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)

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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

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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.

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Attachment 1

_ , IN 92-46 June 23, 1992 c sUNITED STATES

-

• t of ¢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

I It ,

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

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

current to baseline temperatures

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.

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 PIj loCo

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