ML20059A587

Forwards Request for Addl Info Re GL 92-08, Thermo-Lag 330-1 Fire Barriers, Per 10CFR50.54(f)

ML20059A587
Person / Time
Site:	Sequoyah
Issue date:	12/21/1993
From:	Callan L Office of Nuclear Reactor Regulation
To:	Medford M Tennessee Valley Authority
References
GL-92-008, TAC-M85604, TAC-M85605 NUDOCS 9401030047
Download: ML20059A587 (11)

Text

ff o UNITED STATES NUCLEAR REGULATORY COMMISSION y pR g

C WASHINGTON, D, C. 20555 gk S

/ December 21, 1993

....+

Docket Nos. 50-327 and 50-328 Dr. Mark 0. Medford, Vice President Technical Support Tennessee Valley Authority 3B Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801

SUBJECT:

REQUEST FOR ADDITIONAL INF0PJ4ATION REGARDING GENERIC LETTER 92-08,

" THERM 0-LAG 330-1 FIRE BARRIERS," PURSUANT TO 10 CFR 50.54(f) -

SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 (TAC NOS. M85604 AND M85605)

In your response of April 15, 1993, to Generic Letter (GL) 92-08, "Thermo-Lag 330-1 Fire Barriers," you indicated that actions necessary to restore the operability of these barriers at the Saquoyah Nuclear Plant (SQN)

Units 1 and 2 would be based on the results of the industry test program being coordinated by the Nuclear Management and Resources Council (NUMARC), and on testing conducted by the Tennessee Valley Authority to support licensing of the Watts Bar Nuclear Plant. During recent meetings with U.S. Nuclear Regulatory Commission (NRC) staff, the Executive Director for Operations and the Commission, NUMARC described the scope of its Thermo-Lag fire barrier program, the results of the Phase 1 fire tests, and planned Phase 2 tests.

The program is limited to certain 1-hour and 3-hour conduit and cable tray fire barrier configurations and the development of guidance for applying the test results to plant-specific fire barrier configurations. However, NUMARC's program is not intended to bound all in-plant Thermo-Lag fire barrier configurations. During a NUMARC-sponsored industry workshop on December 1 and 2,1993, NUMARC presented the scope of its program and the Phase I test results to the licensees.

In view of the limited scope of the NUMARC program and the limited success of the Phase 1 tests, it is clear to the staff that the NUMARC program will not be sufficient to resolve all Thermo-Lag fire barrier issues identified in GL 92-08. Therefore, licensees may need to take additional actions to address fire endurance and ampacity derating concerns with their in-plant Thermo-Lag barriers.

To help ensure timely resolution of the fire barrier issues at SQN Units 1 and 2, the staff requires additional information on the configurations and amounts of Thermo-Lag fire barriers installed in the plant and the cable loadings within particular Thermo-Lag configurations. This information is necessary to review NUMARC's guidance for applying the test results to plant-specific barrier configurations and to identify configurations that are outside the 9401030047 931221 (x PDR ADOCK 05000327 i F ppg 29001'T Ei MI M!TES MT $0s % .. .. .

1 Dr. Mark 0. Medford - j 1

scope of NUMARC's test program. For those configurations that are outside the scope of the program or for those configurations that you deem are -impractical to upgrade, we request that you provide plans and schedules for resolving tM i technical issues identified in GL 92-08. ,

You are required, pursuant to Section 182(a) of the Atomic Er.ergy Act of 1954, 1 as' amended, and 10 CFR'50.54(f), to submit a. written report that contains the

.information--specified in the enclosure to this letter.within 45 days from i receipt of this letter. Your response must be submitted under oath or-affirmation. . Please submit your response to the undersigned, with a copy to '

the appropriate Regional Administrator. Please retain all-information and-documentation used to respond to this request on site for future NRC audits or inspections. .

This request is covered by. 0ffice of Management and Budget Clearance Number.  !'

3150-0011, which expires June 30, 1994. The estimated average number of ,

burden hours of 300 person-hours is anticipated to increase by an additional .

