ML20212J976

Summary of 870303 Meeting W/Util,Franklin Research Ctr & S&W in Bethesda,Md Re Util Second Proposal to Resolve Cable Concerns.Attendance List & Util Slides Encl

ML20212J976
Person / Time
Site:	Sequoyah
Issue date:	03/04/1987
From:	Alexion T Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
NUDOCS 8703090187
Download: ML20212J976 (25)

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_ , Docket Nos.: 50-327.

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• MAR 1987 LICENSEE: Tennessee Valley Authority (TVA)

FACILITY: Sequoyah Units _1 and 2

SUMMARY

OF MEETING TO DISCUSSJCABLE PULLING 70n' March.3, 1987, representatives of NRC and TVA met to discuss TVA's second 2 proposal to resolve-cable pulling concerns at Sequoyah. Enclosure 1 lists the attendees. Enclosure 2 provides the slides used by TVA during their i presentation..

TVA's second proposal .is a result of their draft response.(first proposal) to the_ staff's January 15, 1987. recommended actions and the staff's draft-comments'on TVA's draft response. TVA stated that the only remaining open items are the basis for selection of test voltages and the. test medium and

, extent for evaluation of cable jamming.

The staff indicated.that they would try to respond to TVA's second proposal

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within the next week or. two. The staff requested that TVA document their l program to resolve cable pulling concerns at Sequoyah following the staff's comments on TVA's second proposal.

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.5, Thomas W. Alexion, Project Manager PWR Project Directorate #4 Division of PWR Licensing-A

Enclosures:

As stated c -cc: See next page f1 'j m

PWR M PWF ff'qi WR-A OSP/DPWR-A

TAledo d BJ1ou igt 1ood JZwolinski 03/ f-/87 03/ /87 03/4(/87 t P M 7

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.a.. . _ . . . _ _ _ _ . _ _ _ _ _ . . . . . . . , _ _ _ . = , _ . _ . . _ _ . . _ . _ _ . _ . _ ,.____..,_.-.,-_,-.-.m,.,. _

l MEETING

SUMMARY

DISTRIBUTION ele File NRC Participants NRC PDR T. Alexion L PDR- J. Knight NSIC P. Gill PRC System' B.D. Liaw PWR#4 Reading File B.J. Youngblood

'M. Duncan- B.K. Singh OGC-Bethesda E. Rossi J. Partlow J. Zwolinski E. Jordan B. Grimes ACRS (10)

TVA0P (3) S. Richardson AR 5029 HDenton JTaylor c- BHayes

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NGrace LSpessard KBarr SAConnelly GZech, RII DMuller TNovak JHolonich CUpright TKenyon WLong TAlexion BKSingh

., KHooks MReinhart, AR JThompson JZwolinski JKeppler SEbneter bcc: Licensee & Service List

Enclosure 1 NRC/TVA CABLE PULLING MEETING March 3, 1987 NAME ORGANIZATION Tom Alexion- NRC/ PAD #4 Jim Knight NRC/EICSB Paul Gill NRC/EICSB B.D. Liaw NRC/OSP Gary Toman Franklin Research Center Faust Rosa NRC/EICSB Mel C. Gervacio TVA SOM Licensing Mark Burzynski TVA SQN Licensing Louis J. Sas TVA Advisor W.S. Faughley TVA/ Chief Electrical Engineer Timothy M. Shea Stone & liebster Engineering Corporation Reinhold Luther Consultant to TVA B.J. Youngblood NRC/PADf4 B.K. Singh NRC/ PAD #4 E. Rossi NRC/AD for PWR-A J. Zwolinski NRC/0SP

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ENCLOSURE 2 1

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TENNESSEE VALLEY AUTHORITY b SEQUOYAH NUCLEAR (SQN) UNITS 1 AND 2 PROPOSAL FOR RESOLUTION OF CABLE PULLING CONCERNS f

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PRESENTED TO THE U.S. NUCLEAR REGULATORY COMMISSION 1

BETHESDA, M.D.

