ML20045H877

Suppls 930119 & 0415 Responses to GL 93-08 Re Confirmatory Testing of Thermo-Lag Fire Barriers.Cable Tray Protected W/ 1/2-inch (Nominal) Thick Thermo-Lag Board Sections W/Ribs

ML20045H877
Person / Time
Site:	Comanche Peak
Issue date:	07/13/1993
From:	William Cahill, Walker R TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-93-08, GL-93-8, TXX-93254, NUDOCS 9307220058
Download: ML20045H877 (11)

Text

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= = = = = = = Log # TXX-93254 7 9 File # 10035(GL-92-08)

-. _- 10119 (NRCB 92-01) 909.5 TUELECTRIC R'I' #

10&Sj July 13, 1993 William J. Cahm, Jr.

tinmp Vice President U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)

DOCKET NO. 50-445 SUPPLEMENTAL RESPONSE FOR GENERIC LETTER 92-08 AND CONFIRMATORY TESTING OF THERM 0-LAG FIRE BARRIERS REF: 1) TV Electric letter logged TXX-93038 from William J. Cahill, Jr., to NRC dated January 19, 1993

2) TV Electric letter logged TXX-93091 from William J. Cahill, Jr., to NRC dated April 15, 1993

3) NRC letter from Suzanne C. Black, to William J. Cahill Jr., dated October 29, 1993 Gentlemen:

Generic Letter 92-08, dated December 17, 1992, stated that all addressees are required, pursuant to section 182(a) of the Atomic Energy Act of 1954, as amended, and 10CFR50.54(f), to submit a written report within 120 days from the date of this generic letter. TU Electric has reviewed the actions requested and reporting requirements of this Generic Letter.

Thermo-Lag 330-1 fire barriers are relied upon to satisfy physical independence of electrical systems as required by Regulatory Guide 1.75 where such systems requiring physical independence also require protection for ensuring fire safe shutdown capability.

Via references 1 and 2, TU Electric provided responses to Generic Letter 92-08 for the Thermo-Lag fire barrier installations at CPSES Units l'and 2.

The response for Unit 1 (reference 2) stated that TU Electfic is currently participating in a generic effort with the rest of the nuclear industry and.

Nuclear Management and Resources Council (NUMARC) to ascertain designs and.  ;

installations of fire barriers which satisfy 10CFR50 Appendix A, General 1 Design Criteria (GDC) 3. Additionally, TU Electric identified that there were various options under consideration to resolve the issue, and.that further assessment was needed to determine an approach which would satisfy O.

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.. A TXX-93254 Page 2 of 6 were various options under consideration to resolve the~ issue, and that ,

further assessment was needed to determine an approach which would satisfy l GDC-3, without causing an unjustified impact on the industry.

The various options identified in reference 2' included the following:

Performing additional testing to demonstrate the acceptability of the installed configurations.

Identifying, testing (if further testing is deemed appropriate) and installing " upgrades" to existing configurations.

During a teleconference with the NRC staff on June 29,.1993, TO Electric verbally provided " preliminary" details regarding the methodology to be used in completion of Thermo-Lag certification for CPSES Unit 1, including additional Thermo-Lag Barrier Fire Endurance Testing.

In completing the Unit 1 Thermo-Lag certification activities, TU Electric will rely upon various certification methods for example, TV Electric will utilize previously accepted Unit 2 test results for some Unit 1 upgrades.

Additionally, TU Electric will perform tests to certify other possible upgrade techniques and other Thermo-Lag configurations.

