ML20004D444

Potential Significant Deficiency Rept Re Defective Cable Tray Tee Sections Mfg by Tj Cope,Initially Reported on 810331.Defective Tees Will Be Repaired or Replaced.Detailed Rept Will Be Provided

ML20004D444
Person / Time
Site:	Millstone
Issue date:	04/29/1981
From:	Counsil W NORTHEAST NUCLEAR ENERGY CO.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
10CFR-050.55E, 10CFR-50.55E, AEC-MP3-235, B10201, NUDOCS 8106090402
Download: ML20004D444 (2)

Text

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140RTHI!MT tlTII.ITII!S w cc cisvim,.i .ae rme etw =

w penometecio.ic'w'*" P o. Box 270

] " HARTFORD CONNECT 6 CUT 06101 5.$2.".$N.M'["

i (203) 666-6911 k L J Z5 OE'57,'c"*C April 29, 1981 Docket No. 50 h23 AEC-MP3-235 B10201  %

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N Mr. Boyce H. Grier , Director

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g Region I . ,

Office of Inspection and Enforcement ,,  %

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U. S. Nuclear Regulatory Commisison 0' 631 Park Avenue -

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King of Prussia, P419406 i "*co lnT* ,

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Gentlemen: (,, g?

Millstone Nuclear Power Station , Unit No. 3 d gep-Eeporting of Potential Significant Deficiencies in Design and Constructions As required by Title 10, Code of Federal Regulations Part 50, Paragraph 55(e),

Northeast Nuclear Energy Cc=pany (NNECO) is reporting a potential significant deficiency in the construction of Millstone Unit No. 3.

On March 31,1981 Mr. 3. L. Carlson of Northeast Utilities Service Company (NUSCO) telephoned to your Mr. H. Kister a potential significant deficiency regarding cable tray tee sections manufactured by T. J. Cope. Field inspection had found a number of cabl? tray teus, carrying safety related cables , to have poor quality rung velds.

It has been determined that a structural failure of one or more rung velds during a seismic event ic possible because of the poor quality velds. Should this occur, it is possible that safety-related cables routed in the tray could be damaged as a result of the relative movement, between the cables and the rungs and/or side rails of the tray, during the seismic disturbance. Failure of the velds could leave sharp edges on Mth the rung ends and the side rails that could impale or abrade cable jackets and insulation ystems , t':ereby, causing circuit grounds and/or short circuits. This then could compromise the integrity of safety-related electric circuits.

A Stop Work Order has been issued to prevent installation of all remaining safety-related cable tray tees. Stone & Webster Field Quality Control personnel have been directed to inspect all tees, both installed and to be installed. All defective tees vill be either repaired or replaced so as to ensure their structural adequacy during a seismic event.

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8106090( Q jo s

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l A later report will provide details of the methods of repair and of the corrective actions to be taken to precluda recurrence of this situation.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY

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rfurts W. G. Counsil '

Senior Vice President cc: Mr. Harold D. Thornberg, Director Division of Reactor Construction Inspection Office of Inspection and Enforcement U. S. Nuclear Regulatory Commissicn Washington, D.C. 20555 e

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