ML20236S032

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Forwards Final Results of Cable Test Program for Concerns Identified in NRC Technical Evaluation Rept & Formally Transmits Special Test Instructions,Raw Data & Associated Conduit Isometric Sketches
ML20236S032
Person / Time
Site: Sequoyah  Tennessee Valley Authority icon.png
Issue date: 11/20/1987
From: Gridley R
TENNESSEE VALLEY AUTHORITY
To:
NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20236S034 List:
References
NUDOCS 8711240177
Download: ML20236S032 (3)
v • d • e


Text

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V'. 4 TENNESSEE VALLEY AUTHORITY.

CHATTANOOGA. TENNESSCE 37401 SN 1578 Lookout Place.

L  : NOV 201987

. U.S. Nuclear Regulatory Commission 9 ATTN: Document. Control Desk

- Washington, D.C. 20555 Gentlemen:

In the Matter of )' Docket Nos. 50-327 Tennessee Valley, Authority. ) 50-328 SEQUOYAH NUCLEAR PLANT (SQN) UNITSL1 AND 2 - CABLE TEST PROGRAM PROCEDURES,
DATA, AND RESULTS

References:

.l . Letter from R. Gridley to NRC dated July 31, 1987, "Sequoyah Nuclear Plant (SQN) Units 1 and 2 - Revised Cable Test Program" l

2. . Letter from B. J. Youngblood to S. A. White dr.ted March 9, 1987, " Evaluation of Sequoyah Units 1 and 2 Cable Pulling and Bend Radii Concerns" Thisl letter provides the final results of TVA's cable test program for concerns identified in the NRC's Technical Evaluation Report (TER)'and formally transmits the Special Test Instructions (STIs), their raw data, and their associated conduit isometric sketches. Enclosure 1 provides a. listing of:each procedure being furnished to NRC. These tests were conducted in accordance with the program detailed in reference 1. Preliminary results were discussed at the September 10, 1987 meeting between NRC and TVA in (noxville,

' Tennessee. The STIs, by which the tests were performed, were informally

transmitted to NRC and its consultants subsequent to the aforementioned

' meeting on September 12, 1987.

It.should'be noted that these STIs are not complete with respect to cable terminations, functional tests, etc. However, they do contain the cable  !

numbers, test voltage levels, and leakage currents for NRC's review. The related STI conduit isometric. sketches are also being sent along with the STI

.' procedures and data in their own separate binder TVA would also like to reassure NRC that no deviations from the instructions )

provided in the STIs occurred with regard to the wet testing of cables witnessed.by NRC on August 20, 1987, during the performance of STI-35. Please refer to section 6.1.6.A of STI-35 for the instructions with regard to wetting of'.the cables. This is in agreement with reference 1, enclosure 2, page 3, where it states, "It is not intended or expected that the cables will remain submersed-throughout the test."

Enclosure 2 contains the "DC High Voltage Cable Test Report," which provides a complete summary of the cable test program and presents the test results for the TER concerns of cable pullbys, jamming, and the lack of support of 12%h b p

' An Equal opportunity Employer

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l U.S. Nuclear Regulatory Commission '

NOV 201987

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-vertical. cable runs with 90-degree condulets at the top of the run. The electricalltests performed on cables insulated with materials other than silicone rubber were successful, thereby demonstrating a high level of cable integrity. The anomalies on silicone-rubber insulated cables were identified

'during the testing for the issue of the lack of vertical support. Further testing determined that-the cause of the anomalies was not the result of, nor l related to, the issue in question. This testing demonstrated that damage i because of the.-lack of support had not occurred.

'Upon forma 1' review of the STI data, TVA discovered that three cables, 2PV418A

.in STI-27, 2PL3775A in STI-30, and 2M1437B in STI-31, were tested at a lower

' . voltage than was specified~in reference 1, enclosure 5 (i.e., cables were

. tested at.4800 volts instead of 7200 volts). A fourth cable, 2V6358B, in STI-32.was' tested above the requirements of reference 1 (i.e., 7200 volts

.instead of'4800 volts) and passed the specified acceptance criteria. As discussed with NRC'on October 1,1987, TVA is providing a technical justification in enclosure 2 for not retesting these cables. The data on these four cables was compared with that of other cables'of similar

. construction, whose conduit configuration was either similar to or of greater complexity. lThe results of the leakage currents and the resultant polarization indexes are quite similar and provide a good degree of confidence that a retest of these cables would not be beneficial and would not yield a significant change.in test data results.

This successfully completes the program for the TER restart items for unit 2

.e and should enable NRC to close these concerns. This also successfc11y

. completes the program for the TER restart concerns of pullbys and javming for unit 1. However, further review will be required by TVA to determine if the worst case vertical support configuration tested in unit 2 envelopes tae unit 1 installations. TVA has.recently completed testing of silicone cable samples with significantly reduced wall thicknesses at Hyle Laboratories and is currently. evaluating these results. 'These results-and TVA's assessment of these results will be forwarded to NRC by way of a separate letter. This letter wil_1 also discuss TVA's resolution of the silicone rubber cable issue.

Also,'TVA will initiate-a letter to NRC that addresses the resolution of the eight TER' recommendations contained in section 14 of reference 2 before the restart of SQN unit 2. Enclosure 3 contains a list of commitments made by this letter.

Very truly yours, TENNESSEE VALLEY AUTHORITY

/

R.

ridley, D 'ector Nuclear Licensing and Regulatory Affairs Enclosures-cc: see page 3

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U.S. Nuclear Regulatory Commission NOV 201987 l

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cc: Mr. G. G. Zech, Assistant Director for. Inspection Programs Office of Special Projects U.S. Nuclear Regulatory Commission 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 l Mr. J. A. Zwolinski, Assistant Director for Projects Division of TVA Projects

' Office of Special Projects U.S. Nuclear Regulatory Commission 4350 East-West Highway EWW 322 Bethesda, Maryland 20814 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry P.oad Soddy Daisy, Tennessee 37379 l-

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