ML20212G356

Summary of 861218 Meeting W/Util,Bechtel,S&W & Southern Co Svcs Re Vertical Cable Supports.Util Presentation & Observation 22-F11 Encl

ML20212G356
Person / Time
Site:	Vogtle
Issue date:	01/13/1987
From:	Mark Miller Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
NUDOCS 8701200248
Download: ML20212G356 (9)

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UNITED STATES NUCLEAR REGULATORY COMMISSION

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Pocket Nos.: 50-4?4 7 I JM 1987 and EO-426 APPLTCANT: Georgia Power Company FACILITY: Vogtle, Units 1 and 2 SUR.1ECT: SU VARY OF MEETING HELD DECEMRER 18, 1986, REGARDING VERTICAL CABLE SUPPORTS On December 18, 1086, the staff met with the applicant and its representatives to discuss the applicant's responses to the staff's request for additional information concerning the seismic adeauacy of plastic cable ties for cable support in vertical raceways dated December 3, 1086 Participants are listed in Enclosure 1 and the meeting agenda is enclosed as Enclosure ?.

In response to the staff's first question in its December 3 letter, the applicant stated that it performed 17 static tests for 9 types of cable ties (types PLTap and PLT 6H). The applicant explained further that it started out with four different cable configuratinns to see if cable bundle size would have any effect on test results. Failure of the cable tie latch mechanism was the failure mode in each test. The applicant found repeatability of data Isimilar failure load for each tie typei and therefore only completed 17 tests rather than the intended 74 Stone and Webster Engineering Corporation (SWEC), the organization that identified this cable tie concern during the independent

' design review portion of the Vogtle Unit I readiness review program, stated its opinion that the number of tests is representative of the industry standard for component testing. SWEC further stated that 3 tests for each tie type would have been sufficient.

The tests assumed no credit for (11 friction, (?) horizontal runs of cable before the vertical run, and (3) terminations. The minimum Safety factor under the safe shutdown earthquake is 1.3 while that under the operating basis earthquake is 1.5.

Test results for the 2 types of cable ties are summarized below:

Coefficient Standard Deviation Mean of Failure Pode of Variation PLT 4H 8.8 lbs 107.7 lbs 5%

(11 testsi PLT 6H 10.? lbs 705.8 lbs 5%

(6 tests)

The staff requested the applicant to also discuss in its response the controllability of the specifications for installing the ties and that if one tie failed, support is still adequate.

B701200248 070113 PDR ADOCK 05000424 A PDR

In response to the staff's second question regarding the effects of aging, relaxation, plastic creep, flammability, and embrittlement, the applicant stated that the minimum safety factor of 1.3 includes an aging effect (6

strength reouction) and a strength reduction of 247 due to elevated  :

ternperature. The applicart statt:d its judgement that such consideration of these effects is acceptable for at least the first fuel cycle, and that consideration of longer tem effects would be provided to the steff by June 1, 1987 In response to the staf"s third question concerning the basis for using equivalent static test data, the apolicant referenced FSAR 3.7.B.3.5 wherein the equivalent static load method was described.

In response to the staff's fourth question regarding slippage of cables in bundles which are not in direct contact with the cable tie, the applicant stated that cable intertwining occurs during the normal cable pulling oper-ation causing increased friction between cables within a bundle and that slippage has not occurred during cable pullino. Tbc coplicant further stateo that the inner cables do see radial pressure from the cable tie.

The staff's fifth question concerned the telerances of plus 1 foot and minus 6 inches on the 4 foot spacino criteria for the cable ties. The applicant respondeo that the ceble tio spacing depends on the weight of the cable needed to maintain the safety factor of 1.3. Therefore, the ir.aximum as-built cable tie spacing is less then or equal to the spacing necessary to get a minimum safety factor of 1.3. Sometimes the spacing was less than 5 ft to get the safety factor of 1.3. The applicant also indicated that a trious 6 inches tolerance is standard industry practice.

In response to the staff's sixth ouestien regarding walkdown compliance with 10 CFR 50 Appendix B, the applicant stated that the walkdowns are docurrented and records are available at the site but that walkdowns are not completed in accordance with Appendix B. The staff stated that this was acceptable.

The staff's seventh question dealt with test criteria for both the static and dynamic tests of the cable ties. The applicant explainco that several of the seismic levels used in the dyner.lic tests exceeded the safe shutdown carthquake acceleration. The staff also requested that the applicant verify (1) that oc slippage occurred during tests. (2) cable similarity between the ANCO test ard Vogtle, and (3) applicability of the ANCO test configuration to Vogtle.

In response to tbc staff's eighth question concerning vectoral surinations to detemine the sofety tactors, the applicant stated that the method of vectoral sumation gives a resultert vector in the most unfavorable position for evaluating the etfectiveness of the lotch locking mechanism. This inethod leads to a nore conservative load capacity. The epplicant then presented comparison infonnation between the Vcgtle and Panduit tests as follows:

PLT 4H PLT 6H Vogtle static test 106 lbs. 208 lbs.

Vendor test 204 lbs. 223 lbs.

The staff's ninth question concerned documentation from SWEC indicating its acceptance of the applicant's resolution of the cable tie issue. SWEC's statevent of the issue is provided as Enclosure 3. SWEC further stated that it concluded that the applicant's resolution of the issue is acceptable at least thrcugh the first refueling cycle.

