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{{#Wiki_filter:'p -UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, D.C. 20555June 23,-1992NRC INFORMATION NOTICE 92-46: THERMO-LAG'FIRE BARRIER MATERIAL SPECIALREVIEW TEAM .FINAL REPORT FINDINGS, CURRENT-FIRE ENDURANCE TESTS, AND AMPACITY' ' CALCULATION ERRORS
{{#Wiki_filter:'p -UNITED STATES NUCLEAR REGULATORY
 
COMMISSION
 
===OFFICE OF NUCLEAR REACTOR REGULATION===
WASHINGTON, D.C. 20555 June 23,-1992 NRC INFORMATION
 
NOTICE 92-46: THERMO-LAG'FIRE
 
BARRIER MATERIAL SPECIAL REVIEW TEAM .FINAL REPORT FINDINGS, CURRENT-FIRE ENDURANCE
 
TESTS, AND AMPACITY' ' CALCULATION
 
ERRORS


==Addressees==
==Addressees==
All holders of operating licenses or construction permi~ sfor'nuclear powerreactors. _ _PurDoseThe U.S. Nuclear Regulatory Commission (NRC) is-issuing this informationnotice to inform addressees of (1)-the findings of the NRC's Thermo-LagSpecial Review Team, (2) current Thermo-Lag 330 fire resistance testing beingconducted by Texas Utilities (TU) and Thermal Science; Inc. (TSI),--and (3)errors found in the calculation of cable ampacity derating factors for Thermo-Lag fire resistive barriers. It is expected that recipients ,will review theinformation for applicability to their facilities and consider actions', as-appropriate, to avoid similar problems. However, suggestions contained in -this information notice are not-NRC requirements; therefore, no specificaction or written response is required.DiscussionFINAL REPORT BY THE SPECIAL REVIEW TEAM FOR THE REVIEW OF THERMO-LAG FIREBARRIER PERFORMANCERThe NRC has been reviewing the qualification of Thermo-Lag-'330-1 fire barriersystems. The NRC previously issued two information notices on these firebarrier systems: (1) Information Notice'91-47, "Failure 6f Thermo-Lag FireBarrier Material to Pass Fire Endurance Test," August 6, 1991, and (2)Information Notice 91-79, "Deficiencies in the Procedures for InstallingThermo-Lag Fire Barrier Materials,' December 6, 1991.On February 12, 1992,'the NRC's Special Review Team for the review of Thermo'Lag fire barrier performance met with the'Nuclear Utilities Management and'Resources Council (NUMARC) to discuss the coordination of the industry's -response to Th'ermo-Lag fire endurance, installation, and-ampacity concerns.During the meeting, the staff provided NUMARC'a proposed draft generic letteron the Thermo-Lag fire barrier issue for review and comment. The draft-generic letter was included in-the-meeting minutes which were placed in thePublic Document Room as an enclosure to a February 24, 1992, letter to NUMARCIn a letter of March 3, 1992, NUMARC commented on the proposed draft generic9206150492 PD R 5O g -\n' 3a
All holders of operating
 
licenses or construction
 
permi~ sfor'nuclear
 
power reactors.
 
_ _PurDose The U.S. Nuclear Regulatory
 
Commission (NRC) is-issuing
 
this information
 
notice to inform addressees
 
of (1)-the findings of the NRC's Thermo-Lag
 
Special Review Team, (2) current Thermo-Lag
 
330 fire resistance
 
testing being conducted
 
by Texas Utilities (TU) and Thermal Science; Inc. (TSI),--and
 
(3)errors found in the calculation
 
of cable ampacity derating factors for Thermo-Lag fire resistive
 
barriers.
 
It is expected that recipients ,will review the information
 
for applicability
 
to their facilities
 
and consider actions', as-appropriate, to avoid similar problems.
 
