ML19339C557

Interim Deficiency Rept Re Inferior Rung Welds on Cable Tray Fittings First Reported on 801015.All Tray Tees & Crosses Not Yet Installed.Welds Presently Installed Will Either Be Repaired or Replaced to Ensure Structural Adequacy

ML19339C557
Person / Time
Site:	Beaver Valley
Issue date:	11/14/1980
From:	Woolever E DUQUESNE LIGHT CO.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
10CFR-050.55E, 10CFR-50.55E, 2DLC-3782, NUDOCS 8011180603
Download: ML19339C557 (3)

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. . a , ; . ' ", G l i 7Akm, r/ rr 2 2, 2xc-3782 (412) 456-6000 435 Sixth Avenue Pittsburgrt, Pennsylvania, '". W,'i C E 3 15219 Novembep 14, 1980 United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 Attention: Mr. Boyce H. Grier, Director Gentlemen:

Subject:

Beaver Valley Power Station Unit No. 2 Docket No. 50-412 Interim Report - Inferior Welds on Cable Tray Fittings Significant Deficiency Report No. 80-05 During a recent site inspection conducted by an NRC inspector and subsequent inspections by S6h' engineers , poor quality rung welds were identified on installed and uninstalled cable tray fittings. This problem was reported to Mr. R. Feil of your office on October 15, 1980 as a significant deficiency.

An investigation into the rung weld deficiencies is currently underway. Pursuant to the requirements of 10CFR50.55 (e) ,

a written interim report to rectify the above problem is here-with submitted. A final written report will be submitted to you on January 30, 1981.

DUQUESNE LIGHT COMPANY by d A,f.2/ & s, E . &J . WOOLEVER '"

Vice President Enclosure cc: Messrs. V. Stello (15)

K. Jabbour 8 01118 0(A3 l

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INTERIM REPORT ON INFERIOR WELDS ON I l

CABLE TRAY FITTINGS '

BEAVER VALLEY POWER STATION - UNIT NO. 2 DUQUESNE LIGHT COMPANY

SUMMARY

Rung welds of poor quality have been found on a number of cable tray " tees" and " crosses" inspected in the field. Field inspection has further disclosed that, when performing the rung welding, the vendor did not adhere to his own detail drawings, which were reviewed and approved by S4W. The fittings, some of which are installed, are used in safety related cable tray systems.

IMMEDIATE ACTION TAKEN A "Stop Work" order has been issued to hold installation of all remaining safety related cable tray fittings (" tees" and " crosses" only). No action has' been taken regarding factory inspection as yet, since all tray ordered to date have been shipped to the jobsite.

DEFICIENCY During a recent site inspection conducted by an'NRC inspector, several installed cable tray fittings were noted as having rung welds that appeared to be of poor quality. Subsequent to the NRC inspectors visit, several SSW engineers inspected both. installed and uninstalled " tees" and " crosses" and found that a number of welds were deficient for the following reasons:

1. excessive porosity

2. discontinuities It was further determined that the vendor deviated from approved detail drawings when fabricating the fittings. Deviations were noted as follows:

1. Rungs were welded on both sides of back plate instead of the outside only, as shown on the drawings, and

2. The third rung in from each end of the " tee" fittings was welded to the back plate. not swaged as shown on the drawings.

.. . .s ANALYSIS OF SAFETY IMPLICATIONS A structural failure of one or more rung welds during a seismic event is possible because of the poor quality welds. Should this occur it is possible that safety related cables routed in the tray might be damaged as a result of the relative movement between the rungs and the side rails which could occur during the seismic disturbance. Failure of the welds could leave sharp edges on both the rung ends and the side rails that could abrade cable jacket and insulation systems causing circuit grounds and/or short circuits and subsequent failure of safety related circuits.

Since these fittings are used on both safety related trains, safe operation of the unit could be compromised.

CORRECTIVE ACTION TO REMEDY DEFICIENCY We have determined that certification of the tray fitting adequacy to sustain a seismic event, by either test er analysis is proble-matic. The randomness of rung weld deficiencies makes selection of a representative sample extremely difficult. Consequently, all tray " tees" and " crosses" not yet installed, and those presently installed in safety related areas, will either be repaired or replaced to ensure their structural adequacy during a seismic event.

Should the trays-be repaired / replaced by the vendor, DLC will:

1. Revise the specification to require DLC's shop inspec-tor to visually inspect each rung weld prior to gal-vanizing touch up, rather than using sampling techniques, so that an accurate assesment of the welds conformance to the specified criteria can be made. All welds will be inspected.

2. The vendor will be required to revise his detail drawings to reflect his latest fabrication procedures and resub-mit the drawings for approval and record. DLC's shop inspector will verify that fittings conform to the approved drawings.

The vendor has been apprised of the weld deficiencies and a meeting was held on October 29, 1980, to discuss them with him and to establish a schedule for component repair.

A procedure for repair of the deficient fittings is being developed.

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