ST-HL-AE-2860, Special Rept:Loose Parts Monitoring Sys (Lpms) Channels 2,6 & 11 Inoperable for 30 Days.Lpms Channel 6 Inoperable Due to Failed Accelerometer.Channels 2 & 11 Inoperable Due to Continuous Alarms.Accelerometer Will Be Replaced

Special Rept:Loose Parts Monitoring Sys (Lpms) Channels 2,6 & 11 Inoperable for 30 Days.Lpms Channel 6 Inoperable Due to Failed Accelerometer.Channels 2 & 11 Inoperable Due to Continuous Alarms.Accelerometer Will Be Replaced

ML20195G959
Person / Time
Site:	South Texas
Issue date:	11/18/1988
From:	Vaughn G HOUSTON LIGHTING & POWER CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
ST-HL-AE-2860, NUDOCS 8811300154
Download: ML20195G959 (4)

Text

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The Light cliouston o rn Lighting p a ny& l'ower Sogh Texas Project Electric Generating P. O. Box 308Station , 77414 Bay City, Texas November 18, 1988 ST-HL-AE-2860 File No.: G26 10CFR50.73 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 South Texas Project Electric Generating Station Unit 1 Docket No. STN 50-498 Special Report Regarding Inoperable Loose Parts Monitoring System Channa1s _

Pursuant to the South Texas Projset Electric Generating Station FSAR Section 4.4.6.4, Houston Lighting & Power submits the attached Special Report regarding inoperable loose parts monitoring system channels.

If you should have any questions on this matter, please contact Mr. C.A. Ayala at (512) 972-8628.

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. g Vice fresident Nuclear Plant Operations GEV/BEH/n1 Attachment Special Report Regarding Inoperable Loose Parts Monitoring System Channels 8811300154 881118 PDR ADOCK 05000498 S PNU 1

NL.88.208.01 ^h

1. 1 A Subsidiary of Houston Industries incorporated l

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llouston 1.ighting & Power Company ST-HL-AE-2860 File No.: G26 Page 2 CCS Regional Administrator, Region IV Rufus S. Scott Nuclear Regulatory Commission Associate General Counsel ,

611 Ryan Plaza Drive, Suite 1000 Houston Lighting & Power Company Arlington, TX 76011 P. O. Pox 1700 .

Houston, TX 77001 l George Dick, Proj ect Manager j U. S. Nuclear Regulatory Commission INFO Vas' ington, DC 20555 Records Center 1100 Circle 75 Parkway Jack E. Bess Atlanta, Ga. 30339-3064 Senior Resident Inspect.or/ Operations e/o U. S. Nuclear Regulatory Commission Dr. Joseph H. Hendrie P. O. Box 910 50 Be11 port Lane l Bay City, TX 77414 Be11 port, NY 11713 7

J. I. Tapia l

Senior Resident Inspeccor/ Construction t c/o U. S. Nuclear Regulatory Commission l P. O. Box 910 '

Bay City, TX 77414 J. R. l'ewman, Esquire .

Newman & Holtzinger, P.C.

1615 L Street, N.V.

Vashington, DC 20036 R. L. Fange/R. P. Verret Central Power & Light Company l P. O. Box 2121 Corpus Christi, TX 78403 I R. John Miner (2 copies) l

Chief Operating Officer

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l City of Austin E1cetric Utility l

! 721 Barton Springs Road

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j Austir. TX 78704 '

i R. J. Costello/M. T. Hardt  !

I City Public Service Board {

P. O. Box 1771  !

San Antonio, TX 78296 [

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l Revised 08/24/88 !

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flouston ij hting g & Power Company South Texas Project Electric Generating Station Unit 1 Docket No. STN 50-498 Special Report Regarding Inoperable Loose Parts Monitpring System Channels DESCRIPTION OF EVENT:

Loose Parts Monitoring System (LPMS) channels 2, 6 and 11 have been inoperable for 30 days at the South Texas Project (STP) Unit 1. In accordance with the STP FSAR and Regulatory Guide 1.133, a special report to the NRC Regional Administrator is required when one or more LPMS channels are inoperable for greater than 30 days. Tne inoperable LPMS channels monitor for loose parts in the following locations:

Channel 2 Lower reactor vessel area i Channel 6 Steam Generator A Hot Leg Hanway Channel 11 Steam Generater D Hot Leg Manway There is an operable redundsnt LPHS channel monitoring for loose parts on each Re etor Coolant System (RCS) compunent listed above.

, LPMS channel 6 is inoperable due to a failed accelerometer which is

inaccessible during power operations.

LPMS channels 2 and 11 are inoperable due to continuous alarms which prevent the channels from alarming if an actual loose part signal is generated in the RCS. The cause of the alarms is a high frequency noise emanating from Reactor Coolant Pumps (RCPS) A and D. The high frequency noise was discovered during Unit 1 Hot Punctional Testing. Westinghouse has evaluated the noise i

and determined that it has no adverse structural effects on RCS components. A modification to all LPMS channels to minimize the impact of the noise on the j loose parts detection circuitry was completed on March 21, 1988. The l modification wes successful on all LPMS channels except 2 and 11. Channels 2 <

and 11 had the highest amplitude vibrations in the RCP noise frequency range l prior to the modification and the modification has failed to reduce the RCP noise signal below the alcrm setpoint.

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O Ilomton 1.ighting & Power Comiu.iy Attachment ST-HL-AE-2860 Page 2 of 2 DESCRIPTION OF EVENT Cont.d Although LPMS channels 2 and 11 are continuously alarming, the audio signal is still available in the control room for monitoring and signal analysis and redundant channels are fully operable. The Shift Technical Advisor (STA) will continue to perform daily channel checks and weekly audio checks for loose parts signals. Signal analysis will be performed quarterly.

CORRECTIVE ACTION:

The following corrective actions '... being taken to restore the Loose Parts Monitoring System to full operability:

1. The inoperable accelerometer for channel 6 will be replaced during the next scheduled Bottom Hounted Instrumentation (BMI) outage.

2. The Support Engineering Department is evaluation methods to eliminate the continuous alarms on channels 2 and 11. A supplement to this report will be submitted by February 8, 1989 outlining the status of the evaluation and a schedule for completion of corrective i

actions.

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