MARCH 3, 1987 DNE1 - 2661W

. g AGENDA MEETING BETWEEN TVA AND NRC CABLE PULLING CONCERNS I. OBJECTIVE OF THE TVA PROGRAM II. IDENTIFICATION OF OPEN ITEMS III. BASIS OF THE TVA PROPOSED PROGRAM A. TEST V0LTAGE B. IN-SITU DC HIGH POTENTIAL TESTS IV.

SUMMARY

0F THE TVA PROPOSED PROGRAM A. CABLE PULLBYS B. CABLE JAMMING 0

CONDULETS C. CABLES SUPPORTED BY 90 V. CONCLUSION DNE1 - 2661W

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OBJECTIVE OF THE TVA PROGRAM TO DEMONSTRATE, THROUGH THE USE OF APPLICABLE, INDUSTRY RECOGNIZED TESTING, THAT THE ELECTRICA'L CABLES AT SQN ARE l THIS CAPABLE OF PERFORMING THEIR SAFETY RELATED FUNCTION.

TESTING WILL ACCOUNT FOR KNOWN AND ACCEPTED REDUCTIONS IN THE CABLES' DIELECTRIC STRENGTH DUE TO THE RIG 0RS OF CABLE SHIPMENT, HANDLING, INSTALLATION, AND OPERATION.

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l IDENTIFICATION OF OPEN ITEMS -

A. BASIS FOR SELECTION OF THE TEST VOLTAGE

1. TVA - IEEE 383-1974

2. NRC - ICEA FACTORY TEST B. TEST MEDIUM AND EXTENT FOR EVALUATION OF CABLE JAMMING

1. TVA - IN-SITU DC HIGH POTENTIAL TEST IN THE PRESENCE OF M0ISTURE ON FIVE WORST CASE SAMPLES

2. NRC - CABLE REMOVAL, LABORATORY INSPECTION, AND DC l

AND AC HIGH POTENTIAL TESTS WHILE SUBMERSED IN WATER ON ONE WORST CASE SAMPLE DNE1 - 1173Y

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NRC PROPOSED TVA '

ICEA D-C PROPOSED D-C '

RATED SERVICE TVA TEST VOLTAGE TEST VOLTAGE -

VOLTAGE VOLTAGE .

TYPE 300 mV NOTE 1 TilERMO ,

COUPLE EXTENSION ,

LEAD

• Y 300 120AC/ NOTE 1 j HULTI-125DC CONDUCTOR SIGNAL .

CABLE 10.5KV 7.2KV 600V 480V SINGLE &

HULTI- 16.5KV 10.8KV CONDUCTOR POWER &

CONTROL (XLPE OR EPR) 0-600v 18KV 10.8KV 600 480V SINGLE CONDUCTOR POWER &

CONTROL (SR) 0-600v SINGLE 45KV 33.6KV CONDUCTOR 8KV 6.9KV POWER S (XLPE OR EPR) 8KV NOTE 1 : AS SPECIFIED BY THE PURCHASER DNE1 - 0041g i

BASIS OF E E TVA PROPOSED PROGRAM TEST VOLTAGE (240' VOLTS / MIL OF INSULATION)

IN ACCORDANCE WIM IEEE 383-1974, SECTION 2.3.3.4. 'lHIS IS'IEE RECOGNIZED INDUSTRY STANDARD TEST FOR DETERMINING E AT CABLES ARE ~ ADEQUATE TO PERFORM 'IMEIR INTENDED CLASS 1E FUNCTION.

PREVIOUSLY PERFORMED QUALIFICATION TESTS AT W IS VOLTAGE ESTABLISH A BASELINE FOR COMPARISON AND TRENDING.

ACCOUNTS FOR 'IHE KNOWN AND ACCEPTED REDUCTION IN CABLE DIELECIRIC STRENGE DUE 'IO 'lHE NORMAL RIGORS OF SHIPPING, HANDLING, INSTALLATION, AND OPERATION.