120 ' person-hours for each addressee's response, including the time required to  :

assess the requirements for information, search data sources, gather and- l analyze the data, and prepare the required letters. This revised estimated ^

average number of burden hours pertains only to the identified response-  ;

related matters and does not include the time to implement the actions r required -to comply with the applicable regulations, license conditions,:or- ,

commitments. Comments on the accuracy of this estimate and suggestions to .

reduce.the burden may be directed to the Office of Information and Regulatory l Affairs (3150-0011), NE0B-3019, Office of Management and Budget, Washington, ,

D.C. 20503, and to the U.S. Nuclear Regulatory Commission, Information and l Records Management Branch (MNBB-7714),-Division.of Information Support .;

Services, Office of Information and Resources Management, Washington, D.C. a 20555.

.t If you have any questions about this matter, please contact David E. LaBarge at 301-504-1472 or Patrick Madden at 301-504-2854. 7 Sincerely,  ;

o Original signed by ,

! L. J. Callan  !

l Acting Associate Director for Projects Office of Nuclear Reactor Regulation j:

Enclosure:

i p Request for Additional Information cc w/ enclosure: i l See next page ,. Aru 3 in

[^ OFFICE / PhW PDII-4/k PDJIr4/D (A)AN d NAME dayta[ DLaBarh E FdNd'on- LJCab DATE 12/3//93 12/2f/93 ' 12/u /93 12M/93 f j OFFICIAL RECORD COPY FILENAME: G:\SQN\THRMOLAG.RAI i

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DISTRIBUTION Docket File.

NRC ' PDR :=

Local PDR SQN Rdg LCallan Glainas LCallan CMcCracken PMadden CBerlinger RJeinkins GMulley (0IG)

FHebdon l

MGamberoni RIngram, PMSB PKellogg, RII OGC ACRS(10)

DLaBarge BClayton GMulley (0IG) ,

EPawlik (RIII/01) 1 1

i

ENCLOSURE

. REQUEST FOR ADDITIONAL INFORMATION REGARDING GENERIC LETTER 92-08

" THERM 0-LAG 330-1 FIRE BARRIERS" PURSUANT TO 10 CFR 50.54(f)

I. Thermo-Lag Fire Barrier Configurations and Amounts A. Discussion Generic Letter (GL) 92-08,"Thermo-Lag 330-1 Fire Barriers," applied to all 1-hour and all 3-hour Thermo-Lag 330-1 materials and barrier systems constructed by any assembly method, such as by joining 1 preforn,ed panels and conduit preshapes, and trowel, spray, and brush-on applications. This includes all fire barriers, all barriers to achieve physical independence of electrical systems, radiant energy heat shields, and barriers installed to enclose intervening combustibles.

B. Required Information

1. Describe the Thermo-Lag 330-1 barriers installed in the plant to ,

a. meet 10 CFR 50.48 or Appendix R to 10 CFR Part 50,

b. support an exemption from Appendix R,

c. achieve physical independence of electrical systems,

d. meet a condition of the plant operating license,

e. satisfy licensing commitments.

The descriptions should include the following information:

the intended purpose and fire rating of the barrier (for example, 3-hour fire barrier, 1-hour fire barrier, radiant energy heat shield), and the type and dimension of the barrier (for example, 8-ft by 10-ft wall, 4-ft by 3-ft by 2-ft equipment enclosure, 36-inch-wide cable tray, or 3-inch-diameter conduit).

2. For the total population of Thermo-Lag fire barriers described under Item I.B.1, submit an approximation of:

a. For cable tray barriers: the total linear feet and square feet of 1-hour barriers and the total linear ,

feet and square feet of 3-hour barriers.

b. For conduit barriers: the total linear feet of 1-hour-barriers and the total linear feet of 3-hour barriers.

c. For all other fire barriers: the total _ square feet of 1-hour barriers and the total square feet of 3-hour barriers. ,

d. For all other barriers and radiant energy heat shields: the total linear or square feet of 1-hour barriers and the total linear or square feet of 3-hour barriers, as appropriate for the barrier configuration j or type.

