ML20133E730

Ro:On 850930,plant Security Computer Experienced Momentary Interruption of Power,Resulting in Loss of Sys Operability. Apparently Caused by Switching Operation in Power Supply Sys to Computer.Security Alert Declared.Corrective Action Taken

ML20133E730
Person / Time
Site:	Palo Verde
Issue date:	10/01/1985
From:	Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF ADMINISTRATION (ADM)
References
ANPP-33632-EEVB, NUDOCS 8510090522
Download: ML20133E730 (2)

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Arizona Nuclear Power Project P O. BOX 52034 e PHOENIX, ARIZONA 85072 2034 October 1, 1985 ANPP-33632-EEVB/GEC U. S. Nuclear Regulatory Commission

Document Control Desk Washington, D. C. 20555

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 1 Docket Nos. STN 50-528, License No. NPP-41 Report of Notification of Unusual Event -

Temporary Loss of Operability of Plant Security Computer File: 85-056-026; G.I.01.10 Gentlemen:

Attached please find a report describing a Notification of Unusual Event at the Palo Verde Nuclear Generating Station on September 30, 1985. This report addresses the temporary loss of operability of the plant security computer due to a momentary interruption of power.

This report is prepared and submitted pursuant to Table 5.3-1 of the PVNGS Emerge.cy Plan. By copy of this letter we are also forwarding a copy of the report to the Regional Administrator of the Region V Office and other offsite authorities.

j If you have any questions or concerns, please contact me.

l Very truly yours, r

Ch h

] E. E. Van Brunt, Jr.

Executive Vice President l Project Director i

EEVB/GEC/sih 1 Attachment cc: J. B. Martin (all w/a)

R. P. Zimmerman R. F. Fish, Jr.

E. A. Licitra R. A. Colson, ADES C. E. Tedford, ARRA R. E. Bluhm, MCDCD&ES

,g g g R. G. Godbehere, MCSO 3-f' g[/J R. T. Milstead, DPS INPO Records Center

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8510090522 851001 PDR ADOCK 05000528 g PDR

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. o PAI,0 VERDE NUCLEAR GENERATING STATION

! NOTIFICATION OF UNUSUAL EVENT ON SEPTEMBER 30 1985 Docket No. STN 50-528 At approximately 1042 MST on September 30, 1985, the NRC Operations Center was notified, via the Emergency Notification System, of the declaration of a NOTIFICATION OF UNUSUAL EVENT for Unit 1 of the Palo Verde Nuclear Generating Station (PVNGS). The notification was made pursuant to the requirements of Emergency Pian Implementing Procedure (EPIP) - 02.

1 l At approximately 1019, the plant security computer experienced a momentary interruption of power which resulted in a loss of system operability. The interruption was apparently caused by a switching operation in the power supply system to the computer and was immediately corrected. As a result of the temporary loss of system operability, the security shift captain declared a security alert to assure that all appropriate compensatory measures were taken. The shift supervisor was notified of the security alert and )

consulted the emergency classification procedure (EPIP-02) to determine any required actions. His initial classification in accordance with the procedure was to declare a NOTIFICATION OF UNUSUAL EVENT at approximately 1029. l Daring the process of making the notifications required by the facility's Emergency Plan, the Shift Supervisor determined that the event had been classified in an overly conservative manner and did not require the implementation of the actions associated with a NOTIFICATION OF UNUSUAL EVENT.

The event was terminated at 1044 MST.

Throughout this event, Palo Verde Unit I was operating in Mode 1 at approximately 80 percent of full power. The event did not affect the operation of the unit or threaten the safety or security of the plant at any time.

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