ML17300B233

Suppl to Special Rept 3-SR-89-006:on 890812,radiation Monitors RU-145 & RU-146 Exceeded 72 H Limit for Returning Monitors to Operable Status.Caused by Malfunction of Monitor RU-146 Resulting in Loss of Capability to Monitor Effluents

ML17300B233
Person / Time
Site:	Palo Verde
Issue date:	12/23/1989
From:	James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
192-00608-JML-T, 192-608-JML-T, 3-SR-89-006, 3-SR-89-6, NUDOCS 9001050309
Download: ML17300B233 (12)

Text

'" g<CELERATED REGUL D MRIBUTION DEMONS Y INFORMATION DISTRIBUTI ATION SYSTEM SYFI'EM (RIDS)

ACCESS10N NBR:9001050309 DOC.DATE: 89/12/23 NOTARIZED: NO DOCKET FACIL:STN-50-530 Palo Verde Nuclear Station, Unit 3, Arizona Publi 05000530 AUTH. 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 3-SR-89-006:on 891223,radiation monitor inoperable for greater than 72 h.

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES:Standardized plant. 05000530 S

RECIPIENT-ID CODE/NAME PD5 LA DAVIS,M.

COPIES LTTR ENCL 1

1 1

1 RECIPIENT ID CODE/NAME PD5 PD 1 ',

COPIES LTTR ENCL INTERNAL: ACRS M1CHELSON 1 1 ACRS MOELLER 2 2 ACRS WYLIE 1 1 AEOD/DOA, 1 1 AEOD/DSP/TPAB .1 1 AEOD/ROAB/DSP 2 2 DEDRO 1 1 NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB9H3 1 1 NRR/DET/ESGB 8D 1 1 NRR/DLPQ/LHFB11 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEABll 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB 7E 1 1 NRR/DST/SPLB8D1 1 1 RR RXB 8E 1 1 NUDOCS-ABSTRACT 1 1 RE FILE 02 1 1 RES/DSIR/EIB 1 1 GN FILE Ol 1 1 EXTERNAL: EG&G WILLIAMS,S 4 4 L ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC MAYSgG 1 1 NSIC MURPHY,G.A 1 1 NUDOCS FULL TXT 1 1 I NOTES: 1 1 S

h D

D HAZE 'IO ALL "RZDS" RECIPZEZIS'IZASE S

HELP US 'iO REDUCE HASTE! CXNZACT 'IHE DOCUMEÃ7 CXÃIBDL DESK, RDCM Pl-37 (EXT. 20079) IO -EZiBG2QQR YOUR TAHE PB3H. DISTBZBUZICN LISTS FOR DOCKS YOU DCÃ'T NEED!

TOTAL NUMBER OF COPI S REQUIRED: LTTR 39 ENCL 39

P Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O, BOX 52034 ~ PHOENIX, ARIZONA 85072-2034 JAMES M. LEVINE 192-00608-JHL/TDS/RKR VICE PRESIDENT December 23, 1989 .

NUCLEAR PRODUCTION 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)

Supplement to Special Report 3-SR-89-006 File: 89-020-404 Attached please find Supplement Number 1 to Special Report 3-SR-89-006 prepared and submitted pursuant to Technical Specification 3.3.3.8 ACTION 42 and 6.9.2. This report discusses a radiation monitor 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. D. Shriver, Compliance Manager, at (602) 393-2521.

Very truly yours, JHL/TDS/RKR/kj Attachment cc: W. F. Conway (all w/a)

J. 8, Hartin T. J. Polich M. J. Davis A, C. Gehr 9001050309 891223 PDR ADOClII 05000530 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-89-006-01 I. DESCRIPTION OF WHAT OCCURRED:

A. Initial Conditions:

At approximately 1155 HST on August 12, 1989, Palo Verde Unit 3 was in Hode 6 (REFUELING).

B. Reportable Event Description ( Including Dates and Approximate Times of Major Occurrences):

Event Classification: Special Report submitted in accordance with ACTION 42.b of Technical Specification 3 '.3.8 This Special Report is being submitted pursuant to Technical Specification 3.3.3.8 ACTION 42.b and Technical Specification 6,.9.2, to report an event in which the Fuel Building Ventilation System High Range Radioactive Gaseous Effluent Monitor RU-146 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 the monitor to an operable status was exceeded at approximately 1155 HST on August 12, 1989.

Prior to the event, at approximately 1155 HST on August 9, 1989, Radiation Monitors RU-145 (Fuel Building Ventilation System L'ow Range Radioactive Gaseous Effluent Monitor) and RU-146 were removed from service, in accordance with an approved work document since their power supply was going to be deenergized for a planned electrical outage. Radiation Monitors RU-145 and RU-146 work as a pair with RU-145 being the low range monitor and RU-146 being the high range monitor. Normal configuration consists of RU-145 operating and RU-146 in standby. When RU-145 reaches a predetermined setpoint, RU-146 starts and RU-145 goes to standby.

