ML17303A644

Special Rept 2-SR-87-021-01:on 870625,condenser Evacuation Sys High Range Monitor Inoperable for Greater than 72 H. Caused by Microprocessor Lockup.Central Processing Unit Replaced

ML17303A644
Person / Time
Site:	Palo Verde
Issue date:	10/23/1987
From:	Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
192-00265-JGH-T, 192-265-JGH-T, 2-SR-87-021-01, 2-SR-87-21-1, NUDOCS 8711030019
Download: ML17303A644 (3)

Text

REGUL* RY INFORMATION DISTR IBUTI SYSTEM (RIDS)

ACCESSION NBR: 871 f030019 DOC. DATE: 87/10/23 NOTARIZED: NO DOCKET FACIL: STN-50-529 Palo Verde Nuc lear Station>

'UTHOR Unit 2> Arizona Pub li 0500052'P AUTH. NAME *FF ILIAT ION HAYNES> J. G. Arizona Nuclear Power Prospect (formerly Arizona Public Serv REC IP. NAME RECIPIENT AFF IL I AT ION Document Control Branch (Document Control Desk)

SUBJECT:

Forwards supp l to Special Rept 2-SR-87-021 prepared 'c submitted per Tech Spec 3. 3. 3. 8 0 6. 9. 2. Rept discusses radiation monitoring unit inoperable for more than 72 h.

DISTRIBUTION CODE: IE22D COPIES RECEIVED: LTR ENCL SIZE:

TITLE: 50. 73 Licensee Event Report (LER)> Incident Rpt> etc.

NOTES: Standardized plant. 05000529 RECIPIENT CQP IES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 L* 1 1 PD5 PD 1 1 LICITRA> E 1 DAVIS> M 1 1 INTERNAL: ACRS MICHELSON 1 1 ACRS MQELLER 2 2 AEOD/DOA 1 AEOD/DSP/NAS 1 1 AEOD/DSP/ROAB 2 2 AEOD/DSP/TPAB 1 ARM/DCTS/DAB 1 1 DEDRO 1 1 NRR/DEST/ADS 1 0 NRR/DEST/CEB 1 1 NRR/DEST/ELB 1 NRR/DEST/ ICSB NRR/DEST/MEB 1 NRR/DEST/MTB 1 NRR/DEBT/PSB 1 1 NRR/DEST/RSB 1 1 NRR/DEST/SGB 1 NRR/DLPG/HFB 1 1 NRR/DLPG/GAB 1 NRR/DOEA/EAB 1 1 NRR/DREP/RAB 1 1 NRR/DREP/RPB 2 2 R- IB 1 1 NRR/PMAS/ILRB 1 1 02 1 1 'ES DEPY GI 1 RES TELFORD> J 1 1 RES/DE/EIB 1 1 RGN5 FILE 01 1 EXTERNAL: EG8(G GROH> M 5 5 H ST LOBBY WARD 1 1 LPDR 1 NRC PDR 1 NSIC HARRIS> J 1 NSIC M*YS> G 1 1 NOTES:

TOTAL NUMBER OF COPIES REQUIRED: LTTR 47 ENCL 46

Arizona Nuclear Power Project P.O. BOX 52034 ~ PHOENIX. ARIZONA85072-2034 192-00265-JGH/TRB/TJB October 23, 1987 NRC Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Dear Si,

rs:

Subject:

Palo Verde Nuclear Generating Station Unit 2 Docket No. STN 50-529 (License NPF-51)

Supplement to Special Report 2-SR-87-021 File: 87-020-404 Attached please find a Supplement to Special Report 2-SR-87-021 prepared and submitted pursuant to Technical Specifications 3.3.3.8 and 6.9.2. This report discusses a radiation monitoring unit which 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 />.

If you have any questions, please contact Tom Bradish, Compliance Supervisor at (602) 393-3531.

Very truly yours, 4 P~-~

J. G Haynes

~

Vice President Nuclear Production JGH/TRB/TJB/cld Attachment cc: 0. M. DeMichele (all w/a)

E. E. Van Brunt, Jr.

R. C. Sorenson J. R. Ball E. A. Licitra A. C. Gehr INPO Records Center jg/$

i l i

87 1 030 7i023 pDR ADOCK 0 ~000529 pDR P

PALO VERDE NUCLEAR GENERATING STATION RADIATION MONITOR INOPERABLE FOR GREATER THAN 72 HOURS License No. NPF-51 Docket No. STN 50-529 Special Report No. 2-SR-87-021-01 This Special Report is being submitted pursuant to Technical Specification (T.S.) 3.3.3.8 ACTION 42b and T.S. 6.9.2 to report an event in which the Condenser Evacuation System high range 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 operability was exceeded at approximately 1043 MST on June 25, 1987. Pursuant to T.S. 3.3.3.8 ACTION 42a the Preplanned Alternate Sampling Program was initiated to monitor the plant ventilation system.

At approximately 1043 MST, on June 22, 1987 Palo Verde Unit 2 was in Mode 1 (POWER OPERATION) at 100 percent power when the Condenser Evacuation System-low range monitor (RU-141) stopped communicating with the mini computer and experienced a microprocessor lockup (monitor will not count). Since RU-141 supplies sample flow to RU-142, the malfunction of RU-141 caused RU-142 to be declared inoperable.

Troubleshooting was conducted in an attempt to reset the Central Processing Unit (CPU) to remove the monitor from the lockup condition. The CPU board was removed and inspected for wear. No evidence of oxidation or excessive wear on the edge connectors was found. A new CPU board was installed and the lockup cleared. The CPU board will be examined in an effort to determine the cause of the malfunction. The monitor was then connected to the test equipment to perform the quarterly functional test. During the test, the monitor did not pass the low flow equipment fail step indicating a leak in the piping connections. Troubleshooting revealed minor air leakage between the flow instrument and the monitor inlet piping. The root cause of the air leakage was found to be a galled swagelock "T" connector. As an immediate corrective action, the "T" was replaced.

Upon completion of the work order and appropriate surveillance test, RU-141 and 142 were restored to an operable status on July 1, 1987 at 1000 MST. The monitor was out of service for 8 days, 23 hours2.662037e-4 days <br />0.00639 hours <br />3.80291e-5 weeks <br />8.7515e-6 months <br /> and 17 minutes.