ML20090L282

Special Rept:On 920204,loose Parts Monitoring Sys Was Declared Inoperable.Cause Is Unknown.Sys Vendor Has Been Contacted for Assistance in Resolving These Issues

ML20090L282
Person / Time
Site:	Millstone
Issue date:	03/13/1992
From:	Scace S NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
MP-92-274, NUDOCS 9203200128
Download: ML20090L282 (2)

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I Docket No. 50-423 l Re: 10CFRf 0.36 March 13, 1992 MP-92-274 U.S. Nuc ear Regulatory Comnnssion  ;

Documeat Control Desk 4 Wasinneton, D.C. 20555 Gent'emen: ,

Millstone Nuclear Power Station, Unit No. 3 Malfunclienintimert. fads Monilentit. Salem This Special Report is being subraitted pursuant to Millstone Unit 3 Technical Specification 3.3.3 S a, Loose Parts Detection System. Plant Technical Specification 3.3,3.8.a rcquires that a Special Report be submitted to the NRC 10 days following one or more channels of the 1.cose Parts Detection System being declared inoperable for more than 30 days while in Mode 1 (Power Operation) or Mode 2 (Startup).

On February 4,1992, at 1057 hours0.0122 days <br />0.294 hours <br />0.00175 weeks <br />4.021885e-4 months <br />, with the plant in Mode 2 (Startup), at 39 power, 2250 psia and $58 degrees Fahrenheit, the Loose Parts Monitoring (LPhD System was declared inoperable. All twelve channels were not functioning uormally.

Loose Parts impacts in the Reactor Coolant System (RCS) are detected by accelerometer.; attached to major RCS components, An impact gcnerates an electrical signal from one or more accelerometers, which triggers the LPM to record information from all twelve channels on a computer did:. and actuates an alarm on the main control  :

board.

The LPM system channel Low Alarm setpoints were chanced to obtain_ a more accurate i reflection of the actual operating plant parameters. After the setpoitus were cPanged the system was calibrated per retest procedures. Upon complenon of the recalioration ,

procedures the system was switched to normal operations at which time all twelve '

channel Low Alarms were actuated.

-The root cause of this event is unknown at the present tirae and is still under investigation llased upon the troubleshooting procedures the old setpoints were reset, The LPM System channel responses are still in question. Investientive steps have focused around the controller card and the system field inputs. The system is currently 3' inoperable pending investigatio' results. The system veador has been contacted for assistance in resching these issues. An update report will be submitted by May 29.1992

/ 2fi to provide resolution information.

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The Licensee contact for this Special lieport is 13urtel N. Forrest, who may be contacted at (203) 447-1791 extension 5442.

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Very truly yours, i NORTHEAST NUCl.liAli ENEllGY CONIPANY

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1. Steph n E Scace Director, hlilktone Station i

SES/13NF:cle ec: T. T. hlariin. Region 1 Administrator i W. J. Rt.ymond. Senior Resident inspector, hiillstone Units Nos.1, 2, and 3 V. L Rooney NRC l'roject Manager. Milbtone Unit No. 3  ;

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