ML17292A590

Special Rept:On 961023,intermediate & High Range Stack Monitors PRM-RE-1B & PRM-RE-1C Declared Inoperable.Caused by Monitor Output Had Upward Trend Due to Electronic Noise Interference.Work Request Generated

ML17292A590
Person / Time
Site:	Columbia
Issue date:	11/08/1996
From:	BEMIS P R WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	CALLAN L J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
GO2-96-221, NUDOCS 9611190144
Download: ML17292A590 (4)

Text

CATEGORY, REGULA'INFORMATION DISTRIBUTI SYSTEM (RIDS)ACCESSION NBR:9611190144 DOC.DATE: 96/ll/08 NOTARIZED:

NO DOCKET FACIAL:50-397 WPPSS Nuclear Project, Unit 2, Washington Public Powe 05000397 AUTH.NAME AUTHOR AFFILIATION BEMIS,P.R.

Washington Public Power Supply System RECIP.NAME RECIPIENT AFFILIATION CAILAN,L.J.

Region 4 (Post 820201)

SUBJECT:

Special rept:on 961023,intermediate

&high range stack monitors PRM-RE-lB 6 PRM-RE-1C declared inoperable.

Caused by monitor output had upward trend due to electronic noise interference.

Work request generated.

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR ENCL SIZE: TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.NOTES: RECIPIENT ID CODE/NAME PD4-2 PD COPIES LTTR ENCL RECIPIENT ID CODE/NAME COLBURNFT COPIES LTTR ENCL INTERNAL: ACRS AEOD/SPD/RRAB NRR/DE/ECGB NRR/DE/EMEB NRR/DRCH/HICB NRR/DRCH/HQMB NRR/DSSA/SPLB RES/DSIR/EIB EXTERNAL: L ST LOBBY WARD NOAC MURPHYFG.A NRC PDR ILE CENT NRR DE EELB NRR/DRCH/HHFB NRR/DRCH/HOLB NRR/DRPM/PECB NRR/DSSA/SRXB RGN4 FILE 01 LITCO BRYCE,J H NOAC POOREFW.NUDOCS FULL TXT E NOTE TO ALL"RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE.TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRIBUTION LZSTSt OR REDUCE THE NUMBER OF COPIES RECEIVED BY YOU OR YOUR ORGANIZATION, CONTACT THE DOCUMENT CONTROL DESK (DCD)ON EXTENSION 415-2083 TOTRL NUMBER OF COPIES REQUIRED: LTTR 26 ENCL WASHINGTON PUBLIC POWER SUPPLY SYSTEM PO.Box 968~3000 George Wasirington Way~Richland, Washington 99352.0968

~(509)372-5000 November 8, 1996 G02-96-221 Docket No.50-397 L.J.Callan Regional Administrator U.S.Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064

Subject:

WNP-2, OPERATING LICENSE NPF-21 SPECIAL REPORT REACTOR BUILDING EFFLUENT MONITORING SYSTEM This special report is submitted pursuant to the requirements of WNP-2 Technical Specification Section 3.3.7.5,"Accident Monitoring Instrumentation," Table 3.3.7.5-1, Item 31,"Reactor Building Effluent Monitoring System." Action Statement 81 for this specification requires that,"With the number of OPERABLE accident monitoring instrumentation channels less than required by the minimum channels OPERABLE requirement, either restore the inoperable channel(s) to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, or initiate the preplanned alternate method of monitoring the appropriate parameters and...prepare and submit a Special Report to the Commission pursuant to Specification 6.9.2 within 14 days following the event..." Three radiation monitors are installed in the Reactor Building elevated release discharge duct to identify and quantify gaseous radionuclide releases which could occur during normal and accident conditions.

These instruments have overlapping ranges and are characterized as low, intermediate and high range monitors.The intermediate and high range monitors, which are governed by the Technical Specifications, comprise the Reactor Building Effluent Monitoring System and provide accident monitoring capability required by Regulatory Guide 1.97.The low range monitor, which is governed by the Offsite Dose Calculation Manual, provides monitoring pursuant to 10 CFR 20 and 10 CFR 50 requirements for normal operation.

9611190144 961108 PDR ADOCK 05000397 8 PDR Page 2 REACTOR BUILDING EFFLUENT MONITORING SYSTEM On October 23, 1996 at 0740 hours0.00856 days <br />0.206 hours <br />0.00122 weeks <br />2.8157e-4 months <br />, intermediate and high range stack monitors PRM-RE-1B and PRM-RE-1C were declared inoperable and the 72-hour Action Statement was entered.The reason for the inoperability determination was that monitor output had trended upward to approximately 2,000 counts per second (cps)due to electronic noise interference.

A chemistry sample of the stack monitor atmosphere had been obtained at 0550 hours0.00637 days <br />0.153 hours <br />9.093915e-4 weeks <br />2.09275e-4 months <br /> and no nuclides were identified in the sample count.On October 26, 1996 at 0740 hours0.00856 days <br />0.206 hours <br />0.00122 weeks <br />2.8157e-4 months <br />, the Reactor Building Effluent Monitoring System was inoperable for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> requiring the submittal of this special report.The following information is provided in accordance with Technical Specification Table 3.3.7.5-1, Action Statement 81.Ac ion Taken l.A Work Request was generated and extensive troubleshooting efforts were performed, with the assistance of a contractor, to determine the cause of the intermediate and high range monitor elevated signals.2.The Backup Emergency Dose Projection System was verified operable as the preplanned alternate monitoring method.The system was initiated on October 26, 1996 at 0700 hours0.0081 days <br />0.194 hours <br />0.00116 weeks <br />2.6635e-4 months <br /> in accordance with Plant Procedure (PPM)13.8.1,"Emergency Dose Projection System Operations." au e of the Ino era ilit The cause of the increased count rate was due to electronic noise interference.

During troubleshooting efforts, signals were monitored and it was determined that 60 Hz noise and frequencies resulting from 60 Hz spiking were transmitted on the shield cables of the radiation monitoring instruments.

As a result, the monitoring instruments were counting some of the 60 Hz generated electronic noise pulses in addition to all of the signals generated from the associated detectors, such that the noise level exceeded the counts from the detector.em Sta u On October 28, 1996 at approximately 1800 hours0.0208 days <br />0.5 hours <br />0.00298 weeks <br />6.849e-4 months <br />, the electrical interference stopped.Following further evaluation, the equipment was declared operable at 1915 hours0.0222 days <br />0.532 hours <br />0.00317 weeks <br />7.286575e-4 months <br /> on October 30, 1996.Although the source of the interference is unknown at this time, efforts to resolve the problem are continuing and being tracked by means of the Problem Evaluation Request process.In addition, Plant Operators record PRM-RE-1B and PRM-RE-1C readings during each shift in accordance with PPM 3.1.10,"Operating Data and Logs." One of the purposes of this procedure is to provide plant personnel with operating information that could indicate potential trends of developing equipment problems.

Page 3 REACTOR BUILDING EFFLUENT MONITORING SYSTEM Further corrective actions consist of a continuing evaluation of: 1)the noise immunity of the radiation monitoring equipment, and 2)the source of the electronic noise interference.

Should you have any questions or require additional information pertaining to this letter, please contact Ms.Lourdes Fernandez at (509)377-4147.Res tfully~~Vi Pr, ear perations M Drop PE23 CC: LJ Callan, NRC-RIV KE Perkins Jr., NRC-RIV, Walnut Creek Field Office NS Reynolds, Winston&Strawn TG Colburn, NRR DL Williams, BPA MD 399 NRC Sr.Resident Inspector, MD 927N