I 15l i Melanie A. Miller, Project Manager

! PPR Projcct Directorate #4 Division of PWR Licensing-A

Enclosures:

As stated i cc: See next page i

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Enclosure 1 Participants NRC Bechtel Diller R. Gross E. Possi D. Jagar,nathan P. Callara J. Holmes D. Jeng S. Hayter S. Chan Georgia Power Coreany Stone and Webster R. Thorr.a5 A. Stakutis

$ Southern Company Services W. Ramsey 1

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Enclosure 2 8

GEORGIA POER COMPANY PRESENTATION VERTICAL CABLE SUPPORT

{:30A.M. 18, 1986 UECEMBER PRESENTATION OUTLINE R. THOMAS R. THOMAS /R. GROSS GPC VERTICAL CABLE SUPPORT PROGRAM SCOPE

• , i SCHEDULE A. STAKUTIS SWEC FINDING DESCRIPTION R. GROSS AND RESPONSE TO NRC QUESTIONS PROJECT STAFF i

CONCLUSIONS SEC R. WlESEL ,

GPC R. THOMAS 1

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Enclosure 3 December 17, 1986

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OBSERVATION NO. 22-F11 CLARIFICATION OF ORIGINAL CONCERN Observation No. 22-F11 addressed the audit team's concern with design criteria X3AR01 that identified cable ties for the support of cables.

The audit team believes that there is a distinctive difference between

" securing" and " supporting" of cables in vertical runs of cables.

" Securing" of cables in raceways is a generally accepted practice to organize and or ensure maintaining cables within the confines of cable tray type raceways.

"S'spporting" of cables in vertical raceways is required to prevent damage to the cables, terminal connection points, other equipment, or personnel due to the weight of the cables. ..

Although the Project has not committed to the National Electrical Code it does provide a point of reference and the 2984 Handbook states as follows:

" Conductors in long vertical runs are to be supported to prevent the weight of the conductors from damaging the insulation where leaving the conduit and to prevent the conductors from being pulled out of terminals."

The type of damage to the insulation due to the forces produced by the cable weight is a reduction in insulation wall either by cut-through, deformation due to reduced bending radius, or insulation creep. These same phenomena may occur either in conduit or tray applications depending on configuration of cable at raceway interfaces. The reduction in insulation wall is a reduction in dielectric strength and may result in the loss of circuit integrity.

Page 2 The weight of cable on terminal assemblies can result not only in pull-out of conductors but possible deformatior, of the terminal mechanisms, either of which may also result in loss of circuit integrity. In a worst case scenario the cables could drop and damage other equipment.

The National Electrical Code. Article 300-19 provides guidance regarding criteria for spacing for supports and support methods. In addition to some specific methods, the code allows "by a method of equal effectiveness." .

At the time of the original observation, sufficient evidence was not available to justify cable ties as a method of equal effectiveness for the

" support" of cables in vertical raceways.

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Pr. J. P. O'Reilly Georgia Power Company Vogtle Electric Generating Plant cc:

Mr. L. T. Gucwa Resident Inspector Chief Nuclear Engineer Nuclear Regulatory Commission Georgie Power Company P. O. Box 572 P.O. Box 4545 Waynesboro, Georgia 30830 Atlanta, Georgia 30302 Mr. Ruble A. Thomas Depoish Kirkland, III, Counsel Vice President - Licensing Office of the Consumers' Utility Vogtle Project Council 1 Georoia Pcher Company / Suite 225 Southern Company Services, Inc. 32 Peachtree Street, it.l!.

P.O. Box 2675 Atlanta, Georgia 30303 Birmingham, Alabama 35202 James E. Joiner Mr. Donald 0. Foster Trcutman, Sanders, Lockerman, Vice President a Project General Manager & Ashmore Georgia Power Company Candler Building r

Post Office Box 299A, Route 2 127 Peachtree Street,it.E.

Waynesboro, Georgia 30830 Atlanta, Georgie 30303 Danny Feig Mr. J. A. Bailey 1130 Alta Avenue Project Licensing Fknager Atlanta, Georgia 30307 Southern Company Services, Ir.c.

, P.O. Box 2625 Carol Stangler Birminghan., Alabama 35202 Georgians Against Nuclear Energy 425 Euclid Terrace Ernest L. Blake, Jr. Atlanta, Georgia 30307 l Bruce W. Churchill, Esq.

Shaw, Pittman, Potts and Trewbridge 2300 N Street, N.W. i Washington,,0. C. 20037 i Mr. G. Bockhold, Jr.

Vogtle Plant itanager Georgia Power Company Route 2, Box 299-A ,

Way esboro, Georgio 30030  !

Reffonal Administrator, Region 1:

< U.S. Nuclear Regulatory Ccr.nission 101 Marietta Street, N.W., Suite 2900 '

Atlanta, Georgia 30373 Mr. R. E. Conway Senior Vice President and Project Director Georgia Power Company i

Rt. 2, P. O. Box 299A

Waynesbere, Georgia 30830

, o MEETING

SUMMARY

DISTRIBUTION TBAlE4' File??} NRC Participants

' NRC" PDR "~~"" M. M11Ier L PDR E. Rossi NSIC R. De11ard PRC System D. Jeng PWR!4 Reading File N. Romney M. Duncan S. Chan OGC-Bethesda J. Partlow E. Jordan B. Grines ACRS (10) t OTHERS bec: Licensec & Service L'ist