ML17304A734

Special Rept 3-SR-88-007:on 881024,reactor Vessel Water Level Sys Declared Inoperable for More than 48 H.Caused by Malfunction in Communications Board.Board Replaced & Installed on 881028

ML17304A734
Person / Time
Site:	Palo Verde
Issue date:	11/07/1988
From:	Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
192-00429-JGH-T, 192-429-JGH-T, 3-SR-88-007, 3-SR-88-7, NUDOCS 8811170211
Download: ML17304A734 (6)

Text

'CCELERATED DISIlIBUTION DEMONSTfOCION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:8811170211 DOC.DATE:

FACIL:STN-50-530 Palo Verde Nuclear Station, 88/11/07 NOTARIZED: NO DOCKET" I Unit 3, Arizona Publi 05000530 AUTH. NAME AUTHOR AFFILIATION HAYNES,J.G. Arizona Nuclear Power Project (formerly Arizona Public Serv RECIP.NAME RECXPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Special Rept 3-SR-88-007:on 881024,reactor vessel water level sys inoperable for more than 48 h.

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR 3 TITLE: 50.73 Licensee Event Report (LER), Incident Rpt, etc.

ENCL I SIZE:

NOTES:Standardized plant. 05000530, 8

RECIPIENT COPIES RECIPIENT COPXES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 DAVIS,M.J. 1 1 DAVIS,M 1 1 INTERNAL: ACRS MICHELSON 1 1 ACRS MOELLER 2 2 D ACRS WYLIE 1 1 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 ARM/DCTS/DAB 1 1 DEDRO NRR/DEST/CEB 8H 1.

1' 1 NRR/DEST/ADS 7E 1 0 NRR/DEST/ESB 8D 1 1 NRR/DEST/ICSB 7 1 l. NRR/DEST/MEB 9H 1 1 NRR/DEST/MTB 9H 1 1 NRR/DEST/PSB 8D 1 1 NRR/DEST/RSB 8E 1 1 NRR/DEST/SGB 8D 1 1 NRR/DLPQ/HFB 10 1 1 NRR/DLPQ/QAB 10 1 1 NRR/DOEA/EAB 11 1 1 NRR/DREP/RAB 10 1 1 NRR/DREP/RPB 10 2 2 NRR/DR /SIB 9A 1 1 NUDOCS-ABSTRACT 1 1 KEG FX 02 1 1 RES/DSIR/EIB 1 1 RES/DSR/PRAB 1 1 RGN5 FILE 01 1 1

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EXTERNAL: EGGG WILLIAMS,S 4 4 FORD BLDG HOY,A 1 1 H ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSXC HARRIS,J 1 1 NSIC MAYS,G 1 1 NOTES: 1 1 D

S more m ALL RIre" PIE'ASE HELP US ZO REDUCE HASTE! CGPZACZ 'THE DOCXJMEÃZ CXWZKIL DESK, RXM P1-37 (EXT. 20079) KO EZQMZHATH KKR MME PRCH DXSTBIBUTIGN ZiZSXS %OR DOCLlMERX8 YOU DGN~T NEEDf TOTAL NUMBER OF COPIES REQUIRED: LTTR 44 ENCL 43

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0 Arizona Nuclear Power Project P.O. BOX 52034 ~ PHOENIX, ARIZONA 85072-2034 192-00429-JGH/TDS/DAJ November 7, 1988 U. S. Nuclear Regulatory Commission NRC Document Control Desk Washington, D.C. 20555

Subject:

'alo Verde Nuclear Generating Station (PVNGS)

Unit 3 Docket No. STN 50-530 (License No. NPF-74)

Special Report 3-SR-88-007 File: 88-020-404 Attached please find Special Report 3-SR-88-007 prepared and submitted

'ery pursuant to Technical Specifications 3.3.3.6, Table 3.3-10, ACTION 32. This report discusses an inoperable Reactor Vessel Water Level System.

If you have any questions, please contact T. D. Shriver, Compliance Manager at (602) 393-2521.

tru y yours, (6

J. G. Hayn s Vice President Nuclear Production JGH/TDS/DAJ/kj Attachment cc: D. B. Karner (all w/a)

E. E. Van Brunt, Jr.

J. B. Martin T. J. Polich M. J. Davis A. C. Gehr INPO Records Center 88iii702ii PDR 88ii07 ADOCK 0 000530 S PDC

t t PALO VERDE NUCLEAR GENERATING STATION UNIT 3 Both Channels of the Reactor Vessel Water Level System Inoperable License No. NPF-74 Docket No. 50-530 Special Report No. 3-SR-88-007 t

This Special Report is being submitted pursuant to Post Accident Honitoring Instrumentation Technical Specification 3.3.3.6, Table 3.3-10, ACTION STATEHENT 32 to report the inoperability of both channels of the Reactor Vessel Water Level System (RVWLS) for a period of greater than forty-eight (48) hours. The forty-eight hour time period expired on October 24, 1988 at approximately 1752 NST. RVWLS consists of two channels ("A" and "B"). Each channel utilizes eight (8) heated junction thermocouples (HJTC) to generate the signals for 8 indicated levels. There are four HJTC's in the Reactor Vessel head region and four HJTC's in the Reactor Vessel outlet plenum. HJTC output signals are processed to provide indication of reactor vessel water level. Level indication is provided on the Qualified Safety ParameterDisplay System (QSPDS).

As previously discussed in Special Report 3-SR-88-004 issued on August 22, 1988, RVWLS Channel "B" has been inoperable since July 25, 1988. On October 22, 1988 at approximately 1752 HST, Palo Verde Unit 3 was operating at approximately 100 percent power when QSPDS channel "A" was noted to be operating improperly and declared inoperable. As a result of QSPDS Channel "A" inoperability, RVWLS Channel "A" indication was not available and consequently also became inoperable.

An approved work document was initiated to determine the cause of the improper QSPDS operation and to perform the necessary rework to return QSPDS Channel "A" to service. During troubleshooting, it was identified that a communications board was malfunctioning. A replacement communications board was not immediately available on-site and efforts were undertaken to obtain a replacement board. On October 28, 1988 a replacement communications board was obtained and installed.

Following the installation of the new communications board, it was noted that the Emergency Response Facilities Data Acquisition and Display System (ERFDADS) data link with QSPDS was not operating properly. Troubleshooting could not determine the cause of the malfunction; however, since ERFDADS is not necessary for QSPDS and/or RVWLS operability, the troubleshooting efforts were terminated in order to return RVWLS to service. Further troubleshooting will be conducted in accordance with an approved work document during Unit 3's next refueling outage.

Appropriate retesting was performed on QSPDS channel "A" and it was declared operable at approximately 2002 HST on October 28, 1988. QSPDS and RVWLS were inoperable for approximately six days, two hours and ten minutes. A Root Cause of Failure engineering evaluation has been initiated for the malfunctioning QSPDS channel "A". A supplement to this Special Report will be provided to discuss the results of the root cause evaluation.

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