ML17304A678

Special Rept 2-SR-88-007:on 881001,condenser Vacuum Pump/ Gland Seal Exhaust Low & high-range Monitors Declared Inoperable for Greater than 72 H.Caused by Defective Mylar Window on Detector.Replacement Detector Installed

ML17304A678
Person / Time
Site:	Palo Verde
Issue date:	10/26/1988
From:	Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
192-00423-JGH-T, 192-423-JGH-T, 2-SR-88-007, 2-SR-88-7, NUDOCS 8811010015
Download: ML17304A678 (7)

Text

l ACCELEMTED DI i IBUTION DEMONSTRA,i ON SYSTEM REGULATORY XNFORMATXON DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:8811010015 DOC.DATE: 88/10/26 NOTARIZED: NO DOCKET FACIL:STN-50-529 Palo Verde Nuclear Station, Unit 2, Arizona Publi'05000529 AUTH. NAME AUTHOR AFFILIATION

-HAYNESPJ.G. Arizona Nuclear Power Project (formerly Arizona Public Serv RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

SPecial Rept 2-SR-88-007:on 881001,radiation monitoring unit inoperable for greater than 72 h.

DISTRIBUTION CODE: IE22D COPIES RECEIVED: LTR I ENCL TITLE: 50.73 Licensee Event Report (LER), Incident Rpt, 4 etc.SIZE:

NOTES:Standardized plant. 05000529 RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 CHAN,T 1' DAVIS,M 1 1 A INTERNAL: ACRS MICHELSON 1 1 ACRS MOELLER 2 2 ACRS WYLXE 1 1 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 ARM/DCTS/DAB 1 1 DEDRO 1 1 NRR/DEST/ADS 7E 1 0 NRR/DEST/CEB 8H 1 1 NRR/DEST/ESB 8D 1 1 NRR/DEST/ICSB 7 1 1 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 NRR/DLPQ/HFB 10 1 1 NRR/DLPQ/QAB 10 1 '11 NRR/DOEA/EAB 11 1 .1 NRR/DREP/RAB 10 1 1 NRR/DREP/RPB 10 2 ~

2 ~RX~ IB 9A 1 1 NUDOCS-ABSTRACT 1 1 1 1 RES/DSIR/EIB 1 1 ES/'DS EPY 1 1 RES/DSR/PRAB 1 1 RGN5 FILE 01 1 1 EXTERNAL: EG&G WILLIAMS,S 4 4 FORD BLDG HOY, A 1 1 H ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC HARRIS,J 1 1 NSIC MAYS,G 1 1 NOTES 1 1 S

A NVZE XO ALL "RIDS" RECIPIENTS:

PIEASE HELP US K) REDUCE WASTE! CXKZACT XHE DOCUMEÃZ CORZROL DESK, RCCM Pl-37 (EXT. 20079) KO ZXZMHCPB YOUR K@K HKH DISXVUBUTXQN IZSTS KR DOCUMEMIS YOU DGNPT NEEDf TOTAL NUMBER OF COPIES REQUIRED: LTTR 45 ENCL 44

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Arizona Nuclear Power Project P.O, BOX 52034 ~ PHOENIX, ARIZONA85072-2034 192-00423-JGH/TDS/JJN October 26, 1988 U. S. Nuclear Regulatory Commission NRC Document Control Desk Washington, D.C. 20555

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

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

Special Report 2-SR-88-007 File: 88-020-404 Attached please find Special Report 2-SR-88-007 prepared and submitted pursuant to Technical Specifications 3.3.3.8 ACTION 42(b) and 6.9.2. This report discusses an inoperable radiation monitoring unit.

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

Very truly yours,

.('. P~

G. Haynes Vice President Nuclear Production JGH/TDS/JJN/kj Attachment cc: D. B. Karner (all w/a)

E. ED Van Brunt, Jr.

J. B. Hartin T. J. Polich H. J. Dav'is A. C. Gehr INPO Records Center SS11010015 SS1026 r-~>

PDR ADOCK 05000525' PDC

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 No. 2-SR-88-007 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 Condenser Vacuum Pump/Gland Seal Exhaust high range effluent monitor (RU-142) 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 />. As anticipated prior to the event, the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> limit for inoperability was exceeded at approximately 0843 MST on October 1, 1988.

At approximately 0843 MST on September 28, 1988, with Palo Verde Unit 2 in Mode 1 (POWER OPERATION) at approximately 100 percent power, the Condenser Vacuum Pump/Gland Seal Exhaust Low and High Range Monitors (RU-141 and RU-142) were declared inoperable to perform the 18 month Surveillance Test (ST)(36ST-9S(09). The ST was reviewed prior to implementation and it was determined that the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> limit would likely be exceeded before the ST and related work would be completed. The coordination of Maintenance and Engineering personnel was planned to support 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> coverage in an attempt to complete the work within the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> limit.

Monitors RU-141 and RU-142 work as a pair with RU-141 as the low range monitor and Ru-142 as the high range monitor, Normal configuration consists of RU-141 operating with RU-142 in standby. Low Range Monitor RU-141 automatically starts RU-142 and initiates filtration of the condenser vacuum pump/gland seal exhaust whenever the monitor registers a HIGH-HIGH alarm condition. RU-142 is provided for tracking radioactive effluents during postulated accident scenarios. RU-142 must be declared inoperable when RU-141 is inoperable.

Pursuant to Technical Specification 3.3.3.8 ACTION 37, the Preplanned Alternate Sampling Program (PASP) was initiated at approximately 0848 MST on September 28, 1988. Implementation of the PASP continued until the radiation monitoring units were returned to service.

During surveillance testing, the RU-141 detector response was determined to be unsatisfactory. An approved work order was issued to troubleshoot and either repair or replace components as required. Troubleshooting. determined that the mylar window on the detector was defective and the detector response was unsatisfactory due to moisture intrusion. A replacement detector was installed and calibrated.

During subsequent testing, the display board was spuriously indicating random characters. An approved work document was issued to troubleshoot and either repair or replace components as required. Troubleshooting determined that the Central Processing Unit (CPU) board was defective. A new CPU board was installed and tested successfully.

Special Report 2-S -007 .

Page 2 During subsequent testing, a high background count rate was observed. An approved work order was initiated to troubleshoot and either repair or replace components as required. Troubleshooting determined that a spurious actuation of the check source was causing the high reading. A modification to the check source circuitry was installed in accordance with an approved work and design change document.

During surveillance testing of RU-142, the power supply voltage was determined to be unsatisfactory. An approved work order was initiated to troubleshoot and either repair or replace components as necessary. A new power supply was installed and tested successfully.

On October ll, 1988 at approximately 0638 NST, RU-141 and RU-142 were restored to service. The monitors were inoperable for 12 days, 21 hours2.430556e-4 days <br />0.00583 hours <br />3.472222e-5 weeks <br />7.9905e-6 months <br />, and 55 minutes. A root cause of failure will be performed for the defective CPU board and the power supply.

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