ML17310A867

Special Rept 1-SR-93-007:on 931215,30 Day Period for Returning Accelerometer to Operable Condition Exceeded. Accelerometer Will Be Replaced During Next Outage of Sufficient Duration

ML17310A867
Person / Time
Site:	Palo Verde
Issue date:	12/15/1993
From:	James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
1-SR-93-007, 1-SR-93-7, 192-00873-JML-T, 192-873-JML-T, NUDOCS 9401040106
Download: ML17310A867 (4)

Text

ACCELERATED ]+TRIBUTION DEMON~TION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9401040106 DOC.DATE: 93/12/15 NOTARIZED: NO DOCKET FACIL:STN-50-528 Palo Verde Nuclear Station, Unit 1, Arizona Publi 05000528 AUTH. NAME AUTHOR AFFILIATION LEVIN,J.M. Arizona Public Service Co. '(formerly Arizona Nuclear Power

.RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Special rept:on 931215,strong motion accelerometer channel of seismic monitoring sys inoperable for more than 30 days.

Caused by single-axis acceleromet'er not responding.

D DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES:STANDARDIZED PLANT 05000528 /

RECIPIENT COPIES RECIPIENT COPIES I D CODE/NAME PDV LA LTTR ENCL 1

ID CODE/NAME LTTR ENCL ~

0 1 PDV PD 1 1 HOLIAN,B 1 1 TRAN,L 1 1 D

INTERNAL: ACRS 2 2 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2

'RR/DE/EELB 1 1 NRR/DE/EMEB 1 1 NRR/DORS/OEAB 1 1. NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 NRR/J)~I L/RPEB 1 1 NRR/DRSS/PRPB 2 2

~G~+FILE RGN5

/DSBA/S PLB 02 01 1

1' 1

1 1

NRR/DSSA/SRXB RES/DSIR/EIB 1

1 1

1 EXTERNAL EG &G BRYCE g J ~ H 2 2 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MURPHY,G.A 1 1 NSIC POOREgW ~ 1 1 NUDOCS FULL TXT 1 1 D

D D

NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOiVI Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 31 ENCL 31

Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O. BOX 52034 ~ PHOENIX, ARIZONA 85072-2034 192-00873-JML/TRB/R JR JAMES M. LEVINE December 15, 1993 VICE PRESIDENT NUCLEAR PRODUCTION 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 1 Docket No. STN 50-528 (License No. NPF-41)

Special Report 1-SR-93-007 File: 93-020-404 Enclosed please find Special Report 1-SR-93-007 prepared and submitted pursuant to Technical Specification 3.3.3.3 ACTION (a) and Technical Specification 6.9.2. This report discusses the inoperability of one (1) Seismic Monitoring System accelerometer channel for more than 30 days.

If you have any questions, please contact B. A, Grabo, Supervisor, Nuclear Regulatory Affairs, at (602) 393-6492.

Sincerely, JMLfTRB/RJR/rv Enclosure cc: W. F. Conway (all with attachment)

B. H. Faulkenberry K. E. Johnston INPO Records Center g(IF 9401040106 931215 PDR ADOCK 05000528 S PDR

PALO VERDE NUCLEAR GENERATING STATION UNIT 1

'I Seismic Monitoring System Strong Motion Accelerometer License No. NPF-41 Docket No. 50-528 Special Report 1-SR-93-007 Initial Conditions:

This special report is being submitted pursuant to Techhical Specification (TS) Limiting Condition for Operation (LCO) 3.3.3.3 ACTION (a) and TS 6.9.2 to report an event in which one (1) strong motion accelerometer channel of the Seismic Monitoring System was inoperable for a period greater than 30 days. This accelerometer is required to be operable at all times to meet the station seismic monitoring requirements of TS LCO 3.3.3.3. The 30 day period for returning the accelerometer to an OPERABLE condition was exceeded at approximately 0932 MST on December 15, 1993.

.S stem Descri tion:

The Seismic Monitoring System (SM) is installed in Unit 1 (only) and consists of six (6) tri-axial strong motion accelerometer assemblies, associated instrumentation, and recording equipment for measuring plant response to earthquake activity. Each tri-axial strong motion accelerometer assembly consists of three (3) single-axis accelerometers.

All six (6) of the strong motion accelerometer channels are installed with a channel orientated vertical, a channel orientated true East-West, and a channel orientated true North-South. A response spectrum analyzer is provided to compare seismic acceleration response spectra with plant design response spectra to determine if design response spectra are exceeded. After an earthquake, the decision to continue operating the units or to shut them down is based on an analysis which is performed to determine whether or not the plant seismic Design Bases Response Spectra (DBRS) (i.e., allowable stresses) have been exceeded.

II Cause of Malfunction:

During the performance of Surveillance Test (ST) 36ST-1SM01, the strong motion accelerometer assembly mounted on the Reactor Coolant Pump (RCP) upper end bell did not have an output to the SM cabinet. Troubleshooting identified that one (1) of the three (3) single-axis accelerometers which make-up this tri-axial channel was not responding.

V

.U. S. Nuclear Regulatory Commission Special Report 1-SR-93-007 Page 2 of 2 Plans for Restoration:

The strong motion accelerometers are Terra Technology, Model SSA-302. The remainder of the system is operating properly and will supply sufficient information to allow detection and evaluation of an earthquake. The accelerometer that failed is located on an RCP housing and can not be replaced with the unit operating. The complete tri-axial assembly will be replaced during the'next outage of sufficient duration.