ML20236R322

Discusses Cable Test Program Developed by Util to Address Staff Concerns Re Cable Installation Practices,Per NRC 870309 Request.Based on Results of Tests Conducted,Util Has Adequately Demonstrated Integrity of Cables in Plant

ML20236R322
Person / Time
Site:	Sequoyah
Issue date:	11/13/1987
From:	James Keppler NRC OFFICE OF SPECIAL PROJECTS
To:	White S TENNESSEE VALLEY AUTHORITY
References
NUDOCS 8711230221
Download: ML20236R322 (3)

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! ~ g?> NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 7,, p

\ / j November 13, 1987 j Docket Nos. 50-327/328 I

i Tennessee Valley Authority 1

ATTN: Mr. S. A. White l Manager of Nuclear Power l 6N 38A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801

SUBJECT:

CABLE TEST PROGRAM FOR SEQUOYAH UNITS 1 & 2

References:

1. Letter from B. J. Youngblood (NRC) to S. A. White (TVA) dated March 9,1987 4

2. Letter from R. L. Gridley (TVA) to NRC dated April 8,1987

3. Public Meeting on Cable Test Program between NRC staff and )

TVA, dated July 13, 1987

4. Letter from R. L. Gridley (TVA) to NRC dated July 31, 1987

5. Public Meeting on Silicone Rubber Cable Testing, between NRC staff.and TVA, dated September 10, 1987 ,

6. Letter from S. A. White (TVA) to J. G. Kepp?er (NRC), dated l September 10, 1987,

Subject:

Preliminary 10 CFR 21 Report 1 on Silicone Rubber-Insulated Cables j In response to TVA employee concerns regarding cable installation practices in enclosed conduits applied at Sequoyah, the NRC staff requested on March 9, 1987, that TVA conduct cable tests prior to restart to assess damage associ-ated with pull-bys, jamming and vertical drop cables supported by 90-degree condulets. TVA developed a test program to address the staff's concerns which was subsequently revised in consultation with the NRC.

TVA has completed its testing of cables to assess the three principal concerns l raised by TVA's Employee Concerns Program. The results of this effort are being documented and will be submitted to the NRC. Based on a review of the preliminary results (which involved the testing of 925 cables), it appears that TVA has adequately demonstrated the integrity of cables in the Sequoyah plant that do not utilize silicone rubber insulation. However, final staff acceptance must await TVA's final submittal of the above results. i On September 10, 1987, in a meeting between NRC and TVA on the cable testing issue. TVA and NRC discussed failures of silicone rubber insulated cables that were identified during in situ testing and from laboratory testing of uninstalled cables. These results demonstrated that silicone rubber lDR711230221 p

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Mr. S. A. White November 13, 1987 insulated cables manufactured by American Insulated Wire (AIW), Anaconda, and Rockbestos have the potential to be seriously damaged by normal stresses expected during shipping, handling and installation. Furthermore, cable insulation breakdowns, at 5,000 to 7,000 volts d.c., for a significant percentage of silicone rubber cables tested have heightened the level of ,

uncertainty with regard to the acceptability of any silicone rubber insulated I

cables installed at Sequoyah. TVA provided a report on these results pursuant to 10 CFR Part 21 because it believed they could affect other plants.

Based on the information developed to date by TVA, the staff must consider all the silicone rubber insulated cables at Sequoyah to be suspect. Although the generic concerns associated with the use of this material in other plants are under review by NRR, it is our position that this issue must be resolved for Sequoyah prior to restart.

As discussed with you earlier, the most expeditious resolution of this problem for Sequoyah may well be the replacement of all silicone rubber cables within containment. If TVA elects not to replace these cables, then TVA will have to demonstrate to the staff's satisfaction prior to restart that these cables will perform their intended safety functions in a harsh environment. The issue of what needs to be done with regard to the silicone rubber cables prior to heat-up will be addressed separately after the staff has receiveo and reviewed TVA's {

submittal on this subject.

J If you have further questions concerning this matter, please contact me.

Sincerely, 1 Original Signed by l James G. Keppler James G. Keppler, Director 1 Office of Special Projects cc: see next page DISTRIBUTION: O GF E/F Docket File JClifford NRC PDR CJamerson LPDR EMcKenna JKeppler/JAxelrad TRotella SEbneter JKelly SRichardson 0GC-Bethesda ,

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Mr. S. A. White Sequoyah Nuclear Plant Tennessee Valley Authority Cc: Regional Administrator, Region II General Counsel U.S. Nuclear Regulatory Commission Tennessee Valley Author.ity 101 Marietta Street, N.W.

400 West Summit Hill Drive Atlanta, Georgia 30323 E11 B33 Knoxville, Tennessee 37902 Resident Inspector /Sequoyah NP Mr. R. L. Gridley c/o U.S. Nuclear Regulatory Commission Tennessee Valley Authority 2600 Igou Ferry Road SN 157B Lookout Place Soddy Daisy, Tennessee 37379 Chattanooga, Tennessee 37402-2801 Mr. Richard King Mr. H. L. Abercrombie e/o U.S. GA0 l 1111 North Shore Driv 2

! Tennessee Valley Authority Sequoyah Nuclear Plant Suite 225, Box 194 Knoxville, Tennessee 37919 P.O. Box 2000 Soddy Daisy, Tennessee 37379 Tennessee Department of ,

Mr. M. R. Hardirig Public Health Tennessee Valley Authority ATTH: Director, Bureau of Sequoyah Nuclear Plant . Environmental Health Services P.O. Box 2000 Cordell Hull Building Soddy Daisy, Tennessee 37379 Nashville, Tennessee 37219 l Mr. D. L. Williams Mr. Michael H. Mobley, Director Tennessee Valley Authority Division of Radiological Health 400 West Summit Hill Drive T.E.R.R.A. Building W10 885 150 9th Avenue North Knoxville, Tennessee 37902 Nashville, Tennessee 37203 County Judge Dr. Henry Myers, Science Advisor Hamilton County Courthouse Committee on Interior Chattanooga, Tennessee 37402 and Insular Affairs

' U.S. House of Representatives Washington, D.C. 20515

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