ML16342A352
| ML16342A352 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 12/21/1993 |
| From: | Callan L Office of Nuclear Reactor Regulation |
| To: | Rueger G PACIFIC GAS & ELECTRIC CO. |
| References | |
| GL-92-08, GL-92-8, NUDOCS 9401030026 | |
| Download: ML16342A352 (22) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2055&0001 December 21, 1993 Docket No. 50-275 and 50-323 Mr. Gregory M. Rueger Nuclear Power Generation, B14A Pacific Gas
& Electric Company 77 Beale Street, Room 1451 P. 0.
Box 770000 San Francisco, California 94177
Dear Mr. Rueger:
SUBJECT:
RE(VEST FOR ADDITIONAL INFORMATION REGARDING GENERIC LETTER 92-08, "THERMO-LAG 330-1 FIRE BARRIERS,"
PURSUANT TO 10 CFR 50.54(f)
DIABLO CANYON, UNITS 1
AND 2 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 Diablo Canyon, Units 1 and 2, would be based on the results of the industry test program being coordinated by the Nuclear Management and Resources Council (NUHARC).
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, NUHARC's program is not intended to bound all in-plant Thermo-Lag fire barrier configurations.
During a NUHARC-sponsored industry workshop on December 1 and 2,
- 1993, NUHARC presented the scope of its program and the Phase 1 test results to the licensees.
In view of the limited scope of the NUHARC program and the limited success of the Phase 1 tests, it is clear to the staff that the NUHARC 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 Diablo Canyon, 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 scope of NUHARC'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 technical issues identified in GL 92-08.
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~ 'r. Gregory H.
Ruege Decembert21,;
1993 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 information specified in the enclosure to this letter within 45 days from 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 Office 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 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),
NEOB-3019, Office of Management and Budget, Washington, D.C. 20503, and to the U.S. Nuclear Regulatory Commission, Information and Records Management Branch (HNBB-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 Sheri Peterson at 301-504-1325 or Patrick Madden at 301-504-2854.
Sincerely,
Enclosure:
Request for Additional Information cc w/enclosure:
See next page Original Signed By:
L. J. Callan Acting Associate Director for Projects Office of Nuclear Reactor Regulation DISTRIBUTION:
Docket File~
NRC& Local PDRs PDV Reading File RJenkins ACRS 10 P315 CHcCracken PHadden CBerlinger
- OGC, 15B18 JLCallan SPeterson
- RIngram, PMSB
- KPerkins, RV EAdensam TQuay EBarnhill GHul l ey, (OIG)
JRoe GMul 1 ey (OIG)
OFFICE LA:PDV PM:PDV PD:PDV A ADP EBarnhil15 12 0 /93 Ye No NAME DATE COPY OFFICIAL RECORD COPY SPeter TQuay L
LJCdktn Ye No e
No es No ENAME:
DC HO.LAG 12 gl 93 12 gl 93 12 93
Mr. Gregory H. Rueger December 23, 1993 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 information specified in the enclosure to this letter within 45 days from 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 Office 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 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),
NEOB-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 Resourc'es Hanagement, Washington, D.C.
20555.
If you have any questions about this matter, please contact Sheri Peterson at 301-504-1325 or Patrick Madden at 301-504-2854.
Sincerely,
Enclosure:
Request for Additional Information cc w/enclosure:
See next page a
an Ac 'ng Associate Director for Projects OF ice of Nuclear Reactor Regulation
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Mr. Gregory M. Rueger Pacific Gas and Electric Company Diablo Canyon CC:
NRC Resident Inspector Diablo Canyon Nuclear Power Plant c/o U.S. Nuclear Regulatory Commission P. 0.
Box 369 Avila Beach, California 93424 Dr. Richard Ferguson, Energy Chair Sierra Club California 6715 Rocky Canyon Creston, California 93432 Ms.
Nancy Culver San Luis Obispo Mothers for Peace P. 0.
Box 164 Pismo Beach, California 93448 Ms. Jacquelyn C. Wheeler 3303 Barranca Court San Luis Obispo, California 93401 Managing Editor The County Telegram Tribune 1321 Johnson Avenue P. 0.
Box 112 San Luis Obispo, California 93406 Chairman San Luis Obispo County Board of Supervisors Room 370 County Government Center San Luis Obispo, California 93408 Mr. Truman Burns Mr. Robert Kinosian California Public Utilities Commission 505 Van Ness, Rm. 4102 San Francisco, California 94102 Diablo Canyon Independent Safety Committee ATTN:
Robert R. Wellington, Esq.
