ML17286A940

Special Rept:On 910604,time History Triaxial Acceleration Sensor Found Malfunctioning During Performance of Seismic Sys Maint Activities.Failed Unit Returned Under Warranty to Supplier for Repair.Sys Now Fully Operational

ML17286A940
Person / Time
Site:	Columbia
Issue date:	07/15/1991
From:	John Baker WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
GO2-91-135, NUDOCS 9107310153
Download: ML17286A940 (5)

Text

FORD 1 REGUL+RY INFORMATION DZSTRZBUTZ+ SYSTEM (RIDE)

ACCESSION NBR:9107310153 DOC.DATE: 91/07/15 NOTARIZED: NO DOCKET I FACIL:50-397 WPPSS Nuclear Project, Unit 2, Washington Public Powe 05000397 AUTH. NAME AUTHOR AFFILIATION BAKER,J.W. Washington Public Power Supply System RECIP.NAME RECIPIENT AFFILIATION MARTIN,J.B. Region 5 (Post 820201)

SUBJECT:

Special rept:on 910604,time history triaxial acceleration sensor found malfunctioning during performance of seismic sys maint activities. Failed unit returned under warranty to supplier for repair.Sys now fully operational.

DISTRIBUTION CODE: ZE22D COPIES RECEIVED:LTR TITLE: 50.73/50.9 Licensee Event Report 2 ENCL Z SIZE."

(LER), Incident Rpt, etc.

NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 ' PD5 PD 1 1 ENG,P.L. 1 1 INTERNAL: ACNW 2 2 ACRS 2 2 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB 7E 1 1 NRR/DLPQ/LHFB10 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB SD 1 1 NRR/DST/SICBSH3 1 1 NR LBSD1 1 1 NRR/DST/SRXB SE 1 1 EG FILE 02 1 1 RES/DSIR/EIB 1 1 RGN5 FILE 01 1 1 EXTERNAL: EGSG BRYCEFJ.H 3 3 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MURPHYFG.A 1 1 NSIC POOREFW. 1 1 NUDOCS FULL TXT 1 1 TOTAL NUMBER OF COPIES REQUIRED: LTTR 33 ENCL 33

vi WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.O. Box 968 ~ 3000 George Washington Way ~ Richland, Washington 99352 Docket No. 50-397 July 15, 1991 7 7 G02-91-135 r ~

t r

Mr. J.B. Martin fr l Regional Administrator USNRC, Region V 1450 Maria Lane, Suite 210 Walnut Creek, Ca. 94596

Subject:

NUCLEAR PLANT NO. 2, LICENSE NO. NPF-21 SPECIAL REPORT: SEISMIC MONITORING INSTR UMEN1'ATION This Special Report is submitted pursuant to the requirements of WNP-2 Technical Specification section 3.3.7.2 "Seismic Monitoring Instrumentation" which requires the instruments to be operable at all times.

The seismic monitoring system has been designed and installed to record the response of plant buildings and systems to ground motions produced by earthquakes, This information would be used by plant operators to immediately gauge the relative size of the event and, over the long term, to verify the performance of plant design, The ac tion statement for this specification requi res that "with one or more of the above required seismic monitoring instruments inoperable for more than 30 days, in lieu of any other report reqUired by Specification 6.9.1, prepare and submit a Special Report to the Commission pursuant to Specification 6.9.2 within the next 10 days outlining the cause of the malfunction and the plans for restoring the instrument(s) to operable status."

91073iOi53 9i0715 PDR S

ADDCK 05000397 PDR (pPS/q

I On June 4, 1991 with the plant in Node 4 {cold shutdown) during the extended maintenance outage the Time History Triaxial Acceleration Sensor (SEIS-SHA-3) was found to be malfunctioning during the performance of Seismic System maintenance activities. This free-field accelerometer is located 1000 feet from all large structures and transmits electrical signals to the main control room where they are, recorded on magnetic tape. The operator can obtain a visual output on paper tape by removing the magnetic tape from the tape recorder and playing it back on the Playback Unit located immediately above the recorder. There are no alarms or lights in the control room associated with 'this sensor. This sensor is normally not energized unless the reactor building foundation experiences accelerations greater than 0.01g, at which time the seismic trigger will activate all of the triaxial time history accelerometers and recorders.

Performance of maintenance work to determine the cause oF spurious noise pulses on the seismic system tape recording, found the accelerometer to not be responding in one of the three axis. The failed unit was returned, under warranty, to the supplier for repair. The supplier of the failed accelerometer is Kinemetrics/Systems 222 Vista Avenue Pasadena, CA 91107. The cause of the failure is unknown. No fai lure analysis was done at WNP-2 because of warranty considerations. At the time of the event, al1 oF the WNP-2 spare accelerometers were at the suppliers being re-spanned and no accelerometers were'vai lab'le to replace the failed unit. A accelerometer was received from the supplier, and it was installed on July 10, 1991; The system is now fully operational.

Very truly yours,

. Baker (H/0 927M)

WNP-2 Plant Manager cc: NRC Document Control Desk Hr. C, Sorenson,, NRC Resident Inspector (H/D 901A)

INPO Records Center Atlanta, GA Ms. DotLie Sherman, ANI Hr. D. L. Williams, BPA (H/D. 399)

NRC Resident Inspector Walkover Copy

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