L CONSISTENT WITH PREVIOUSLY PERFORMED AND NRC ACCEFFED TESTING FOR E E IDENTICAL CONCERN OF CABLE PULLBYS (GRAND GULF). ,

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'IVA COWENTS ON NRC SPECIFIED TEST VOLTAGE 1

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. SPECIFIED FOR USE BY 'IHE CABLE INDUS'IRY ONLY FOR FACTORY NEW CABLE, PRIOR 'IU LEAVING THE MANUFAC'IURING FACILITY.

. MAY DAMAGE CABLES WHIGI ARE OEERWISE ACCEPTABLE DUE TO 'IEE KNOWN AND EXPECTED REDUCTION IN CABLE DIELECTRIC STRENGTH.

. EXCEEDS MANUFACIURERS' RECOWENDATIONS FOR INSTALLATION AND MAINTENANCE PROOF TESTING m , .-m.e-.--,-. -r,- .-, , - . , , ,---,w,m- c- , ,,-,---------e---=--,--_,,-- w-

CABG VERIFICATION OPTIONS ULTIMATE CAPACITY PROOF TESTING TESTING -

DETERMINE W E DEMONSTRATE THAT THE OBJECTIVE ULTIMATE FUNCTIONAL W E INSTALLED CAPABILITY OF M E CABLES WILL PERFORM

. INSTALLED CABG M EIR 1E FUNCTION PULL- TEST USING TEST USING PROPOSED BY FAC110RY VOLTAGE IEEE 383-1974 EVALUATION (240 V PER MIL)

TECHNIQUE JAWING CABLE REMOVAL 6 COMPARATIVE IAB. TESTS TO FAILURE PULL- .MAY DAMAGE CABG . ACCEPTED INDUSTRY TEGINICAL BY . EXCEEDS STANDARDS NONDESTRUCTIVE TEST ASSESSMENT

.N0 INDUSTRY CONCENSUS . ADEQUATE MARGIN OF ACCEMANCE STANDARD .WITHIN MANUFACTURERS PROPOSED

. EXCEEDS MFR. RECO WENDATIONS EVALUATION

-TEGINIQUES RECO MENDATIONS f JAMMING .NO INDUSTRY CONCENSUS

! - ACCEPTANCE CRITERIA FOR A/C DIELECIRIC TESTS

.INDEIERMINATE DAMAGE ""

INCREMENT DUE 10 CAB G REMOVAL

. WIDE VARIABILITY IN W E FAILURE VOLTAGE FOR NEW CABLES

.NO FAILURE VOLTAGE /

CABLE DAMAGE CORRELATION EXISTS l

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SUMMARY

OF THE TVA PROPOSED PROGRAM CABLE PULLBYS

1. SELECT 10 REPRESENTATIVE WORST CASE CONDUITS AND CABLES A. MINIMUM 0F 7 CABLES B. MINIMUM 0F 2 PULLBYS C. MINIMUM OF 3 PVC JACKETED CABLES SUBJECTED TO PULLBY D. MINIMUM 0F 2 PULLBYS MADE WITH OTHER THAN POLYWATER J LUBRICANT F. CONDUIT IS LONG IN LENGTH AND CONTAINS A LARGE DEGREE OF BENDS G. CONDUIT CONTAINS AT LEAST TWO CONDULETS H. PREFERENCE FOR MECHANICAL PULLS OR WHERE ABILITY TO LUBRICATE WAS INHIBITED

2. PERFORM A DC HIGH V0LTAGE TEST AT 240 VOLTS / MIL FOR 5 MINUTES IN THE DRY CONDUIT

3. INTRODUCE ORDINARY TAP WATER INTO THE CONDUIT (CONSIDERING EQUIPMENT INTEGRITY AND PERSONNEL SAFETY)

4. PERFORM A DC HIGH VOLTAGE TEST AT 240 VOLTS / MIL FOR 5 MINUTES IN THE PRESENCE OF MOISTURE DNE1 - 0043G

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SUMMARY

OF THE TVA PROPOSED PROGRAM ,

CABLE JAMMING ,

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1. SELECT FlVE REPRESENTATIVE WORST CASE CONDUlTS AND CABLES:

!, a. CONDUlT CONTAINS THREE LARGE SINGLE CONDUCTOR CABLES.

