RBG-37-685, Suppl 1 to Special Rept:On 920901,abnormal Traces Observed on Primary & Secondary 150-ft Wind Direction Analog Chart Recorders.Caused by Aged/Weathered Cable.All Cables Running Between Instruments & Boom Junction Boxes Replaced

Suppl 1 to Special Rept:On 920901,abnormal Traces Observed on Primary & Secondary 150-ft Wind Direction Analog Chart Recorders.Caused by Aged/Weathered Cable.All Cables Running Between Instruments & Boom Junction Boxes Replaced

ML20116H093
Person / Time
Site:	River Bend
Issue date:	11/05/1992
From:	Odell W GULF STATES UTILITIES CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RBG-37-685, NUDOCS 9211120269
Download: ML20116H093 (3)

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v w e m: sw u v a ec w - v n u-.sa + wman n A u f .i c r text 6 3 6 f,0 M 34e B631 November 5 ,1992 RBG. 37,685 File Nos. G9.5, G9.25.1.3 U.S. Nuclear Regulatory Commission Document Control Des'-

Washington, D.C. 20555 Gentlemen:

River Bend Station - Unit 1 Docket No. 50-458 Enclosed please find Supplement I to Gulf States Utilities Company's Special Report concerning inoperative meteorological instru:nentation at River Bend Station (RBS). This report is submitted pursuant !o RBS Technical Specification , 3.3.7.3 and 6.9.2

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[ W. H. Odell Manager - Oversight River Bend Nuclear Group WLA PDG/FRC/DNL/SMF

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cc: U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 NRC Resident Inspector P.O. Box 1051 St. Francisville, LA 70775 INPO Records Center 1100 Circle 75 Parkway Atlanta, G A 30339-3064 Mr. C. R. Oberg Public . Utility Commission of Texas 7800 Shoal Creek Ilied., Suite 400 North Austin, TX 78757 Louisiana Department of Environmental Quality Nuclear Energy Division P.O. Box 82135 Baton Rouge, LA 70884-2135 A'ITN: Administrator 5

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REPORTED CONDITION On September 1,1992, with the reactor shut down for refueling (Operational Condition 5),

abnonnal traces on the primary and sccendary 150 foot wind direction analog chart mcor<lers were observed during a routine surveillance. These square corner traces were indicative of failure of both primary and secondary channel wind direction sensers at the 150 foot location.

Note that the primary channel instrumentation had been previously rendered inoperable. On October 28, 1992, associated maintenance was completed and the meteorological tower was returned to service. Therefore, this report is submitted pursuant to Technical Specifications 3.3.7.3 and 6.9.2.

INVESTIGATI9N

'lhe metcorological tower at River Bend Station is a 150 foot open luticed tower located approximately 2800 feet west of the reactor building. Meteorological instrumentation on the tower is located at elevations of 30 feet and 150 feet, and was supplied by Teledyne-Geotech.

The secondary channel failure was investiga'ed under MWO Rl53300. Note that the previous failure of the primag channel was attributed to an aged and weathered cable. With no obvious damage present, and secondary sensor chart recordings sir.:ilar to those of the primag sensor chart recording, the failure of the secondary sensor was caused by an aged and weathered cable.

This natural aging / weathering process may have been aggravated by hurricane Andrew, which passed within 25 miles of River Bend Station. Hurricane Andrew's wmds of up to 84 miles per hour were recorded at the meteorological tower.

CORRECTIVE ACTION Maintenance Work Order (MWO) R153300 provided for the replacement of some damaged stmetural cross-arms and all insttamentation ori the meteorological tower, which consists of j primary and secondary wind speed sensors at the 30 foot and 150 foot locations, and primary -

and seccndaiy wind direction sensors at the 30 foot and 150 foot locations. In addition, all cables running between these instmments and the boom carriage ,iunction boxes were replaced under MWO R153300. Su veillance procedures have been performed and the meteorological tower has been returned to service.

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