ML20059A698

Forwards RAI Re GL-92-08, Thermo-Lag 330-1 Fire Barriers, Per 10CFR50.54(f) for Plant,Unit 1

ML20059A698
Person / Time
Site:	Davis Besse
Issue date:	12/21/1993
From:	Callan L Office of Nuclear Reactor Regulation
To:	Storz L CENTERIOR ENERGY
References
TAC-M85542, NUDOCS 9401030091
Download: ML20059A698 (10)

Text

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p It UNITED STATES j .. .j NUCLEAR REGULATORY COMMISSION

-* g WASHINGTON, D.C. 20555-0001

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Docket No. 50-346 Mr. Louis F. Storz Vice President, Nuclear - Davis-Besse Centerior Service Company c/o Toledo Edison Company Davis-Besse Nuclear Power Station 5501 North State Route 2 Oak Harbor, Ohio 43449

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION REGARDING GENERIC LETTER 92-08, " THERM 0-LAG 330-1 FIRE BARRIERS," PURSUANT TO 10 CFR 50.54(f) - DAVIS-BESSE NUCLEAR POWER STATION, UNIT NO. 1 (TAC NO. H85542) ,.

In your response of April 16, 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 Davis-Besse would be based on the results of the industry test program being coordinated by the Nuclear '

Management and Resources Council (NUMARC). 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 i 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 I 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 Davis-Besse, the staff requires additional information on the configurations and amounts of. t Thermo-Lag fire barriers installed in the plant and the cable loadings within i 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 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 the g

s i technical issues identified in GL 92-08.

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.Mr. Louis F. Storz. December 21, 1993 f

You are required, pursuant to Section 182(a) of the Atomic. Energy Act of 1954,  !

as amended, and 10 CFR 50.54(f), to submit a written report that contains the l information specified in the enclosure to this letter within 45 days from  ;

receipt of this letter. Your response must be submitted under oath or l 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. ,

t This request is covered by Office of Management and Budget Clearance Number  !

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

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 Affairs (3150-0011), NE08-3019, Office of Management and Budget, Washington, D.C. 20503, and to the U.S. Nuclear Regulatory Commission, Information and Records Management Branch (MNBB-7714), Division of Information Support  ;

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

20555.  ;

If you have any questions about this matter, please contact Jon Hopkins at ,

301-504-3027 or Patrick Madden at 301-504-2854. I Sincerely, ORIGINAL SIGNED BY L. J. Callan  !

Acting Associate Director for Projects Office of Nuclear Reactor Regulation

Enclosure:

Request for Additional Information j cc w/ enclosure: )

See next page 1 DISTRIBUTION CDocketcFile CMcCracken MGamberoni JHopkins l NRC PDR PMadden RIngram, PMSB MRushbrook i Local PDR CBerlinger EGreenman, RIII GMulley (0!G) ,

PDIII-3 Rdg RJenkins EPawlik (RIII/01) OGC l JRoe ACRS (10) JZwolinski LCallan  !

JHannon u ,, ,,m

-6 uw 0FFICE LA: PQ33 , PM:PD33 PD:P033 (A)ADP NAME MRuhdok JHopki M JHannon$ LJCabn DATE 12/h/93 12/M /93 12/M/9k 124] /93 COPY [Y)/No [Ye)/No 6s/No /fes/No 0FFICIAL RECORD COPY F IL1!NAME: G:\dhisbes\dbthermo.ltr

, _ _= _

Mr. Louis F. Storz Davis-Besse Nuclear Power Station Toledo Edison Company Unit No. I cc: '

Mary E. O'Reilly Robert E. Owen, Chief Centerior Energy Corporation Bureau of Radiological Health 300 Madison Avenue Services Toledo, Ohio 43652 Ohio Department of Health Post Office Box 118 Mr. William T. O'Connor, Jr. Columbus, Ohio 43266-0118  :

Manager - Regulatory Affairs Toledo Edison Company Attorney General Davis-Besse Nuclear Power Station Department of Attorney General 5501 North State - Route 2 30 East Broad Street Oak Harbor, Ohio 43449 Columbus, Ohio 43216 Gerald Charnoff, Esq. Mr. James W. Harris, Director Shaw, Pittman, Potts Division of Power Generation and Trowbridge Ohio Department of Industrial 2300 N Street, N. W. Regulations Washington, D. C. 20037 P. O. Box 825 Columbus, Ohio 43216 '

Regional Administrator, Region III '

U. S. Nuclear Regulatory Commission Ohio Environmental Protection Agency  !

801 Warrenville Road DERR--Compliance Unit Lisle, Illinois 60532-4351 ATTN: Zack A. Clayton  :

P. O. Box 1049 Mr. Robert B. Borsum Columbus, Ohio 43266-0149 Babcock & Wilcox  !

Nuclear Power Generation Division State of Ohio 1700 Rockville Pike, Suite 525 Public Utilities Commission Rockville, Maryland 20852 180 East Broad Street l Columbus, Ohio 43266-0573 Resident Inspector ,

