ML17303A676

Special Rept 2-SR-87-027:on 871009,high Range Noble Gas Monitor Inoperable for Greater than 72 H.Caused by Malfunctioning of RU-143 Smic Display Board.Display Board Replaced

ML17303A676
Person / Time
Site:	Palo Verde
Issue date:	11/05/1987
From:	Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
2-SR-87-027, 2-SR-87-27, NUDOCS 8711120157
Download: ML17303A676 (4)

Text

REGULA RY INFORMATION DISTRIBUTI SYSTEM (RIDS)

ACCESSION NBR: 8711120157 DOC. DATE: 87/11/05 NOTARIZED: NO 'OCKET Unit 2i Arizona Publi 05000529 FACIL: STN-50-529 Palo VeT de Nuclear Stations AUTH. NAME AUTHOR AFFILIATION HAYNESI J. G." Arizona Nuclear Power ProJect (formerly Arizona Public Serv REC IP. NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk>

SUBJECT:

Special Rept 2-SR-87-027: on 871009'igh range noble gas monitor inoperabl'e for greater than 72 h. Caused by malfunctioning of RU-143 SMIC display board. Display board rep laced.

DISTRIBUTION CODE: IE22D COPIES RECEIVED: LTR TITLE: 50. 73 Licensee Event Report (LER) Incident Rpti

~

Q ENCL g etc.SIZE:

NOTES: Standardized plant. 05000529 REC IP IENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 PD5 PD 1, 1 LICITRAz E 1 1 DAVISi M 1 1 INTERNAL: ACRS MICHELSON 1 1 ACRS MOELLER 2 2 AEQD/DQA 1 AEOD/DSP/NAS 1 1 AEQD/DSP/RQ*B 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 1 NRR/DEBT/MEB 1 1 NRR/DEBT/MTB 1 NRR/DEBT/PSB 1 1 NRR/DEST/RSB 1 1 NRR/DEST/SGB 1 1 NRR/DLPG/HFB 1 1 NRR/DLPG/GAB 1 1 NRR/DQEA/EAB 1 NRR/DREP/RAB 1 NRR/DREP/RPB 2 2 S/SIB 1 1 NRR/PMAS/ILRB 1 1 REG FILE 02 1 1 RES DEPY GI 1 1 GRDCE J 1 1 RES/DE/EIB 1 1 RGN5 FILE 01 1 1 EXTERNAL: EG5G GROHi M 5 5 H ST LOBBY WARD 1 LPDR 1 NRC PDR 1 1 NSIC HARRIS' 1 1 NSIC MAYST G 1 1 NOTES:

TOTAL NUMBER QF COPIES REQUIRED: LTTR 47 ENCL 46

Arizona Nuclear Power Project P.O. SOX 52034 ~ PHOENIX. ARIZONA85072-2034 192-00308-JGH-TRB/KCP November 5, 1987 U.S. Nuclear Regulatory Commission NRC Document Control Desk Washington, D.C. 20555

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 2'ocket No. STN 50-529 (License NPF-51)

Special Report 2-SR-87-027 File: 87-020-404 Attached please find Special Report 2-SR-87-027 prepared and submitted pursuant to Technical Specifications 3.3.3.8 and 6.9.2. This report discusses a radiation monitor that 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 T. R. Bradish, Compliance Supervisor at (602) 393-3531.

Very truly yours, VI" J. G. H ynes Vice President Nuclear Production JGH/TRB/KCP/cld 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 87iil201S7 87ii05 PDR ADOCK 05000M9 S PDR

PALO VERDE NUCLEAR GENERATING STATION RADIATION MONITORING UNIT INOPERABLE FOR GREATER THAN 72 HOURS License No. NPF-51 Docket No. STN 50-529 Special Report No. 2-SR-87-027 This Special Report is being submitted in accordance with Technical Specification (T.S.) 3.3.3.8 ACTION 42 (b) and 6.9.2 to report an event in which a high range noble gas monitor 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 inoperability was exceeded at approximately 1010 MST on October 9, 1987.

At approximately 1010 MST on October 6, 1987, the Plant Vent Low and High Range Monitors (RU-143/144) were declared inoperable to permit surveillance testing in accordance with 36ST-9SQ04, "Radiation Monitoring Quarterly Functional Test."

As a prerequisite to testing, rework was required for a faulty display on the skid mounted indicator and control unit (SMIC) for RU-143. Compensatory measures were established in accordance with the applicable requirements of T.S.

3.3.3.8, ACTIONS 36, 37, 40 and 42.

Monitors RU-143 and RU-144 monitor the plant vent exhaust for particulate, iodine and gaseous activity. The monitors work as a pair, with RU-143 as the low range monitor and RU-144 as the high range monitor. Normal configuration consists of RU-143 operating with RU-144 in standby. When RU-143 reaches its maximum range, RU-144 starts and RU-143 goes to standby. RU-143 and RU-144 are required to be operable at all times. Since the monitors operate in tandem, RU-144 must be declared inoperable if RU-143 is inoperable.

Subsequent evaluation revealed that the RU-143 SMIC display board would not light one of the hexidecimal light emitting diodes (LEDs). The display board was replaced and functionally tested as satisfactory, but RU-143 and RU-144 remained inoperable to support ongoing surveillance testing activities. These testing activities identified an additional, separate problem in which a defective data relay board on RU-144 prevented the monitor from being placed on-line from the Radiation Monitoring System minicomputer terminal. The data relay board was replaced under an approved work document, and testing resumed.

A root cause of the evaluation of the defective SMIC display board and data relay board has been initiated to determine why these components failed.

At approximately 1400 MST on October 12, 1987, RU-143 and RU-144 were declared operable after satisfactory completion of surveillance testing. The. duration of this event was approximately 6 days.