ML20059D544
| ML20059D544 | |
| Person / Time | |
|---|---|
| Issue date: | 12/30/1993 |
| From: | Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | |
| References | |
| M931029, SECY-93-362, NUDOCS 9401070358 | |
| Download: ML20059D544 (22) | |
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December 30, 1993 SECY-93-362 (Information)
FOR:
The Commissioners FROM:
James M. Taylor Executive Director for Operations
SUBJECT:
RESOLUTION OF ISSUES CONCERNING THERMO-LAG FIRE BARRIERS (M931029)
PURp0SE:
To provide the information requested in the staff requirements memorandum (SRM) of November 15, 1993.
DISCUSSION:
On October 29, 1993, the NRC staff briefed the Commission on the status of the actions to resolve the Thermo-Lag fire barrier issues. During the briefing, the Commission expressed concern that industry efforts to resolve technical issues through a test program may not lead to timely resolution of the issues.
In an SRM of November 15, 1993, the Commission requested that the staff perform several tasks. These tasks and the staff actions are reported below.
SRM Item 1: Have the ACRS [ Advisory Committee on Reactor Safeguards] review the technical differences that remain between NUMARC [ Nuclear Management and Resources Council] and the staff on the NUMARC test program. The Commission would appreciate the ACRS' views on this issue.
Staff Action: On November 19, 1993, the Office of Nuclear Reactor Regulation (NRR) staff briefed the ACRS Subcommittee on Auxiliary and Secondary Systems on the NRC's proposed fire endurance test methodology and acceptance criteria and the technical differences that remain between the staff and NUMARC.
(These differences are discussed under Item 2, below.) Texas Utilities Electric Company (TV Electric), Tennessee Valley Authority, and NUMARC also made presentations during the subcommittee meeting. NRR staff and industry briefed the full ACRS on December 9,1993.
The ACRS provided its views in a memorandum to the Chairman of December 16, 1993. The staff is reviewing the CONTACT:
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. ACRS comments and will provide the results of its review to the Commission when completed.
SRM ltem 2:
Inform the Commission of the proposed course of action for resolving the methodology and criteria differences especially with respect to the following issues:
a.
the degree of conservatism or margin provided by testing without cables in the trays as compared to testing with cables in the trays, b.
the difference in measured temperature with thermocouples located as proposed by NUMARC compared with staff's placement.
Illustrations of these situations would be useful, and c.
information necessary to extrapolate data from simple, reference tNts to actual as-built configurations.
Staff Action: At the time of the Commission briefing on October 29, 1993, technical disagreements remained between the staff and NUMARC on two fire test criteria issues. These were:
thermocouple placement for the bottom surface of cable tray test specimens and using cable fill in cable tray test assemblies. To help resolve these differences, the staff consulted with the ACRS (discussed under Item 1, above) and increased senior management (NRR Office Director and NUMARC executive level) involvement in the issues (discussed under Item 3, below). The staff will also issue a request for additional information pursuant to 10 CFR 50.54(f) to each licensee that uses Thermo-Lag fire barriers (discussed under Item 4, below).
In the following response, Item 2b is discussed before Item 2a.
Thermocouple Placement For cable trays, the staff position specifies that the temperature rise from the bottom surface of the barrier be measured by thermocouples attached to a bare copper conductor installed on the bottom of the cable tray rungs.
Despite concerns expressed by the staff to NUMARC prior to construction of the Phase I cable tray test specimens, NUMARC installed this bare copper conductor above the cable tray rungs with the cable fill.
However, during the ACRS meeting on December 9,1993, NUMARC stated that, for the Phase 2 cable tray test specimens, it would install thermocouples both above and below the cable tray rungs.
This change in the NUMARC test methodology resolved the disagreement between the staff and NUMARC on thermocouple placement for cable tray test specimens.
The enclosure illustrates the thermocouple placements.
Although the difference in temperature with thermocouples located as proposed by NUMARC compared with the staff's placement has not been measured during any previous test, the results of NUMARC's Phase 2 tests will provide the data needed to assess the significance of the different placements.