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b. CONDUlT AND CABLES HAVE A JAM RATIO OF 2.8-3.1 PER IEEE 690-1984. i 1

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! c. CONDUIT CONTAINS FIELD OR FACTORY BENDS.

i d. CONDUIT IS LONG IN LENGTH AND CONTAINS A LARGE DEGREE OF BENDS.

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I e. MINIMUM OF TWO POTENTIAL PULLING POINTS PRIOR TO CONDUlT SEGMENT OF '

INTEREST.

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f. PREFERENCE FOR MECHANICAL PULLS AND FIELD CONDUlT BENDS.

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2. PERFORM A DC HIGH VOLTAGE TEST AT 240 VOLTS /Mll FOR FIVE MINUTES IN THE DRY CONDUlT.

3. INTRODUCE ORDINARY TOP WATER INTO THE CONDUIT (CONSIDERING EQUlPMENT

' INTEGRITY AND PERSONNEL SAFETY.

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4. PERFORM A DC HIGH VOLTAGE TEST AT 240 VOLTS /Mll FOR FIVE MINUTES IN THE PRESENCE OF MOISTURE.

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SUMMARY

OF THE TVA PROPOSED PROGRAM 0

CABLE SUPPORTED BY 90 CONDULETS

1. SELECT A WORST CASE CONDUIT AND CABLES A. CONDUIT CONTAINS ONLY CABLES WITH SILICON RUBBER INSULATION B. CONDUIT HAS A MINIMUM 0F 5 CABLES AND A MINIMUM FILL OF 20 PERCENT 0

C. CABLES ARE SUPPORTED BY A 90 CONDULET D. CABLES HAVE A VERTICAL DROP BELOW THE CONDULET WHICH EXCEEDS NEC ARTICLE 300-19

2. PERFORM A DC HIGH P0TENTIAL TEST AT 240 VOLTS / MIL FOR 5 MINUTES

3. IF TEST IS SUCCESSFUL EVALUATE ALL 10CFR50.49 SILICON t

l RUBBER INSULATED CABLES INSIDE CONTAINMENT AGAINST CRITERIA 1C AND 1D AB0VE. RESUPPORT THOSE WHICH ARE EXPOSED TO A SIGNIFICANT STRAIN, PRIOR TO RESTART. IF THE

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! TEST IS UNSUCCESSFUL, THE TEST CABLE WILL BE REWORKED AND THE NEXT WORST CASE SELECTED, AND TESTED UNTIL THE PROBLEM IS BOUNDED.

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CONCLUSION .

THE TVA PROPOSED TEST PROGRAM, THROUGH THE APPLICABLE USE OF INDUSTRY RECOGNIZED TESTING, WILL CONCLUSIVELY DETERMINE THE IN OPERATIONAL STATUS OF THE ELECTRICAL CABLES AT SON. '

ADDITION, THE PROPOSED METHODOLOGY WILL ALLOW FOR THE DECISIVE DETERMINATION OF THE ROOT CAUSE OF ANY FAILURES AND THE ~

REQUIRED CORRECTIVE ACTION.

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ini!TED JT/b'ES GOVk.RNMENT - '

T NNESSEE VALLEY AUTHORITY M'emorandum ,

TO  : M.-R. Harding, Nanager, Site Licensing$'taff, ONP, O&PS-4 /. M Nuclear Plant ek

D. W. Wilson y Project Engir.eer, Sequoyah Engineep.in [ ,

-FROM DSC-E, Seg;ioyah '

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DATE  :

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W PONSE TO PULLING CONCERNS

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SUBJECT:

SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 A.

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References:

1. Letter from B. J. Youngb1 4L(USNRC) to S. A. White (TVA) dated

[ January 15, 1987 (A02 070123 001) . .