However, suggestions
 
contained
 
in -this information
 
notice are not-NRC requirements;  
therefore, no specific action or written response is required.Discussion
 
FINAL REPORT BY THE SPECIAL REVIEW TEAM FOR THE REVIEW OF THERMO-LAG
 
===FIRE BARRIER PERFORMANCER===
The NRC has been reviewing
 
the qualification
 
of Thermo-Lag-'330-1 fire barrier systems. The NRC previously
 
issued two information
 
notices on these fire barrier systems: (1) Information
 
Notice'91-47, "Failure 6f Thermo-Lag
 
Fire Barrier Material to Pass Fire Endurance
 
Test," August 6, 1991, and (2)Information
 
Notice 91-79, "Deficiencies
 
in the Procedures
 
for Installing
 
Thermo-Lag
 
Fire Barrier Materials,'  
December 6, 1991.On February 12, 1992,'the
 
NRC's Special Review Team for the review of Thermo'Lag fire barrier performance
 
met with the'Nuclear
 
Utilities
 
Management
 
and'Resources
 
Council (NUMARC) to discuss the coordination
 
of the industry's
 
-response to Th'ermo-Lag
 
fire endurance, installation, and-ampacity
 
concerns.During the meeting, the staff provided NUMARC'a proposed draft generic letter on the Thermo-Lag
 
fire barrier issue for review and comment. The draft-generic letter was included in-the-meeting
 
minutes which were placed in the Public Document Room as an enclosure
 
to a February 24, 1992, letter to NUMARC In a letter of March 3, 1992, NUMARC commented
 
on the proposed draft generic 9206150492 PD R 5O g -\n' 3a
 
I L r -, I IN 92-46 June 23, 1992 letter and committed
 
to coordinate
 
the industry's
 
efforts associated
 
with the issues involving
 
Thermo-Lag.
 
In addition, NUMARC requested
 
that the NRC make available
 
any additional.
 
information
 
on the qualification
 
of these barriers.In response to this request, the NRC provided NUMARC the "Final Report-Special Review Team for the Review of Thermo-Lag
 
Fire Barrier Performance," of April 21, 1992, (Attachment
 
1). The final report concluded
 
that some licensees
 
have not adequately
 
reviewed and evaluated
 
the fire endurance
 
and ampacity test results for applicability
 
to the Thermo-Lag
 
fire barrier systems installed-in
 
their facilities.
 
In addition, the final report stated that some facilities
 
have used inadequate
 
installation
 
procedures
 
to construct
 
Thermo-Lag fire barriers on electrical
 
raceways and equipment.
 
CURRENT THERMO-LAG
 
330-1 FIRE BARRIER ENVELOPE TESTING As a result of the concerns in Information
 
Notices 91-47 and 91-79, TU instituted
 
a fire endurance
 
testing program to qualify the Thermo-Lag
 
fire barrier protective
 
system specifically
 
for its Comanche Peak Steam Electric Station.'
This testing was conducted
 
during the weeks of June 15 and 22, 1992.The NRC witnessed
 
the preparation
 
of test specimens
 
and the actual testing of the TU electric test articles.The tests consist of a series of 1-hour fire endurance
 
tests on a variety of cable tray and conduit "mock-ups".
 
The "mock-ups" were designed to duplicate actual plant configurations.
 
TU installed
 
the fire barriers using stock material and actual plant procedures
 
and personnel.
 
The first actual tests occurred on June 17,1i992.
 
Three-quarter-inch, and one-inch and five-inch
 
conduit configurations
 
were tested. All tests passed American Nuclear Insurers criteria, in that electrical
 
cable continuity
 
was -not lost. However, several temperature
 
readings were above specifications
 
for the 3/4-inch and 1-inch conduit tests, and for a junction box that was common to all the conduits.
 
Additionally, subsequent
 
investigation
 
of the cabling revealed evidence of charring and blistering.
 
NRC standards
 
require that the protected
 
components
 
be free of fire damage.Preliminary
 
information
 
from the second test of a 12-inch cable tray configuration
 
on June 18, -1992, showed satisfactory
 
results. Thermocouple
 
temperatures
 
on the protected
 
cables were less than 325 'F.The third test was conducted
 
on June 19, 1992. This article was a wide (30-inch)
ladder back cable tray configuration.
 