Use of Cable Fill As stated in the final draft of Supplement 1 to Generic Letter (GL) 86-10,
" Fire Endurance Test Acceptance Criteria for Fire Barrier Systems Used to
. Separate Redundant Safe Shutdown Trains Within the Same Fire Area," it is the staff view that fire tests of raceway fire barrier systems intended for generic applicability (for example, where the barriers will protect raceways with a range of cable types and fills) should be conducted without cables in the test specimens.
Excluding cables from the test. specimen eliminates any bias in the test results created by the thermal mass of the cables.
Without this thermal mass, the internal temperature conditions measured by the test specimen thermocouples during the fire exposure will provide a more accurate measure of fire barrier thermal performance. The use of cable fill, which can influence the temperature profiles, has the potential, therefore, to limit the plant-specific applicability of fire test results.
In addition, when cables are used, inore precise information on certain configuration attributes (such as cable fill and the proximity of cables to the inside barrier surfaces) is needed to assess the applicability of the test results to the in-plant fire barrier configurations.
Draft 14 of the American Society for Testing Materials standard for fire tests of raceway fire barriers states:
" testing shall be conducted without cables."
The appendix (commentary) to the draft standard states:
" electrical conductors are not evaluated or included in these test methods.
In addition, concerning thermal mass, excluding cables from the test specimens would be more conservative and therefore more supportive of the generic applicability of these test methods. This is however not intended to prevent users from including cables or other components in test specimens which are representative of field conditions or end use thermal mass.
Testing of such specimens may require additional instrumentation to demonstrate fire barrier system performance.
The final draft of Supplement 1 to GL 86-10 also states that tests with cables in the test specimens are acceptable for plant-specific tests that use representative cable types and fills.
1 i
Fire endurance tests have not been conducted of duplicate cable tray test i
specimens with and without cables. Therefore, a quantitative measure of the reduction of conservatism provided by testing with cables as compared to testing without cables is not available.
The staff is not aware of any l
existing test standard, any test standard under development, or any test program that has defined or quantified this margin.
The margin would be a function of the a wide variety of variables such as raceway type and size, percent cable fill, fire barrier thickness and construction techniques.
The impact of such parameters is discussed below.
Application of Test Data The information and configuration parameters needed to apply fire test data to actual as-built fire barrier configurations is well understood and is not a point of contention between the staff and NUMARC.
The proposed staff acceptance criteria state that the test specimen should be representative of the construction for which a fire rating is desired, as to materials, workmanship, and such details as dimensions of parts.
In addition, the fire test program should bound the in-plant raceway sizes and configurations that will be protected with fire barriers.
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. tests to qualify the various Thermo-Lag fire barrier configurations installed at Comanche Peak Unit 2.
The principal test specimen attributes are raceway type (conduit or cable trays), material (aluminum or steel), and size; fire barrier material thicknesses; types of joints and joint sealing methods (pre-buttered or post-buttered) and details (laced with tie wire, or not laced); direction of structural ribs and orientation of stress skin; unsupported span distances and internal supports (if any); band or tie-wire type and spacing; support and penetrating element protection; cable types and fill; and transitions or interfaces between Thermo-Lag fire barrier materials and any cther fire barrier material.
Typically, the weakest or less robust attributes are tested, thereby qualifying both the weak attribute and any stronger attribute.
For example, if a test specimen with band spacing of 10 inches on center satisfies the test acceptance criteria, then barrier configurations with band spacing less than 10 inches would also be qualified.
Similarly, if a test specimen with post-buttered joints (i.e., the joint is sealed by applying trowel-grade Thermo-Lag over the joint after the individual barrier pieces are assembled) satisfies the criteria, then the more robust prebuttered joint (i.e., one in which the trowel-grade material is applied to the edges of the pieces to be joined before they are assembled to ensure that Thermo-Lag material completely fills the joint) would also be qualified by the fire test.
Extrapolation of test results or data in a less conservative direction (for example, allowing band spacing of 12 inches based on a test of 10-inch spacing) must be evaluated on a case-by-case basis.
