BVY-96-145, Responds to RAI Re Request for Exemption from Requirement of 10CFR50,App R,Section Iii.G to Permit Use of Rockbestos Firezone

Responds to RAI Re Request for Exemption from Requirement of 10CFR50,App R,Section Iii.G to Permit Use of Rockbestos Firezone

ML20134L269
Person / Time
Site:	Vermont Yankee
Issue date:	11/15/1996
From:	Reid J VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BVY-96-145, NUDOCS 9611200213
Download: ML20134L269 (7)

Text

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. ViLRMONT YANKEE NUCLEAR POWER CORPORATION Ferry Road, Brattleboro, VT 05301-7002 y ,,, I ENGINEERING OFFICE f

. 580 MAIN STREET

. BOLTON, MA 01740 (508)779-6711 November 15,1996 BVY 96-145 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

References:

(a) License No. DPR-28 (Docket No. 50-271) )

(b) Letter, WNPC to USNRC, BW 96-58, dated May 28,1996 l (c) Letter, USNRC to WNPC, NW 96-117, dated June 28,1996 (d) Letter, WNPC to USNRC, BW 96-94, dated July 26,1996 (e) Telecon, USNRC to WNPC, November 8,1996 (f) Underwriter's Laboratory Test Report, File R10925-1, dated April 10,1984

Subject:

Response to Request for Additional Information Regarding Vermont Yankee Request for Exemption from 10 CFR Part 50, Appendix R j in Reference (b), Vermont Yankee requested exemption from the requirements of 10CFR50, Appendix R, Section Ill.G, " Fire protection of safe shutdown capability," to permit use of Rockbestos Firezone*R fireproof cable in plant areas th::t 9 quire enclosing cables in a fire barrier having a 1-hour fire rating. The plant areas identi' J in the exemption request were the Cable Vault and the 280 foot elevation of the Reactor B/ Jing.

In Reference (c), the NRC requested additionalinform aon needed to complete review of our exemption request. In Reference (d) Vermont Yankee submitted the requested information and revised the exemption request so that it now applies to the use of Rockbestos Firezone*R cable only in the Cable Vault.

In Reference (e), the NRC requested further information regarding our request. The information requested is attached.

We trust that the information provided is acceptable; however, should you have any questions, please contact this office.

Sincerely, VERMONT YANKEE NUCLEAR POWER CORPORATION 1

[ffftpf 2000$

James J. Duffy Licensing Engineer

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9611200213 961115 PDR ADOCK 05000271 F PDR

4 VERMONT YANKEE NUCLEAR POWER CORPORATION United States Nuclear Regulatory Commission

'Noverbber 15 1996 '

. Pags 2 of 2 Attachment 1: Response to Request for Additional Information Attachment 2: Rockbestos Firezone*R cable Vendor information c: USNRC Region I Administrator USNRC Resident inspector - VYNPS USNRC Project Manager- VYNPS

o VERMONT YANKEE NUCLEAR POWER CORPORATION United States Nuclear Regulatory Commission

• Noveinber 15,1996 Attachment 1

- Page 1 of 3 ,

l Request for Additional Information Vermont Yankee Nuclear Power Station Request for Additional Information #1 Describe and justify the differences between the tested (Reference (f)] and installed Firezone*R cable configurations. Describe why and how the tested configurations bound the installed 4

configurations. In addition, state the maximum temperature attained during the test and provide the limiting temperature for cable damage.

Response to Request for Additional !nformation #1 The cable which is the subject of Vermont Yankee's exemption request, installed in the Cable l Vault, is a two-conductor (2/C) #14 AWG Firezone*R cable with a stairless steel sheath (see Attachment 2). The cables tested in Reference (f) included a 3/C #14 AWG cable. As demonstrated below, the 2/C cable is identical to the 3/C cable in all critical fire protection attributes except for having one less conductor. Also, as demonstrated below, the test .

I configurations exposed the Firezone*R cable to conditions more severe than the instal;ed configuration. Based on these facts, the tested configurations bound the installed configuration and therefore the use of the 2/C Firezone*R cable requested in Reference (b) is considered acceptable.

