ML17305A437

Special Rept 1-SR-89-003-02:on 890402,radiation Monitoring Unit Inoperable for More than 72 H.Caused by Questionable Accuracy of Gas Chamber & Lack of Addl Heat Tracing on Stated Monitors.Tracing to Be Installed

ML17305A437
Person / Time
Site:	Palo Verde
Issue date:	11/20/1989
From:	James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
1-SR-89-003-02, 1-SR-89-3-2, 192-00553-JML-T, 192-553-JML-T, NUDOCS 8912130273
Download: ML17305A437 (8)

Text

. ACCELERATED DI BUT)ON. DEMONSTR ON SYSTEM REGULATOR INFORMATION DISTRIBUTION STEM (RIDS)

ACCESSION NBR:8912130273 DOC.DATE: 89/11/20 NOTARIZED: NO DOCKET

. FACIL:STN-50-528 Palo Verde Nuclear Station, Unit '1, Arizona Publi 05000528 AUTH. NAME AUTHOR AFFILIATION LEVINEiJ.M. Arizona Public Service Co. (formerly Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

RO 1-SR-89-003-02:on 890402,radiation monitoring unit inoperable for more than 72 h.

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR L ENCL L TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

SIZE: 3 D

NOTES: 05000528 8

RECIPIENT ID CODE/NAME COPIES LTTR ENCL RECIPIENT ID CODE/NAME COPIES LTTR ENCL

/

PD5 LA 1 1 PD5 PD 1 1 h CHAN,T 1 1 DAVISgM. 1 1 INTERNAL: ACRS MICHELSON 1 1 ACRS MOELLER 2 2 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/PRPB11 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB 7E,, 1 1 NRR/DST/SPLB8D1 1 1 NRR SRXB 8E 1 1 NUDOCS-ABSTRACT 1 1 REG FILE 02 1 1 RES/DSIR/EIB 1 1 G FILE 01 1 1 I

EXTERNAL: EG&G WILLIAMSiS 4 4 L ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC MAYSiG 1 1 NSIC MURPHYiG.A 1 1 NUDOCS'ULL TXT 1 1 NOTES: 1 1 h

D

. TOTAL NUMBER OF COPIES REQUIRED: LTTR 40 ENCL 40

0 E Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O. BOX 52034 ~ PHOENIX. ARIZONA 85072-2034 192-00553-JML/TDS/DAJ November 20, 1989 U. S. Nuclear Regulatory Commission NRC Document Control Desk Washington, D.C. 20555

Dear Sirs:

Subj ect: Palo Verde Nuclear Generating Station (PVNGS)

Unit 1 Docket No. STN 50-528 (License No. NPF-41)

Special Report 1-SR-89-003-02 File: 89-020-404 Attached please find Supplement Number 2 to Special Report 1-SR-89-003 prepared and submitted pursuant to Technical Specification 3.3.3.8 ACTION 42(b) and 6.9.2.

This report discusses an inoperable radiation monitor.

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

Very, truly yours, M. Levine ice President Nuclear Production JML/TDS/DAJ/kj Attachment cc: W. F. Conway (w/attachment)

J. B. Martin T. J. Polich M. J. Davis A. C. Gehr 8'7I12130273 891'120 PDR ADDCK 05000528 8 PNU

PALO VERDE NUCLEAR GENERATING STATION UNIT 1 Radiation Monitoring Unit Inoperable for Greater Than 72 Hours License No. NPF-41 Docket No. 50-528 Special Report No. 1-SR-89-003-02 This Special Report is submitted in accordance with Technical Specification 3.3.3.8 ACTION 42(b) and 6.9.2 for an event in which the Unit 1 Condenser Evacu'ation System 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 />. 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 1135 MST on April 2, 1989. Pursuant to Technical Specification 3,3.3.8 ACTIONS 37 and 40, the Preplanned Alternate Sampling Program (PASP) was initiated at approximately 1135 MST on March 30, 1989.

At approximately 1135 MST on March 30,,1989, RU-142 was declared inoperable as a result of the Condenser Evacuation System low range effluent monitor (RU-141) being declared inoperable. RU-141 was declared inoperable due to engineering, concerns regarding the effects of moisture in the gas channel. Radioactive effluent monitor RU-141 continuously monitors the condenser vacuum pump/gland seal exhaust for gaseous activity resulting from primary to secondary leakage.

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.- Based upon gas channel readings, low range monitor RU-141 automatically starts RU-142 and initiates filtration of the condenser vacuum pump/gland seal exhaust whenever a HIGH-HIGH alarm condition is registered. RU-142 is provided for tracking radioactive effluents during postulated accident scenarios. RU-142 must be declared inoperable when RU-141 is inoperable.

PVNGS has experienced several instances wherein moisture buildup has resulted in Condenser Evacuation System radioactive effluent monitor improper operation.

In order to correct this problem, PVNGS 'engineering personnel, with the assistance of an independent consulting firm, were reviewing the design of the monitor. During, this review, information was obtained from the independent consulting firm on March 27, 1989, which brought into question the sensitivity, and thus the accuracy of the gas chamber. This information was reviewed by PVNGS engineering and management personnel's a prudent measure, RU-141 was declared inoperable until engineering resolution of the moisture problem could be effected. APS engineering personnel also discovered that additional heat tracing required by the manufacturer's original design specifications had not been installed in the Condenser Evacuation System Effluent monitors. (Further information concerning this problem is contained in Palo Verde Unit 3 LER 530/88-008.)

Based upon the results of the APS design review, it has been concluded that installation of heat tracing required by the original design specification should preclude moisture collection in the detection chamber. Therefore, the heat tracing will be installed in Unit 1, and RU-141 and -142 will be returned to service prior to restart from the current refueling outage. The peat tracing

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1-SR-89'-003-02 Page 2 N

has been installed in Units 2 and 3.

Furthermore, additional long term design modifications will be implemented to provide an increased level of assurance that moisture buildup will not result in monitor inoperability. These long term design enhancements will be installed during each unit's next refueling outage as it is not considered prudent to remove the monitors from service to implement the design enhancements. However, if further information is developed which indicates that installation of the design enhancement is necessary to assure monitor operability, the modifications will be performed as soon as practical following parts availability.

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