ML20084F552

Final Deficiency Rept 83-14 Re Cable Grip Installation. Initially Reported on 840131.Deficiency Also Noted as Item of Noncompliance from IE Insp Repts 50-454/83-49 & 50-455/83-35.Installation Determined Adequate

ML20084F552
Person / Time
Site:	Byron, Braidwood
Issue date:	03/19/1984
From:	Tramm T COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
8235N, 83-14, NUDOCS 8405040230
Download: ML20084F552 (3)

Text

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Commonwe:lth Edison i 7 One First National Plaza. Chicago, Ilknots O ~7 Address Reply to. Post Office Box 767

\ / Chicago. filinois 60690 March 19, 1984 Mr. James G. Keppler Regional Administrator U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137

Subject:

Byron Generating Station Units 1 and 2 I&E Inspection Report Nos. 50-454/83-49 and 50-455/83-35 References (a): November 17, 1983 letter from R. C.

Knop to Cordell Reed.

(b): December 30, 1983 letter from D. L.

Farrar to J. G. Keppler.

(c): February 7, 1984 letter from C. E.

Norelius to Cordell Reed.

(d): January 31, 1984, letter from T. R.

Tramm to J. G. Keppler:

Dear Mr. Keppler:

This is to provide additional information regarding actions taken to correct the item of noncompliance regarding cable grip installation wi'ich was identified in reference (a).

In reference (b) we indicated that tie wraps were not required in the installation of cable grips. In reference (c) the NRC requested additional information regarding the acceptability of cable grip installations where the cable weight was being supported only at the point of contact with the tie wrap rather than over the extended length of the cable grip. Additional information regarding nonconformance F-869 was also requested.

Tie Wraps As indicated in reference (b) the use of tie wraps is not required for cable grips to function properly. The installation of tie wraps will not prevent cable grips from functioning properly. The. installation of tie wraps may affect the amount of cable slippage that can occur.

8405040230 840319 DR ADOCK 05000 FO[

APR 51984'

o' s J. G. Keppler March 19, 1984 In any cable grip there is a chance of some cable slippage under minimum loading conditions. Cable slippage does not occur as the loading on the grip approaches its maximum capability. The installation of a tie wrap at the bottom of the grip will: a) reduce the chance of cable slippage under minimum loads; b) aid gripping of cables with hard or slick jackets (not applicable to Byron /Braidwood); and c) aid in preventing the bottom of the grip from being snagged. The installation of a tie wrap at the top of.the grip may increase the chance of cable slippage under minimum loading conditions. If the grip is stretched over the cables before installing the tie wraps at the top of the grip, the chance of cable slippage is reduced.

We expect that no damage to cables has resulted from the inctallation of tie wraps for the following reasons:

(1) The support of the cables only at the point of installation of the upper tie-wrap would not have damaged the cable jacket or insulation because the tie-wrap is installed only snug tight; i.e., the pressure on the cable would have been less than that of the cable grip.

(2) The total lack of support of a cable at a grip location would not have damaged the cable. The design requirement that the cable be supported every 35 feet is a conservative requirement based on a variety of factors including various cable constructions and seismic considerations.

Resolution of Nonconformance Report F-869 As indicated in reference (b), 140 cable grip installations were examined to assess the impact of the inadequacy in the acceptance criterion used in QC inspections. Discrepancies identified in this review were documented in nonconformance report F-869 and reported to the NRC as described in reference (d).

The engineering review of the 23 discrepancies reported has been completed. S&L has determined that none of the discrepancies has any design significance and none require rework. The review determined there are supports above and/or below the subject 23 cable grips which will support the cables in the grips and that none of the cables have exceeded the cable manufacturer's maximum unsupported length.

The sample of 140 installations exceeds the minimum sample requirements for random sampling in Military Standard 1058. We have evaluated the implication of similar discrepancies elsewhere in the plant and it is our judgment that the installation is adequate.

1 J. G. Keppler March 19, 1984 This letter should also be considered to be our final report on 50.55(e) discrepancy 83-14 reported in reference (d).

Please address any further questions regarding this matter to this office.

Very truly yours, f'

T. R. Tramm Nuclear Licensing Administrator i

1m cc: Byron Resident Inspector l

8235N

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