ML17305A656

Special Rept 3-SR-90-003:on 900302,radiation Monitoring Unit RU-1 Removed from Svc for More than 72 H Due to Differences in Indicated 10 Minute & 1 H Average Particulate Channel Radiation Levels.Alternate Monitor Installed

ML17305A656
Person / Time
Site:	Palo Verde
Issue date:	04/04/1990
From:	James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
192-00644-JML-T, 192-644-JML-T, 3-SR-90-003, 3-SR-90-3, NUDOCS 9004170140
Download: ML17305A656 (8)

Text

=ACCELERATED STBZBUTION DEMONS . TION SYSTHQ REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9004170140 DOC.DATE: 90/04/04 NOTARIZED: NO DOCKET AF

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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-90-003:on 900302,radiation monitoring unit 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 RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 PETERSON,S. 1 1 CHAN,T 1' INTERNAL: ACNW 2 2 ACRS 2 2 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DS P 2 2 'EDRO 1 1 NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB9H3 1 1 NRR/DET/ESGB 8D 1 NRR/DLPQ/LHFB1 1 1 1 NRR/DLPQ/LPEB10 .1 1 NRR/DOEA/OEABll 1 1 NRR/DREP/PRPBll NRR/DST/SELB 8D NRR/DST/SICB 7E NRR/DST/SRXB 8E 2

1 1

2 1

1 NRR/J3SZ/WM B~ 1 1

1 1

1 1

RES/DSIR/EIB 1 1 RGN5 FILE ~ 01 1 1 EXTERNAL EGGG STUART i V A 4 4 L ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC MAYS,G 1 1 NSIC MURPHY,G.A 1 1 NUDOCS FULL TXT 1 1 NOTES: 1 1 NOTE TO ALL "RIDS" RECIPIENTS; PLEASE HELP US TO REDUCE WAFCEI CONTACT THEDOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISIS FOR DOCUMENTS YOU DON'T NEEDI TOTAL NUMBER OF COPIES REQUIRED: LTTR 39 ENCL 39

Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O. BOX 52034 ~ PHOENIX, ARIZONA85072-2034 JAMES M. LEVINE 192-00644-JML/TRB/DAJ VICE PRESIDENT NUCLEAR PRODUCTION April 4, 1990 U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

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

Special Report 3-SR-90;003 File 90-020-404 Attached please find Special Report 3-SR-90-003 prepared and submitted pursuant to Technical Specifications 3.3.3.'1 and 6.9.2. This report discusses an inoperable Containment Building atmosphere monitor.

If you have any questions, please contact T. R. Bradish, (Acting) Compliance Manager at (602) 393-2521.

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

J. B. Martin E. E. Van Brunt D. H. Coe T. L. Chan A. C. Gehr J. R. Newman

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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-90-003 DESCRIPTION OF WHAT OCCURRED:

Ini.tial Conditions:

At approximately 2230 MST on March 2, 1990, Palo Verde Unit 3 was in Mode 1 (Power Operation) at approximately 98 percent power.

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

Event Classification: Special Report This Special Report is being submitted pursuant to Technical Specification 3.3.3.1 ACTION 27 and Technical Specification 6.9.2 to report an event in which the Containment Building Atmosphere Monitor (RU-1) 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 service was exceeded at approximately 2230 MST on March 5, 1990. The backup, moveable air monitor (RU-52) was placed in service at approximately 1620 MST on March 5, 1990, pursuant to Technical Specification 3.3.3.1 ACTION 27.

At approximately 2230 MST on March 2, 1990, RU-1 was removed from service since particulate channel indication appeared abnormally low and due to differences in the indicated ten (10) minute and one (1) hour average particulate channel radiation levels. An approved work authorization document was initiated to troubleshoot and rework/replace components as necessary to correct the problem.

Troubleshooting determined that no component malfunctions occurred and RU-1 was working properly.

RU-1 continuously monitors the Containment Building atmosphere for particulate and gaseous activity. The particulate and gaseous channels serve as two (2) methods of Reactor Coolant System (RCS) leak detection. The particulate channel uses a rate of change algorithm to provide qualitative indication of RCS leakage. If an RCS leak were to occur, the particulate channel would sense the change and indicate a value above normal. During periods that no particulate activity level change existed, the particulate channel indicates a low value (e.g. 10E-9 u Ci/cc) even though some activity above the indicated value exists. Therefore, it is normal for the particulate channel to indicate an apparently

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Special Report 3-SR-90-003 Page 2 abnormal low valve if no RCS leak rate change occurred.

Following the determination that the particulate channel had been operating properly, RU-1 remained out of service in order to perform scheduled 18-month surveillance testing. Following satisfactory completion of surveillance testing, RU-1 was returned to service at approximately,1348 MST on March 13, 1990. RU-1 was inoperable approximately 10 days 15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br />.

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

Other than RU-1 being inoperable as described in Section I.B, no structures, systems, or components were inoperable at the start of the event which contributed to the event.

D. Cause of each component or system failure, if known:

Not applicable - no component or system failures were involved.

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

Not applicable - no component failures were involved.

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

Not applicable - no component failures were involved.

For failures that rendered a train of a safety system inoperable, estimated time elapsed from the discovery of the failure until the trains were returned to service:

H. Not applicable - no failures were involved.

Method of discovery of each component or system failure or procedural error:

Not applicable - there were no component or system failures or procedural errors.

Cause of Event:

The cause of RU-1 being declared inoperable was plant staff unfamiliarity with the unique characteristics of the particulate channel indication which was correct for the existing plant conditions. RU-1 remained inoperable in order to perform 18-month surveillance testing.

I Special Report 3-SR-90-003 Page 3 J. Safety System Response:

Not applicable - no safety system responses occurred and none were necessary.

K. Failed Component Information:

Not applicable - no component failures were involved.

II. ASSESSMENT OF THE SAFETY CONSEQUENCES AND IMPLICATIONS OF THIS EVENT:

There were no safety consequences or implications resulting from this event. As discussed in Section I.B., RU-l operated properly for the conditions which existed at that time. Additionally, backup, alternate containment atmosphere monitoring was implemented in accordance with Technical Specifications ACTION requirements.

III. CORRECTIVE ACTIONS:

Immediate:

As immediate corrective action, the backup, alternate containment atmosphere monitor was installed as described in Section I.B.

Action to Prevent Recurrence:

Engineering, operations, and, instrumentation and control personnel met to discuss the operation of RU-l. Engineering promulgated a memo to the appropriate plant staff personnel describing the expected response of RU-1 under various plant conditions.