ML20134M598
| ML20134M598 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 02/07/1997 |
| From: | Jeffery Wood CENTERIOR ENERGY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 2434, NUDOCS 9702200311 | |
| Download: ML20134M598 (2) | |
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CENTERIOR ENERGY l
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%01 N. State Aoute 2 419 249-2300 John K, wood Oak Hart.ior OH 43449 FAX. 419021-8337 Vice Presdent. Nuclear I
Davis-BeS5e l
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Docket Number 50-346 i
License Number NPF-3 Serial Number 2434 i
February 7, 1997 United States Nuclear Regulatory Commission Document Control Desk Washington, D. C.
20555-0001 I
subject: Combustibility Testing of 3M Interan Material Ladies and Gentlemen During a meeting conducted at the Davis-Besse Nuclear Power Station (DBNPS) on May 9, 1996, and during a later meeting in Chicago on September 26, 1996, members of the NRC staff expressed concern over the potential combustibility of 3M Interam material. This material is planned for use as a Thermo-Lag replacement material for various fire barrier applications at DBNPS, including radiant energy shield applications inside containment. Following the September 26, 1996 meeting, in a conference call with the DBNPS Staff, the NRC Staff identified the Watts Bar Safety Evaluation Report, NUREG-0847, Supplement 18, l
Appendix FF, Section 6.2, pages 93-95, as the source of the NRC staff concerns regarding combustibility of 3M Interam material.
The DBNPS staff has obtained a copy of the NUREG-0847 reference for review and has determined that the issues identified concerned the use of the M-20 series of 3M Interam Material for radiant energy shields. The DBNPS plans to utilize the E-50 series (E-54c) of 3M Interam material for radiant energy shields, which includes a 2 mil stainless steel foil laminated to the material.
It is important to note that the compositions of the two products are dissimilar, and the fire resistances of the two products are achieved by two entirely different processes. The M-20 series is an intumescent, whereas the E-50 series employs an insulative endothermic reaction.
Generic Letter 86-10, "Implemente. tion of Fire Protection Requirements," section 3.6.2, in part, defines a noncombustible material as "...having a structural base of non-combustible material... with a surfacing not over 1/8-inch thick that has a flame spread rating not higher than 50 when measured using ASTM E-84 The E-50 series of 3M Interam base material has passed the ASTM E-136, l
" Behavior of Materials in a Vertical Tube Furnace at 750*C," testing l
requirements for noncombustible materials. This material has also passed the ASTM E-84, " Surface Burning Characteristics of Building Materials," testing g
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Docket Number 50-346 Ficanse Numbar NPF-3
. Serial Number 2434 Page 2 requirements for surface flame spread, with a flame spread rating of 0.7.
The ASTM E-136 and ASTM E-84 tests for the E-50 series of 3M Interam material were conducted by Omega Point Laboratories and Underwriters Laboratories Inc.,
1 respectively. The test reports have been received and reviewed by the DBNPS I
staff.
l Based on the satisfactory ASTM E-136 and E-84 test results for the E-50 series f
of 3M Interam Material, the DBNPS staff concludes this material to be acceptable I
for the construction of radiant energy shields. The referenced test reports are l
available onsite for future inspection or audit review.
This letter requires no specific NRC action or response. However, should you have any questions or require additional information, please contact Mr. James L. Freels, Manager - Regulatory Affairs at (419) 321-8466.
i Very truly yours, j
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MAR /laj
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cc A. B. Beach, Regional Administrator, NRC Region III A. G. Hansen, NRC/NRR Project Manager S. Stasek, NRC Region III, DB-1 Senior Resident Inspector 6
Utility Radiological Safety Board i
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