ML20099J547

Interim Deficiency & Part 21 Rept Re Low Voltage Cut Off Setting on GE Supplied Topaz Inverters.Initially Reported on 841009.Engineering Dept Reviewing Bechtel Analysis & Proposed Corrective Action.Final Rept Expected by 841214

ML20099J547
Person / Time
Site:	Hope Creek
Issue date:	11/08/1984
From:	Martin T Public Service Enterprise Group
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
REF-PT21-85-012-000 PT21-85-012-000, PT21-85-12, NUDOCS 8411290111
Download: ML20099J547 (2)

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Sc- 359 Public Service Electric and Gas Company Thomas J. Martin 80 Park Plaza, Newark, NJ 07101 201-430-8316 Mailing Address: P.O. Box 570, Newark, NJ 07101 Vice President Engineering end Construction d

November 8, 1984 Dr. Thomas E. Murley, Administrator U. S. Nuclear Regulatory Commission Office _of Inspection and Enforcement Region'I 631 Park Avenue King of Prussia, Pennsylvania 19406

Dear Dr. Murley:

POTENTIAL CONSTRUCTION DEFICIENCY GE SUPPLIED TOPAZ INVERTERS HOPE CREEK GENERATING STATION On October 9, 1984, a verbal report was made to Region I, Office of Inspection and Enforcement representative, Mr. E.

Kelly, advising of a potentially significant construction deficiency concerning the low voltage cut off setting on Topaz inverters supplied by General Electric. General Electric has reported the problem to the NRC in accordance with 10CFR21.. The following interim report is submitted in accordance with 10CFR50.55(e).

Our Architect / Engineer and Constructor, Bechtel, has advised us that the low voltage cut off and turn-on adjustment for GE Class lE inverters was set too high by the original manufac-turer, Power Mark, a division of Topaz. The GE dedication process was checking for an operable range of 105 to 140 volts DC, instead of 100 to 140 volts DC. Topaz had been routinely setting the low voltage cut off at 105 volts DC. General Electric has specified typical DC bus voltages to range from 108 to 132 volts with momentary voltage dips to 105 volts DC i during the startup of large DC loads. This results in a condition where the inverter may not start or restart until the voltage is increased, not just to 105 volts DC, but to above 118 volts (13 volt fixed offset). Since the allowable momentary dip of the input bus voltage is equal to the factory preset inverter low voltage cut off (105VDC), this dir could result in an inverter trip and a failure to restart during a design base accident.

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J Dr. T. E..Murley 2 11/8/84 F'

Bechtel has determined that Topaz inverters have only been.

i supplied to Hope Creek by General Electric for use in panels Hil-P617, P618, P620, P621, P640 and P641. The safety systems-affected by these panels are RHR, Core Spray, HPCI and RCIC.

Public Service Engineering Department is presently reviewing Bechtel's analysit and proposed corrective action. We anticipate providing.you with c final report by December 14, 1984, t

very truly yours, I

b

, C Office of Inspection and Enforcement Division of Reactor Construction Inspection Washington, D. C. 20535 i'

NRC Resident Inspector - Hope Creek l P. O. Box 241 Hancocks Bridge, NJ 08038 I

Records Center Institute of Nuclear Power Operations i 1100 Circle 75 Parkway, Suite 1500

Atlanta, GA 30339 4

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