ML17306B129

Special Rept 2-SR-92-003:on 921113,reactor Trip Occurred While Motor Generator Set a Out of Svc for Scheduled Maint & Set B Inadvertently Deenergized,Resulting in Loss of Power. State & Local Agencies Notified & Sys Reset

ML17306B129
Person / Time
Site:	Palo Verde
Issue date:	11/17/1992
From:	James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
192-00813-JML-T, 192-813-JML-T, 2-SR-92-003, 2-SR-92-3, NUDOCS 9211230233
Download: ML17306B129 (8)

Text

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ACCESSION NBR:9211230233 DOC.DATE 92/11/17 NOTARIZED: NO DOCKET ¹ FACIL:STN-50-529 Palo Verde Nuclear Station,'nit 2, Arizona Publi 05000529 AUTH. NAME AUTHOR AFFILIATION LEVINEiJ.M. Arizona Public Service Co. (formerly .Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document r Control Desk)

SUBJECT:

. Special Rept 2-SR-92-003:on 921113,reactor trip occurred while motor generator set A out of svc for scheduled maint &

set B inadvertently deenergi'zed,resulting in loss of power.

State & local agencies notified & sys reset.

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc. S NOTES:Standardized plant. 05000529 RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD .1 1 D TRAMMELLi C 1 1 INTERNAL: .ACNW 2 2 ACRS 2 2 AEOD/DOA 1 1 AEOD/DSP/TPAB 1' S

AEOD/ROAB/DSP 2 2 NRR/DET/EMEB 7E 1 1 NRR/DLPQ/LHFB10 'NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB8H3 1 1 NR+R~DST SPLB8Dl 1 1 NRR/DST/SRXB 8E 1 1 REG FIT E 02 1 1 RES/DSIR/EIB 1 1 GN5 FTCE 01 1 1 EG&G BRYCE g J H L ST LOBBY WARD EXTERNAL NRC PDR 2

1 2

1 NSIC MURPHY,G.A l.

1 1 1

NSIC POOREiW. 1 1 NUDOCS FULL TXT 1 1 NOTE TO ALL RIDS RECIPIENTS PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK.

ROOM Pl-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T FREED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 31 ENCL 31

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Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O. BOX 52034 ~ PHOENIX. ARIZONA 85072-2034 JAMES M, LEVINE VICE PRESIOENT 192-00813-JML/TRB/KR NUCI.EAR PRODUCTION November 17, 1992 r

U. S. Nuclear Regulatory Commission Attention: Document Control Desk Mail Station P1-37 Washington, D.C. 20555

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 2 Docket No. STN 50-529 (License No. NPF-51)

Special Report 2-SR-92-003 File: 92-020-404 Attached please find Special Report 2-SR-92-003 prepared and submitted pursuant to Emergency Plan'Implementing Procedure (EPIP-03). This report discusses an event in Palo Verde Unit 2 which resulted in a Safety Injection Actuation System (SIAS) actuation and the declaration of a Notification of Unusual Event.

If you have any questions, please contact T. R. Bradish, Manager, Nuclear Regulatory Affairs at (602) 393-5421.

Sincerely, JML/TRB/KR Attachment cc: W. F. Conway (all with attachment)

J. B. Martin J. A. Sloan zAAII90 9211230233 05000529 II21117 PDR ADOCK PDR

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PALO VERDE NUCLEAR GENERATING STATION UNIT 2 NOTIFICATION OF UNUSUAL EVENT Docket No. 50-529 LIcense No. NPF-51 Report No..2-SR-92-003

'pecla'I This Special Report is being provided pursuant to Emergency Plan Implementing Procedure (EPIP;03), "Notification of Unusual Event Implementing Actions" to report a condition requiring the declaration of a Notification of Unusual Event for Palo Verde Unit 2 at approximately 1405 MST on November 13, 1992. The Notification of Unusual Event was terminated at approximately 1439 MST on November 13, 1992.

On November 13, 1992, at approximately 1354 MST, Palo Verde Unit 2 was operating at approximately 100 percent power in Mode 1 (POWER OPERATION) when a reactor "A" was out of, trip occurred. Prior to the reactor trip, Motor Generator (MG) Set service for scheduled preventive maintenance and MG Set "B" was supplying power to the Control Element-Drive Mechanisms (CEDMs). At approximately 1354 MST, MG Set "B" was.inadvertently deenergized resulting in the loss of power to,the CEDMs, the insertion of the Control Element Assemblies'CEAs) into the reactor core, and a Main Turbine trip. As the CEAs inserted into the reactor core, the Core generated Low Departure from Nucleate Boiling Ratio reactor trip signals Protection'alculators due to the CEA deviation, resulting in the opening of the reactor trip switchgear breakers. Normally, this would cause the CEAs to insert into the reactor core, shutting down the reactor. However, due to the loss of power to the CEDM MG Set "B", the CEAs were already inserting.

The Steam Bypass Control System responded as designed to the resulting change in steam flow (i.e., rising main steam pressure due to the Main Turbine trip) with a quick.

open signal to the steam bypass control valves (SBCVs) in order to control the secondary side pressure. The opening of the SBCVs caused primary system temperature to decrease resulting in a pressure decrease below the low pressurizer pressure Engineered Safety Feature System actuation setpoint of 1837 psia. A valid actuation of the Safety Injection Actuation System (SIAS) and the Containment Isolation Actuation System (CIAS) occurred due to low pressurizer pressure. The Emergency Plan Implementing Procedures require the declaration of a Notification of Unusual Event for an event resulting in a SIAS actuation, caused by a valid low pressurizer pressure condition. By approximately 1409 MST, Control Room personnel stopped Trains A and B Containment Spray pumps, High Pressure Safety Injection pumps, and Low Pressure Safety Injection pumps. The plant was stabilized in Mode 3 (HOT STANDBY) By approximately 1413 MST, on November 13, 1992, the

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appropriate state and local agencies were notified of the condition requiring the declaration of a Notification of Unusual Event. At approximately 1439 MST on

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NRC Document Control Desk Special Report 2-SR-92-003 Page 2 November 13, 1992, the Notification of Unusual Event was terminated in accordance with EPIP-03. By approximately 1450 MST on November 13, 1992, the appropriate state and'local agencies were notified of the termination of the Notification of Unusual Event. The Nuclear Regulatory Commission (NRC) Operations Center was notified at approximately 1454 MST of the declaration and termination of the Notification of Unusual Event. By approximately 1517 MST, following verification of proper safety system actuation, the SIAS and CIAS were reset.

Further investigation into the circumstances surrounding this event is being performed in accordance with the APS Incident Investigation Program. The results of the investigation will be reported pursuant to 10CFR50.73.

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