ML17303A697

Special Rept 3-SR-87-005:on 871020,condenser Evacuation Sys Radioactive Gaseous Effluent Monitors Declared Inoperable Due to Erratic Readings on RU-141.Caused by Noise within Detector.Detector Replaced & Surveillance Commenced

ML17303A697
Person / Time
Site:	Palo Verde
Issue date:	11/18/1987
From:	Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
192-00315-JGH-T, 192-315-JGH-T, 3-SR-87-005, 3-SR-87-5, NUDOCS 8711250198
Download: ML17303A697 (6)

Text

REGUL*TORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR: 8711250198 DOC.,DATE: 87/11/18 NOTARIZED: NO . DOCKET 4 FACIL: STN-50-530" Palo Verde Nuclear Stations Unit 3i Arizona Publi 05000530 AUTH. NAME AUTHOR AFFILIATION HAYNES'. G. Arizona Nuclear Power ProJect (formerly Arizona Public Serv RECIP. NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Special Rept 3-SR-87-005: on 871020T condenser evacuation sos radioactive gaseous ef fluent monitors declared inoperable due to erratic readings on RU-141. Caused bg noise within detector. Detector r ep laced 8c surveillance commenced.

DISTRIBUTION CODE: IE22D COPIES 'RECEIVED: LTR Q ENCL TITLE: 50. 73 Licensee Event Report (LER)i Incident Rpti etc.

g SIZE:

NOTES: Standardized plant. 05000530 RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 L* 1 1 PD5 PD 1 LICITRAiE 1 DAVIS' 1 INTERNAL: ACRS MICHELSON 1 1 ACRS MOELLER 2 2 AEOD/DOA 1 1 AEOD/DSP/NAS 1 AEOD/DSP/ROAB 2 2 AEOD/DSP/TPAB 1 ARM/DCTS/DAB 1 1 DEDRO 1 NRR/DEST/ADS 1 0 NRR/DEST/CEB 1 NRR/DEST/ELB 1 NRR/DEST/ICSB 1 1 NRR/DEST/MEB 1 1 NRR/DEST/MTB 1 NRR/DEST/PSB 1 NRR/DEBT/RSB 1 1 NRR/DEST/SGB 1 1 NRR/DLPG/HFB 1 NRR/DLPG/GAB 1 1 NRR/DOE*/EAB 1 1 NRR/DREP/RAB 1 1 NRR/DREP/RPB 2 2 N / S/SIB 1 1 NR R /P MAS/ I LRB 1 1 REG LE 02 1 1 RES DEPY GI 1 1 RDi J 1 1 RES/DE/EIB 1 1 RGN5 FILE 01 1 1 EXTERNAL: EQSQ GROHi M 5 5 H ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC HARRIS. J 1 1 NSIC MAYSe G 1 1 NOTES:

TOTAL NUMBER OF COPIES REQUIRED: LTTR 47 ENCL 46

Arizona Nuctear Power Project P.O. BOX 52034 ~ PHOENIX. ARIZONA 85072-2034 192-00315- JGM/TRB/ JEM November 18, 1987 U.S. Nuclear Regulatory Commission NRC Document Control Desk Washington, D .C. 20555

Dear Sirs,

'ubject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 3 Docket No. STN 50-530 (License No. NPF-65)

Speci a 1 Report 3-SR-87-005 Fi le: 87-020-404 f

Attached please ind Special Report 3-SR-87-005 prepared and submitted pursuant to Technical Specifications.3.3.3.8 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, please contact T. R. Bradish,'ompliance Lead at (602) 393-3531.

P Very truly yours, J. G. Maynes Vice President Nuclear Production JGM/TRB/JEM/kj Attachment cc: 0. M. DeMichele (all w/a)

E. E. Van Brunt, Jr.

J. B. Martin J. R. Ball E. A. Licitra A. C. Gehr INPO Records Center 8712P50298 8 pp05gp PDR ADOCK 0 PDR S

0 PALO VERDE NUCLEAR GENERATING STATION Radiation Monitoring Unit Inoperable for Greater Than 72 Hours License No. NPF-65 Docket No. STN 50-530 Special Report No. 3-SR-87-005 This Special Report is being submitted pursuant to Technical Specification 3.3.3.8 ACTION 42b and Technical Specification 6.9.2 to report an event in which a Radioactive Gaseous Effluent Monitor, (Condenser Evacuation High Range Noble Gas Activity 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 returning to operability was exceeded at approximately 1000 MST on October 23, 1987. Pursuant to Technical Specification 3.3.3.8 ACTION 42a the Preplanned Al'ternate Sampling Program was initiated to monitor the Condenser Evacuation System.

At approximately 1000 MST on October 20, 1987, Palo Verde Unit 3 was in Mode 3 (HOT STANDBY) when the Condenser Evacuation System Radioactive Gaseous Effluent Monitors, low range RU-141 and high range RU-142, were declared inoperable due to erratic readings on RU-141.

Monitors RU-141 and RU-142 work as a pair with RU-141 being the low range monitor and RU-142 being the high range monitor. Normal configuration consists of RU-141 operating and RU-142 in standby. When RU-141 reaches its

'maximum range, RU-142 starts and RU-141 goes to standby. Since RU-141 and RU-142 work in tandem, both monitors must be declared inoperable if the other ma 1 functions.

Troubleshooting, rework, and replacement of components was performed in accordance with an approved work control document. The cause of the erratic readings was determined to be noise within the detector. The detector was replaced and surveillance testing to return the monitor to operable status was commenced. During performance of the surveillance test it was identified that there was a lack of response in the Skid Mounted Indicator Controller (SMIC).

Further troubleshooting identified that the SMIC interface board was faulty.

The interface board was replaced and troubleshooting was completed. The interface board was sent to the Instrument and Control rework shop for rework or to be forwarded to the vendor for rework.

Surveillance tests are being performed in order to return RU-141 and RU-142 to operable status. It is anticipated that the monitors will be returned to operable status by November 30, 1987.

0 I