At 17 minutes into the test, the Thermo-Lag
 
panel on the bottom of the test article began to sag and the stainless
 
steel banding was carrying the load of the panel. At 18 minutes, the joint at the interface
 
between the tray support and the tray showed signs of weakening
 
and separation.
 
Internal temperatures
 
within areas of this cable tray assembly exceeded 325 'F at 25 minutes. The joint fully separated
 
in 41 minutes resulting
 
in cable circuit integrity
 
failure and fire damage to the cables..,.. ., .,;~~~ -, , I
 
Attachment
 
1_ , IN 92-46 June 23, 1992 c sUNITED STATES* of -t ¢NUCLEAR REGULATORY
 
COMMISSION
 
-WASHINGTON.
 
D. C. 2555 April 21, 1992 MEMORANDUM
 
FOR: William T. Russell, Assiciate
 
Director for Inspection
 
and Technical
 
Assessment
 
===Office of Nuclear Reactor Regulation===
FROM: Thomas E. Murley, Director Office of Nuclear Reactor Regulation
 
SUBJECT: FINAL REPORT -SPECIAL REVIEW TEAM FOR THE REVIEW OF THERMO-LAG
 
===FIRE BARRIER PERFORMANCE===
On February 12, 1992, the special review team for the review of Thermo-Lag
 
fire barrier performance
 
met with the Nuclear Utilities
 
Management
 
and Resources
 
Council (NUMARC) to obtain a commitment
 
for a coordinated
 
industry response to our concerns.
 
During the meeting, the team presented
 
the results of its review and gave the attendees
 
a proposed generic letter on Thermo-Lag
 
fire barriers.By a letter of March 3, 1992; NUMARC committed
 
to coordinate
 
the industry's
 
efforts and requested
 
additional
 
technical
 
information.
 
The review team's final technical
 
report is enclosed for transmittal
 
by your staff to NUMARC and the vendor. The report, which has been reviewed by your staff, documents
 
the results of the team's review and provides the technical
 
bases for its findings and recommendations.
 
The report identifies
 
the full scope of the concerns and will facilitate
 
discussions
 
between the staff and NUMARC needed to resolve their questions
 
and proceed with the issuance of the proposed generic letter.The special review team is available
 
to discuss its final report with you or your staff at your convenience.
 
===Thomas E.ector Office of Nuclear Reactor Regulation===
Enclosure:
As stated cc w/enclosure:
J. Sniezek'"- 92X05120277--920421 PDR REVGP ERONUMRC PDR
 
IN 92-46 June 23, 1992 TU has established
 
roving fire watches for Unit 1, in accordance.-with
 
its Fire Protection
 
Manual. The roving fire watches cover plant areas where Thermo-Lag
 
fire barrier configurations, similar to those'which
 
failed, are used to provide a fire endurance
 
barrier'for
 
safe-shutdown
 
equipment.
 
TSI is also instituting
 
a fire endurance
 
testing program. This program includes testing a new installation
 
technique
 
required for cable trays installed
 
with gap widths greater than 0.030 inches. The new seam joining technique
 
requires that either (1):stainless
 
steel tie wires be placed through the stress skin'at specified
 
intervals
 
or (2) stress skin and a layer of Thermo-Lag.trowel
 
grade material be placed over the entire seam length and banded in place. Preliminary
 
results of a June 9, 1992, test using the new seam joining technique (on seams without wide gaps) on a 36-inch cable tray system and a 3/4-inch conduit assembly were considered
 
successful
 
by the vendor and testing laboratory.
 
The NRC will provide additional
 
information
 
on these fire endurance
 
testing programs as it becomes available.
 