Cable Construction As described in Attachment 2, all Firezone*R cables have the same cable jacket construction including: flame retardant binder tape, glass braid covering and a continuously welded, corrugated stainless steel sheath. Additionally, each individual conductor in a #14 AWG Firezone*R cable has the same conductor construction including: conductor size, composite inorganic layer fire barrier, silicone rubber insulation, mica tape and glass braid conductor i

covering with high temperature finish. Finally, conductor to conductor spacing and conductor to cable jacket spacing are the same for the installed 2/C cable as for the tested 3/C cable. The critical electrical insulation properties of the cable when exposed to the fire are therefore the

! same.

Fire Test Confiauration The configuration of the 2/C cable installed at Vermont Yankee is less severe than the test configuration of the 3/C cable in Reference (f). The installed 2/C cable is routed outside of

cable trays, away from non-fire-resistant electrical cables (see description of 2/C cable routing provided in Reference (d)]. As described in Reference (f), the tested 3/C cable was placed in a cable tray assembly among non-fire-resistant electrical cables to simulate the fuel loading of an actual installation. Despite the additional exposure of ignited non-fire-resistant cables, a configuration more severe than Vermont Yankee's configuration, the Firezone*R cable remained functional throughout the test.

Also, the installed 2/C cable is used in a 120Vac circuit and the cable insulation is rated for 600Vac. The tested cable was subjected to a 78 minute fire exposure with the furnace temperatures controlled in accordance with the Standard for Fire Tests of Building Construction

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r VERMONT YANKEE NUCLEAR POWER CORI' ORATION United States Nuclear Regulatory Commission l

' Noveinber 15,1996 Attachment 1

)

Page 2 of 3 and Materials, ASTM E119. During the fire endurance test, the 3/C cable was connected to three phase Y voltages of 480/277V and 960/555 Vac (Reference (f), p. 32]. This test configuration is clearly more severe than the installed configuration. The temperatures measured on the stainless steel sheath of the tested cable are contained in Appendix D of Reference (f). The maximum ambient temperature attained was 1740'F and the maximum 3/C cable temperature attained was 1671.9'F. Although the limiting temperature for cable damage was not determined during the test, the test results demonstrate that the limiting temperature

, for cable damage is in excess of that required to achieve a one-hour fire rating.

1 Therefore, because the 2/C Firezone*R cable installed at Vermont Yankee is essentially the same in construction and fire protection features as the tested 3/C Firezone*R cable and because the 3/C cable passed an ASTM E119 fire test whose configuration and test conditions were more severe than the 2/C cable installation at Vermont Yankee, use of the 2/C

! Firezone*R cable is bounded by the tested configuration and its use as a 1-hour fire barrier is i therefore acceptable.

Reauest for AdditionalInformation #2 Describe the conditions and functionality of the Firezone*R cables throughout the test. Indicate whether the cables were energized and carrying load or de-energized, as well as whether the

cables were capable of performing their function. Discuss the criteria used to determine functionality of the cable such as insulation resistance, physical damage, or others.

Response to Reauest for Additional Information #2

, "The fire endurance test was conducted with the furnace temperatures controlled in accordance with the Standard for Fire Tests of Building Construction and Materials, ASTM E119."

- Reference (f), p.15 4

"Immediately before the fire endurance test, the fire resistant cables were energized with predetermined steady-state ac electrical currents. The cables remained energized throughout the fire exposure except for a 10 s period immediately preceding an inrush current test on each fire resistant cable. Following the fire endurance test, the cables were deenergized for the water hose stream test. Following the water hose stream test, the cables were again energized with predetermined steady state ac electrical currents. The cables remained energized throughout a 93 h cooldown period except for a 10 s period just prior to the application of four supplemental inrush current tests. Following the 93 h extended cooldown period the cables were again deenergized for a second hose stream test. Immediately following the second hose stream test the cables were subject to a final inrush current test."

