ML18033A726

Forwards Response to 890321 Request for Addl Info Re Electrical Cable Ampacity,Consisting of Results of Two NRC Cable Tray Simulation Cases

ML18033A726
Person / Time
Site:	Browns Ferry
Issue date:	04/27/1989
From:	Fox C TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TAC-62260, NUDOCS 8905080134
Download: ML18033A726 (11)

Text

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ACCESSION NBR:8905080134 DOC.DATE: 89/04/27 NOTARIZED: NO DOCKET g FACIL:50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 AUTH. NAME AUTHOR AFFILIATION FOX,C.H. Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Forwards response to 890321 request for addi info re electrical cable ampacity.

DISTRIBUTION CODE: D030D COPIES. RECEIVED:LTR . ENCL SIZE:

TITLE: TVA Facilities Routine Correspondence NOTES:1 Copy each to: S.Black,D.M.Crutchfield,B.D.Liaw,L.Watson 05000260 ~

R.Pierson RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID>> CODE/NAME LTTR ENCL SIMMS,M 1 1 PD 1 1 GEARS,G 1 1 D

INTERNAL: ACRS 1 1 NUDOCS-ABSTRACT OC/L~P 1 0 OGC/HDS2 S EG FILE 1 1 EXTERNAL: PDR 1 1 NRC PDR NSIC 1 1 NOTES 5 5 R

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TOTAL NUMBER OF COPIES REQUIRED: LTTR 16 ENCL 14

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TENNESSEE VALLEY AUTHORITY CHATTANOOGA, TENNESSEE 37401 SN 1578 Lookout Place APR 27 1%3 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:

In the Matter of Docket No.=50-260 Tennessee Valley Authority BROWNS FERRY NUCLEAR PLANT (BFN) ELECTRICAL CABLE AMPACITY RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION (TAC 62260)

This letter provides TVA's response to an NRC request, dated March 21, 1989, for additional information on the above subject. The results of our analyses of your two cable tray simulations cases are provided in the enclosure. This information along with our previous submittals should provide the staff with the information necessary to complete its review of the subject program.

If you have any questions, please telephone Patrick P. Carier, BFN, Site Licensing, at (205) 729-3570.

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Very truly. yours

,TEN SSEE A UTHORITY

. Fo , Jr., Vice President and Nuclear Technical Director Enclosure cc: See page 2 S9050S0i34 S90427 PDR ADOCK 05000260 P PDC An Equal Opportunity Employer

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U.S. Nuclear Regulatory Commission APR 87 1888 cc (Enclosure):

Ms. S. C. Black, Assistant Director for Projects TVA Projects Division U.S. Nuclear Regulatory Commission One Nhlte Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. B. A. Hi lson, Assistant Director for Inspection Programs TVA Projects Division U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NH, Suite 2900 Atlanta, Georgia 30323 Browns Ferry Resident Inspector Browns 'Ferry Nuclear Plant Route 12, Box 637 Athens, Alabama 35609-2000

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ENCLOSURE Page 1 of 3 CASE 1: Overloaded cables not to exceed hot spot critical area.

DATA: 22 cables in 18 inch wide tray, size 4/0 with 16 cables unloaded, Four cables loaded to 100 percent of the Stolpe value, and two cables overloaded by the same amount.

QUESTION'.. Hhat. is the greatest amount of overload allowed by the diversity program for the two overloaded cables assuming the overloaded cables are not safety-related, but the cables loaded at 100 percent are safety-related? Also, what is the predicted maximum temperature in the 100 percent loaded and in the overloaded cables?

.- TVA RESPONSE BACKGROUND The model used for both this case and the following case two is a tray with 22 1C-4/0 AHG cables laid in one packed layer. Specific generic data utilized in both case analyses is provided in Table l.

CONCLUSION The analysis results for case one indicates that the maximum load is 177.5 percent of the Stolpe allowable 264.77 amps or 470 amps. The maximum predicted temperature in the safety cables would be their temperature rating or 90'C. The temperature in the overloaded cables would be 114 C. Any further load applied to the already overloaded cables would result in an ampacity failure of the safety cables. The complete analysis results are presented in Table 2.

0 ENCLOSURE Page 2 of 3 Table 1 System Input Information Cable Information TVA mark WDK, 1C-4/0 AWG, 90'C temperature rated Diameter .723 Inches Ambient Temperature 40'C Tray Size 18 inches Wide x 4 inches Deep Cable Mass Width 1 Layer, 22 1C-4/0 Cables, 15.906 inches Cable Mass Depth 1 Cable Diameter, .723 Inches Allowable (Stolpe) 166 Amps Ampacity at 30/.

(1.528 inches deep) tray fill Adjusted Allowable 264.77 Amps (Stolpe) Ampacity at reduced fill of .723 inches deep 80 percent Free Air Ampacity 320 Amps Table 2 Percent of No, of Load Stolpe Diversity Pass or Cable Safet (?) Conductors Am s Allowable Tem C Fail 16 lc-4/0 N/A 16 0 0 69 p 4 1C-4/0 Y 4 264. 77 100 90 p 2 lc-4/0 N 2 470 177.5 114 F CASE 1 Maximum allowable load on nonsafety 2 1C-4/0 cable to produce 90'C on 4 1C-4/0 safety cables.

ENCLOSURE Page 3 of 3 U

CASE 2: Overloaded cables to exceed the hot spot critical area.

22 cables in 18 inches wide tray, size 4/0 with 16 cables unloaded and 6 cables overloaded by the same amount.

DATA'VA gUESTION: Nhat is the greatest amount of overload allowed by the diversity program for the 6,overloaded cables, assuming the overloaded cables are safety-related? Also, what is the predicted maximum temperature in the overloaded cables?

RESPONSE

CONCLUSION The results of the analysis for case two indicates that the greatest allowable load for 6 1C-4/0 safety cables'ould be 106.9 percent of the Stolpe allowable 264.77 amps or 283 amps. The maximum predicted temperature of the safety cables would be equal to their temperature rating or 90'C. Any further load applied to the safety cables would result in an ampacity failure since they would operate at a temperature greater than their rating. The complete analysis results are presented in Table 3.

Table 3 Percent of No. of Load Stolpe Diversity Pass or Cable Safet (?) Conductors Am s Allowable Tem C Fail 16 lc-4/0 N/A 16 0 0 58 6 lc-4/0 Y 6 283 106.9 90 CASE 2 Maximum allowable load on 6 1C-4/0 safety cables to produce 90'C with no load on 16 1C-4/0 cables.

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