2. Letter from R. L. Gridley (TVA) to B. J. Youngblood (USNRC) dated October 31. 1986 (L44 861031 811)

3. Memorandum from Thomas W. Alexion (USNRC) to B. J. Youngblood (USNRC) dated February 20, 1987 i

The purpose of this memorandua is to propor,e a program to resolve the NRC's j

concerns relative to cable pullbys, jasuning, and lack of support of vertical cable runs with 90* condulets at the top of the run. These ' concerns were l

provided lu reference 1 above and were discussed ,st a meetirig between TVA and

$ the NRC in Bethesda. M e yland. pn January 29, 1987. TVA's draft response to 0N ..

the NRC's recommande0 Lactions g:td the NRC's draf t comuments on this response gr's provided in refer'ance.3. s ourproposalconsistsofats$t.programwhichwillbeperformedpriorto restart of S9N enit 2. The rarpose of the program is to conduct in-situ l

nondestructive LL ts on representative worst case cables. This program will

' aupport the adequacy of SQN'seinstalletion practices and will verify theThe parformance capabilities of the cable system in view of the concerns.

inspection and acceptance, proposed criteria for cable selection, testing, j

for cable pullbys, jamming and cables supported Jr 90* condulets are provided in attachments 1, 2, and 3 respectively.

l In evaluating tua attached SQN proposals, TVA requests that the NRC consider the following:

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differ from L ,The SQN installacion

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other plants of'its vin ~ cage.

configaration does not significantlyIn many respects th l conservatism such as the installation of numerous pull points and short conduit runs. Following plant walkdowns at SQN and Watts Bar (WBN), the t

superiority of the SQN installation was visible to both TVA and NRC 4

personnel. Those differences should be considered when determining the i

extent; of testing required for resoluticn of issues on SQN.

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2. Recent' interviews of Electricians who had actually performed the cable i

installation, conducted by the NRC/ Consultants, indicated a thorough I understanding of the cable installation process and the relevant C -

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D. W. Wilson , f1 Afa.**'

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% RESPONSE TO C ULLING CONCERNS SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND concerns. These interviews substantiated conformance to proper construction practices used throughout the industry and utilization of the engineering approved installation procedures and specification, and confirmed the presence of a Quality Control Inspector on all Class IE cable pulls. In addition, the close working relationship betweep construction and engineering was outlined including the evaluation made prior to each Class lE pull to determine the best method of installation, including determining the direction of the pull and the need for manual assistance at pull points to reduce tensions. The testimony in these interviews was contrary to employee concerns in this area.

3. The test voltage proposed by TVA parallels the industry established acceptance criteria for end of life environmental qualification tests and therefore has a baseline for comparison and trending.

4. SQN has completed tests on its cable system consistent with current day industry practices that establish adequacy of the installation.

If you have any questions or require additional information, please contact W. S. Raughley at Extension 2441 in Knoxville.

D. W. Wilson WSR:TMS:BW Attachments cc: RIMS, SL26 C-K, w/l C. H. Fox, Jr., LP 6N 38A-C R. W. Cantrell, W12 A12 C-K J. A. Kirkebo, W12 A21 C-K W. E. Pennell, W12 A8 C-K W. S. Raughley, W8 C126 C-K R. C. Williams, DNE, DSC-P107, SQN Principally Prepared By: Timothy M. Shea, Extension 2672 DNE1 - 2265W

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ATTACHMENT 1 CABLE PULLBYS Cable Selection Criteria The following criteria will be utilized to select ten representative worst case conduits and cables for evaluation of potential damage which could have resulted from cable pullbys. For the purposes of this evaluation, a representative worst case conduit and cables will be considered to be any that meet, or come closest to meeting, the following:

1. The conduit contains a minimum of seven cables.

2. There were at least two separate pullbys in the conduit.

3. At least three PVC jacketed cables were present in the conduit before the final pullby.

4. The initial pull and at least two pullbys were made before Polywater J was used as a lubricant (August 1984).

5. At least two of the pullbys made before August 1984 contained a minimum of two cables with hypalon or chlorinated polyethylene (CPE) jackets.

6. The total length and number of bends between a set of adjacent pull points exceeds or comes closest to exceeding the requirements of G-38 Appendiz F.

