ML20035A990

Summary of 930209 Meeting W/Util Re Plant Fire Protection Issues as Discussed in Sser 26.List of Attendees & Meeting Handouts Encl

ML20035A990
Person / Time
Site:	Comanche Peak
Issue date:	03/25/1993
From:	Brian Holian Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
NUDOCS 9303300315
Download: ML20035A990 (23)

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4, UNITED STATES j

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ys NUCLEAR REGULATORY COMMISSION

.g WASHINGTON, D. C. 20555 March 25, 1993 Docket Nos. 50-445 and 50-446 LICENSEE: Texas Utilities Electric Company (TU Electric)

FACILITY: Comanche Peak Steam Electric Station (CPSES), Units 1 and 2

SUMMARY

OF MEETING ON CPSES FIRE PROTECTION ISSUES A meeting was held on February 9, 1993 to discuss fire protection issues as discussed in Supplemental Safety Evaluation Report (SFER) No. 26.

The primary issues discussed were TV Electric's commitments as stated in SSER 26. These 1

commitments can be summarized as follows:

to maintain fire watches in place as compensatory measures for inoperable " box-type" configurations and for those configurations that did not have a 30 day cure time, to perform a confirmatory fire test on a 36-inch wide cable tray barrier (or provide additional information which adequately addresses staff concerns), and to perform plant-specific ampacity derating testing.

TV Electric provided information further describing the " box-type" configurations installed in the plant. The staff further described to the utility that the protective envelope associated with the specific configurations was not a direct extension of the cable tray coverage, but was rather a " box-type" design, necessitating either specific testing or additional upgrades installed in order to be bounded by the junction box tested configuration (which had two layers of barrier material).

TV Electric also provided details of their proposed 36-inch cable tray confirmatory test, and verbally committed to perform the test in early March 1993. TV Electric discussed their plan of performing the test with upgrade techniques designed for the Unit I plant configurations (using stress skin over the joints, but absent the extra stitching that was used on Unit 2).

Additionally, the licensee stated that it was considering conducting the test with a cure time of less than 30 days, but within the manufacturer's recommendations.

Proposed ampacity derating testing was also discussed. TU Electric discussed their proposed use of a plastic sheet in the cable tray tests to minimize air l

flow through the configuration (similar to original ICEA test programs). The staff was concerned with this approach since the orig.nal ICEA testing provided an acceptable ampacity derating margin, in order for tested configurations to effectively bound all in-plant configurations. The staff recommended that the utility ampacity derating tests should model cable in-l plant configurations to determine ampacity derating solely due to the fire barrier material.

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TU Electric was informed that the staff is continuing their review of the TV i

Electric ampacity derating test results and engineering documents and will address these remaining fire barrier issues in a future safety evaluation.

J NOTE: TU Electric followed up this meeting with a letter dated February 26, 1993, which provided additional information regarding the above items. The i

letter described the 36-inch cable tray confirmatory test and schedule, i

verified the number of box-type configurations to be upgraded with a second i

layer of barrier material, and provided a copy of their ampacity derating test i

pl an. Also, by letter dated March 10, 1993, TU Electric provided preliminary data from both the 36-inch cable tray test (conducted on March 4, 1993) and the first series of ampacity derating tests, and stated that the box-type configuration upgrades had been completed.

Original Signed By Brian E. Holian, Senior Project Manager Project Directorate IV-2 Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation i

Enclosures:

DISTRIBUTION:

1.

List of Attendees Docket Filesi 2.

Maeting Handouts NRC POR Local PDR cc w/ enclosures:

PDIV-2 RF See next page PDIV-2 PF TMurley FMiraglia JPartlow JRoe-MVirgilio BHolian EPeyton 0GC EJordan NRC Participants l

ACRS (10) t LYandell, RGN-IV RArchitzel AGill PBaranowsky NRR:EELB PDIV-2/D o m er PDIV-2/LA PDIV-2/PM NRR:SPLB w

m EPEffoY BEHolian[nE RArchitzef PGill k ).

