ML20055G661

Forwards Justification for Continued Operation for safety- Related Cables Installed at Plant,Per 900717 Telcon.No Operability Concern Exists at Plant & No Programmatic Problems Have Been Identified.Summary of Commitments Encl

ML20055G661
Person / Time
Site:	Sequoyah
Issue date:	07/17/1990
From:	Wallace E TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9007240040
Download: ML20055G661 (6)

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TENNESSEE VALLEY AUTHORITY

$N 157B Lookout Place July 17, 1990 U.S. Nuclear Regulatory Commission ATTN Document Control Desk Washington, D.C. 20555 Gentlement In the Matter of ) Docket Nos. 50-327 1 Tennessee Valley Authority ) 50-328 l SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 - CONDITION ADVERSE TO QUALITY REPORT (CAQR) SQP900305 REVISION O - OPERABILITY DETERMINATION During a telephone call on July 17, 1990, Jack N. Donohew of your staff requested that TVA provide the enclosed justification for continued operation related to safety-related cables installed at SQN.

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The subject CAQR was written to document discrepancies found in the

, implementation of the conduit selection criteria for the SQN cable test program. Based on the enclosed evaluation (Enclosure 1), TVA has concluded that there is not an operability concern with the safety-related cables at SQN. This conclusion is based on the fact that SQN has not exhibited any of the programmatic problems that have been identified.at our Watts Bar facility ,

(i.e., overfilled conduits, nylon (parachute cord] pull ropes, or long' conduit l runs with numerous bends between pull points) that the computed side-wall \

bearing pressures of the SQN cables is below the values that the Browns Ferry Cable Test Pregram tested and passed and that SQN has, to date, not identified any cable failures that are a result of installation damage.

Therefore we believe that the safety-related cables installed at SQN vill perform their intended function.

Sununary statements of commitments contained in this submittal are provided in Enclosure 2.

We are continuing to investigate the subject CAQR and will provide NRC with additional information in a meeting scheduled for July 19, 1990, at NRC's offices in Rockville, M&ryland. Please direct questions concerning this issue to Bruce S. Schofleid at (615) 843-6172.

Very truly yours, l

TENNESSEE VALLEY AUTHORITY g E. G. Wallace. . nager l Nuclear Licensing and j l

Regulatory Affairs l Enclosures

% cc N f P.',W See page 2 $6[

I 9007240040 900717 gDR ADOCK0500g7 An Equal opportunity Employer

U.S. Nuclear Regulatory Commission JU'L 171990 cc (Enclosures): ,

Ms. S. C. Black, Deputy Director Project Directorate 11-4 U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville. Maryland 20852 Mr. J. N. Donohew Project Manager U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Rockville Maryland 20852 NRC Resid'ent Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy. Tennessee 37379 Mr. B. A. Wilson. Project Chief U.S. Nuclear Regulatory Commission Region II 101 Marietta Street NW Suite 2900 '

Atlanta Georgia 30323 l

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o ENCLOSURE 1 CONDITION ADVERSE TO QUALITY REPORT (CAQR) SQP900305 REVISION 0 (RO)

OPERABILITY DETERMINATION Discussion Continued operation of Sequoyah Nuclear Plant (SQN) Units 1 and 2 in light of the deficiencies discovered and documented in CAQR SQP900305 RO is justified by the following:

1. The original (July 1987) SQN Cable Test Program (CTP) resulted from a concern at Watts Bar Nuclear Plant (WBN) about the adequacy of their cable pulling practices. There was not then, nor is there now, any evidence that SQN has any safety-related cables installed that were damaged by the SQN cable pulling practices. This includes cable pullbys, cable jamming, and cables supported in vertical conduits. Additionally, SQN has not exhibited the programmatic problems that WBN has with overfilled conduits, nylon (parachute cord) pull ropes, long conduit runs with excessive bends between pull points, etc., (Reference 1).

2. The SQN CTP did in-situ testing of over 900 safety-related conductors at voltages between 4.8 kilovolt (kV) and 7.2 kV direct current, and ali passed without exception. The severity of these tests and the multitude l

' of cables tested would have revealed a programmatic problem if one had '

existed (Reference 1).