7. The conduit contains at least two condulets.

8. Preference shall be given to those conduit.S which meet all of the above and any or all of the following:

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a. If it is determined through analysis that any of the cable pulls required mechanical assistance,

b. The length of the conduit between potential lubrication points exceeds the requirements of G-38 Appendix F.

c. If the direction of pull of any of the pullbys is determined, and the conduit bends were near the pull point (i.e., end of pull).

d. If the direction of pull of any of the pullbys is determined, and the i

I first portion of the conduit was an upward or horizontal section such that lubricant could not be poured into the conduit.

Cable Test and Inspection Criteria As stated by the NRC in reference 1 above, the predominate concerns during cable pullbys are for saw-through and mashing of the jacket'and insulation.

In all cases any potential damage would occur to the jacket first and to the insulation only if the protective jacket had been totally compromised in the area of concern. The postulated failure mode is the degradation of dielectric properties due to a reduction in insulation wall thickness, perhaps influenced by the presence of moisture. The following test program is specifically designed to identify if such a potential condition exists.

1. After having selected the ten representative worst case conduits and cables, the conduits' installed configuration shall be reviewed to determine the feasibility of introducing water into the conduit system without compromising equipment integrity or personnel safety. It is preferred that the entire conduit be subjected to the water injection.

However, as a minimum, the conduit segment which contains the field or factory bend which would have seen the highest pull tension during the cable pullbys must be configured to allow for such testing. If the conduit configuration does not allow for wet testing of a segment of conduit of sufficient length or number of bends to be justified as the segment with the greatest potential for damage due to pullbys, a new conduit shall be selected in its place and evaluated as above.

2. With the cables in the dry conduit, perform a 5-minute de high voltage test at 240 volts / mil of insulation (per IEEE 383-1974, Section 2.3.3.4).

For nonshielded cables the test will be performed between each conductor and the remaining conductors in the conduit and the conduit tied together. For shielded cables the test will be performed between each individual conductor and the remaining conductors in the conduit, the shield and the conduit tied together.

3. The entire length of each of the ten conduits, or, if the entire length does not allow, the segments of the conduits justified as having the greatest potential for damage, shall be subjected to the introduction of ordinary tap water. The purpose is to ensure, as a minimum, the presenceIt of moisture along the entire segment of conduit and cables of concern.

is not intended or expected that the cables will be submersed, but rather that a tracking path will be established which would identify, through the de high potential testing, any reduction in the cable's integrity or ability to perform its intended function.

4.

While in the presence of moisture each conductor shall be subjected to a 5-minute de high voltage test as specified in item 2 above.

Cable Acceptance Criteria

1. The cables must pass the in-conduit de high voltage tests, both dry and in the presence of moisture.

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2. If the cables fail either of the high voltage tests, the location of the-failure shall be determined, and the cables shall be removed If the from causethat is conduit segment and inspected to determine the cause.

determined to be isolated and the result of other than cable pullbys, the above tests shall be considered nonconclusive and a new conduit segment shall be selected and the tests repeated. If the failures are due to cable pullbys, the failed test cables will Thisbewill reworked, continueanduntilthe thenext 10 problem worst case conduits will be tested.

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ATTACHMENT 2 CABLE JAMMING Cable Selection Criteria The following criteria will be utilized to select five representative worst case conduits and cables for evaluation of potential damage which could have resulted fron cable januning. For the purposes of this evaluation, a representative worst case conduit and cables will be considered to be any that meet, or come closest to meeting, the following:

1. The conduit contains three single conductor cables (larger than No. 10 AWG) of the same conductor size.

2. The cables are routed in a conduit such that the ratio of the inside diameter of the conduit' divided by the average diameter of one of the cables is in the range of 2.8-3.1. This is in accordance with IEEE 690-1984 Section A9.2.4.4 and as stated, accounts "for tolerances in cable and conduit sizes, and for ovality in the. conduit at a bend..." (An initial review indicates that SQN Units 1 and 2 have approximately 46 conduits which meet the above criteria all containing low voltage unshielded power cable.)

3. The conduit contains field or factory fabricated bence.

4. The total length and number of bends between a set of adjacent pull points exceeds or comes closest to exceeding the requirements of G-38 Appendix F.