These decisions would be supported by engineering evaluations based largely on such fire test results as temperature profiles and barrier condition at the end of the fire and hose stream tests, and the application of engineering judgment.
For example, the temperature profile was well within the acceptance criteria, the joints survived the fire and hose stream tests with margin, and there was virgin fire barrier material remaining at the end of the test, some extrapolation may be acceptable.
GL 86-10, " Implementation of Fire Protection Requirements," of April 24, 1993, also provided the following guidance, which is not changed by the clarified staff position, for extrapolating test data to as-built configurations:
"Where exact replication of a tested configuration cannot be achieved, the field installation should meet all of the following criteria:
1.
The continuity of the fire barrier material is maintained.
2.
The thickness of the barrier is maintained.
3.
The nature of the support assembly is unchanged from the tested configuration.
4.
The application or end use of the fire barrier is unchanged from the tested configuration."
. t The staff will work with NUMARC in the development of its Application Guide.
This guide will provide detailed guidelines to the industry for the application of test results and the evaluation of test attributes to in,lant fire barrier configurations.
I sri 1 Item a:
Encourage NUMARC to complete the testing and analyze the results.
The :taff should promptly review the test results when available.
Staff Action: NUMARC has completed its Phase 1 fire tests and has informed the staff that the Phase 1 test reports will be submitted during January 1994.
Construction of the ten Phase 2 test specimens is currently underway at Omega Point Laboratories (OPL), San Antonio, Texas.
NUMARC plans to complete Phase 2 construction during the first part of January 1994 and to conduct the Phase 2 fire endurance tests between the week of January 24, 1993 and the end of February 1994. NUMARC plans to submit the Phase 2 fire test reports within 60 days of the completion of the fire tests.
NUMARC has informed the staff that it is considering additional fire tests (Phase 3), but has not reeched any final decisions on this possibility.
During a meeting with NUMARC on November 19, 1993, the EDO and NRR staff emphasized the need to expeditiously achieve a final solution to the Thermo-Lag fire barrier concerns. The EDO encouraged NUMARC to complete its test program and to develop its Application Guide.
In a subsequent senior management meeting on December 21, 1993, senior NRR managers reemphasized these points.
NUMARC is proceeding with its program.
The NUMARC test program milestones, NRR staff review of the program, and NRR staff review of the test results and Application Guide are included in the Thermo-Lag Action Plan.
The staff is auditing the construction activities at OPL and will witness the fire endurance tests.
The staff will review the fire test reports and the Application Guide in a timely manner in accordance with the action plan.
During the meeting, the NRC staff expressed concern about the scope and timeliness of the NUMARC program and suggested monthly senior management (NRR Office Director and NUMARC executive level management) meetings for the duration of the program. NUMARC management agreed.
The first meeting, as discussed above, was held December 21, 1993.
The staff will inform the Commission of the status regarding the completion of the NUMARC program and the staff review of program results.
j i
SRM Item 4: Consider alternatives to the current program in the event the present course of action is not sufficient to reach an acceptable solution to this issue in a reasonable amount of time.
Staff Action:
In response to this request, the staff reassessed the present course of action and identified and assessed a range of options.
These included:
continue with the current course of action with adjustments to j
achieve more timely resolution of the issues, increase staff interaction with individual licensees either in parallel with or independent of the NUMARC effort, grant generic or plant-specific exemptions from NRC fire barrier
2 requirements, qualify 3-hour fire barriers as 1-hour barriers and order the licensees to install fire detection and suppression systems in areas that have such barriers, allow permanent use of fire watches as compensation for degraded barriers, defer fire barrier upgrades until a performance-based fire protection rule is promulgated, and conduct an NRC-sponsored fire and ampacity derating test program to qualify existing (baseline) in-plant Thermo-Lag fire barriers and barrier upgrades.
On the basis of this assessment, the staff concluded that, at this time, the most viable course of action is the current course of action, with adjustments. The current course of action calls for completing the industry (NUMARC) test program, coupled with plant-specific application of the industry test results, and development of plant-specific resolution plans for configurations particular to the specific plant.
