GO2-93-293, Special Rept:On 931116,loose Parts Detection Sys Channel 5 Did Not Pass Daily Channel Surveillance.Exact Cause Not Determined.Need to Provide Addl Notifications Should Other Channels Become Inoperable Not Necessary

Special Rept:On 931116,loose Parts Detection Sys Channel 5 Did Not Pass Daily Channel Surveillance.Exact Cause Not Determined.Need to Provide Addl Notifications Should Other Channels Become Inoperable Not Necessary

ML17290A887
Person / Time
Site:	Columbia
Issue date:	12/17/1993
From:	Parrish J WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	Faulkenberry B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
GO2-93-293, NUDOCS 9401190007
Download: ML17290A887 (3)

Text

ACCELERATED DTRIBUTION DEMONS~TION SYSTEM h

REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9401190007 DOC.DATE: 93/12/17 NOTARIZED:

NO DOCKET FACIL:50-397 WPPSS Nuclear Project, Unit 2, Washington Public Powe 05000397 AUTH.NAME AUTHOR AFFILIATION PARRISH,J.V.

Washington Public Power Supply System RECIP;NAME RECIPIENT AFFILIATION FAULKENBERRY,B.

Region. 5 (Post 820201)

SUBJECT:

Special rept:on 931116,loose parts detection sys channel 5

did not pass daily channel surveillance. Exact cause not determined.

DISTRIBUTION CODE:

IE22D COPIES RECEIVED:LTR L ENCL 0 SIZE:

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

NOTES:

D RECIPIENT ID CODE/NAME PDV LA CLIFFORD,J INTERNAL: ACRS AEOD/DSP/TPAB NRR/DE/EELB NRR/DORS/OEAB NRR/DRCH/HICB NRR/DRIL/RPEB N~/J3SSA/SPLB EG FILE~

02 RGN5 FILE 01 EXTERNAL: EGGG BRYCE,J.H NRC PDR NSIC POORE,W.

COPIES LTTR ENCL 2

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RECIPIENT ID'CODE/NAME PDV PD AEOD/DOA AEOD/ROAB/DSP NRR/DE/EMEB NRR/DRCH/HHFB NRR/DRCH/HOLB NRR/DRSS/PRPB NRR/DSSA/SRXB RES/DSIR/EIB L ST LOBBY WARD NSIC MURPHY,G.A NUDOCS FULL TXT COPIES LTTR ENCL 1,

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D NOTE TO ALL"RIDS" RECIPIENTS PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM P 1-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCVMENIS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED:

LTTR 30 ENCL

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A WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.O. Bar 968 ~ 3000 George Wasbtngton Way ~ Rtebland, 1Pasbtngton 99352-096'8

~ (509) 372-5000 December 17, 1993 G02-93-293 li Docket No. 50-397 Mr, B, H. Faulkenberry Regional Administrator US Nuclear Regulatory Commission Region V 1450 Maria Lane Walnut Creek, Ca. 94596 LD H ~

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Subject:

WNP-2, OPERATING LICENSE NO. NPF-21 SPECIAL REPORT: LOOSE-PART DETECTION INSTRUMENTATION

'his special report is submitted pursuant to the requirements ofWNP-2 Technical Specification Section 3.3.7.2 "Loose-Part Detection Instrumentation" which requires the instruments to be operable at all times. The action statement for this specification requires that "with one or more Loose-Part Detection System (LPDS) channels 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 channel(s) to OPERABLE status."

The Loose-Part Detection System has been designed and installed to detect the presence of internal loose parts in the Reactor Pressure Vessel (RPV). This system is dedicated to monitor the RPV via the use of ten permanently-mounted sensors in various locations around the Reactor Vessel.

A signal of twice the general background noise for each sensor willgenerate an alarm.

The alarm would alert the Shift Technical Advisor to listen to the signals with head phones and try to determine the cause of the alarm.

The signals causing the alarm are automatically recorded and are available for analysis.

On November 16, 1993, LPDS channel ¹5 did not pass its daily channel check surveillance.

The channel was observed to periodically driftin and out of operation.

On December 1, 1993, the channel remained out of operation for a period of time sufficient for persorinel to troubleshoot the problem.

The system engineer worked with the technicians to isolate the problem. It was determined that the channel ¹5 problem was with its associated equipment in the Drywell, and because of its location, the exact cause of the failure cannot presently be determined.

940ii90007 93i2i7 PDR ADOCK 05000397 S

PDR

Page Two SPECIAL REPORT: LOOSE-PART DETECTION INSTRUMENTATION Channel ¹5 is located on the Reactor Recirculation System B Suction in the Drywell. Analysis of the signal relationship from the 10 channels is used to determine the location of the suspected loose part.

There is one sensor located on each Reactor Recirculation line to monitor this portion of the Vessel.

Therefore determining the location of suspected loose parts at this region of the vessel willbe impacted with the loss of channel ¹5.

The alarm logic is. determined by the relationship of the background noise level gong time constant RMS average) of a channel versus the signal noise level (short time constant RMS average) of the same channel and is independent of the number ofchannels in service.

The system output is an annunciator on Board S in the Main Control Room and a magnetic tape recording of all ten signals at the time of the alarm.

There are no automatic actuations produced by this instrument.

'hile the Technical Specifications require the system to be declared inoperable, the loose parts monitor system design allows the system to be functional when less than the full ten channels are operational.

The failed equipment is located in the Drywell and is not accessible during ~

reactor operation.

An MWR has been initiated to repair the failed channel the next time the Drywell is accessible.

With the LPDS System now not operable, the Supply System does not believe that there is a requirement to provide additional notifications should other channels become inoperable while the LPDS System is still inoperable.

Sincerely,

. V. Parrish (Mail Drop 1023)

Assistant Managing Director, Operations DLO!bk CC:

BH Faulkenberry - NRC RV NS Reynolds - Winston E. Strawn JW Clifford - NRC DL Williams - BPA/399 NRC Site Inspector - 927N