U. S. Nuclear Regulatory Commission Mr. James R. Williams +

5503 N. State Route 2 State Liaison to the NRC Oak Harbor, Ohio 43449 Adjutant General's Department Office of Emergency Management Mr. Donald C. Shelton Agency ,

Senior Vice President - Nuclear 2825 West Granville Road Centerior Service Company Columbus, Ohio 43235-2712 6200 Oak Tree Boulevard Independence, Ohio 44101 Mr. John K. Wood, Plant Manager Toledo Edison Company Davis-Besse Nuclear Power Station 5501 North State Route 2 Oak Harbor, Ohio 43449

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ENCLOSURE l REQUEST FOR ADDITIONAL INFORMATION-  !

REGARDING GENERIC LETTER 92-08 t

" THERM 0-LAG 330-1 FIRE BARRIERS" l PURSUANT 10 10 CFR 50.54(f) j 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 -i preformed 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, i radiant energy heat shields, and barriers installed to enclose -

intervening combustibles, j B. Required Information  !

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

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

c.

support an exemption from Appendix R, achieve physical independence of electrical systems, l

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d. meet a condition of the plant operating license, i

e. satisfy licensing commitments. '

The descriptions should include the following information:

the intended purpose and fire rating of the barrier (for r example, 3-hour fire barrier, 1-hour fire barrier, radiant energy heat shield), and the type and dimension of the  ;

barrier (for example, 8-f t by 10-ft wall, 4-ft by 3-ft by l 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: i

a. For cable tray barriers: the total linear feet and l square feet of 1-hour barriers and the total linear .l feet and square feet of 3-hour barriers. j i

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

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  !

or type.

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II. Important Barrier Parameters t

A. Discussion In a letter of July 29,.1993, from A. Marion, NUMARC, to t C. McCracken, NRC, NUMARC stated: " Relative to bounded configurations, ... [i]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 i data from the industry Thermo-Lag fire barrier test program are: j

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

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) i

8. Air drops

9. Baseline fire barrier panel thickness i Preformed conduit panels 10.

11. Panel rib orientation (parallel or perpendicular to the  ;

raceway) ,

12. Unsupported spans  ;

13. Stress skin orientation (inside or outside) i

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

15. Stress skin ties or no stress skin ties i

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

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

22. No internal bands in trays

23. No additional trowel material over sections and joints or +

additional trowel material applied

24. No edge guards or edge guards Each NUMARC cable tray fire test specimen includes 15 percent cable I fills (i.e., a single layer of cables uniformly distributed across 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 i 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 i Thermo-Lag or may come into contact during a fire if the Thermo-Lag l material sags). In its letter of July 29, 1993, NUMARC stated:  !

" Utilities using the results of the NUMARC testing will need to

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s 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.

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.

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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 l

interfaces between Therino-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 j obtained or verified. Retain detailed information on site for j

i 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.

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

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

III. Thermo-Lag Fire Barriers Outside the Scope of the NUMARC Program A. Discussion In your response of to GL 92-C3, 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 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. In view of the scope of the NUMARC program and the limitcd success of the Phase I tests, it is clear that the NUMARC program wi'l 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 test program.

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.

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-5 IV. Ampacity Derating  ;

A. Discussion l NUMARC has informed the staff that it intends to use the Texas Utilities (TV) 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

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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. l B. Required Information

1. For the barriers described under Item I.B.1, describe those that '

you have determined will fall within the scope of the NUMARC  !

program for ampacity derating, those that will not be bounded by ,

the NUMARC program, and those for which ampacity derating does  ;

not apply.

2. For the barriers you have determined fall within the scope of the NUMARC program, 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 test program, describe your plan for t 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 NUMARC 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 j performing those actions) to confirm that the ampacity derating l factors were derived by valid tests and are applicable to the  !

modified plant design. )

l Your response to Section IV.B may depend on unknown specifics of the NUMARC ampacity derating test program (for example, the final barrier upgrades). However, your response should be as complete as possible.

In addition, your response should be updated as additional information becomes available on the NUMARC program.

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s c V. Al ternatives A. cascussion On the ba' sis 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 i 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 fc11owing:

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. Schadules A. '

. cssion -

w 4taff expects the licensees to resolve the Thermo-Lag fire barrier ass identified in GL 92-08 or to propose alternative' fire

p. .ection measures to be implemented to bring plants into compliance 1 with NRC fire protection 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, P

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2. implementation and completion of plant-specific analyses, testing, or alternative actions for fire barriers outside the scope of the HUMARC 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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