AMPACITY DERATING CALCULATION
 
ERROR In April 1992, the Washington
 
Public Power Supply System, the licensee for Washington
 
Nuclear Project, Unit 2,-found a mathematical
 
error in the calculation
 
of the ampacity derating factor for the Thermo-Lag
 
fire barrier enclosure
 
of cable trays in Industrial
 
Testing Laboratories (ITL) Incorporated
 
Test Report ITL-82-5-355C.
 
The error occurred when ITL adjusted the test current to baseline temperatures
 
of 40 0 C ambient and 90 0 C cable. This adjustment
 
is required when tests are performed
 
at different
 
ambient and cable temperatures.
 
ITL used the correct equation for adjusting
 
to temperature
 
parameters
 
that differ from the Insulated
 
Cable Engineers
 
Association (ICEA)publication
 
P-46-426:
I' = I X MF (where "I" is at 40 "C ambient and 90 "C cable temperature, and "I'" is at other ambient and cable temperature
 
conditions).
 
However, in calculating
 
II," ITL multiplied
 
WI'" by "MF" instead of dividing.
 
The NRC determined
 
that the ampacity derating factor will change from 18 to 33 percent when the mathematical
 
error is corrected.
 
While reviewing
 
other ITL test reports, the NRC staff found similar errors in other calculations
 
performed
 
by ITL in the adjustment
 
equation for ambient and cable temperature
 
conditions.
 
The NRC also noted that the baseline currents obtained from the test vary widely (up to 32 percent) from those published
 
in the ICEA publication
 
P-54-440.I It ,
WU IN 92-46 June 23, 1992 This information
 
notice requires nonspecific
 
action or written response.
 
If you have any questions
 
about the information
 
in this notice, please contact one of the technical
 
contacts listed below or the appropriate
 
Office of Nuclear Reactor Regulation (NRR) project manager.i.C Car es E. Rossi, Direct o Division of Operational
 
Events Assessment- Office of Nuclear Reactor Regulation'.


I Lr -, IIN 92-46June 23, 1992 letter and committed to coordinate the industry's efforts associated with theissues involving Thermo-Lag. In addition, NUMARC requested that the NRC makeavailable any additional. information on the qualification of these barriers.In response to this request, the NRC provided NUMARC the "Final Report-Special Review Team for the Review of Thermo-Lag Fire Barrier Performance," ofApril 21, 1992, (Attachment 1). The final report concluded that somelicensees have not adequately reviewed and evaluated the fire endurance andampacity test results for applicability to the Thermo-Lag fire barrier systemsinstalled-in their facilities. In addition, the final report stated that somefacilities have used inadequate installation procedures to construct Thermo-Lag fire barriers on electrical raceways and equipment.CURRENT THERMO-LAG 330-1 FIRE BARRIER ENVELOPE TESTINGAs a result of the concerns in Information Notices 91-47 and 91-79, TUinstituted a fire endurance testing program to qualify the Thermo-Lag firebarrier protective system specifically for its Comanche Peak Steam ElectricStation.' This testing was conducted during the weeks of June 15 and 22, 1992.The NRC witnessed the preparation of test specimens and the actual testing ofthe TU electric test articles.The tests consist of a series of 1-hour fire endurance tests on a variety ofcable tray and conduit "mock-ups". The "mock-ups" were designed to duplicateactual plant configurations. TU installed the fire barriers using stockmaterial and actual plant procedures and personnel.The first actual tests occurred on June 17,1i992. Three-quarter-inch, andone-inch and five-inch conduit configurations were tested. All tests passedAmerican Nuclear Insurers criteria, in that electrical cable continuity was -not lost. However, several temperature readings were above specifications forthe 3/4-inch and 1-inch conduit tests, and for a junction box that was commonto all the conduits. Additionally, subsequent investigation of the cablingrevealed evidence of charring and blistering. NRC standards require that theprotected components be free of fire damage.Preliminary information from the second test of a 12-inch cable trayconfiguration on June 18, -1992, showed satisfactory results. Thermocoupletemperatures on the protected cables were less than 325 'F.The third test was conducted on June 19, 1992. This article was a wide(30-inch) ladder back cable tray configuration. At 17 minutes into the test,the Thermo-Lag panel on the bottom of the test article began to sag and thestainless steel banding was carrying the load of the panel. At 18 minutes,the joint at the interface between the tray support and the tray showed signsof weakening and separation. Internal temperatures within areas of this cabletray assembly exceeded 325 'F at 25 minutes. The joint fully separated in41 minutes resulting in cable circuit integrity failure and fire damage to thecables..,.. ., .,;~~~ -, , I
Technical