5. There were at least two potential pulling points prior to the segment of conduit of highest interest (i.e., the segment which would have experienced the highest pull tension).

6. Preference shall be given to those conduits which meet all of the above and any or all of the following:

a. If it is determined that the conduit bends were made in the field as opposed to the factory

b. If it is determined through analysis that the cable pull required mechanical assistance DNE1 - 2251W

4 Cable' Test and Inspection Criteria Jamning is a consideration when three single conductor cables of like diameter are being pulled into a conduit. As described in IEEE Standard 690-1984, Section A9.2.4.4, ". . . Up to a ratio of 2.5 the cables are constrained into I a triangular configuration. However, as the value approaches 3.0, jamming of

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the cables could occur and the cables would freeze in the duct causing serious cable damage . . ."

Once jamming occurs, it can only be overcome by " brute force". Either the pulling rope or conductors break or the insulation and jacket are deformed by crushing to relieve the wedging action. In either case the damage extends

• over a considerable length of the cable and is severe.

Please note that based on the fact that the damage caused by jamming is expected to be severe and to be consistent with the test program for pullbys we have modified the previously proposed test procedure to dry and wet test the cables in the conduit.

The following test program is specifically designed to determine whether or not such damage occurred.

1. After having selected the five representative worst case conduit and cables, a field measurement of the actual cable diameter shall be made to verify that the selected cable does, in fact, fall within the range specified in Cable Selection Criteria No. 2. If they do not, another conduit will be selected.

2. After having selected the five representative worst case conduits and cables, the conduits' installed configuration shall be reviewed to determine the feasibility of introducing water into the conduit system without compromising equipment integrity or personnel safety. It is preferred that the entire conduit be subjected to the water injection.

However, as a minimum, the conduit segment which contains the field or factory bend which would have seen the highest pull tension during cable pulling must be configured to allow for such testing. If the conduit configuration does not allow for wet testing of a segment of conduit of sufficient length or number of bends to be justified as the segment with the greatest potential for damsge a new conduit shall be selected in its place and evaluated as above.

3. With the cables in the dry conduit, perform a 5-minute de high voltage test at 240 volts / mil of insulation (per IEEE 383-1974, Section 2.3.3.4).

The test will be performed between each conductor and the remaining conductors in the conduit and the conduit tied together.

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"PREUMARY _ ,

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The entire length of each of the five conduits, or, if the entire length does not allow, the segments of the conduits justified as having the greatest potential for damage, shall be subjected to the introduction of ordinary tap water. The purpose is to ensure, as a minimum, the presence It of moisture along the entire segment of conduit and cables of concern.

is not intended or expected that the cables will be submersed but rather that a tracking path will be established which would identify, through the de high potential testing, any reduction in the cable's integrity or ability to perform its intended function.

5. While in the presence of moisture each conductor shall be subjected to a 5-minute de high voltage test as specified in item 2 above.

Cable Acceptance Criteria

1. The cable must pass the in-conduit de high voltage tests, both dry and in the presence of moisture.

2. If the cables fail either of the high voltage tests, the location of the failure shall be determined, and the cable (s) shall be removed from that conduit segment and inspected to determine the cause. If the cause is determined to be isolated and the result of other than cable jamming, the above tests shall be considered nonconclusive and a new conduit segment shall be selected and the tests repeated. If the failures are due to cable jamming, the failed test cables will be reworked, and the next five This will continue until the problem worst case conduits will be tested.

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ATTACHMENT 3 CABLES SUPPORTED BY 90* CONDULETS Cable Selection Criteria The following criteria will be utilized to select a worst case conduit and cables for evaluation of potential damage which could have resulted from During the selection process, if a single

upporting cables by 90* condulets." worst-case" it not obviously apparent several rep conduits may be examined. Selection of the " worst" case will then be based upon examination of the cables in the 90* condulets to determine Forthe thecable purposes with the highest force being exerted by the condulet corner.

of this evaluation, a representative worst case conduit and cables will be considered to be any that meet the following:

1. The conduit shall contain only cables with silicon rubber insulation. (An initial review indicates that SQN Unit 2 has approximately 340 conduits which contain only 10CFR50.49 cables with silicon rubber insulation.)

