ML17306A796

Special Rept 1-SR-92-003:on 920514,unit 1 Entered Mode 3 & PASS Declare Inoperable & Failed Surveillance Test.Caused by Leaking Relief Valve & Malfunctioning Pressure Transducer. Relief Valve & Pressure Transducer Replaced

ML17306A796
Person / Time
Site:	Palo Verde
Issue date:	06/18/1992
From:	James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
1-SR-92-003, 1-SR-92-3, 192-00789-JML-T, 192-789-JML-T, NUDOCS 9206260230
Download: ML17306A796 (4)

Text

ACCELERATED DISTjUBUTION DEMONSTjRATION SYSTEM REGULA iY INFORMATION DISTRIBUTIO YSTEM (RIDS)

ACCESSION NBR:9206260230 DOC.DATE: 92/06/18 NOTARIZED: NO DOCKET ¹ FACIL:STN-50-528 Palo Verde Nuclear Station, Unit 1, Arizona Publi 05000528 AUTfi.NAME AUTHOR AFFILIATION LEVINE,J.M. Arizona Public Service Co. (formerly Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk).

SUBJECT:

Special rept 1-SR-920003:on 920514,unit 1 entered mode 3 &

PASS declare inoperable & failed surveillance test. Caused by leaking relief valve & malfunctioning pressure transducer.

Relief valve & pressure transducer replaced.

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR 3 ENCL TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

4 SIZE:

NOTES:STANDARDIZED PLANT 05000528 RECIPIENT .COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 TRAMMELLFC 1 1 THOMPSONFM 1 1 INTERNAL: ACNW 2 2 ACRS 2 2 AEOD/DOA l. 1 AEOD/DSP/TPAB 1 1

,AEOD/ROAB/DSP 2 2 NRR/DET/EMEB 7E 1 1 NRR/DLPQ/LHFB10 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB8H3 1 1 1 1 NRR/DST/SRXB 8E 1 1 QEEGF LE/ 02 1 1 RES/DSIR/EIB 1 1 RGN5 FILE 01 1 1 EXTERNAL 'G&G BRYCE F J ~ H 3 3 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MURPHYFG.A 1 1 NSIC POOREFW. 1 1 NUDOCS FULL TXT 1 1 NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WAS'ONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 33 ENCL 33

Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O. BOX 52034 ~ PHOENIX. ARIZONA85072-2034 192-00788-JML/TRB/RKR JAMES M. LEVINE VICE PRESIDENT June .18, 1992 NUCLEAR PRODUCTION U. S. Nuclear Regulatory Commission Attention: Document Control Desk Mail Station Pl-37 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-92-003 File'2-020-404 Attached please find Special Report 1-SR-92-003 prepared and submitted pursuant to Technical Specifications 3.3.3.1 ACTION 28 and 6.9.2. This report discusses the Post Accident Sampling System being inoperable for greater than seven (7) days. A copy of the Special Report is being forwarded to the Regional Administrator, NRC Region V.

If you have any questions, please contact Thomas R. Bradish, Compliance Manager, at (602) 393-5421.

Very truly yours, JML/TRB/RKR/mh Attachment cc: W. F. Conway (all with attachment)

J. B. Martin D. H. Coe 920b2b0230 920bi8 PDR ADOCK 05000528 S PDR

PALO VERDE NUCLEAR GENERATING STATION UNIT 1 Post Accident Sampling System Inoperable Greater Than Seven Days License No. NPF-41 Docket No. 50-528 Special Report 1-SR-92-003 Initial Conditions:

This Special Report is being submitted pursuant to Technical Specification (TS) 3.3.3.1 ACTION 28 and TS 6,9.2 to report an event in which the Post Accident Sampling"System (PASS) was inoperable for a period greater than seven days. The seven day period for returning PASS to. service was exceeded at approximately 0927 MST on May 21, 1992. At 0927 MST on May 21, 1992, Palo Verde Unit 1 was in Mode 2 (STARTUP) during startup following a scheduled refueling outage.

Back round Information:

PASS is designed to sample reactor coolant and containment atmosphere under post accident conditions. The liquid sample portion of the system provides cooled and depressurized reactor coolant samples as required for. analysis.

The gas sample portion of the system provides containment atmosphere samples as required for analysis.

Actions Taken:

On May 14, 1992, Palo Verde Unit 1 entered Mode 3 (HOT STANDBY), and PASS was declared inoperable for Mode 3 surveillance testing. On May 15, 1992, the PASS Reactor Coolant System (RCS) hot leg pressurized sample point failed its surveillance test. The cause of the failure was the inability of the PASS Remote Grab Sampler (RGS) to maintain the necessary vacuum in the off-gas chamber due to a leaking relief valve and a malfunctioning pressure transducer. Work was started to repair the leaking valve on May 19, 1992. At approximately 0927 MST on May 21, 1992, the Pr'eplanned Alternate Sampling Program was initiated in accordance with TS 3.3.3.1 ACTION 28 for PASS inoperable for greater than seven days.

On May 22, 1992, replacement of the relief valve and pressure transducer was completed and the PASS RCS hot leg pressurized sample point was retested. An additional leaking valve was discovered during this testing. Repair of the valve was started on May 24 and completed on May 26, 1992, however, during the post repair functional testing of the system, a switching problem was identified which was causing improper valve actuation. Troubleshooting and repair of the switch problem was completed on May 28, 1992. Retest of the RCS hot leg'ressurized sample point was successfully completed on May 28, 1992.

PASS Mode 3 surveillance testing was completed on May 29, 1992. At approximately 1530 MST on May 29, 1992, PASS was returned to OPERABLE status.

NRC Document Control Desk Special Report 1-SR-92-003 Page 2 Cause of e no crab it Troubleshooting and testing determined that the cause of the inability to maintain a vacuum in the off gas chamber was due to a leaking relief valve, a leaking three-way ball valve, and a malfunctioning pressure transducer. A switch problem was also identified which caused improper valve actuation.

These problems were identified during post maintenance surveillance testing of the PASS. The malfunction of the relief valve was due to normal aging of the valve. APS is evaluating the preventive maintenance schedule for the relief valve. The malfunction of the three-way ball valve and pressure transducer is believed to be due to foreign material interfering with proper operation. The foreign material in the valve appeared to be hard plastic which probably came from the demineralized water or nitrogen systems. APS engineering concluded that this was an isolated case. The improper valve actuation was due to two wires that were mispositioned. The cause of the wires being mispositioned was investigated in accordance with the APS Incident Investigation Program. The investigation could not identify the cause of the wires being mispositioned.

A review of the PASS operating procedure determined that the improper valve actuation would not have affected PASS operability.

Plans a d Schedule for Restorin the S stem to Service:

Following satisfactory completion of repairs and required surveillance testing, PASS was returned to OPERABLE status at approximately 1530 MST on May 29, 1992.