- Reference (i), p.1 "In addition to the low voltage ac electrical current applied to each conductor of the nine fire resistant cable configurations, each fire resistant cable was energized with a de voltage and monitored continuously for electrical faults. The electrical fault monitor panel was connected to

l l

1

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VERMONT YANKEE NUCLEAR POWER CORPORATION l

• ~. United States Nuclear Regulatory Commission Nove'mber 15,1990 Attachment 1 Page 3 of 3 an automatic data logger which scanned each circuit and provided a printed record to show electrical faults."

- Reference (f), p.17 The test results indicated that no " electrical faults occurred in any of the nine fire resistant cable configurations." To " substantiate the determination that no electrical faults were present in the nine fire resistant cable configurations, insulation resistance and dielectric voltage-withstand tests were conducted on each conductor of the nine cables. The results of the insulation resistance and dielectric voltage-withstand tests are contained in Appendices B and C, respectively," of Reference (f).

- Reference (f), p. 23 "As evidenced from the tables in Appendices A, B and C, (electrical current, insulation resistance and dielectric voltage-withstand measurements) each of the nine fire resistant cable configurations in the full-scale test assembly remained electrically functional during the fire endurance test and during the extended cool-down period."

- Reference (f), pp. 31-32 Request for Additional Information #3 Descr be the magnitude of current loading during the testing in Reference (f).

l Response to Reauest for AdditionalInformation #3 The following table provides a comparison of loads carried by the tested and installed cables:

Cable Type Steady State Current inrush Current Tested: 3/C #14 AWG ~4A* ~ 17 A (for 30 sec)*

Installed: 2/C #14 AWG 0.2 A 1.3 A (for 8.3 msec)

• See Appendix A, p. A3, of Reference (f) for exact values for each conductor l

The latest vendor catalog establishes conduction ampacity at 1700 F (based on an 1800 F conductor temperature) as follows:

Cable Type Ampacity at 1700 F ambient 3/C #14 AWG 14.9 A 2/C #14 AWG 14.9 A The significantly higher current loading of the tested cable and the manufacturer's published l ampacity provide further evidence that the use of the 2/C Firezone*R cable at Vermont Yankee is bounded by the tested configuration and is therefore acceptable.

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. Firezone'" R '

Appenda. .. R ..

i t Armor (optional *) Binder Ta'pe C$nductor

! . Continuously welded  : Flame retardant lL stranded ;

Flexibly Fireproof Cable l corrugated , l nickel-coated

stainless steel- '

copper -

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Class 1E Nuclear l l Overall Covering . Fire Barrier 1 i Glass brald ~ , i ~ Mica Tape Composne Inorganic layer Spec. RSS-5-144 Conductor Cov'ering , LOCA Dielectric l i

-Glass braid - -i Stitcone rubber '

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! Scope l Firezone*Ris a fireproof cable specifically designed to address redundant safety l circuit requirements within nuclear generating stations. This unique Class 1E nuclear qualified cable system insures safety-related circuit integrity in the event of a fire as required by Appendix "R". (Code of Federal Regulations: Title 10, Part

50.48). It is intended for use on low voltage control, power and instrumentation l circuits and can be supplied in either armored or unarmored

• versions. Construction

! Features Performance Standards Conductor:

l Flexible strand, high temperature, nickel-

• Cost-efficient altemative to thermal wrap-

• Minimum one hour fire rating at 1700*F c ted copper conductor ping of cable trays or cable re-routing as defined by the ASTM standard E-119 Fire Barrier:

• Can be installed within trays containing

• Greater than three hour fire survival at Composite inorganic layer i typical plant cables 1500*F LOCA Dielectric:

l

• Other cables within tray do not have to be

• Class 1E qualified in accordance with Silic ne rubber insulation layer l derated (as is necessary with ampacities IEEE-383 and IEEE-323. (Rockbestos l for cables inside thermally wrapped trays) Report QR-9801) Conductor Covering:

I

• Additional circuits can be easily added

• Full ASTM E-119 fire test report avail- Mica tape and glass braid with high tempera-

• Does not require costly inspection, main- able under UL report file #R109254, ture finish l

tenance and record keeping associated pro)ect #84NK2320 (Note: this is not a Circuit identification:

with tray wrapping UL listed cable) White braids with colored tracers

• Full traceability provided

• Cable passed the IEEE-383 70,000 BTU /

hr vertical tray flame test cabling:

