ML20056G180

Documents 930722 Telcon W/Util Re Thermo-Lag Mfg Specs.Info Did Not Change NRC Previous Conclusions Re Thermo-Lag Fire Barriers or Affect NRC Ongoing Review Activities

ML20056G180
Person / Time
Site:	Comanche Peak
Issue date:	08/17/1993
From:	Black S Office of Nuclear Reactor Regulation
To:	William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
References
TAC-M85536, TAC-M85537, NUDOCS 9309020205
Download: ML20056G180 (3)

Text

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• • • • • August 17, 1993 Docket Nos. 50-445 and 50-446 l

Mr. William J. Cahill, Jr.

Group Vice President, Nuclear TU Electric Company 400 North Olive Street, L.B. 81 Dallas, Texas 75201

SUBJECT:

THERM 0-LAG FIRE BARRIER MATERIALS PROVIDED BY THERMAL SCIENCE, l INCORPORATED FOR USE AT COMANCHE PEAK STEAM ELECTRIC STATION UNITS 1 l AND 2 (TAC NOS. M85536 AND M85537)

The purpose of this letter is to document the discussions between the NRC staff and TU Electric related to Thermo-Lag manufacturing specifications.

l During a conference call of July 22, 1993, we discussed several issues, which stemmed from a letter of January 21, 1993, from Thermal Science, Incorporated (TSI), to TU Electric, with your staff and consultants. After reviewing the letter and discussing the information in question with your staff, we 3 determined that the information did not change our previous conclusions regarding Thermo-Lag fire barriers or affect our ongoing review activities.

During the conference call, your staff and consultants informed us that the letter of January 21, 1993, addressed manufacturing changes implemented by TSI for flat panels (those without "V" ribs) and preshaped conduit sections. The changes, which were made at TU Electric's request, were: (1) the production molds were modified to obtain better control of the placement and shape of the stress skin while the Thermo-Lag material was poured and cured, (2) the edges of panels were truad to improve packaging and to protect their edges from damage during handling, (3) over-specification panels were ground down to the proper specified thickness after curing, and (4) extra care was taken to control the roundness of the preshaped conduit sections.

Your staff and consultants also informed us that the manufacturing changes i were part of your continuing efforts to obtain consistent Thermo-Lag materials. Details of previous actions taken by TU Electric in this regard i were documented in a letter of December 15, 1993 (TXX-92589), to the NRC. We addressed this letter in Supplemental Safety Evaluation Report 26 (SSER 26) of February 1993. Your staff stated that your objectives were to reduce manufacturing defects, reduce waste during construction, and simplify and improve fire barrier construction. For exarrple your staff stated that by modifying the molds for the flat panels to keep the stress skin flat and firmly in place, TSI was able to eliminate waviness from the panels. The resulting straight, flat panels were easier to cut to shape and to install on raceways. Similarly, extra care in forming the preshaped conduit sections I during the manufacturing process reduced waste and facilitated their installation. During the conference call, your staff also confirmed that the Thermo-Lag materials used for the Comanche Peak Steam Electric Station fire 9309020205 DR 930817 ADOCK 05000445

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Mr. William J. Cahill, Jr. August 17, 1993 tests were representative of the materials installed in Comanche Peak Steam Electric Station Unit 2. This is consistent with SSER 26. On the basis of our assessment of this information we concluded that the manufacturing improvements would not materially enhance or improve the fire endurance '

capabilities of either the basic Thermo-Lag materials or the finished fire i barriers.

Please contact Tom Bergman at (301) 504-1330 if you have a different understanding of any of the issues documented in this letter.

Sincerely, Original Signed By Suzanne C. Black, Director Project Directorate IV-2 Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation cc: See next page DISTRIBUTION Docket'.cile '

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Mr. William J. Cahill, Jr. August 17, 1993 cc:

Senior Resident Inspector Jack R. Newman, Esq.

U.S. Nuclear Regulatory Commission Newman & Holtzinger P. O. Box 1029 1615 L Street, N.W.

Granbury, Texas 76048 Suite 1000 Washington, D. C. 20036 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Chief, Texas Bureau of Radiation Control 611 Ryan Plaza Drive, Suite 1000 Texas Department of Health Arlington, Texas 76011 1100 West 49th Street  ;

Austin, Texas 787Fr Mrs. Juanita Ellis, President Citizens Association for Sound Energy Honorable Dale McPherson 1426 South Polk County Judge Dallas, Texas 75224 P. O. Box 851 Glen Rose, Texas 76043 Owen L. Thero, President Quality Technology Company P. O. Box 408 201 West 3rd Lebo, Kansas 66856-0408 Mr. Roger D. Walker, Manager Regulatory Affairs for Nuclear Engineering Organization Texas Utilities Electric Company 400 North Olive Street, L.B. 81 Dallas, Texas 75201 Texas Utilities Electric Company c/o Bethesda Licensing 3 Metro Center, Suite 610 Bethesda, Maryland 20814 William A. Burchette, Esq.

Counsel for Tex-La Electric Cooperative of Texas Jorden, Schulte, & Burchette 1025 Thomas Jefferson Street, N.W.

Washington, D.C. 20007 GDS Associates, Inc.

Suite 720 1850 Parkway Place Marietta, Georgia 30067-8237