SBlar$kN uw 3/.?/93 3/M/93 3/ M /93 I

3/ 24 /93 3/ @ /93 DATE Yes/No)

/Ye2/No Yb/No Ts'/No Yes/ND cwr file Name: b:\\CPSESMIG.393 W

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' March 25,1993 cc w/ enclosures:

Senior Resident Inspector Jack R. Newman, Esq.

U.S. Nuclear Regulatory Commission Newman & Holtzinger P. O. Box 1029 1615 L Street, N.W.

Granbury, Texas 76048 Suite 1000 Washington, D. C.

20036 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Chief, Texas Bureau of Radiation Control 611 Ryan Plaza Drive, Suite 1000 Texas Department of Health Arlington, Texas 76011 1100 West 49th Street Austin, Texas 78756 i

Mrs. Juanita Ellis, President Citizens Association for Sound Energy Honorable Dale McPherson 1426 South Polk County Judge i

Dallas, Texas 75224 P. O. Box 851 Glen Rose, Texas 76043 Owen L. Thero, President Quality Technology Company Mr. William J. Cahill, Jr.

Lakeview Mobile Home Park, Lot 35 Group Vice President 4793 East Loop 820 South.

TU Electric Fort Worth, Texas 76119 400 North Olive Street, L.B. 81 l

Dallas, Texas 75201 Mr. Roger D. Walker, Manager 4

Regulatory Affairs for Nuclear Engineering Organization Texas Utilities Electric Company 400 North Olive Street, L.B. 81 Dallas, Texas 75201 Texas Utilities Electric Company c/o Bethesda Licensing 3 Metro Center, Suite 610 Bethesda, Maryland 20814 William A. Burchette, Esq.

Counsel for Tex-La Electric Cooperative of Texas Jorden, Schulte, & Burchette 1025 Thomas Jefferson Street, N.W.

Washington, D.C.

20007 GDS Associates, Inc.

Suite 720 1850 Parkway Place Marietta, Georgia 30067-8237

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ENCLOSURE 1 MEETING ATTENDEES NAMES ORGANIZATION Brian Holian NRC Suzanne Black NRC Ralph Architzel NRC Conrad McCracken NRC Patrick Madden NRC Ronaldo V. Jenkins NRC l

Paul Gill NRC K. S. West NRC l

C. H. Berlinger NRC f

Roger Walker TU Electric Charles L. Terry TV Electric Richard L. Dible TU Electric Dale Walling TV Electric L. Zerr STS l

l ENCLOSURE 2 CPSES AMPACITY DERATING TESTS FOR CABLES IN THERMO-LAG i

i 9 Conduct ampacity baseline test O Conduct ampacity derating test l

9 Calculate ampacity derate factor 3

Derate factor = 1-(I /I) r o

where Ir = derated ampacity I

= basehne ampacity o

S Evaluate derate factor against CPSES as-built circuit design margms P

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CPSES AMPACITY-DERATING TESTS-FOR CABLES IN THERMO-LAG.

i e Six conngurations will be tested 1 ladder back cable tray section, 24" wide x 4" deep x 12' long filled to j

40% with 3/C 6 AWG Cu cable, clad in 1/2" Thermo-Lag.

1 3 configurations of rigid conduit O 3/4" conduit with a single 3/C 10AWG Cu cable, clad in 1/2"Thermo-Lag w/1/4" overlay 1

9 2" conduit withsingle 3/C 6AWG j

Cu cables, clad in 1/2"Thermo-1 Lag w/1/4" overlay 9 5" conduit with three 1/C.

750kemil Cu cables clad in 1/2"Thermo-Lag

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CPSES i

AMPACITY DERATING TESTS FOR CABLES IN THERMO-LAG 2 configurations of cable bundle free air drops will be tested O Single 3/C 6AWG Cu 600v cable, clad in three layers of Thermo-Lag 660 flex blanket e Three 1/C 750kemil Cu 600v cables, clad in three layers of.

