ML20148C591

Reviews SER on Voltage Degradation at Class IE 480-volt Buses.Degradation Could Jeopardize Fuses in ECCS Control Circuits.Licensee Mod Acceptable

ML20148C591
Person / Time
Site:	Arkansas Nuclear
Issue date:	10/27/1978
From:	Lainas G Office of Nuclear Reactor Regulation
To:	Reid R Office of Nuclear Reactor Regulation
Shared Package
ML20148C596	List: ML20148C591 ML20148C610
References
NUDOCS 7811020091
Download: ML20148C591 (1)

Text

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YWL POR UNITED STATES pg '

,, NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 h

• ..Y..* OCT 2 71978 MEMORANDUM FOR:

R. Reid, Chief, Operating Reactors Branch #4, Division of Operating Reactors FROM:

G. Lainas, Chief, Plant Systems Branch, Division of Operating Reactors

SUBJECT:

V0LTAGE DEGRADATION AT CLASS IE 480-V0LT BUSES Plant Name: Arkansas Nuclear One, Unitl Licensee: Arkansas Power and Light Company Docket No.: 50-313 Project. Manager: G. Vissing The licensee has advised us that the simultaneous starting of all ESF loads from the offsite power system would cause a substantial voltage degradation at the Class IE 480-volt buses. Such a degradation could jeopardize some fuses in the ECCS control circuits.

The licensee has proposed to modify the start circuits for some ESF loads to provide for sequential starting instead of block starting. The Plant Systems Branch has reviewed this modification and has concluded that it is required and acceptable. Enclosed is our safety evaluation report.

D

/ G. Lainas, Chief Plant Systems Branch Division of Operating Reactors

Enclosure:

SER l

7311.03