. II. Important Barrier Parameters A. Discussion In a letter of July 29, 1993, from A. Marion, NUMARC, to C. McCracken, NRC, NUMARC stated: " Relative to bounded configurations, ... [1]t will be the utilities' responsibility to verify their baseline installations are bounded." furthermore, NUMARC stated that the parameters of importance for utility use of data from the industry Thermo-Lag fire barrier test program are:

1. Raceway orientation (horizontal, vertical, radial bends)

2. Conduit

3. Junction boxes and lateral bends

4. Ladder-back cable tray with single layer cable fill

5. Cable tray with T-Section

6. Raceway material (aluminum, steel)

7. Support protection, thermal shorts (penetrating elements)

8. Air drops

9. Baseline fire barrier panel thickness

10. Preformed conduit panels

11. Panel rib orientation (parallel or perpendicular to the raceway)

12. Unsupported spans

13. Stress skin orientation (inside or outside)

14. Stress skin over joints or no stress skin over joints

15. Stress skin ties or no stress skin ties

16. Dry-fit, post-buttered joints or prebuttered joints l

17. Joint gap width

18. Butt joints or grooved and scored joints

19. Steel bands or tie wires

20. Band / wire spacing  ;

21. Band / wire distance to joints i

22. No internal bands in trays  ;

23. No additional trowel material over sections and joints or l additional trowel material applied j

24. No edge guards or edge guards l Each NUMARC cable tray fire test specimen includes 15 percent cable fills (i.e., a single layer of cables uniformly distributed across J the bottom of the cable tray). This approach requires consideration of plant-specific cable information during the assessments of tested configurations and test results in relation to plant-specific Thermo-Lag configurations; for example, cable trays with less thermal mass (cable fill) than the NUMARC test specimens, different cable types, and the proximity of the cables to the Thermo-Lag -

(e.g., cables may be installed in contact with the unexposed surface of the Thermo-Lag or may come into contact during a fire if the Thermo-Lag material sags). In its letter of July 29, 1993, NUMARC

1

.. stated: " Utilities using the results of the NUMARC testing will need to evaluate their installed cable fill and ensure that it is bounded by the tested cable fill." NUMARC is not conducting any cable functionality tests or evaluations and stated that cable functionality evaluations will be performed by utilities using data from the generic program. l The parameters of importance concerning cables protected by fire ,

barriers are:

1. Cable size and type (power, control, or instrumentation).

2. Cable jacket type (thermoplastic, thermoset) and materials.

3. Cable conductor insulation type (thermoplastic, thermoset plastic) and materials.

4. Cable fill and distribution of cables within the protected conduit or cable tray.

5. Proximity of cables to the unexposed (inside) surfaces of the fire barrier. ,

6. Presence of materials between the cables and the unexposed side of the fire barrier material (for example, Sealtemp cloth, which is used in the NUMARC test specimens).

7. Cable operating temperature.

8. Temperatures at which the cables can no longer perform their intended function when energized at rated voltage and current.

Other parameters that are unique to particular barriers, such as interfaces between Thermo-Lag materials and other fire barrier materials or building features (walls, etc.) and internal supports, are also important. In addition, because of questions about the uniformity of the Thermo-Lag fire barrier materials produced over time, NUMARC stated in its letter of July 29, 1993, that "[c]hemical "

analysis of Thermo-lag materials provided for the program, as well as samples from utility stock, will be performed, and a test report prepared comparing the chemical composition of the respective samples." The results of the chemical analyses may indicate that variations in the chemical properties of Thermo-Lag are significant and may require additional plant specific information in the future.

B. Required Information

1. State whether or not you have obtained and verified each of the aforementioned parameters for each Thermo-Lag barrier installed in the plant. If not, discuss the parameters you have not obtained or verified. Retain detailed information on site for NRC audit where the aforementioned parameters are known.

2. For any parameter that is not known or has not been verified, describe how you will evaluate the in-plant barrier for acceptability.