This approach considers 1
fully both the regulatory process and the safety significance of the issues.
The staff did, however, identify weaknesses with the present course of action and will, as discussed below, make several adjustments and take additional actions to ensure timely resolution of the remaining issues.
The principal weakness with the current plan of action is that it assumed that workable generic Thermo-Lag-based upgrades could be developed for existing in-plant barriers and that this could be done in a timely manner.
However, on the basis of testing of Thermo-Lag fire barriers to date, it appears that it may not be possible to develop generic upgrades (using additional Thermo-Lag materials) for all 3-hour barrier configurations and for some 1-hour barriers.
For example, 1-hour barriers on wide cable trays, with post-buttered joints i
and no internal supports. Moreover, some barrier upgrades may be difficult and costly to implement and those that rely on additional thicknesses of Thermo-Lag material (or other fire barrier materials) may adversely affect i
ampacity derating characteristics. These fectors have complicated the final solution and have extended the completion schedule originally targeted by the i
staff.
In addition, individual licensees may not be sufficiently sensitive to the importance of timely resolution of the concerns and may be placing too much emphasis on the NUMARC program.
To address these identified weaknesses and to provide an acceptable solution in a reasonable amount of time, the staff will implement two additional actions in the near term. These actions, or program adjustments, are (1) increase senior management inv. mnt in resolving issues with NUMARC and (2) issue a request for additiom i: )rmation pursuant to 10 CFR 50.54(f) to each licensee that uses Thermo-i i fir barriers as a follow-up to the GL 92-08 responses to facilitate ass v c of the resolution plans on a plant-specific basis as discussed below.
The increased senior management involvement was discussed under Item 3, above.
Although NUMARC took the lead for developing.an overall industry response to the Thermo-Lag issues, it is the individual responsibility of each reactor licensee to ensure that its facilities fully conform to NRC requirements. The staff review of the licensee responses to GL 92-08 indicated that 71 units are awaiting the results of the NUMARC test program before developing resolution plans and completion schedules. The program is limited to certain 1-hour and
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i 1 i 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.
Based on the scope of the NUMARC program and the results of NUMARC's Phase 1 fire tests, it is clear that NUMARC's program will not be sufficient to resolve the Thermo-Lag fire barrier issues stated in GL 92-08 at many plants.
Therefore, licensees relying on NUMARC's program may need to take actions above and beyond the NUMARC program to address fire endurance and ampacity derating concerns with their in-plant Thermo-Lag barriers.
The basis for issuing the request for additional information pursuant to 10 CFR 50.54(f) (memorandum from T.E. Murley, Director, NRR, to L.J. Callan, Acting Associate Director for Projects, NRR), the 50.54(f) letter, and the request for additional information are enclosed. The staff plans to issue the 50.54(f) letters by December 31, 1993.
Licensees will be required to respond within 45 days of the date of the letter.
The staff expects to complete its review and evaluation of the data and information provided in response to the letters within 60 days of receipt of the licensees' responses.
The staff will then reassess the Thermo-Lag Action Plan and will consider all practical alternatives that originate from the licensee responses and this reassessment. The staff will inform the Commission of any significant issues that stem from or any programmatic adjustments made as a result of this review.
SRM ltem 5:
Revise the staff's action plan to include points in the process where it would be prudent to consider implementing the alternatives and a reasonable deadline for resolving the Thermo-Lag issue. On this issue the Commission wants to know the number of plants that use only 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> barriers and how many use 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> barriers.
For those using 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> barriers, provide some measure of the extent of usage.
Staff Action: The staff ir taking measures at present to address the identified weaknesses while maintaining the current course of action and to provide an acceptable solution in a reasonable amount of time. These actions were discussed above. The staff will revise the Thermo-Lag Action Plan to include these actions and the points in the process at which it would be prudent to consider implementing the alternatives and a reasonable deadline for resolving the Thermo-Lag issue. These actions will be reflected in the quarterly update of the Thermo-Lag Action Plan, which is due to the Commission January 21, 1994.