)

• Radiation resistant

• Silicone rubber insulation layer is in ac_ Required number of conductors cabled I

• Flame retardant

• Nuclear qualified with a minimum 40- cordance with ICEA standard S-19-81 Binder Tape:

, year thermallife expectancy at 90*C**

• Quality Assurance program in accordance Flame retardant binder tape j with 10 CFR Appendix B Armor: (optional *)

f Continuously welded, corrugated, stainless i steel sheath 1

• Unarmored cable must be installed in steel conduit l **Sihcone rubber insulation has an inheren' 125'C 40-

year thermal hie.

l 'The Rockbestos Company 285 Nicoll Street New Itaven, Connecticut 06511 (203)772-2250 800 327-7625 US-7 I

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! Firezone*R l Appendir "R" i Fireproof Cable l 90*C, 600 Volt Class 1E Nuclear l .

i ,

(Inorganic Layers) spec. nss-5444 1

4 .

I Stainless Steel Armored Single Conductor Nominal Overall Approximate Product Number of Conductor Number of Diameter Diameter Net Weight Code Conductors Size Strands (In) (In) (Ibs/M')

F54-3017 2 14 AWG 19 .27 .78 260 i F54-3041 3 14 AWG 19 .27 .92 320 i F54 3045 4 14 AWG 19 .27 .96 390 j F54-3053 7 14 AWG 19 .27 1.00 540 t

! F54-3004 2 12 AWG 19 .29 .84 290 l F54 3042 3 12 AWG 19 .29 .96 370 F54 3046 4 12 AWG 19 .29 1.00 450 F54 3054 7 12 AWG 19 .29 1.13 650 F54 3040 2 10 AWG 49 .33 .96 360 F54-3005 3 10 AWG 49 .33 1.00 430 F54-3047 4 10 AWG 49 .33 1.00 530 F54-3055 7 10 AWG 49 .33 1.33 820 3

l F54 3043 3 3AWG 133 .39 1.26 600 l F54 3048 4 8AWG 133 .39 1.26 740 l F54-3044 3 6AWG 133 .44 1.26 730 t

' F54-3049 4 6AWG 133 .44 1.46 930 F54-3014 3 4AWG 133 .54 1.50 1150 F54-3050 4 4AWG 133 .54 1.56 1220 F54 3016 3 2AWG 665 60 1.61 1470 F54-3051 4 2AWG 665 .60 1.71 1650 F54-3057 3 1AWG 817 .67 1.80 1630 F54-3052 4 1AWG S17 .67 2.02 2100 Unarmored (Must be installed in conduit)

Fb4 3019 2 14 AWG 19 .27 .62 150 F54-3025 3 14 AWG 19 .27 .66 200 l F54-3030 4 14 AWG 19 .27 .73 250 F54-3021 7 14 AWG 19 .27 .88 400 l

F54 3010 2 12 AWG 19 .29 .66 170 F54 3020 3 12 AWG 19 .29 .70 240 F54-3031 4 12 AWG 19 .29 .78 300 F54 -3009 7 12 AWG 19 .29 .94 480 l

F54 3024 2 10 AWG 49 .33 .73 220 F54-3011 3 10 AWG 49 .33 .78 290 F54 3032 4 10 AWG 49 .33 .87 380 f 54 3038 7 10 AWG 49 .33 1.05 620 F54 3026 3 8AWG 133 .39 .93 430 F54 3033 4 8AWG 133 .39 1.03 560 F54 3027 3 6AWG 133 .44 1.02 550 F54-3034 4 6AWG 133 .44 1.14 720 F54-3028 3 4AWG 133 54 1.15 760 F54-3055 4 4AWG 133 .54 1 29 990 F54-3029 3 2AWG 665 60 1 29 1070 F54 -3036 4 2AWG 065 60 1 44 1100 F54 3058 3 1AWG Hl7 67 1 51 1180 f 54 3037 4 1AWG H17 67 1 68 1800

[1% 8 rn io "The Hot kbestos Company 2H5 Nicoil Street New flaven, Cmme< tic ut 06511 (203)772 2250 800 327 7625