Thermo-Lag 660 flex blanket t

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COOLING EFFECT OF AIR FLOW i

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l Heat generated by cable induces air o

flow through cables in tray i

o Air flow cools cable Ampacity of cable (Io) increases o

o Air flow depends on many factors which vary from test to test Tests are not repetitive o

Figure 1

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CABLE TRAY CABLE AMPACITIES H

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i t'3 MIL PLASTIC SHEET CABLES LADDER RUNG AIR SPACE CREATED BY T,C WIRE 1'

CPSES uses ICEA 54-440 the industry standard for cable l

o ampacities ICEA 54-440 based on Stopic Mathematical Model o

Mathematical Model does not model air flow o

Stople supported mathematical ampacity values by test with o

plastic sheet at bottom of tray Figure 2

24" TitAY AMPACITY BASELINE TEST

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Heat dissipates upward o

o No air flow Baseline ampacity (L) approach o

ICEA 54-440 values i

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I 24" TRAY AMPACITY DERATING TEST i

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F Heat dissipation limited by Thermo-Lag o

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Ampacity (Ir) decreases due to Thermo-Lag o

Thermo-Lag ampacity derating o

factor =

1 - ( Ir/Io )

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__.__ ____ _ ______j

CPSES EVALUATION OF TEST RESULTS i

e CPSES has evaluated the acceptability of 40% derate factor for cable tray i

installations with Thermo-Lag l

1 Ampacity margins for all Thermo-Lagged circuit designs will be calculated Calculated derate factors will be compared to these margins to i

identify those circuits whose margin is less than the derate factor i

Circuits whose margin is less than the derate factor will be dispositioned by:

Reviewing the circuit installation to j

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adjust the ampacity calculation for the as-built circuit configuration, or Modifying the circuit

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CAllLE DERATING EVAI,UATION I.O A D l'I. A Calli,E DEMAND CAHl,E T RAY 1.25 N l'i,A AI,1,0WAlli,E Amp DI:H ATE M ARGIN TEST DEH ATE l

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1.15" depth @ 50"C ambient temperature A = (l - (1/I )) x 100%

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11 = calculated derate factor from test If A > ll, calile is acceptalile If A<11, evaluation / circuit modification is required

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UNIT 2 THERMO-LAG " BOX ENCLOSURE" CONFIGURATIONS e

UTILIZED IN SPECIFIC APPLICATIONS ONLY.

e CRITICAL ATTRIBUTES OF THESE CONFIGURATIONS HAVE BEEN QUALIFIED BY TEST.

THERMAL PERFORMANCE ATTRIBUTES:

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MATERIAL THICKNESS PROTRUDING ITEM AND SUPPORT COVERAGE MATERIAL INTERFACES STRUCTURAL PERFORMANCE ATTRIBUTES:

JOINT REINFORCEMENT TECHNIQUES REPRESENTATIVE MATERIAL SPANS CONDUIT / CABLE ENTRANCES j

S IF SPECIFIC ATTRIBUTES WERE NOT TESTED; CONSERVATIVE MEASURES WERE SPECIFIED BASED ON i

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EXPERIENCED GAINED DURING TEST PROGRAM:

I POSITIVE MECHANICAL ATTACHMENT TO CONCRETE STRUCTURE OR EMBEDDED SLEEVES.

ERECTION OF SPECIAL STEEL FRAMEWORK TO j

SUPPORT THERMO. LAG ENCLOSURES.

CONSERVATIVE JOINT REINFORCEMENT TECHNIQUES USING COMBINATIONS OF ANCHOR BOLTS, STRESS l

SKIN OVERLAY AND TIE WIRE

• STITCHING".

8 SPECIFIC DESIGNS WERE ISSUED FOR THESE CONFIGURATIONS I

BASED ON INSTALLATION TECHNIQUES QUALIFIED BY (OR REPRESENTATIVE OF) TESTED ASSEMBLIES.