Based upon current NUMARC test schedules and replies to the 50.54(f) letters, the staff expects to address the Thermo-Lag fire barrier concerns or to propose alternative fire protection measures to be implemented to bring plants into compliance with Appendix R.
The staff requested licensees to begin corrective actions as information and test data become available.
The staff will receive the licensee responses to the 50.54(f) letter after the January 1994 quarterly update of the Thermo-Lag Action Plan.
The staff will evaluate these responses and will reassess the alternatives and goals discussed above and any other alternatives offered by the licensees responses.
1 i
~ j' The staff will continue to review and update the Thermo-Lag Action Plan quarterly and will inform the Commission of the results of its review.
In a letter of November 8, 1993, NUMARC informed the staff that 23 operating units use only 1-hour Thermo-Lag fire barriers,15 operating units use only 3-hour Thermo-Lag fire barriers, and 40 operating units use both 1-hour and 3-hour Thermo-Lag fire barriers.
Of the 55 units that use 3-hour barriers, 24 units have minimal amounts of 3-hour Thermo-Lag material (less than 500 linear feet) and 31 units have moderate to extensive amount of i
material installed (greater than 500 linear feet).
(The Electric Power Research Institute (EPRI) collected this information through an industry survey for NUMARC. NUMARC used the data to design the industry test program.)
As discussed above, the CFR 50.54(f) letters will request additional i
information on the configurations and amounts of Thermo-Lag fire barriers installed in each unit. The staff will provide this information to the Commission after it is reviewed and compiled.
1 Foreion Reauirements: The Commission is interested in a comparison of the fire protection requirements at foreign reactors with those in the U.S. and the design (including materials) or operational measures being taken in foreign reactors with respect to this issue.
j Staff Action: The staff is compiling the requested information and will submit it to the Commission by January 14, 1994, as requested in the SRM.
/
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N nes M. Ta or ecutive Director for Operations
Enclosures:
l As stoied DISTRIBUTION:
Conunissioners OGC OCAA OIG OPA j
OCA OPP DCD Central Files Regional Offices EDO ACRS SECY
THERMOCOUPLE PLACEMENT CABLE TRAY SPECIMENS WITH CABLES l
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CABLE TRAY CABLE TRAY THERMOCOUPLE THERMOCOUPLE LOCATIONS TYP.
LOCATIONS TYP.
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UNITED STATES I
ie( ' E NUCLEAR REGULATORY COMMISSION E
WASHINGTON, D.C. 20555-0001 l,
'%c MEMORANDUM FOR:
Leonard J. Callan, Acting Associate Director for Projects Office of Nuclear Reactor Regulation FROM:
Thomas E. Murley, Director Office of Nuclear Reactor Regulation
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING GENERIC LETTER 92-08, " THERM 0-LAG 330-1 FIRE BARRIERS," PURSUANT TO 10 CFR 50.54(f)
In their responses to Generic Letter (GL) 92-08, "Thermo-Lag 330-1 Fire Barriers," licensees for 71 units indicated that actions necessary to restore the operability of these barriers 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.
In addition, in a staff requirements memorandum of November 15, 1993 (M931029), the Commission asked the staff to reassess its current program for resolving the fire barrier technical issues.
The reassessment resulted in a number of adjustments to the current program, one of which is the action discussed below.
Based on the limited scope of the NUMARC program and the limited success of NUMARC's Phase 1 fire tests, it is clear that NUMARC's program will not be sufficient to resolve the Thermo-Lag fire barrier issues stated in GL 92-08 at many plants. Therefore, licensees relying on NUMARC's program may need to l
take actions above and beyond the NUMARC program to address fire endurance and ampacity derating concerns with their in-plant Thermo-Lag barriers.
In addition, although NUMARC took the lead for developing an overall industry response to the Thermo-Lag issues, it is the responsibility of each reactor licensee to ensure that its facilities conform to NRC requirements.
I am concerned that individual licensees may not be sufficiently sensitive to the importance of timely resolution of the concerns and may not have fully evaluated the applicability of the NUMARC program.