Attachment 1_ , IN 92-46June 23, 1992c sUNITED STATES* of -t ¢NUCLEAR REGULATORY COMMISSION-WASHINGTON. D. C. 2555April 21, 1992MEMORANDUM FOR: William T. Russell, Assiciate Directorfor Inspection and Technical AssessmentOffice of Nuclear Reactor RegulationFROM: Thomas E. Murley, DirectorOffice of Nuclear Reactor RegulationSUBJECT: FINAL REPORT -SPECIAL REVIEW TEAM FOR THE REVIEW OFTHERMO-LAG FIRE BARRIER PERFORMANCEOn February 12, 1992, the special review team for the review of Thermo-Lagfire barrier performance met with the Nuclear Utilities Management andResources Council (NUMARC) to obtain a commitment for a coordinated industryresponse to our concerns. During the meeting, the team presented the resultsof its review and gave the attendees a proposed generic letter on Thermo-Lagfire barriers.By a letter of March 3, 1992; NUMARC committed to coordinate the industry'sefforts and requested additional technical information. The review team'sfinal technical report is enclosed for transmittal by your staff to NUMARC andthe vendor. The report, which has been reviewed by your staff, documents theresults of the team's review and provides the technical bases for its findingsand recommendations. The report identifies the full scope of the concerns andwill facilitate discussions between the staff and NUMARC needed to resolvetheir questions and proceed with the issuance of the proposed generic letter.The special review team is available to discuss its final report with you oryour staff at your convenience.Thomas E.ectorOffice of Nuclear Reactor RegulationEnclosure:As statedcc w/enclosure:J. Sniezek'"- 92X05120277--920421PDR REVGP ERONUMRCPDR
contacts:
Ralph Architzel, NRR (301) 504-2804 Patrick Madden, NRR (301) 504-2854 Attachments:  
S e PI j loC o 1. "Final Report -Special Review Team for the Review of Thermo-Lag


IN 92-46June 23, 1992 TU has established roving fire watches for Unit 1, in accordance.-with its FireProtection Manual. The roving fire watches cover plant areas where Thermo-Lagfire barrier configurations, similar to those'which failed, are used toprovide a fire endurance barrier'for safe-shutdown equipment.TSI is also instituting a fire endurance testing program. This programincludes testing a new installation technique required for cable traysinstalled with gap widths greater than 0.030 inches. The new seam joiningtechnique requires that either (1):stainless steel tie wires be placed throughthe stress skin'at specified intervals or (2) stress skin and a layer ofThermo-Lag.trowel grade material be placed over the entire seam length andbanded in place. Preliminary results of a June 9, 1992, test using the newseam joining technique (on seams without wide gaps) on a 36-inch cable traysystem and a 3/4-inch conduit assembly were considered successful by thevendor and testing laboratory.The NRC will provide additional information on these fire endurance testingprograms as it becomes available.AMPACITY DERATING CALCULATION ERRORIn April 1992, the Washington Public Power Supply System, the licensee forWashington Nuclear Project, Unit 2,-found a mathematical error in thecalculation of the ampacity derating factor for the Thermo-Lag fire barrierenclosure of cable trays in Industrial Testing Laboratories (ITL) IncorporatedTest Report ITL-82-5-355C. The error occurred when ITL adjusted the testcurrent to baseline temperatures of 40 0C ambient and 90 0C cable. Thisadjustment is required when tests are performed at different ambient and cabletemperatures. ITL used the correct equation for adjusting to temperatureparameters that differ from the Insulated Cable Engineers Association (ICEA)publication P-46-426: I' = I X MF (where "I" is at 40 "C ambient and 90 "Ccable temperature, and "I'" is at other ambient and cable temperatureconditions). However, in calculating II," ITL multiplied WI'" by "MF" insteadof dividing. The NRC determined that the ampacity derating factor will changefrom 18 to 33 percent when the mathematical error is corrected. Whilereviewing other ITL test reports, the NRC staff found similar errors in othercalculations performed by ITL in the adjustment equation for ambient and cabletemperature conditions. The NRC also noted that the baseline currentsobtained from the test vary widely (up to 32 percent) from those published inthe ICEA publication P-54-440.I It ,
Fire Barrier Performance," April'21, 1992 2. List of Recently Issued NRC Information
WUIN 92-46June 23, 1992 This information notice requires nonspecific action or written response. Ifyou have any questions about the information in this notice, please contactone of the technical contacts listed below or the appropriate Office ofNuclear Reactor Regulation (NRR) project manager.i.CCar es E. Rossi, Direct oDivision of Operational Events Assessment-Office of Nuclear Reactor Regulation'.Technical contacts: Ralph Architzel, NRR(301) 504-2804Patrick Madden, NRR(301) 504-2854Attachments: S e PI j loC o1. "Final Report -Special Review Team for the Review of Thermo-Lag FireBarrier Performance," April'21, 19922. List of Recently Issued NRC Information Notices


