ML20084B759

AO 2-72-9:on 720524,essential Svc Motor Generator Set Failed to Transfer from Normal Ac Supply to Backup Dc Supply.Feed Water Control Sys Inoperable Resulting in Low Reactor Water Level Scram

ML20084B759
Person / Time
Site:	Quad Cities, 05000000
Issue date:	05/24/1972
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	Jorden NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20084B716	List: ML20084B712 ML20084B746 ML20084B759
References
AO-2-72-9, AO-720524, NUDOCS 8304070078
Download: ML20084B759 (1)

Text

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l s T. ^ j' . j ATOMIC ENERGiY COMMISc3'ON g] 2 DIE CTO MTE OF REGULATORY OPERATIONS RcolCN IH 45 ; 799 ROOSLVr.LT RO AD p' GLEN CLLYN. ILLINots 60137 sh Jun* 7, 1972

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Commonwealth Edison Company Docket Nos. 50-237 .

ATTN: Mr. Byron Lee, Jr. 50-249 Assistant to the President ,50-254

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P. O. Box 707 50-265 Chicago, Illinois 60690 t- '

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W recently received information, from a licensee operating a boiling *

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water reactor which may relate to the perforcance of the essential ' ij

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serv!ces power supply in your Dresden and Quad-Cities facilities. The -

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information is as follows: "

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a. Descrip tion o f C i rcums t ance s

. bI f Two failures of essential services power supply at a reactor p%j . d' ([ I('

undergoing startup testing have resulten in low water levet scrams due to the inability to control fcedwater. The ..

essential services power supply system consists of a 120/200 V, single phase 33.3 KVa AC generator which is driven alternately by a 440 V, 3 phase 50 h.p. AC motor or in the event of loss of AC power, a 125 V 50 h.p. DC motor.

In the event of a failure of the essential services power --

suppl, a manual trans fer to a reserve 480-120/240 V, 37.5 KVa ..

transformer is required to regain power to essential services buses. Inis manual trans fer must ce performed in the auxiliary electric room located two stories below the control room.

Another similar facility Sas experienced a loss of essential services power with tue same low water level scram results, and requiring the same manual switching remote from the control room.

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