I have determined that to help ensure timely resolution of the Thermo-Lag issues at each plant, it is appropriate at this time for the staff to obtain additional information from each licensee that uses Thermo-Lag fire barriers to meet NRC fire protection requirements.
The request for additional information addresses 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
L.J. Callan 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 that the licensee deems impractical to upgrade, the request asks for information on plans schedules for resolving the technical issues identified in GL 92-08. The request for additional information is within the scope of GL 92-08 as related to the licensees' original GL responses and the context of the NUMARC program.
Thermo-Lag barriers are currently installed in the plants that will receive a request for additional information. The barriers are required to meet either a condition of the plant operating license or NRC requirements such asSection III.G of Appendix R to 10 CRF Part 50.
The information is needed to verify licensee compliance with its current licensing basis.
There is no new staff position reflected in the request for information. Therefore, actions taken by licensees to provide the requested information are necessary to bring licensees into compliance with existing NRC rules and regulations, and are not the result of any new staff requirement or position.
Accordingly, the request for information will be issued pursuant to 10 CFR 50.54(f).
The Commission, the Executive Director for Operations (EDO), and the Chairman of the Committee for the Review of Generic Requirements will be informed of this action.
The Office of the General Counsel has reviewed the 50.54(f) letter and the request for information and has no legal objection.
The 50.54(f) letter, the request for information, and a list of the plants that will receive the letter are enclosed.
Each project manager should fill in the plant-specific information, tailor the letter to the particular plant in accordance with the guidance prepared by the lead project manager and the Plant Systems Branch, and issue the letter to his or her licensee pursuant to 10 CFR 50.54(f) no later than December 22, 1993. The EDO has requested that you should sign the letters.
Please comply with this request.
The 50.54(f) letter requests that licensees respond within 45 days of receipt of the letter.
Information regarding processing of the responses should be coordinated between the lead project manager and the Plant Systems Branch.
If you have any questions, please contact Conrad McCracken at 504-2873, or Steven West at 504-1220.
Thomas E. Murley, Director Office of Nuclear Reactor Regulation
Enclosures:
As stated cc w/ enclosures:
J. Taylor, EDO
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NUCLEAR REGULATORY COMMISSION
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Docket No. 50-[#]
[ LICENSEE ADDRESS)
Dear [ TITLE /NAME]:
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING GENERIC LETTER 92-08, "THERMO-LAG 330-1 FIRE BARRIERS," PURSUANT T0 10 CFR 50.54(f) -
[ PLANT NAME]
)
In your response of [DATE], 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 [ PLANT NAME] 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 i
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, i
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 1 test results to the licensees.
I In view of the limited scope of the NUMARC program and the limited success of I
the Phase 1 tests, it is clear to the staff that the_NUMARC program will_not i
be sufficient to resolve all Thermo-Lag fire barrier. issues identified in j
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 [ PLANT NAME),
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 i
NUMARC's test program.
For those configurations that are outside the scope.of i
the program or for those configurations that you deem are impractical to upgrade, we request that you provide plans schedules for resolving the technical issues identified in GL 92-08.
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[ LICENSEE] 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 under;igned, with a copy to the appropriate Regional Administrator.
Please retair 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 esi.imated 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), NE0B-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 [ PLANT PM] at 301-504-[#] or Patrick Madden at 301-504-2854.
Sincerely, Leonard J. Callan, Acting Associate Director for Projects Office of Nuclear Reactor Regulation
Enclosure:
Request for Additional Information cc:
[]
4
[L1CENSEE] 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 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 Office of Management and Budget Clearance Number I
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), 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 i
Services, Office of Information and Resources Management, Washington, D.C.
20555.
If you have any questions about this matter, please contact [ PLANT PM] at 301-504-[ NUMBER] or Patrick Madden at 301-504-2854.
