ML17304A341

Special Rept 3-SR-88-003:on 880714,radioactive Gaseous Effluent Monitors Declared Inoperable for Greater than 72 H. Caused by Incorrect Diodes Installed on High Voltage Circuit Board.Voltage Board Replaced & Test Procedure Revised

ML17304A341
Person / Time
Site:	Palo Verde
Issue date:	08/10/1988
From:	Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
192-00400-JGH-T, 192-400-JGH-T, 3-SR-88-003, 3-SR-88-3, NUDOCS 8808190310
Download: ML17304A341 (8)

Text

acczmm~'"'5~8~&'5885M%%".5M "'%'rrzx ACCESSION NBR: 880815'0310 DOC. DATE: 88/08/10 NOTARIZED: NO DOCKET ¹ FAC I L: STN-50-530 Palo Verde Nuclear Stations Unit 3i Arizona Pub AUTH. NAME AUTHOR AFFILIATION li 05000530 HAYNES'. G. Arizona Nuclear Poser Prospect (formerly Arizona Public Serv RECIP. NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Spec ial Rept 3-SR-88-03: on 880714'adioactive gaseous effluent monitors declared inoperable greater than 72 h.

DISTRIBUTION CODE: IE22D COPIES RECEIVED: LTR I ENCL Q SIZE:

TITLE: 50. 73 Licensee Event Report (LER)i 3

Incident Rpti etc.

NOTES: Standardized plant. 05000530 RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PDS LA 1 1 PDS PD 1 1 LICITRAiE 1 1 DAVIS' 1 1 INTERNAL: ACRS MICHELSON 1 1 ACRS MOELLER 2 2 ACRS WYLIE 1 1 AEOD/DOA 1 1 AEOD/DSP/NAS 1 AEOD/DSP/ROAB 2 2 AEOD/DSP/TPAB 1 1 ARM/DCTS/DAB 1 1 DEDRO 1 NRR/DEBT/ADS 7E 1 0 NRR/DEST/CEB 8H 1 1 NRR/DEST/ESB 8D 1 1 NRR/DEST/ICSB 7 1 1 NRR/DEST/MEB 9H 1 1 NRR/DEST/MTB 9H 1 NRR/DEST/PSB 8D 1 1 NRR/DEST/RSB 8E 1 NRR/DEST/SGB 8D 1 1 NRR/DLPG/HFB 10 1 1 NRR/DLPG/GAB 10 1 1 NRR/DOEA/EAB 11 1 NRR/DREP/RAB 10 1 1 NRR/DREP/RPB 10 2 2 NRR/DRIS/SIB 9A 1 1 NUDOCS-ABSTRACT 1 1 G IL 02 1 1 RES TELFORDi J 1 1 S DEPY 1 1 RES/DSIR/EIB 1 1 RGN5 FILE 01 1 1 EXTERNAL: EG&G WILLIAMS' 4 FORD BLDG HOYLE

• 1 .1 H ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC HARRIS> J 1 1 NSIC MAYST G 1 NOTES:

TOTAL NUMBER OF COPIES REQUIRED: LTTR 48 ENCL 47

1

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Arizona Nuclear Power Project P.O. BOX 52034 ~ PHOENIX. ARIZONA85072-2034 192-00400-JGH/TDS/DAJ August 10, 1988 U. S. Nuclear Regulatory Commission NRC Document Control Desk Washington, D.C. 20555

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 3 Docket No. STN 50-530 (License No. NPF-74)

Special Report 3-SR-88-003 File: 88-020-404 Attached please find Special Report 3-SR-88-003 prepared and submitted pursuant to Technical Specifications 3.3.3.8 and 6.9.2. This report discusses an inoperable Plant Vent Monitor.

If you have any questions, please contact T. D. Shriver, Compliance Manager at (602) 393-2521.

Very truly yours,

. G. Haynes Vice President Nuclear Production JGH/TDS/DAJ/kj Attachment cc: D. B. Karner (all w/a)

E. E. Van Brunt, Jr.

J. B. Martin T. J. Polich E. A. Licitra A. C. Gehr INPO Records Center 8808l90310 880810 PDR ADOCK 05000530 8 PNU

PALO VERDE NUCLEAR GENERATING STATION Radiation Monitoring Unit Inoperable for Greater Than 72 Hours License No. NPF-74 Docket No. STN 50-530 Special Report No. 3-SR-88-003 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 (Plant Vent High Range Gaseous Activity Monitor RU-144) 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 0500 HST on July 14, 1988. Pursuant to Technical Specification 3.3.3.8 ACTION 42a the Preplanned Alternate Sampling Program was initiated to monitor the Plant Vent System.

At approximately 0500 HST on July ll, 1988, Palo Verde Unit 3 was in Mode 1 (POWER OPERATIONS) at approximately 100% power when the Plant Vent System Radioactive Gaseous Effluent Monitors (RU-143 and RU-144) were declared inoperable for the implementation of a Plant Change Package (PCP) which would improve the monitors'eliability and for the performance of 18 month surveillance testing. Monitors RU-143 and RU-144 work as a pair with RU-143 being the low range monitor and RU-144 being the high range monitor. Normal configuration consists of RU-143 operating and RU-144 in standby. When RU-143 reaches a predetermined setpoint, RU-144 starts and RU-143 goes to standby.

RU-144 is provided for tracking oF postulated accident releases.

An authorized work document was issued to implement the PCP for RU-143 which would change the default parameters in the monitor's software. In the event of a Loss of Power (LOP), the default parameters provide conservative setpoints upon restoration of power. The new default parameters will improve the reliability of RU-143 by assuring that the setpoints provide sufficient operating margin to minimize spurious alarms following a loss of power, but, are still conservative enough to ensure that the limits of TS 3.11.2. 1 are not exceeded. The software was successfully installed and the 18 month surveillance testing was commenced.

The 18 month surveillance test procedure had recently been revised to require obtaining additional data for monitoring detector performance. The additional data was intended to be utilized to enhance ANPP's methodologies for monitoring detector performance. During field implementation of the new procedure, it was discovered that not all of the information required by the new procedure could be obtained and surveillance testing was discontinued.

During ANPP's investigation into the procedural problems, it was discovered that the procedure requested data that could not be obtained due to test equipment limitations. The procedure was revised to return to the original testing methodology and surveillance testing was continued.

During ANPP's investigation into the procedural problems, that it was identified a high voltage circuit board on RU-143 had incorrect diodes installed.

The incorrect diodes would not allow the high voltage to the detector to reach

Special Report 3-SR-88-003 Page 2 maximum output. The inability to achieve maximum high voltages does not affect monitor performance since the voltages which cannot be obtained are above that necessary for detector performance. Futhermore, the incorrect diodes are in the particulate sampling channel of the monitor and are not required for Technical Specification OPERABILITY considerations. The incorrect diodes were supplied by the original equipment manufacturer (Kaman Electronics) as part of the high voltage board and will be replaced by ANPP per approved work documentation.

It was n

also discovered than an air-flow sampling pump was not providing specified flow. The air pump was replaced and surveillance testing completed. The unsatisfactory air pump performance is not considered to have any adverse impact on the health and safety of the public since air flow was above the minimum required (a low air-flow alarm would have provided indication of air-flow below minimum). RU-143 and RU-144 were returned to service at approximately 1520 HST on August 4, 1988. The monitor was out of service for approximately 24 days.