Information Notice 1992-46, Thermo-Lag Barrier Material Special Review Team Final Report Finding, Current Fire Endurance Tests, and Ampacity Calculation Errors

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
Issue date:	06/23/1992
From:	Murley T Office of Nuclear Reactor Regulation
To:
References
IN-92-046, NUDOCS 9206150492
Download: ML031200204 (5)

'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