2. The conduit shall(An have a minimum initial of five cables review indicates and a minimum that approximately 180fillof the of 20 percent. After applying the minimum above 340 conduits contain 5 or more cables.

fill requirement to these 180, it is expected that a sufficient population will exist to select a representative worst case. The intent of the minimum fill and number of cables requirement is to obtain a conduit in which the cables lie on top of one another, thereby exerting more force on the lower cables.)

3. The cables shall be supported by a 90* condulet.

4.

The cables shall have a vertical drop inunediately belowpreference the 90* condulet should which exceeds the requirements of NEC Article 300-19.

be given to a conduit that exceeds the NEC Article 300-19 requirements by l the greatest amount when compared to other similar installations.

I Cable Test and Inspection Criteria

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As stated by the NRC in reference 1 above, the predominate concern from l

supporting cables by 90* condulets is the potential for cutting the insulation l The following test program is specifically l by the corner of the condulet.

designed to identify if such a potential condition exists:

With the cables in the conduit, perform a 5-minute de high voltageThe testtest at 240 volts / mil of insulation (per IEEE 383-1974 Section 2.3.3.4).

will be performed between each conductor and the remaining conductors in the conduit and the conduit tied together.

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'. s Cable' Acceptance Criteria The cables must pass the in-conduit de high voltage test. If the cables fail the high voltage test, the location of the failure shall be determined, and the cables shall be removed from that conduit segment and inspected to determine the cause. If the cause is determined to be isolated, and the result of other than supporting the cable by a 90* condulet, the above test shall be considered nonconclusive and a new conduit segment shall be selected and the test repeated. If the failure is due to supporting the cable by 90*

condulets, the extent of the problem will be evaluated and the need for further corrective action determined.

If the representative worst case cable passes the test it will demonstrate that damage due to supporting cables by a 90* condulet has not occurred.

Furthermore, prior to restart, TVA will evaluate all conduits inside containment which contain 10CFR50.49 silicon rubber insulated cables. The cables in those conduits which contain a 90* condulet, and which have a vertical drop immediately below the condulet which exceeds the requirements of NEC Article 300-19, will be examined. Only those cables which are exposed to a significant strain will be resupported prior to restart. Those cables which could not easily be lifted off the condulet corners by hand or were found to be severely indented will be considered to be under significant strain. The

support method which will be utilized is expected to be the insertion of a rubber-like pad between the cables and the inner radius of the condulet.

DNEl - 2251W

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Mr. S.A. White Tennessee Valley Authority Sequoyah Nuclear Plant cc:

Tennessee Department of Public Regional Administrator, Region II Health U.S. Nuclear Regulatory Commission, ATTN: Director, Bureau of 101 Marietta Street, N.W., Suite 2900.

Environmental Health Services Atlanta, Georgia 30323 Cordell Hull Building Nashville, Tennessee 37219 R. W. Cantrell ATTN: D.L. Williams Mr. Michael H. Mobley, Director Tennessee Valley Authority Division of Rediological Health 400 West Summit Hill Drive W12 A12 T.E.R.R.A. Building Knoxville, Tennessee 37902 150 9th Avenue North Nashville, Tennessee 37203 Mr. Bob Faas Westinghouse Electric Corp. County Judge P.O. Box 355 Hamilton County Courthouse Pittsburgh, Pennsylvania 15230 Chattanooga, Tennessee 37402 R. L. Gridley Tennessee Valley Authority SN 157B Lookout Place Chattanooga, Tennessee 37402-2801 M.'R. Harding Tennessee Valley Authority Sequoyah Nuclear Plant P.O. Box 2000 Soddy Daisy, Tennessee 37379 Resident Inspector /Sequoyah NPS c/o U.S. Nuclear Regulatory Commission 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 H.L. Abercrombie Tennessee Valley Authority Sequoyah Nuclear Plant P.O. Box 2000 Soddy Daisy, Tennessee 37379 g,