ML17305A903

Suppl 2 to Special Rept 2-SR-89-007:on 890929,radioactive Gaseous Effluent Monitors Declared Inoperable for Greater than 72 H Due to Frequent Low Flow Alarms.Caused by Limit Switch Out of Adjustment.Limit Switch Readjusted

ML17305A903
Person / Time
Site:	Palo Verde
Issue date:	06/22/1990
From:	James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
192-00672-JML-T, 192-672-JML-T, 2-SR-89-007-02, 2-SR-89-7-2, NUDOCS 9006280302
Download: ML17305A903 (7)

Text

ACCELERATED STRIBUTION DEMON MJ!!.TION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9006280302 DOC.DATE: 90/06/22 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 Control, Branch (Document Control Desk)

AFFILIATION'ocument

SUBJECT:

Special Rept 2-SR-89-007,Suppl 2:on 891002,radiation monitoring unit unit inoperable for greater than 72 h.

DISTRIBUTION CODE IE22D COPIES RECEIVED:LTR ENCL SIZE:

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

NOTES:Standardized plant. 05000529 RECIPIENT 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.

1' 2 AEOD/DOA 1 1 AEOD/DSP/TPAB AEOD/ROAB/DSP 2 2 DEDRO 1 1 NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB9H3 1 1 NRR/DLPQ/LHFB11 1 1 NRR/DLPQ/LPEB10 1 1 NOTES'OPIES NRR/DOEA/OEAB11 NRR/DST/SELB 8D EG

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FILE PLBBD1 02 1

1 1

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1 NRR/DREP/PRPB11 NRR/DST/SICB 7E NRR/DST/SRXB 8E RES/DSIR/EIB 2

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1 R LE 01 1 1 EXTERNAL:- EGGG STUART,V.A 4 4 L 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 1 1 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 38 ENCL 38

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Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O. BOX 52034 ~ PHOENIX. ARIZONA85072-2034 JAMES M. LEVINE 192-00672-JML/TRB/RKR YICE PRESIDENT June 22, 1990 NUCLEAR PRODUCTION U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Subject:

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: 90-020-404 Attached please find Supplement No. 2 to Special Report 2-SR-89-007 prepared and submitted pursuant to Technical Specifications 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 />. This supplement provides the schedule for implementing the modification to correct flow problems discussed in this report.

If you have any questions, please contact T. R.,Bradish, Compliance Manager at (602) 393-'2521.

Very truly yours, JML/TRB/RKR/tlg Attachment cc: W. F. Conway (all with attachment)

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

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NRC Document Control Desk Special Report 2-SR-89-007-02 Page 2 192-00672-JML/TRB/RKR

-June 22, 1990 bcc J. M. Levine 6125 J. N. Bailey 1966 W. C. Marsh 6123 W. E. Ide 6932 D. R. Heinicke 7294 R. J. Adney 6915 R. F. Schaller 6932 R. K. Flood .7294 J.'A. Bailey 6915 J. J. Scott 6428 F. C. Buckingham 7298 R. E. Gouge 6486 M. L. Clyde 6079 B. E. Ballard 6128 D. N. Stover (NSD) 1536 J. R. LoCicero (ISEG) 6144 R. W. Page 1938 D. B. Andrews 6345 E. E. Van Brunt 1922 Source Document File 6715 PRS File: 0000434 E. G. Firth (Training) 6155 W. F. Quinn 1502 R. J. Bouquot 6795 R. D. Baggett 6086 A. C. Rogers 1515 P. J. Coffin 6148 B. A. Brown 6148 Responsible Department (required review):

C. D. Churchman 6915 P. J. Wiley 7299 T. D. Shriver 6259 C. S. LaPeter 6259 Compliance Supervisor Compliance Manager

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-89-007-02 This Special Report is submitted in accordance with Technical'pecifications 3.3.3.8 ACTION 42.b and 6.9.2 to report an event in which the Fuel Building Ve'ntilation 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 Bui.lding System Radioactive Gaseous Effluent Monitors (RU-145 and RU-146) 'entil'ation 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'f 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 signal oscillations, sample flow oscillations, and process flow signal inconsistencies. N'o 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 has been developed to correct the flow problems that resulted in the low flow alarms discussed above. The required parts will be ordered and Units 1, 2 and 3 expect to implement the modification approximately 120 days after parts receipt.

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