ML17305A730

Special Rept 1-SR-89-009,Suppl 1:on 890907,radiation Monitoring Unit Inoperable in Excess of 72 H.Caused by Failure of Sys Board Zero Insertion Connecting Socket to Ensure Solid Contact.Engineering Evaluation Completed

ML17305A730
Person / Time
Site:	Palo Verde
Issue date:	05/02/1990
From:	James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
1-SR-89-009, 1-SR-89-9, 192-00657-JML-T, 192-657-JML-T, NUDOCS 9005080083
Download: ML17305A730 (10)

Text

ACCELERATED ISTIUBUTION DEMObRATION SYSTEM l

REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9005080083 DOC.DATE: 90/05/02 NOTARIZED: NO DOCKET FACIL:STN-50-528 Palo Verde Nuclear Station, Unit 1, Arizona Publi 05000528 AUTH. NAME AUTHOR AFFILIATION LEVINE,J.M. Arizona Public Service Co. (formerly Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Special Rept 1-SR-89-009,Suppl 1:on 890907,radiation monitoring unit inoperable in excess of 72 h.

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR ENCL SIZE:

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

NOTES: 05000528 RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 PETERSON,S. 1 1 CHAN,T 1 1 INTERNAL: ACNW 2 2 ACRS 2 2 AEOD/DOA 1 1 AEOD/DS P/TPAB 1 1 AEOD/ROAB/DS P 2 2 DEDRO 1 1 NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB9H3 1 1 NRR/DET/ESGB 8D 1 1 NRR/DLPQ/LHFB11 1 1

'I NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB11 1 1 NRR/DREP/PRPBll 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB 7E 1 1 NRR/DST/SPLB8D1 1 1 NRR/DST/SRXB 8E 1 1 1 1 RES/DSIR/EIB 1 1 RG E "' 1 1 EXTERNAL: EG&G STUART,V.A 4 4 ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC MAYS,G 1 1 NSIC MURPHY,G.A 1 1 NUDOCS FULL TXT 1 1 NOTES:

NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASIEI CONTACT THEDOCUMENT CONTROL DESK, ROOM PI-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEEDl TOTAL NUMBER OF COPIES REQUIRED: LTTR 39 ENCL 39

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Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O. BOX 52034 ~ PHOENIX. ARIZONA 85072-2034 JAMES M. LEVINE 192-00657-JML/TRB/SBJ YtCC >RESIOENT NCC<5AR PAOOVCTION May 2, 1990 U. S. Nuclear Regulatory Commission NRC Document Control Desk 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-89-009 File'9-0 0-404 Attached please Supplement Number 1 to Special Report 1-SR-89-009 prepared and submitted pursuant to Technical Specification 3.3.3.8 ACTION 42(b) and 6.9.2.

This report discusses a radiation monitor inoperable for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Additionally, a copy of this report is being sent to the Regional Administrator.

If you have any questions on this matter, please contact Mr. Thomas R.

Bradish, Compliance Manager at (602) 393-2521.

Very truly yours, JML/TRB/SBJ/tlg Attachment CC: W. F. Conway (w/attachment)

J. B.'Martin D. H. Coe T. L. Chan A. C. Gehr A. L. Gutterman INPO Records Center 9005080083 900502 PDR ADOCK 05000528 C; PDC

I PALO VERDE NUCLEAR GENERATING STATION Radiation Monitoring Unit Inoperable for Greater Than 72 Hours License No. NPF-41 Docket No. STN 50-528 Supplement 1 to Special Report 1-SR-89-009 This Special Report is submitted in accordance with Technical Specifications 3.3.3.8 ACTION 42(b) and 6.9.2 for an event in which the Plant Vent High Range Effluent Monitor (RU-144) was inoperable for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> was exceeded at approximately 0623 MST on September 10, 1989 Verde Unit 1 was in a refueling outage with the core off-loaded to the

'alo spent fuel pool at the time of this event. At approximately 0623 on September 7, 1989, the plant vent low and high range effluent monitors (RU-143 and RU-144) were declared inoperable because the Skid Mounted Indication and Control (SMIC) Unit for the low range monitor was not operating properly. Pursuant to Technical Specification 3.3.3.8 ACTION 37, the Preplanned Alternate Sampling Program (PASP) was initiated at approximately 0705 MST on September 7, 1989 and continued until the radiation monitors were declared operable.

RU-143 and RU-144 radiation monitors work as a pair, with the low range monitor normally operating and the high range monitor in standby. When the low range monitor reaches a predetermined setpoint, the high range monitor starts and the low range monitor goes to standby. The high range monitor provides tracking of radioactive effluents during postulated accident scenarios. The high range monitor must be declared inoperable when the low range monitor is inoperable.

Each radiation monitor has a detector communicating with a microcomputer. The microcomputer for RU-143 is located in the post accident monitoring unit (PAMU). Routine radiation information in the microcomputer can be accessed at the radiation monitor using the SMIC unit. A portable indication and control (PIC) unit can be plugged into the microcomputer to access information, Remote access to the microcomputer is through the minicomputer. Actuations of the radiation monitor are processed by the minicomputer.

The SMIC inability to communicate with the microcomputer was intermittent.

Maintenance monitored RU-143 SMIC performance daily after the radiation monitor was declared inoperable. As part of the troubleshooting, the CPU board and system board for the SMIC were replaced. After the board chargeout, SMIC again operated intermittently. The system board was then removed and reinserted. SMIC operated properly after this readjustment.

The intermittent inability of SMIC to communicate with the microcomputer has been attributed to the system board zero insertion connecting socket. The connecting socket did not ensure solid contact at all times. Since the condition does not effect the operability of the radiation monitor, no additional corrective actions for this problem are necessary. The old sockets will be removed whenever it is necessary to replace a system board and new sockets are available. New system boards procured have a different connecting socket.

Special Report 1-SR-89-009-01 Page 2 An engineering evaluation completed on October 10, 1989 determined that the inability of RU-143 SMIC to communicate with the microcomputer did not affect the operability of the radiation monitor. SMIC is only used for accessing data. The radiation monitor was capable of initiating the required annunciations and actuations (see attached drawings). Therefore, RU-143 and RU-144 were declared operable at approximately 1300 MST on October 13, 1990.

In addition, to preclude unnecessarily declaring radiation monitors inoperable, a engineering evaluation has been completed that identifies the minimum requirements for Technical Specification radiation monitors to be operable.

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SMXC MONITORS Skid Mounted I Indicating Unit P. -141/1 2 located at Ru-143/144 monitors Ru-145/ 146 MICRO-COMPUTER Controller/Brains of the RMS system (1 per monitor )

t(EPIC Ru-141/142/143/144 located in PAMU For'. Ru-141/142 Cabinet Ru-143/144 Indicating unit Ru-145/146 connected to located on 120'f NERXC micro in PAMU Control Bldg.

For '. Ru-145/146 only, Xndicating unit located outside I l Control Room SYSTEM Console MXHX"COMPUTER (DECVRXTER) (DEC) 140'ccesses the Receives and Mini for shut- stores info from down/reboot each micro and operations and sends data to trend data, DCU terminal and located in the printer, located EFF. Office in Eff Office

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SYSTEM PRINTER (TERMINET)

Provides hard DCU Console copy of all RMS events, CRT 8 keyboard for located in C.R.

accessing mini-computer and providing alarm display and acknowledge

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