3. To evaluate NUMARC's application guidance, an understanding of the types and extent of the unknown parameters is needed.

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Describe the type and extent of the unknown parameters at your plant in this context.

4. Discuss the applicability of the Tennessee Valley Authoritty Watts Bar Nuclear Plant (TVA WBN) test program.on these parameters.

III. Thermo-Lag Fire Barriers Outside the Scope'of the NUMARC Program A. Discussion In your response'of to GL 92-08, you indicated that actions necessary to restore the operability of these barriers would be based.on the results of the NUMARC test program. During recent meetings with the NRC staff, the Executive Director for Dperations and the Commission, NUMARC described the scope of its Thermo-Lag fire barrier. program,.the results of the Phase I fire tests, and planned Phase 2 tests. The program is limited to certain 1-hour and 3-hour conduit ~and cable tray fire barrier configurations:and the development of guidance for applying the test results to plant-specific fire barrier configurations. However, NUMARC's program is not intended to bound all in-plant Thermo-Lag fire barrier configurations. In view of the scope of the NUMARC program and the limited success of the Phase I tests, it is clear that the NUMARC program will not be sufficient to resolve all Thermo-Lag fire barrier issues identified in GL 92-08. Therefore, licensees may need to take additional actions to address fire endurance and ampacity derating concerns with in-plant Thermo-Lag barriers.

B. Required information

1. Describe the barriers discussed under Item I.B.1 that you have determined will not be bounded by the NUMARC or TVA WBN test programs.

2. Describe the plant-specific corrective action program or plan you expect to use to evaluate the fire barrier configurations particular to the plant. This description should include a discussion of the evaluations and tests being considered to resolve the fire barrier issues identified in GL 92-08 and to demonstrate the adequacy of existing in-plant barriers.

3. If a plant-specific fire endurance test program is anticipated, describe the following:

a. Anticipated test specimens.

b. Test methodology and acceptance criteria including cable functionality.

IV. Ampacity Derating A. Discussion NUMARC has informed the staff that it intends to use the Texas Utilities (TU) Electric Company and Tennessee Valley Authority (TVA) ampacity derating test results to develop an electrical raceway component model for the industry. Additional information is needed to determine whether or not your Thermo-Lag barrier configurations (to protect the safe-shutdown capability from fire or to achieve physical independence of electrical systems) are within the scope of the NUMARC program and, if not, how the in-plant barriers will be evaluated for the ampacity derating concerns identified in GL 92-08.

B. Required Information I. For the barriers described under Item I.B.I, describe those that you have determined will fall within the scope of the NUMARC or TVA WBN programs for ampacity derating, those that will not be bounded by the these programs, and those for which ampacity derating does not apply.

2. For the barriers you have determined fall within the scope of the NUMARC or TVA WBN programs, describe what additional testing or evaluation you will need to perform to derive valid ampacity derating factors.

3. For the barrier configurations that you have determined will not be bounded by the NUMARC or TVA WBN test prescams, describe your plan for evaluating whether or not the ampacity derating tests relied upon for the ampacity derating factors used for those electrical components protected by Thermo-Lag 330-1 (for protecting the safe-shutdown capability from fire or to achieve physical independence of electrical systems) are correct and applicable to the plant design. Describe all corrective actions needed and submit the schedule for completing such actions.

4. In the event that the NUMAP,C or TVA WBN fire barrier tests indicate the need to upgrade existing in-plant barriers or to replace existing Thermo-Lag barriers with another fire barrier system, describe the alternative actions you will take (and the schedule for performing those actions) to confirm that the ampacity derating factors were derived by valid tests and are applicable to the modified plant design.

Your response to Section IV.B may depend on unknown specifics of the NUMARC or TVA WBN ampacity derating test programs (for example, the final barrier upgrades). However, your response should be as complete as possib M. In addition, your response should be updated as additional information becomes available on these programs.

• V. Alternatives A. Discussion On the basis of testing of Thermo-Lag fire barriers to date, it is not clear that generic upgrades (using additional Thermo-Lag materials) can be developed for many 3-hour barrier configurations or for some 1-hour barriers (for example,1-hour barriers on wide cable trays, with post-buttered joints and no internal supports).