During this teleconference the NRC staff requested a description of subjects ,

which were verbally discussed. TU Electric is complying with the NRC: Staff's  !

request, however, TU Electric wishes to make certain that the Staff is fully- 1 cognizant that the information being provided is " preliminary" in nature and >

may change as the proposed testing and work activities progresses. The -)

teleconference subjects of discussion are addressed below, including J descriptions of the evaluation process, test attributes, test i configurations, and the required reports: ]

A) Evaluation Process Evaluate Thermo-Lag configurations to determine:

i) which installed raceway configurations in Unit 1 are qualified based on the results of the existing CPSES tests; ^

ii) which installed raceway configurations warrant adoitional fire endurance testing to qualify cost effective upgrades; iii)whichconfigurationswillbeupgraded; iv) cable functional performance acceptability for 1-1/2 inch and 2 inch non-upgraded conduits using the temperature profiles obtained from the existing CPSES fire test results of non-upgraded conduits (refer to previous CPSES test scheme 9-3);

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TXX-93254 Page 3 of 6 v) acceptability of Unit i raceway supports which may be impacted oy the preferred upgrades (i.e., weight). Confirm the acceptability of the supports and/or initiate design changes as required; and j vi) potential impact to existing ampacity derating factors. Reevaluate the cables utilizing the results of the recently performed tests.

Initiate cable modification as required.

A preliminary review of the above evaluations is depicted in attachment 1 of this letter.

B) Test Attributes i Testing will be performed utilizing the acceptance criteria established in your staff's memorandum dated October 29, 1992 (reference 3), and as  ;

amended by CPSES Safety Evaluation Report (NUREG-0797), Supplement 26 and Supplement 27. The exceptions would be:  :

I No continuous circuit monitoring during performance of the tests.

Utilization of a seven day cure time versus the thirty day cure time, as was approved via SSER Supplement 27 for previous CPSES test scheme 15-1.

C) Test Configurations -

, TV Electric currently plans to perform fire endurance tests on five (5)  !

raceway configurations (also referred tc as test schemes) during the upcoming tests. These schemes are described below.

i) Scheme #11-2; consists of a 24"x4" ladder back tray with two air drop configurations (2 inch and 1-1/2 inch diameter).

1 (a) The cable air drop bundles are protected with two layers of Thermo-Lag 330-660 "flexi-blanket" material.

i (b) The cable tray is protected with 1/2 inch (nominal) thick i Thermo-Lag board sections with ribs. Vertical and bottom-  :

butt joints will be reinforced with a layer of stress skin with trowel grade Thermo-Lag material. ,

(c) Tne 2 inch airdrop and a single' cable protruding airdrop will be reinforced where they enter the 24 inch cable tray using flexible stainless steel mesh with trowel grade Thermo-Lag material.

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TXX-93254 Page.4 of 6 (d) The Thermo-Lag attributes being tested are 2 inch and 1-1/2 inch diameter airdrops protected with 2 layers of "flexi-blanket" and the interface region between airdrops and cable ,

trays reinforced with flexible mesh with trowel grade Thermo-Lag material.

ii) Scheme #11-4; consists of cables airdropping from embedded wall ~

sleeves-into two, stacked, 24"x4" ladder back trays.

(a) A Thermo-Lag box design enclosure will cover the airdrop cables including both trays and continuing over to the wall penetration. The box will be constructed of 1/2 inch (nominal) thick Thermo-Lag board sections with ribs. All joints will be reinforced with a layer of stress skin with trowel grade Thermo-Lag material.

(b) The remainder of the 2 cable trays not included;with the box coverage will be protected with 1/2 inch (nominal) thick Thermo-Lag board sections with ribs. Vertical and bottom butt joints will be reinforced with a layer of stress skin with trowel grade Thermo-Lag material.

(c) The Thermo-Lag attribute being tested is the " box" design configuration protected with a single layer of.Thermo-Lag  :

prefabricated panels and its interface region to the concrete structure surrounding the embedded sleeves, iii) Scheme #11-5; consists of three 24"x4" ladder back tray assemblies with various methods of joint reinforcement methods.

(a) The trays will be protected with 1/2 inch (nominal) thick Thermo-Lag board sections with ribs.