}}
Notices}}


{{Information notice-Nav}}
{{Information notice-Nav}}

Revision as of 13:09, 31 August 2018

Thermo-Lag Barrier Material Special Review Team Final Report Finding, Current Fire Endurance Tests, and Ampacity Calculation Errors
ML031200204
Person / Time
Site: Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant  Entergy icon.png
Issue date: 06/23/1992
From: Murley T E
Office of Nuclear Reactor Regulation
To:
References
IN-92-046, NUDOCS 9206150492
Download: ML031200204 (5)
v • d • e


'p -UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 June 23,-1992 NRC INFORMATION

NOTICE 92-46: THERMO-LAG'FIRE

BARRIER MATERIAL SPECIAL REVIEW TEAM .FINAL REPORT FINDINGS, CURRENT-FIRE ENDURANCE

TESTS, AND AMPACITY' ' CALCULATION

ERRORS

Addressees

All holders of operating

licenses or construction

permi~ sfor'nuclear

power reactors.

_ _PurDose The U.S. Nuclear Regulatory

Commission (NRC) is-issuing

this information

notice to inform addressees

of (1)-the findings of the NRC's Thermo-Lag

Special Review Team, (2) current Thermo-Lag

330 fire resistance

testing being conducted

by Texas Utilities (TU) and Thermal Science; Inc. (TSI),--and

(3)errors found in the calculation

of cable ampacity derating factors for Thermo-Lag fire resistive

barriers.

It is expected that recipients ,will review the information

for applicability

to their facilities

and consider actions', as-appropriate, to avoid similar problems.

However, suggestions

contained

in -this information

notice are not-NRC requirements;

therefore, no specific action or written response is required.Discussion

FINAL REPORT BY THE SPECIAL REVIEW TEAM FOR THE REVIEW OF THERMO-LAG

FIRE BARRIER PERFORMANCER

The NRC has been reviewing

the qualification

of Thermo-Lag-'330-1 fire barrier systems. The NRC previously

issued two information

notices on these fire barrier systems: (1) Information

Notice'91-47, "Failure 6f Thermo-Lag

Fire Barrier Material to Pass Fire Endurance

Test," August 6, 1991, and (2)Information

Notice 91-79, "Deficiencies

in the Procedures

for Installing

Thermo-Lag

Fire Barrier Materials,'

