ML17289B128

Update to 921007 Special Rept Re Inoperability of Loose Parts Detection Instrumentation Following Failure of Channel 1 on 921113.On 921128,constant Alarm Received on Channel 8. Maint Work Request Initiated to Repair Failed Channels

ML17289B128
Person / Time
Site:	Columbia
Issue date:	01/11/1993
From:	John Baker WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
GO2-93-012, GO2-93-12, NUDOCS 9302020008
Download: ML17289B128 (3)

Text

ACCELERAIED DOCUMENT DISAISVTION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESS ')N NBR:9302020008 DOC.DATE: 93/01/11 NOTARIZED: NO DOCKET FACILf50-397 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:

Update to 921007 special rept re inoperability of loose parts detection instrumentation following failure of Channel 1 on 921113.0n 921128,constant alarm received on Channel 8; Maint work request initiated to repair failed channels.

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR r TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

ENCL g SIZE: R.

NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA PD5 PD D CLIFFORDFJ D

INTERNAL: ACNW ACRS AEOD/DOA AEOD/DSP/TPAB AEOD/ROAB/DSP NRR/DET/EMEB 7E NRR/DLPQ/LHFB10 NRR/DLPQ/LPEB10 NRR/DOEA/OEAB NRR/DREP/PRPB11 NRR/DST/SELB 8D NRR/DST/S I CB8H3 NRR/DS LB8D1 NRR/DST/SRXB 8E EG FILE 02 RES/DSIR/EIB RGN5 FILE 01 EXTERNAL: EG&G BRYCE,J.H L ST LOBBY WARD NRC PDR NSIC MURPHY,G.A NSIC POOREFW. NUDOCS FULL TXT D

S D

NOTE TO ALL"RIDS" RECIPIENTS:

S PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 31 ENCL fg

A WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.O. Box 968 ~ 3000 George Washington Way ~ Richland, Washington 99352<968 ~ (509) 372-5000 January *ll, 1993 G02-93-012 Docket No. 50-397 Mr. J. B. Martin Regional Administrator US NRC, Region V 1450 Maria Lane, Suite 210 Walnut Creek, CA 94596

Subject:

WNP-2, OPERATING LICENSE NPF-21 SPECIAL REPORT UPDATE:

LOOSE-PART DETECTION INSTRUMENTATIONTECHNICAL SPECIFICATION 3.3.7.10

Reference:

Letter G02-92-234, dated October 7, 1992, JW Baker (SS) to JB Martin (NRC),

Special Report: Loose-Part Detection System Instrumentation This submittal updates information previously provided regarding the status of Loose-Part Detection System (LPDS) instrumentation, and is presented on a voluntary basis. As described in the referenced Special Report, the LPDS was declared inoperable following failure of LPDS Channel 1 on September 5, 1992. Although the LPDS was no longer considered operable following failure of LPDS Channel 1, it was described as functionally available due to the existence of other LPDS channels that were operating properly.

Subsequent to submittal of the referenced Special Report, the signal from LPDS Channel 2 was found in a degraded condition during routine performance of a Technical Specification required channel check on November 11, 1992. Following further investigation, it wa's determined that LPDS Channel 2 was inoperative on November 13, '1992, and that the malfunction was associated with equipment in the drywell. The detector for LPDS Channel 2 is installed on the nozzle for main steam line B, and is one of two loose part sensors installed on the main steam lines. The other main steam line LPDS detector, LPDS Channel 1, is located on main steam line D. LPDS Channel 2, in conjunction with LPDS Channel 1, provides loose parts monitoring for the upper region of the reactor vessel.

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9302020008 PDR ADOCK

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Page Two l OOSE-PART DETECTION INSTRUMENTATION Additionally, on November 28, 1992, a constant alarm condition was received on LPDS Channel 8 with no indication of activity resembling a loose part. Troubleshooting efforts subsequently determined on December 1, 1992, that the alarm condition on LPDS Channel 8 was associated with malfunctioning equipment in the drywell. LPDS Channel 8 is one of four LPDS detectors that are located on control rod drive mechanisms. These detectors provide monitoring for the lower region of the reactor vessel.

The LPDS uses permanently mounted sensors located in various locations around the reactor vessel to detect the presence of internal loose parts in the reactor vessel, The location of suspected loose parts is determined by performing a vector analysis of the signal relationship between these channels. The ability to perform vector analysis of suspected loose parts in the upper region of the reactor vessel is significantly impaired by the loss of both of the main steam line LPDS channels, as is the ability to perform vector analysis of suspected loose parts in the lower region of the reactor vessel that are in proximity to the azimuth corresponding with the detector for LPDS Channel 8.

A Maintenance Work Request has been initiated to repair the failed LPDS channels. However, repair work cannot be performed while the reactor is at power because inoperative equipment associated with LPDS Channels 1, 2, and 8 is located in the drywell. Repair efforts will be undertaken at the next available and prudent outage of sufficient duration. Investigative efforts will also be made to ascertain the mechanism for each LPDS channel failure in order to identify if a common cause exists.

With the loss of LPDS Channels 1, 2, and 8, the LPDS is not only inoperable from a Technical Specifications perspective, but functionally unavailable as well. For the present, WNP-2 will continue to monitor the remaining LPDS Channels.

Sincerely; J.W Baker (M/D 927M)

WN -2 Plant Manager RJP cc: NRC Document Control Desk Mr. J. W. Clifford - NRC Mr. R. Barr, NRC Resident Inspector - (M/D 901A)

Mr. D. L. Williams, BPA (M/D 399)