(b) One tray will be upgraded with circumferential1'y wrapped stress skin and trowel grade Thermo-Lag material around butt joints and on 2 foot intervals. One tray will be upgraded with stress skin and trowel grade material applied along longitudinal joints only. One tray will be upgraded with a braided ceramic banding material wrapped circumferential1y around butt joints and on 2 foot intervals. *

(c) The Thermo-Lag attributes being tested are the various cable tray joint upgrade techniques utilizing stress skin and- e trowel grade Thermo-Lag material and ceramic banding material. N, iv) Scheme #13-2; consists of a 12"x4" ladder back cable tray with 90 i degree bends and a 2 inch diameter conduit with two radial bends.

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TXX-93254 Page 5 of 6 u

(a) The cable tray is-protected with 1/2 inch (nominal) thick Thermo-Lag board sections with ribs. This tray configuration will be tested as currently installed in Unit I without any upgrade of butt.or longitudinal joints.

(b) A 2 inch diameter conduit is protected with 1/2 inch i (nominal) thick prefabricated Thermo-Lag material. The l radial bends will be upgraded with flexible stainless steel mesh and trowel grade Thermo-Lag material.

(c) The Thermo-Lag attributes being tested are 12 inch cable tray coverage with no joint upgrade and conduit radial bend upgrade with the flexible mesh.

v) Scheme #15-2; consists of Thermo-Lag 330-660 "flexi-blanket" ,

material wrapped cables in an exposed 36"x4" ladder back cableL ,

tray.

(a) There will be two wrapped cable bundles, one with two layers of "flexi-blanket" and one with three layers of-flexi- a blanket".

(b) The 36 inch cable tray in which the wrapped cables are  !

installed will have no Thermo-Lag protection for the tray or '

for the cable tray supports.

(c) The Thermo-Lag attributes being. tested are "flexi-blanket" wrapped cables in exposed cable tray.

r D) Reports Provide reports to the NRC which; i) identifies which installed Unit 1 Thermo-Lag configurations are qualified and the basis for their qualification, -'

ii) identifies which installed Unit 1 configurations will be upgraded d and the basis for the qualification of the upgrades, and j P

iii) identifies any Unit 1 configurations which deviate.from a one-hour

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fire rating and the basis for the deviation.

Please note that the description above and the attached tables are l preliminary.

a A preliminary schedule of the testing at Omega Point Laboratory, San j Antonio, Texas, has been provided to your staff. The preliminary sketches j of the configurations-(schemes) will be hand delivered to your staff as soon-as they become available.

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TXX-93254' Page 6 of 6

-Please contact Obaid Bhatty at (817) 897-5839 should you require additional information.

Sincerely, fe 3hr William J. Cahill, Jr.

By: M '

N Roger D. Walker Manager of Regulatory Affairs for Nuclear Production 08:tg .

Attachment cc: Mr. J. L. Milhoan, Region IV Mr. L. A. Yandell, Region IV Mr. T. A. Bergman, NRR Mr. S. K. West, NRR Resident inspectors, CPSES (2) s I

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l Attachment 1 to TXX-93254 Page 1 of 5 l

l PRELIMINARY PLAN FOR CERTIFYING CPSES UNIT 1 THERMO-LAG CONDUITS (1) (2) (3) (4)

ACCEPTANCE SUPPORT COMMODITY TEST UPGRADE ,,

EVAL. AMPACITY 3/4" UNIT 2 YES/ UPGRADE YES UNIT 2 TEST COMPLETED I" UNIT 2 YES/ UPGRADE YES UNIT 2 TEST COMPLETED 1 1/2" UNIT 2 W/ CABLE RADIAL BENDS & YES UNIT 2 TEST FUNCTION EVAL. COUPLINGS ONLY 2" UNIT 2 W/ CABLE RADIAL BENDS & YES UNIT 2 TEST FUNCTION EVAL. COUPLINGS ONLY (RE-TEST SCHEME) 3" & UNIT 2 RADIAL BENDS YES UNIT 2 TEST LARGER ONLY