Legal Counsel 857 Cass Street, Suite D
Monterey, California 93940 Mr. Steve Hsu Radiologic Health Branch State Department of Health Services Post Office Box 942732 Sacramento, California 94234 Regional Administrator, Region V
U.S. Nuclear Regulatory Commission 1450 Maria Lane, Suite 210 Walnut Creek, California 94596 Mr. Peter H. Kaufman Deputy Attorney General State of California 110 West A Street, Suite 700 San Diego, California 92101 Christopher J. Warner, Esq.
Pacific Gas
& Electric Company Post Office Box 7442 San Francisco, California 94120 Mr. John Townsend Vice President and Plant Manager Diablo Canyon Power Plant P. 0.
Box 56.
Avila Beach, California 93424
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 205664001 ENCLOSURE RE(VEST FOR ADDITIONAL INFORMATION REGARDING GENERIC LETTER 92-08 "THERMO-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 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, radiant energy heat shields, and barriers installed to enclose intervening combustibles.
B.
Required Information Describe the Thermo-Lag 330-1 barriers installed in the plant to
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b.
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d.
e.
meet 10 CFR 50.48 or Appendix R to 10 CFR Part 50, support an exemption from Appendix R, achieve physical independence of electrical
- systems, meet a condition of the plant operating license, satisfy licensing commitments.
2.
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).
For the total population of Thermo-Lag fire barriers described under Item I.B.1, submit an approximation of:
cl 0 b.
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.
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.
1 d.
For all other barriers and radiant energy heat shields:
the total linear or square feet of I-hour barriers and the total linear or square feet of 3-hour
- barriers, as appropriate for the barrier configuration or type.
II.
Important Barrier Parameters A.
Discussion In a letter of July 29,
- 1993, from A. Harion, NUHARC, to C. HcCracken,
- NRC, NUHARC stated:
"Relative to bounded configurations,... [i]twill be the utilities responsibility to verify their baseline installations are bounded."
Furthermore, NUHARC stated that the parameters of importance for utility use of data from the industry Thermo-Lag fire barrie test program are:
l.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
I2.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
Raceway orientation (horizontal, vertical, radial bends)
Conduit Junction boxes and lateral bends Ladder-back cable tray with single layer cable fill Cable tray with T-Section Raceway material (aluminum, steel)
Support protection, thermal shorts (penetrating elements)
Air drops Baseline fire barrier panel thickness Preformed conduit panels Panel rib orientation (parallel or perpendicular to the raceway)
Unsupported spans Stress skin orientation (inside or outside)
Stress skin over joints or no stress skin over joints Stress skin ties or no stress skin ties Dry-fit, post-buttered joints or prebuttered joints Joint gap width Butt joints or grooved and scored joints Steel bands or tie wires Band/wire spacing Band/wire distance to joints No internal bands in trays No additional trowel material over sections and joints or additional trowel material applied No edge guards or edge guards Each NUHARC cable tray fire test specimen includes 15 percent cable 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 Thermo-Lag configurations; for example, cable trays with less thermal mass (cable fill) than the NUHARC test specimens, different cable
1 0
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- 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, NUHARC stated:
"Utilities using the results of the NUHARC testing will need to evaluate their installed cable fill and ensure that it is bounded by the tested'cable fill."
NUHARC 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.
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 NUHARC test specimens).
7.'able 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, NUHARC 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.
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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 NUHARC'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 NUHARC 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 NUHARC test program.
During recent meetings with the NRC staff, the Executive Director for Operations and the Commission, NUHARC 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 I-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, NUHARC's program is not intended to bound all in-plant Thermo-Lag fire barrier configurations.
In view of the scope of the NUHARC program and the limited success of the Phase I tests, it is clear that the NUHARC 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 NUHARC 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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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 NUHARC 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.1, describe those that you have determined will fall within the scope of the NUHARC program for ampacity derating, those that will not be bounded by the NUHARC program, and those for which ampacity derating does not apply.
2.
For the barriers you have determined fall within the scope of the NUHARC 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 NUHARC test program, 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 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 performing those actions) to confirm that the ampacity derating factors were derived by valid tests and are applicable to the modified plant design.
0 ~
Your response to Section IV.B may depend on unknown specifics of the NUHARC 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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V.
Alternatives VI.
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 I-hour barriers (for example, I-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 comp'tiance 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.
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 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 NUHARC program,
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2.
implementation and completion of plant-specific analyses,
- testing, or alternative actions for fire barriers outside the scope of the NUNRC 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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