ML17300A979

Special Rept 2-SR-87-023:on 870717,condenser Vacuum Pump/ Gland Seal Exhaust Monitors Inoperable for Greater than 72 H.Caused by Broken Directional Wire.Mod/Design Enchancement Currently Being Evaluated.Monitors Restored

ML17300A979
Person / Time
Site:	Palo Verde
Issue date:	08/03/1987
From:	Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
192-00249-JGH-T, 192-249-JGH-T, 2-SR-87-023, 2-SR-87-23, NUDOCS 8708170040
Download: ML17300A979 (3)

Text

/ I REGULATO INFORMATION DISTRIBUTION TEM (RIDS)

ACCESSION NBR: 8708170040 DOC. DATE: 87/08/03 NOTARIZED: NO DOCKET FACIL: STN-50'-529 Palo Verde Nuclear Stations Unit 2i Arizona Pub li 05000529 AUTH. NAME AUTHOR AFFILIATION HAYNES'. G., Arizona Nuclear Poeer Prospect (formerly Arizona Public Serv RECIP. NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Special Rept 2-SR-87-023: on 870717'ondenser vacuum pump/

gland seal exhaust monitors cere inoperable for greater than 72 h. Caused bg broken directional eire. Mod/design enchancement currently being evaluated. Monitors restored.

DISTRIBUTION CODE: IE22D COPIES RECEIVED: LTR l ENCL J SIZE:

TITLE: 50. 73 Licensee Event Report (LER)i Incident Rpti etc.

NOTES: Standardi zed plant. M. Davis'RR: iCg.

05000525'ECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 LICITRAiE 1 1 DAVIS' 1 1 INTERNAL: ACRS MICHELSON 1 1 ACRS MOELLER 2 2 AEOD/DOA 1 1 AEOD/DSP/NAS 1 -1 AEOD/DSP/ROAB 2 2 AEOD/DSP/TPAB 1 1 DEDRO 1 1 NRR/DEST/ADE 1 0 NRR/DEST/ADS 1 0 NRR/DEST/CEB 1 1 NRR/DEST/ELB 1 NRR/DEST/ICSB 1 1 NRR/DEST/MEB 1 1 NRR/DEST/MTB 1 1 NRR/DEBT/PSB 1 NRR/DEST/RSB 1 1 NRR/DEST/SGB 1 1 NRR/DLPG/HFB 1 1 NRR/DLPG/GAB 1 1 NRR/DOE*/EAB 1 1 NRR/DREP/RAB 1 1 2 2 NRR/PMAS/ILRB 1 1 EG F~IL 02 1 1 RES DEPY GI 1 1 RES TELFORD> J 1 1 RES/DE'/E I B 1 1 RGN5 FILE 01 1 1 EXTERNAL: EG8cG GROHt M 5 5 H ST LOBBY WARD 1 1 LPDR NRC PDR 1 1 NSIC HARR IS> J 1 1 NSIC MAYST G 1 NOTES: 1 1 TOTAL NUMBER OF COPIES REQUIRED: LTTR 46 ENCL 44

Arizona Nuclear Power Project P,O. 8OX 52034 ~ PHOENIX. ARIZONA 85072-2034 192-00249-JGH-TRB/ESP August 3, 1987 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 NPF-51)

Special Report SR-87-023 File: 87-020-404

Dear Sirs:

Attached please find a Special Report SR-87-023 prepared and submitted pursuant to Technical Specifications 3.3.3.8 and 6.9.2. This report discusses Radiation Monitoring units 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, Compliance Supervisor at (602) 393-3531.

Very truly yours, J. G. Haynes Vice President Nuclear Production JGH/TRB/ESP/cld Attachment cc: 0. M. DeMichele (all w/a)

E. E. Van Brunt, Jr.

J. B. Martin R. P. Zimmerman R. C. Sorenson E. A. Licitra A. C. Gehr INPO Records Center 8708170040 870803 PDR ADOCK 05000529 pS S PDR

PALO VERDE NUCLEAR GENERATING STATION RADIATION MONITORS INOPERABLE FOR GREATER THAN 72 HOURS License No. NPF-51 Docket No. STN 50-529 Special Report No. 2-SR-87-023 This Special Report is being submitted pursuant to Technical Specification (T.S.) 3.3.3.8 ACTION 42 and T.S. 6.9.2 to report an event in which the Condenser Vacuum Pump/Gland Seal Exhaust Monitors (RU-141 and -142) 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 operability was exceeded at approximately 1645 MST on July 17, 1987. Since RU-141 supplies sample flow to RU-142, the malfunction of RU>>141 caused RU-142 to be declared inoperable.

At approximately 1645 MST on July 14, 1987, Palo Verde Unit 2 was in Mode 1 (POWER OPERATION) when RU-141 and -142 were taken out of service to allow the performance of the scheduled quarterly functional test.

During calibration testing low flow alarms were received on RU-141. Work authorizing documents were issued to troubleshoot the monitor. Troubleshooting revealed a damaged arc suppression circuit which in turn had impaired the directional capability of the flow control board and its output to the flow control valve. This caused intermittent low flow alarms. The arc suppression circuit serves as a circuit protector for the valve controllers. As an immediate corrective action the arc suppression circuit and flow control board were replaced. The root cause of arc suppression circuit damage was attributed to a broken directional wire. This wire caused a short which then shorted out the suppression circuit. The short in the suppression circuit caused the low flow alarms.

The broken wire is believed to have been a result of the location of the wire which increases the possibility of damage during repair and troubleshooting. To prevent recurrence a modification/design enhancement is currently being evaluated which would minimize the need to access this area during troubleshooting or repair activities.

Upon completion of the work order and appropriate surveillance test, RU-141 and RU-142 were restored to an operable status at 0522 on July 18, 1987. The monitors were unavailable for 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br /> and 37 minutes.