ML20205J834
| ML20205J834 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 03/27/1987 |
| From: | Goldberg J HOUSTON LIGHTING & POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| ST-HL-AE-2000, NUDOCS 8704010432 | |
| Download: ML20205J834 (4) | |
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The Light
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iIouston 1.ightmg & Power P.O. Ikn 1700 Ifouston,'lixas 77001 (713) 228-9211
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7 March 27, 1987 ST-HL-AE-2000 File No.: G12.366,G2.2 10CFR50.55(e)
U. S. Nuclear Regulatory Commission Attention:
Document Control Desk Washington, DC 20555 South Texas Project Units 1 and 2 Docket Nos. STN 50-498, STN 50-499 Final Report Concerning Nylon and Tefzel Ties on Class lE Cables On February 27, 1987, Ho>ston Lighting & Power Company notified your office, pursuant to 10CFR50.55(.,'i, of an item concerning nylon and Tefzel ties securing Class lE cables in vertical cable trays.
Enclosed is our Final Report on this item.
This item has been determined to be reportable pursuant to 10CFR50.55(e).
If you should have any questions on this matter, please contact Mr.
C. A. Ayala at (512) 972-8628.
J. H. Goldberg Group Vice President, Nuclear RLP/yd
Attachment:
Final Report Concerning Nylon and Tefzel Ties on Class lE Cables G704010432 870327 PDR ADOCK 05000498 S
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ST-HL-AE-2000 F h No.:. G12.366,G2.2 llouston 1.ighting & Power Company cc:
Regional Administrator, Region IV M.B. Lee /J.E. Malaski Nuclear Regulatory Commission City of Austin 611 Ryan Plaza Drive, Suite 1000 P.O. Box 1088
. Arlington, TX 76011 Austin, TX 78767-8814 N. Prasad Kadambi, Project Manager A. von Rosenberg/M.T. Hardt U.S. Nuclear. Regulatory Commission City Public Service Board 7920 Norfolk Avenue P.O. Box 1771 Bethesda, MD 20814 San Antonio, TX 78296 Robert L. Perch, Project Manager Advisory Committee on Reactor Safeguards U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue 1717 H Street j
Bethesda, MD 20814 Washington, DC 20555 l
Dan R. Carpenter I
Senior Resident Inspector / Operations
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c/o U.S. Nuclear Regulatory
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Commission P.O. Box 910 j
Bay City, TX 77414 l
Claude E. Johnson Senior Resident Inspector /STP y
c/o U.S. Nuclear Regulatory Commission P.O. Box 910 Bay City, TX 77414 M.D. Schwarz, Jr., Esquire 4
Baker & Botts One Shell Plaze.
Houston, TX 77002
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J.R. Newman, Esquire i
Newman & Holtzinger, P.C.
j-1615 L Street, N.W.
Washington, DC 20036 l
T.V. Shockley/R.L. Range Central Power & Light Company j
P. O. Box 2121 i
Corpus Christi, TX 78403 i
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Ll/NRC/cl/hg-1 Revised 2/3/87
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Attachmsnt s
ST-HL-AE-2000 File No.: G12.366,G2.2 Page 1 of 2 South Texas Project Units 1 and 2 Docket Nos. STN 50-498, SIN 50-499 Final Report Concerning Nylon and Tefzel Ties on Class 1E Cables I. Summary On February 27, 1987, Houston Lighting & Power Company (HL&P) notified your office, pursuant to 10CFR50.55(e), of an item concerning the use of nylon and Tefzel cable ties to support cable bundles in vertical cable trays.
Over a 40-year period, the load bearing capacity of these cable ties could be reduced due to environmental effects of temperature and humidity. This could result in the weight and seismic loading of a cable bundle exceeding the cable ties' load bearing capacity which could cause cable damage or severing of terminations resulting in safety related circuit failures. Therefore, HL&P has determined that this item is reportable pursuant to 10CFR50.55(e).
II. Description The cables in long vertical runs of tray must be adequately supported to prevent damage to the cable or damage to conductor terminations due to the cable weight.
STP has used nylon and Tefzel cable ties supplied by Thomas & Betts to support the cables in vertical cable trays.
The ties secure cable bundles which are up to four inches in diameter at maximum intervals of five feet.
Given the long term environmental effects, the load bearing capacity of these cable ties may be reduced significantly.
For long vertical runs of cable in tray, this could result in the weight and seismic loading of a cable bundle exceeding the capacity of the cable ties.
III. Corrective Action Walkdowns and analyses have been performed to evaluate each vertical safety related cable configuration against support loading criteria for the 40-year life of the plant.
Environmental, weight and seismic loading factors were used in the calculation to determine the load bearing capacity of the cable ties at the end of a 40 year period.
It was determined that approximately fifteen percent of the safety related vertical runs require additional cable support.
i For Unit 1, the existing cable ties will be supplemented with Panduit heavy cross section stainless steel cable ties with neoprene cable pads where it has been determined that the present cable ties may not provide i
sufficient cable support for the 40-year plant lifetime. This will be completed prior to Unit 1 fuel load.
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Attachment ST-HL-AE-2000 File No.- G12.366,G2.2 Page 2 of 2 For Unit 2 and future installations in Unit 1, project documentation (e.g., specification and Standard Site Procedure) has been revised to require the use of the Panduit steel ties where the length of vertical cable run in tray exceeds the maximum spacing interval requirements of the National Electric Code section 300-19.
IV.
Recurrence Control The revised documents outlined in the corrective action specify the use of Panduit steel ties where cable support in vertical trays is required.
V.
Safety Analysis Inadequate support of cables by the nylon and Tefzel ties could result in cable damage or severing of terminations. Had this deficiency been left uncorrected, safety class cable failures could occur resulting in loss of safety function. Therefore, this item has been determined to be report-able pursuant to 10CFR50.55(e).
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