Sincerely, Leonard J. Callan, Acting Associate Director for Projects Office of Nuclear Reactor Regulation
Enclosure:
Request for Additional Information cc:
[]
DISTRIBUTION Docket File CMcCracken MGamberoni PM NRC PDR PMadden RIngram, PMSB LA Local PDR CBerlinger Region [#]
GMulley (0IG)
PD[#] Rdg RJenkins OGC EPawlik (Rlll/01)
Div Dir GMulley (0IG)
ACRS (10)
Asst Dir 0FFICE LA:PD PM:PD PD:PD DD:
NAME DATE 12/ /93 12/ /93 12/ /93 12/ /93 COPY Yes/No Yes/No Yes/No Yes/No Yes/No 0FFICIAL RECORD COPY FILENAME:
G:\\WPDOCS\\[NAME]
[G:\\THERMOLA\\50.54F.10]
i ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION l
REGARDING GENERIC LETTER 92-08 l
" THERM 0-LAG 330-1 FIRE BARRIERS" l
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 l
1 systems constructed by any assembly method, such as by joining preformed panels and conduit preshapes, and trowel, spray, and i
brush-on applications. This includes all fire barriers, all barriers to achieve physical independence of electrical systems, j
radiant energy heat shields, and barriers installed to enclose i
l 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 the following information.
a.
For cable tray barriers:
state 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:
state the total linear feet of 1-hour barriers and the total linear feet of 3-hour barriers.
c.
For all other fire barriers:
state 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:
state 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.
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,... [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 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
- 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 i
- 24. No edge guards or edge guards Each NUMARC 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 in 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 4
Thermo-Lag or may come into contact during a fire if-the Thermo-Lag j
material sags).
In its letter of July 29, 1993, NUMARC stated:
l
" Utilities using the results of the NUMARC testing will need to
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. 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.
i 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 i
t 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 t
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, NUMARC 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 is 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.
. 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 92-08, 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 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 i
configurations.
In view of the scope of the NUMARC program and the limited success of the Phase 1 tests, it is clear that the NUMARC program will not be sufficient to resolve all Thermo-Lag fire l
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.
I 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 i
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.
'i IV.
Ampacity Derating A.
Discussion 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
. j component model for the industry.
Additional information is' needed to determine whether or not your Thermo-Lag barrier configurations a
(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.
4 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 de nting does not apply.
2.
For the barriers you have determined fall within the scope of the NUMARC program, describe what additional testing or j
evaluation you will need to perform to derive valid ampacity
/
derating factors.
3.
For the barrier configurations that you have determined wili not be bounded by the NUMARC 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 inaependence of electrical systems) are correct and applicable to the plant design.
Describe all corrective actions needed and submit the schedule for completing such actions.
1 4.
In the event that the NUMARC fire barrier tests indicate the 1
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 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.
VI. 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 i
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.
Vll. 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 NUMARC program, 2.
implementation and completion of plant-specific analyses, testing, or alternative actions for fire barriers outside the scope of the NUMARC program,
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t VIII.
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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ENCLOSURE 2 PLANTS THAT WILL RECEIVE A 50.54(f) LETTER Arkansas Nuclear One 2 Beaver Valley 1,2 Braidwood 1,2 Brunswick, 1,2 Byron 1,2 Callaway Clinton Cooper Crystal River 3 Davis Besse D.C. Cook 1, 2 Diablo Canyon 1, 2 Duane Arnold Fermi 2 Grand Gulf I Haddam Neck Harris 1 Hatch 1, 2 Indian Point 2 La Salle 1, 2 Limerick 1, 2 McGuire 1, 2 Millstone 1, 2, 3 Nine Mile Point 1, 2 North Anna 1, 2 Oyster Creek Palisades Palo Verde 1, 2, 3 Peach Bottom 2, 3 Perry 1 Prairie Island 1, 2 River Bend 1 Saint Lucie 1, 2 Sequoyah 1, 2 South Texas 1, 2 Summer Surry 1, 2 Susquehanna 1, 2 Three Mile Island 1 Turkey Point 3, 4 Vogtle 1, 2 Washington Nuclear 2 Waterford 3 Wolf Creek 1 Zion 1, 2 G:\\THERMOLA\\50_54F.EN2
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