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3. Subsequent evaluations and calculations of 55 (15 tested and l 40 screened-out) SQN-CTP conduits reveal that the computed side-wall  !

bearing pressures (SWBP) of the SQN cables are below the values that the  !

Browns Ferry Nuclear Plant Cable Test Program tested and passed (Reference 2 and Attachment A).

4. In January 1989 SQN implemented a Cable Monitoring Program and Assessments to test, document, and trend problems with installed cables.

These problems include age-related failures that would surface if a cable was installed improperly. To date, no cables have been identified as incapable of performing their safety-related function by this program (Reference 3).

Conclusion The completed testing coupled with no known cable failures attributed to cable installation practices, provides a high degree of confidence that the SQN safety-related cables will perform their intended functions.

References

1. TVA letter to NRC dated March 28, 1990 "Sequoyah Nuclear Plant (SQN) -

Reevaluation of Cable Testing Program - Watts Bar Nuclear Plant (WBN)

Pullby Damage"

2. Electrical Calculation SQN-CSS-032

3. TVA letter to NRC dated January 23, 1989, "Sequoyah Nuclear Plant (SQN)

Units 1 and 2 - Cable Monitoring Program and Assessments" l

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? SEQUOYAII AND BROWN'S FERRY COMPARISON SIDEWALL BEARING PRESSURE VALUES l

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ibs/n (Thousands) t 300 ' _. __. _ _ . _ _ _ _ _ _ . . _ _ _ _.

j.'f 250 - . . . .

. 200 - .

150 - ._

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100 - __  ; _ _ _ _ _ _ _ _ _ . . _ _ . . _ . __.

m>"

50 -

/ ' s

/ l-- // / lf / / //

o /Q / / ma l , , , ,

1. 1 #2 #3 #4 #5 [E>

Sequoyali 32,817 8,654 4,816 4,493 3,216

. Browns Ferry 282,971 24,365 8,873 7,014 3,644

+

[ SQN AND BFN SWBP TOP FIVE CONDUITS -

i CALCULATED MAX SWBP mb Sequoyah WA Browns Ferry JUNE ID,1990

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Attcchu nt A Pegs 2 of 2 SEQUOYAH AND BROWN'S FERRY CONDUIT COMPARISON CALCULATED MAXIMUM SIDEWALL BEARING PRESSURES PLANT BROWN'S FERRY SEQUOYAH RANKING SWBP SWBP SWBP SWBP NUMBER RANKING VALUES

========= RANKING VALUES

======================= ======================

1 3ES4177-IID 282,971.00 1PM1332II e 32,817.21 2 ES2052-IB 24,364.86 1PM4704A 0 8,653.95 3 ES337-I 8,873.29 MC1750A

• 4,816.27 4 3ES3677-II 7',014.47 1PM1192II O 4,492.52 5 ES4508-IIC 3,643.81 2PM1192II e 3,216.05 6 3ES1676-ID 3,103.71 1PM2136I 2,448.81 i

7, ES1540-I 3,098.04 1PM20801 1,348.65 8 ES2051-IB 2,123.72 , MC1754A

• 842.20 9 ES223-1 1,212.23 1PM4995II e 631.85 10 3ES4538-IIC 1,171.94 1PM2094III 826.47 11 ES1539-I 974.94 MC1730B

• 824.20 12 ES2000-IA 93P.30 ,

MC1751A

• 803.25 i

13 ES345-I 923.71 1PM2087II 771.89 ,

14 ES2032-IA 692.75 MC1728B

• 679.95 ..

. 15 ES2083-IB 682.30 2PM2140I 607.98 16 ES4561-IID 651.01 2PM2084I 503.11

, 17 ES335-I 622.49 1PM2111II 482.61 .

18 ES2837-II 592.21 2PM2111II, 462.22

19 ES4035-II 588.39 MC1606A

• 331.88 20 ES4558-IID 452.18 1PM2107II 317,80 Cono11ts tested under original Sequoyah selection critoria g

0 "ALARA" conduits contained in SQN-CSS-032 l 10 BFN conduits tested and successfully passed cable testing

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ENCLOSURE 2 LIST OF COMMITMEhTS SQN is continuing to investigate the subject CAQR and will provide NRC with additional information in a meeting scheduled for July 19, 1990, at NRC's offices in Rockville, Maryland.

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