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Attachment 1 to TXX-93254 Page 2 of 5 l

l PRELIMINARY PLAN FOR CERTIFYING CPSES UNIT 1 THERMO-LAG (CONT'D)

FLEXIBLE CONDUITS & AIRDROPS (1) (2) (3) (4)

ACCEPTANCE SUPPORT COMMODITY TEST UPGRADE EVAL. AMPACITY 3/4" & UNIT 2 YES YES UNIT 2 TEST SMALLER 1" UNIT 2 YES YES UNIT 2 TEST 1 1/2" RE-TEST NO NO UNIT 2 TEST (SCHEME 11-2) 2" RE-TEST NO NO UNIT 2 TEST (SCHEME 11-2) 3" & UNIT 2 NO NO UNIT 2 TEST .

LARGER

Attachment I to TXX-93254 Page 3 of 5 PRELIMINARY PLAN FOR CERTIFYING CPSES UNIT 1 THERMO-LAG (CONT *D)

MISCELLANEOUS (1) (2) (3) (4)

ACCEPTANCE SUPPORT COMMODITY TEST UPGRADE EVAL, AMPACITY AIRDROPS RE-TEST YES YES UNIT 2 TEST AT CABLE (SCHEME 11-2) l TRAYS CONDUIT UNIT 2 YES YES UNIT 2 TEST LATERAL BENDS &

PULL BOXES CONDUIT RE-TEST YES YES UNIT 2 TEST RADIAL (SCHEME 13-2) l BENDS 1

JUNCTION UNIT 2 YES YES UNIT 2 TEST BOXES "B0X" RE-TEST YES YES UNIT 2 TEST CONFIG- (SCHEME 11-4)

URATIONS l

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Attachment 1 to'TXX-93254 Page 4 of 5 PRELIMINARY PLAN FOR CERTIFYING CPSES UNIT 1 THERMO-LAG (CONT'D)

CABLE' TRAYS (1) (2) (3) (4)

ACCEPTANCE SUPPORT COMMODITY TEST __, UPGRADE EVAL. AMPACITY 12" RE-TEST NO NO UNIT 2 TEST (SCHEME 13-2) 18" RE-TEST YES YES UNIT 2 TEST (SCHEME 11-5) 24" RE-TEST YES YES UNIT 2 TEST (SCHEME 11-5) 3 C UNIT 2 YES- YES UNIT 2 TEST 36" UNIT 2 YES YES UNIT 2 TEST TEES UNIT 2 YES YES UNIT 2 TEST FIRE STOPS UNIT 2 YES YES UNIT 2 TEST CABLES RE-TEST NO NO UNIT 2 TEST WRAPPED (SCHEME 15-2)

IN EXPOSED TRAY i

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Attachment 1 to TXX-93254 Page 5 of 5 LEGEND (1) ACCEP1ANCE TEST: This is either the existing CPSES test or the retest' which will be the basis for the acceptability of the Thermo-Lag coverage on the commodity.

(2) UPGRADE: This refers to whether physical work will need to be done on the existing Thermo-Lag configuration to make it acceptable. For commodities being retested, a "NO" entry assumes the test will be satisfactory to qualify the specific configuration without upgrade.

(3) SUPPORT EVALUATION: This pertains to taking into consideration the additional Thermo-Lag weights on the structural steel support qualification.

Special Note: 1-1/2 inch and larger flexihle conduits and air drops stow " upgrade" but no support evaluation because the' upgrade only involves reinforcement of "flexi-blanket" material coverage where it ,

overlaps onto the Thermo-Lag material.

Ini; refers to evaluating the affect of Thermo-Lag coverage (4) AMPACITY:

on the ampacity of the enveloped cables. This involves incorporating the results of the recently performed CPSES ampacity test results into the applicable cable ampacity evaluations and evaluating the effect of any upgrades.

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