Since RU-145 and RU-146 work in tandem, both monitors must be declared inoperable if the other monitor is out of service.

Pursuant .to Technical Specification 3.3.3.8 ACTION 42.a, the Preplanned Alternate Sampling Program was initiated to monitor the Fuel Building Ventilation System.

0 Special Report 3-SR-89-006-01 Page 2 The electrical outage was completed at approximately 2251 HST on August 11, 1989. At approximately 0400 HST on August 12, 1989, a functional test of RU-145 was in progress when Radiation Honitor RU-146 malfunctioned. At the time, RU-146 was in standby.

The Radiation Honitors RU-145 and RU-146 were returned to service at approximately 1650 HST on October 4, 1989.

C. Status of structures, systems, or components that were inoperable at the start of the event that contributed to the event:

Other than the Fuel Building Ventilation System Radioactive Gaseous Effluent Honitors RU-145 and RU-146; no structures, systems or components were inoperable which contributed to this event.

D. Cause of each component or system fail'ure, if known:

The cause of the monitor RU-146 malfunction described in Section I.B was due to low power supply voltage at the flow transmitter which affects calibration of the flow transmitter. Radiation Honitors RU-142, RU-144, and RU-146 are designed to be powered by an AC or DC power source. APS uses a 24 VDC power supply for these monitors'here is a rectifier in the power supply circuit to convert AC supplied power to the 24 VDC used by the monitor.

Troubleshooting of the monitor found that with a 24 VDC power supply input to the rectifier, the rectifier reduces the actual supply voltage to the monitor's flow transmitter. This provides marginal operating voltage for this design and affects calibration of the flow transmitter.

E. Failure mode, mechanism, and effect of each failed component, if known:

r The malfunction of monitor RU- 146 resulted in loss of the capability to monitor post accident radioactive effluents in the Fuel Building Ventilation System. The failure described in Section I.B was due to low power supply voltage to the flow transmitter affecting calibration of the flow transmitter.

For failures of components with multiple functions, list of systems or secondary functions that were also affected:

Not applicable - there were no failures of components with multiple functions.

G. For failures that rendered a train of- a safety system inoperable, estimated time elapsed from the discovery of the failure until the train was returned to service:

Not applicable - there were no failures which rendered a train of a safety system inoperable.

Special Report 3-SR-89-006-01 Page 3 H. Method of discovery of each component or system failure 'or procedural error:

h The malfunction of RU-146 was discovered while performing a functional test of RU-145 as described in Section I.B.

I. Cause of Event:

See,Section I.D for cause of event.

J. Safety System Response:

Not applicable - no safety system response was expected and none were received.

K. Failed Component Information:

RU-146 is manufactured by Kaman Sciences Corporation. It is model number KMG-HRH-S(N-RU-146.

II. ASSESSMENT OF THE SAFETY CONSE(UENCES AND IMPLICATIONS OF THIS EVENT:

l The radioactive gaseous effluent instrumentation is provided to monitor

-and control, as applicable, the releases of radioactive materials in gaseous 'effluents'during actual or potential releases of gaseous

, effluents. The alarm/trip setpoints for these instruments are calculated and adjusted in accordance with the methodology and parameters in. the Off-Site Dose Calculation Manual (ODCM) to ensure that the alarm/trip will occur prior to exceeding the limits of 10 CFR Part 20.

There are two separate radioactive gaseous effluent'monitoring systems:

the low range effluent monitors for normal radioactive gaseous effluents and the high range effluent monitors for post-accident radioactive, gaseous effluents. The low range monitors operate at .all times until the concentration of radioactivity in the effluent becomes too high during post-accident conditions. The high range monitors only operate when the concentration of radioactivity in the effluent is above the setpoint of the low range monitors. Radiation Monitors RU-145 and ,

RU-146 monitor the Fuel Building Ventilation Exhaust for release of activity due to a fuel handling accident. These monitors initiate a Fuel Building Essential Ventilation Actuation Signal (FBEVAS) when the activity exceeds a predetermined limit.

During the period of monitor inoperability, the Fuel Building Ventilation Exhaust is being monitored in accordance with the Preplanned Alternate Sampling Program. No fuel movement occurred. There have been no fuel handling accidents requiring operation of RU-146. Thus,, there is no impact on the health and safety of the public.

Special Report 3-SR-89-006-01 Page 4 I I I. CORRECTIVE ACTIONS:

The Fuel Building Ventilation System Radioactive Gaseous Effluent Monitors RU-145 and RU-146 were declared inoperable. The Preplanned Alternate Sampling Program was initiated.

A site modification was developed which byoasses the rectifier in the power supply circuit for radiation monitors RU-142, RU-144, and RU-146.

This site modification has been completed in Units 2 and 3. Unit 1 will complete the site modification prior to startup from the current outage.