ML20237F029

Special Suppl Rept:On 960425,one Loose Part Detection Sys (Lpds) Was Identified to Be Inoperable.Initially Reported on 960531.Caused by Loose Parts Detector Module.Repairs Performed & Intermittent Ground No Longer Present

ML20237F029
Person / Time
Site:	Limerick
Issue date:	08/27/1998
From:	Gallagher M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9809020003
Download: ML20237F029 (2)

Text

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L. . -_-__---___------__--_---_--.----_--------------------------------.Ccliagher,P.E.

Michael P

' Plant Manager Limerick Generating Station kPECO NUCLEAR PECO Energy Company Limenck Generating Station

- A Unit of PECO Energy

[,y,y,,3I19464-0920 P

610 718 2000 T.S. 3.3.7.10 T.S. 6.9.2 August 27, 1998 Docket No. 50-352 License No. NPF-39 i' 1 U.S. Nuclear Regulatory Commission Attn: Document Control Desk  ;

Washington, DC 20555

SUBJECT:

Limerick Generating Station, Unit 1 i t

Special Report Supplement for the Inoperability of j a Loose-Part Detection System Channel for More Than 30 Days This Special Report supplement is being submitted pursuant to the requirements of Limerick Generating Station (LGS),

Unit 1 Technical Specifications (TS) Section 6.9.2 as required by TS Section 3.3.7.10, " Loose-Part Detection System." TS Section 3.3.7.10 requires that with one or more of the required Loose-Part Detection System (LPDS) channels inoperable for more than 30 days, a special Report must be  ! ,)

prepared and submitted within 10 days outlining the cause of the malfunction and the plans for restoring the channel (s) to operable status.

On May 31, 1996, the original version of this Special Report was. submitted and provided information regarding one LPDS channel that was identified to be inoperable on April 25,

') .

1996. Initial troubleshooting isolated the malfunctions of channel 1, control rod housing 02-31, to the inaccessible J[2y Unit 1 Primary Containment, and an outage was necassary to determine the cause and corrective actions. The original ,

version of this Special Report stated that inspections of l the inoperable LPDS channel would be performed during the next Unit 1 outage of sufficient duration.

During a Unit 1 forced outage (i.e., 1F27) conducted in July 1996, the line driver, accelerometer, and cabling associated with the LPDS channel 1, control rod housing 02-31, were i 9909020003 990827 "  ;

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August:27, 1998  :

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replaced. On August 2, 1996, a functional surveillance test (ST) of the channel was satisfactorily performed and the system was declared operable. However, with the unit at )

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power, additional testing of the LPDS channel 1, control rod 1 housing 02-31, was performed which revealed an intermittent ground was present. As a result, additional troubleshooting i l of the associated drywell components had to be performed l during the'next Unit 1 outage of sufficient duration or the seventh Unit 1 refueling outage (1RO7) scheduled for Ar~il 3, 1998.

In March 1998 prior to 1R07, during the biannual performance of the ST procedure for calibration of the LPDS detectors, i

Instrumentation and Controls technicians detected an anomaly l in the Unit 1, channel 1 sensor. .Upon further investigation, a cold solder joint on the input / output connection of the loose parts detector module (i.e., VIY-XG-124-1) was identified. Repairs were performed and the ST l procedure was completed satisfactory.

During 1R07 (April 1998), the line driver and accelerometer l were replaced. Following 1R07 with the unit at power, the  !

channel 1 control rod housing 02-31 LPDS signal was again evaluated, and the signature of the intermittent ground was j no longer present. j The control rod housing 02-31 LPDS channel 1 sensor was declared operable on June 6, 1998, following successful completion of the functional ST at rated power. The Unit 1 LPDS:is operable at this time. This is the final supplement to the Special Report.

If you have any questions or require additional information, i please contact Mr. Timothy A. Moore at (610) 718-3400.  !

Very truly yours, DMS cc: H. J. Miller, Administrator Region I, USNRC A. L. Burritt, USNRC Senior Resident Inspector, LGS

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