Moreover, some upgrades that rely on additional thicknesses of Thermo-Lag material (or other fire barrier materials) may not be practical due to the effects of ampacity derating or clearance problems.

B. Required Information Describe the specific alternatives available to you for achieving compliance with NRC fire protection requirements in plant areas that contain Thermo-Lag fire barriers. Examples of possible alternatives to Thermo-Lag-based upgrades include the following:

1. Upgrade existing in-plant barriers using other materials.

2. Replace Thermo-Lag barriers with other fire barrier materials or systems.

3. Reroute cables or relocate other protected components.

4. Qualify 3-hour barriers as 1-hour barriers and install detection and suppression systems to satisfy NRC fire protection requirements.

VI. Schedules A. Discussion The staff expects the licensees to resolve the Thermo-Lag fire barrier issues identified in GL 92-08 or to propose alternative fire protection measures to be implemented to bring plants into compliance with NRC fire protectior. requirements. Specifically, as test data becomes available, licensees should begin upgrades for Thermo-Lag barrier configurations bounded by the test results.

B. Required Information Submit an integrated schedule that addresses the overall corrective action schedule for the plant. At a minimum, the schedule should  ;

address the following aspects for the plant:

1. implementation and completion of corrective actions and fire barrier upgrades for fire barrier configurations within the scope of the NUMARC program, l

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• 2. implementation and completion of plant-specific analyses, testing, or alternative actions for fire barriers outside the scope of the NUMARC program, including barrier configurations bounded by the TVA WBN test program.

VII. Sources and Correctness of Information Describe the sources of the information provided in response to this request for information (for example, from plant drawings, quality assurance documentation, walk downs or inspections) and how the accuracy and validity of the information was verified.

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' Tennessee Valley Authority SEQUOYAH NUCLEAR PLANT ATTN: Dr. Mark 0. Medford '

cc:

Mr. Craven Crowell, Chairman TVA Representative i Tennessee Valley Authority Tennessee Valley Authority ET 12A 11921 Rockville Pike ,

400 West Summit Hill Drive Suite 402 i Knoxville, TN 37902 Rockville, MD 20852 Mr. W. H. Kennoy, Director General Counsel Tennessee Valley Authority Tennessee Valley Authority ET 12A ET 11H 400 West Summit Hill Drive 400 West Summit Hill Drive Knoxville, TN 37902 Knoxville, TN 37902 Mr. Johnny H. Hayes, Director Mr. Michael H. Mobley, Director Tennessee Valley Authority Division of Radiological Health ET 12A 3rd Floor, L and C Annex ,

400 West Summit Hill Drive 401 Church Street Knoxville, TN 37902 i Nashville, TN 37243-1532 '

Mr. Robert Fenech County Judge  !

Site Vice President Hamilton County Courthouse l Sequoyah Nuclear Plant Chattanooga, TN 37402 Tennessee Valley Authority ,

P.O. Box 2000 Regional Administrator Soddy, Daisy, TN 37379 U.S. Nuclear Regulatory Commission Region 11 '

Mr. R. M. Eytchison, Vice President 101 Marietta Street, NW., Suite 2900 Nuclear Operations Atlanta, GA 30323 Tennessee Valley Authority 3B Lookout Place Mr. William E. Holland 1101 Market Street Senior Resident Inspector Chattanooga, TN 37402-2801 Sequoyah Nuclear Plant U.S. Nuclear Regulatory Commission Mr. B. S. Schofield, Manager 2600 Igou Ferry Road Nuclear Licensing and Regulatory Affairs Soddy Daisy, TN 37379 Tennessee Valley Authority 4G Blue Ridge Mr. D. E. Nunn, Vice President 1101 Market Street Tennessee Valley Authority Chattanooga, TN 37402-2801 3B Lookout Place i

1101 Market Street Mr. Ralph H. Shell Chattanooga, TN 37402-2801 Site Licensing Manager Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37379 l

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