ML20069B092

Telecopy Message of Ro:On 811208 24-volt Dc Sys Trouble Alarm Received in Control Room.Output of Negative 24-volt Dc Charger 1D62 Was 21-volt Dc.No Definitive Cause Found. Event re-evaluated as 14-day RO on 811211

ML20069B092
Person / Time
Site:	Duane Arnold
Issue date:	12/11/1981
From:	Mineck D IES UTILITIES INC., (FORMERLY IOWA ELECTRIC LIGHT
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
DAEC-81-594, NUDOCS 8112240100
Download: ML20069B092 (1)

Text

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Towa Electric Light and Ibwer Company December 11, 1981 j DAEC-81 594  ;)

y Mr. James G. Keppler, Director Office of Inspection and Enforcement - Region III .

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U. S. Nuclear Regulatory Commission , ,\)p# - 4 799 Roosevelt' Road Glen Ellyn, IL 60137 ',/ / OCayc

Subject:

Prompt Notification of a 2; DEC 23 7939,, F Reportable Occurrence ( "? '";~-- a : .,,3u p, 3

File: A-118a \- /3

Dear Mr. Keppler:

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-This letter, telecopied to your office, is intended to satisfy the requirement for' prompt notification of' a Reportable Occurrence in accordance with Specification 6.ll.2.a of the Duane Arnold Energy Center Technical Specifications.

Technical Specification paragraph (s) violated: 3.8.B-Description Occurrence:

During normal operation on 12/8/81, a "24 Volt D-C System Trouble" alarm was received in the control room. Investigation revealed that the output of negative 24 VDC charger 1062 was 21 VDC. Technical Specification 3.8.8 requires this charger be operable during power.

operation. However, the only load supplied by this charger is startup range neutron monitoring' instrumentation. -During trouble shooting the charger resumed normal voltage output. No definitive cause could be found. This event was initially classified as not report'able but was reevaluated as a 14 day R.0. on 12/11/81.

Very truly yours, ,

fi W Daniel L. Mineck Chief Engineer Duane Arnold Energy Ceriter DLM/JVS/p1 cc: NRC Resident Inspector

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