused the failures.
This document has been prepared following Corporate procedures which incorporate a reasonable set of controls to insure its accuracy and completeness prior to. signature by the undersigned.
Very truly yours,
<t 9601290111 860109 PDR ADOCK 05000316 g
PDR M.
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Vice President
[ 'h cm cc: John E. Dolan L
W. G. Smith, Jr. - Bridgman R. C. Callen G. Bruchmann G. Charnoff fg NRC Resident Inspector - Bridgman f
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