December 6, 1991.On February 12, 1992,'the

NRC's Special Review Team for the review of Thermo'Lag fire barrier performance

met with the'Nuclear

Utilities

Management

and'Resources

Council (NUMARC) to discuss the coordination

of the industry's

-response to Th'ermo-Lag

fire endurance, installation, and-ampacity

concerns.During the meeting, the staff provided NUMARC'a proposed draft generic letter on the Thermo-Lag

fire barrier issue for review and comment. The draft-generic letter was included in-the-meeting

minutes which were placed in the Public Document Room as an enclosure

to a February 24, 1992, letter to NUMARC In a letter of March 3, 1992, NUMARC commented

on the proposed draft generic 9206150492 PD R 5O g -\n' 3a

I L r -, I IN 92-46 June 23, 1992 letter and committed

to coordinate

the industry's

efforts associated

with the issues involving

Thermo-Lag.

In addition, NUMARC requested

that the NRC make available

any additional.

information

on the qualification

of these barriers.In response to this request, the NRC provided NUMARC the "Final Report-Special Review Team for the Review of Thermo-Lag

Fire Barrier Performance," of April 21, 1992, (Attachment

1). The final report concluded

that some licensees

have not adequately

reviewed and evaluated

the fire endurance

and ampacity test results for applicability

to the Thermo-Lag

fire barrier systems installed-in

their facilities.

In addition, the final report stated that some facilities

have used inadequate

installation

procedures

to construct

Thermo-Lag fire barriers on electrical

raceways and equipment.

CURRENT THERMO-LAG

330-1 FIRE BARRIER ENVELOPE TESTING As a result of the concerns in Information

Notices 91-47 and 91-79, TU instituted

a fire endurance

testing program to qualify the Thermo-Lag

fire barrier protective

system specifically

for its Comanche Peak Steam Electric Station.'

This testing was conducted

during the weeks of June 15 and 22, 1992.The NRC witnessed

the preparation

of test specimens

and the actual testing of the TU electric test articles.The tests consist of a series of 1-hour fire endurance

tests on a variety of cable tray and conduit "mock-ups".

The "mock-ups" were designed to duplicate actual plant configurations.

TU installed

the fire barriers using stock material and actual plant procedures

and personnel.

The first actual tests occurred on June 17,1i992.

Three-quarter-inch, and one-inch and five-inch

conduit configurations

were tested. All tests passed American Nuclear Insurers criteria, in that electrical

cable continuity

was -not lost. However, several temperature

readings were above specifications

for the 3/4-inch and 1-inch conduit tests, and for a junction box that was common to all the conduits.

Additionally, subsequent

investigation

of the cabling revealed evidence of charring and blistering.

NRC standards

require that the protected

components

be free of fire damage.Preliminary

information

from the second test of a 12-inch cable tray configuration

on June 18, -1992, showed satisfactory

results. Thermocouple

temperatures

on the protected

cables were less than 325 'F.The third test was conducted

on June 19, 1992. This article was a wide (30-inch)

ladder back cable tray configuration.

At 17 minutes into the test, the Thermo-Lag

panel on the bottom of the test article began to sag and the stainless

steel banding was carrying the load of the panel. At 18 minutes, the joint at the interface

between the tray support and the tray showed signs of weakening

and separation.

Internal temperatures

within areas of this cable tray assembly exceeded 325 'F at 25 minutes. The joint fully separated

in 41 minutes resulting

in cable circuit integrity

failure and fire damage to the cables..,.. ., .,;~~~ -, , I

Attachment

1_ , IN 92-46 June 23, 1992 c sUNITED STATES* of -t ¢NUCLEAR REGULATORY

COMMISSION

-WASHINGTON.

D. C. 2555 April 21, 1992 MEMORANDUM

FOR: William T. Russell, Assiciate

Director for Inspection

and Technical

Assessment

Office of Nuclear Reactor Regulation

FROM: Thomas E. Murley, Director Office of Nuclear Reactor Regulation

SUBJECT: FINAL REPORT -SPECIAL REVIEW TEAM FOR THE REVIEW OF THERMO-LAG

FIRE BARRIER PERFORMANCE

On February 12, 1992, the special review team for the review of Thermo-Lag

fire barrier performance

met with the Nuclear Utilities

Management

and Resources

Council (NUMARC) to obtain a commitment

for a coordinated

industry response to our concerns.