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i UNIT 2 THERMO-LAG " BOX ENCLOSURE" l

CONFIGURATIONS (CONT'D) 9 THEREFORE, IN ACCORDANCE WITH GL 86-10, UNIT 2 THERMO-LAG " BOX ENCLOSURE" COMFIGURATIONS PROVIDE A-SUFFICIENT LEVEL OF PROTECTION TO ASSURE AT LEAST ONE TRAIN OF SAFE SHUTDOWN SYSTEMS AND COMPONENTS WILL l

REMAIN FREE FROM FIRE DAMAGE; J

CONTINUITY OF MATERIAL IS CONSISTENT WITH TESTED CONFIGURATIONS.

EFFECTIVE THICKNESS OF MATERIAL IS CONSISTENT WITH TESTED CONFIGURATIONS.

THE NATURE AND EFFECTIVENESS OF SUPPORT ASSEMBLIES AND MECHANISMS ARE CONSISTENT WITH TESTED CONFIGURATIONS.

THE APPLICATION OR END USE OF THE MATERIAL IS CONSISTENT WITH TESTED CONFIGURATIONS.

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THE CONFIGURATIONS HAVE BEEN REVIEWED BY QUALIFIED FIRE PROTECTION ENGINEERS AND DETERMINED TO PROVIDE AN EQUIVALENT LEVEL OF PROTECTION TO TESTED CONFIGURATIONS.

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" BOX CONFIGURATION" APPLICATIONS CABLE AIR DROPS THROUGH EMBEDDED SLEEVES INTO HORIZONTAL OR VERTICAL CABLE TRAYS.

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1 CONFIGURATION ENCLOSES PORTIONS OF 3 HORIZONTAL (STACKED) TRAYS AT A BANK OF EMBEDDED SLEEVES.

3 CONFIGURATIONS ENCLOSE PORTIONS OF 2 HORIZONTAL OR VERTICAL TRAYS AT BANKS OF EMBEDDED SLEEVES.

i CRITICAL ATTRIBUTES BOUNDED BY CABLE TRAY TESTS:

TRAY TESTS DEMONSTRATED NO SIGNIFICANT INCREASE IN SIDE RAIL OR CABLE TEMPERATURES I

RESULT WITH INCREASE IN ENCLOSURE SURFACE AREA.

REINFORCEMENT TECHNIQUES FOR REPRESENTATIVE l

HORIZONTAL AND VERTICAL JOINTS (TIE WIRE l

" STITCHING" AND STRESS SKIN OVERLAY).

ADDITIONALLY, CONSERVATIVE MEASURES WERE PROVIDED TO ASSURE STRUCTURAL LOADS OF THE ENCLOSURES ARE ADEQUATELY DISTRIBUTED AND SUPPORTED:

1 ANCHOR BOLTS SECURE THE ENCLOSURES TO.

CONCRETE STRUCTURE.

REINFORCING STEEL MEMBERS OR FRAMEWORK i

WHERE REQUIRED.

i ENCLOSURE BOTTOM PANELS SECURED TO CABLE i

TRAY RUNGS WHERE APPLICABLE.

MEASURES WERE TAKEN TO PREVENT CONTACT BETWEEN l

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CABLES AND THERMO-LAG PANELS.

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" BOX CONFIGURATION" APPLICATIONS (CONT'D)~

O CABLE AIR DROPS BETWEEN ADJACENT TRAYS.

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APPROXIMATELY 12 CONFIGURATIONS.

CRITICAL ATTRIBUTES BOUNDED BY CABLE TRAY TESTS:

THERMAL PERFORMANCE OF THERMO-LAG PANELS.

REPRESENTATIVE PANEL ORIENTATION AND SPANS.

REINFORCEMENT TECHNIQUES FOR HORIZONTAL AND VERTICAL JOINTS.

NO CONTACT BETWEEN CABLES AND PANELS.

4