ML17305A497

Supplemental Special Rept 2-SR-89-007:on 890929,radioactive Gaseous Effluent Monitors Declared Inoperable Due to Frequent Low Flow Alarms.Monitors Returned to Operable Status on 891002,violating 72 H Limit

ML17305A497
Person / Time
Site:	Palo Verde
Issue date:	01/29/1990
From:	James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
192-00626-JML, 192-626-JML, 2-SR-89-007, 2-SR-89-7, NUDOCS 9002080133
Download: ML17305A497 (6)

Text

t ACCELERATED DISTBZBUTION DEMONSTRATION SYSTEM t

REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9002080133 DOC.DATE: 90/01/29 NOTARIZED: NO DOCKET FACIL:STN-50-529 Palo Verde Nuclear Station, Unit 2, Arizona Publi 05000529 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:

Suppl to Special Rept 2-SR-89-007:on 89102,radiation monitor inoperable for greater than 72 h.

DISTRIBUTION CODE: IE22D COPIES RECEIVED LTR ENCL SIZE: D TITLE: 50.73/50.9 Licensee Event Report (LER), ncident pt, etc.

S NOTES:Standardized plant. 05000529

/

RECIPIENT COPIES RECIPIENT COPIES A ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 D CHAN,T 1 1 PETERSON,S 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 AEOD/ROAB/DSP 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 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 RR/~ST/ LBBD1 1 1 NRR/DST/SRXB 8E 1 1 REC FILE 02 1 1 RES/DSIR/EIB 1 1 GN FILE Ol 1 1 EXTERNAL EG&G WILLIAMSi S 4 4 L ST LOBBY WARD 1 1

LPDR 1 1 NRC PDR 1 NSIC MAYS,G 1 1 NSIC MURPHY,G.A 1 1 NUDOCS FULL TXT 1 1 NOTES 1 1 D

D D

NOTE TO ALL "RIDS" RECIPIENTS:

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

TOTAL NUMBER OF COPIES REQUIRED: LTTR 39 ENCL 39

1 I

k

Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O. 8OX 52034 ~ PHOENIX. ARIZONA85072-2034 JAMES M. I L"'Il*F, 192-00626-JML/TRB/RKR VICE PREL;0';

NUCLEAR PR<'.!C.ION January 29, 1990 U. S. Nuclear Regulatory Commission NRC Document Control Desk Washington, D.C. 20555

Dear Sirs:

Subj ect: Palo Verde Nuclear Generating Station (PVNGS)

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

Supplement to Special Report 2-SR-89-007 File'9-020-404 Attached please find Supplement to Special Report 2-SR-89-007 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 />.

If you have any questions on this matter, please contact Mr. Thomas Bradish, (Acting) Compliance Manager at (602) 393-2521.

Very truly yours'ML/TDS/RKR/kj Attachment cc: W. F. Conway (w/attachment)

J. B. Martin D. H. Coe T. L. Chan A. C. Gehr J. R. Newman

~00208013. P0012o F'DR ADOCK 0500052'P' PDC

I PALO VERDE NUCLEAR GENERATING STATION Radiation Monitoring Unit Inoperable for Greater Than 72 Hours License No. NPF-51 Docket No. STN 50-529 Special Report 2-SR-89-007-01 This Special Report is submitted in accordance with Technical Specifications 3.3.3.8 ACTION 42.b and 6.9.2 to report an event in which the Fuel Building Ventilation System Low Range Radioactive Gaseous Effluent Monitor (RU-145) and High Range Radioactive Gaseous Effluent Monitor (RU-146) were 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 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> limit for returning the monitors to an operable status was exceeded at approximately 0305 MST on October 2, 1989.

At approximately 0305 MST on September 29, 1989 Palo Verde Unit 2 was in Mode 1 (POWER OPERATION) at approximately 100 percent power when the Fuel Building Ventilation System Radioactive Gaseous Effluent Monitors (RU-145 and RU-146) were declared inoperable due to frequent low flow alarms on the radiation monitor sample flow. The problem was discovered by control room personnel.

Pursuant to Technical Specification 3.3.3.8 ACTION 42.a the Preplanned Alternate Sampling Program was initiated to monitor the appropriate parameters.

Monitors RU-145 and RU-146 work as a pair with RU-145 being the low range monitor and RU-146 being the high range monitor. Normal configuration consists of RU-145 operating and RU-146 in standby. When RU-145 reaches a predetermined level, RU-146 starts and RU-145 goes to standby. Since RU-145 is inoperable, RU-146 must also be declared inoperable.

An authorized work document was issued to troubleshoot and rework or replace components as necessary to correct the low flow alarms. The initial investigation revealed that a majority of the low flow alarms were a result of actual low flow conditions due to the low flow limit switch being out of adjustment. The limit switch was readjusted in accordance with an approved procedure. The cause of the remaining low flow alarms was due to the radiation monitor's microprocessor operating on instantaneous flow which resulted in process flow oscillations, sample flow oscillations, and process flow signal inconsistencies. No component failures were identified and all components were found to be working within their design capabilities.

As short term corrective action, the microprocessor is being operated in the manual process flow control mode to reduce the oscillations ~ Radiation Monitors RU-145 and RU-146 were returned to service at approximately 1735 MST on January 27, 1990. As long term corrective action, a modification is being developed to average the flow in the microprocessor. This modification is expected to be issued by May 1990. Following development of the modification, implementation will be scheduled in Units 1, 2, and 3 based on the scope of work involved and material delivery dates. A supplement to this report will be submitted by June 22, 1990 with the implementation schedules for this modification in Units 1, 2, and 3.

11 e