During the meeting, the team presented

the results of its review and gave the attendees

a proposed generic letter on Thermo-Lag

fire barriers.By a letter of March 3, 1992; NUMARC committed

to coordinate

the industry's

efforts and requested

additional

technical

information.

The review team's final technical

report is enclosed for transmittal

by your staff to NUMARC and the vendor. The report, which has been reviewed by your staff, documents

the results of the team's review and provides the technical

bases for its findings and recommendations.

The report identifies

the full scope of the concerns and will facilitate

discussions

between the staff and NUMARC needed to resolve their questions

and proceed with the issuance of the proposed generic letter.The special review team is available

to discuss its final report with you or your staff at your convenience.

Thomas E.ector Office of Nuclear Reactor Regulation

Enclosure:

As stated cc w/enclosure:

J. Sniezek'"- 92X05120277--920421 PDR REVGP ERONUMRC PDR

IN 92-46 June 23, 1992 TU has established

roving fire watches for Unit 1, in accordance.-with

its Fire Protection

Manual. The roving fire watches cover plant areas where Thermo-Lag

fire barrier configurations, similar to those'which

failed, are used to provide a fire endurance

barrier'for

safe-shutdown

equipment.

TSI is also instituting

a fire endurance

testing program. This program includes testing a new installation

technique

required for cable trays installed

with gap widths greater than 0.030 inches. The new seam joining technique

requires that either (1):stainless

steel tie wires be placed through the stress skin'at specified

intervals

or (2) stress skin and a layer of Thermo-Lag.trowel

grade material be placed over the entire seam length and banded in place. Preliminary

results of a June 9, 1992, test using the new seam joining technique (on seams without wide gaps) on a 36-inch cable tray system and a 3/4-inch conduit assembly were considered

successful

by the vendor and testing laboratory.

The NRC will provide additional

information

on these fire endurance

testing programs as it becomes available.

AMPACITY DERATING CALCULATION

ERROR In April 1992, the Washington

Public Power Supply System, the licensee for Washington

Nuclear Project, Unit 2,-found a mathematical

error in the calculation

of the ampacity derating factor for the Thermo-Lag

fire barrier enclosure

of cable trays in Industrial

Testing Laboratories (ITL) Incorporated

Test Report ITL-82-5-355C.

The error occurred when ITL adjusted the test current to baseline temperatures

of 40 0 C ambient and 90 0 C cable. This adjustment

is required when tests are performed

at different

ambient and cable temperatures.

ITL used the correct equation for adjusting

to temperature

parameters

that differ from the Insulated

Cable Engineers

Association (ICEA)publication

P-46-426:

I' = I X MF (where "I" is at 40 "C ambient and 90 "C cable temperature, and "I'" is at other ambient and cable temperature

conditions).

However, in calculating

II," ITL multiplied

WI'" by "MF" instead of dividing.

The NRC determined

that the ampacity derating factor will change from 18 to 33 percent when the mathematical

error is corrected.

While reviewing

other ITL test reports, the NRC staff found similar errors in other calculations

performed

by ITL in the adjustment

equation for ambient and cable temperature

conditions.

The NRC also noted that the baseline currents obtained from the test vary widely (up to 32 percent) from those published

in the ICEA publication

P-54-440.I It ,

WU IN 92-46 June 23, 1992 This information

notice requires nonspecific

action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager.i.C Car es E. Rossi, Direct o Division of Operational

Events Assessment- Office of Nuclear Reactor Regulation'.

Technical

contacts:

Ralph Architzel, NRR (301) 504-2804 Patrick Madden, NRR (301) 504-2854 Attachments:

S e PI j loC o 1. "Final Report -Special Review Team for the Review of Thermo-Lag

Fire Barrier Performance," April'21, 1992 2. List of Recently Issued NRC Information

Notices


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