U-600182, Requests Deviation from Branch Technical Position Cmeb 9.5.1 Re Internal Sealing of Fire Barrier Penetration Conduits. Openings Inside Conduits Larger than 4 Inches Would Be Sealed at First Accessible Points of Fire Barrier
| ML20132E723 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 07/16/1985 |
| From: | Spangenberg F ILLINOIS POWER CO. |
| To: | Butler W Office of Nuclear Reactor Regulation |
| References | |
| U-600182, NUDOCS 8507180059 | |
| Download: ML20132E723 (2) | |
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'A U-600182 L30-85 ( 07-16)--L B51-85 ( 07-l@ -L IA.120 ILLINOIS POWER COMPANY IP CLINTON POWER STATION. P.o. 80x 678, CLINTON. ILUNoIS 61727 July 16, 1985
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Docket No. 50-461 Director af Nuclear Reactor Regulation Attn:
Mr. w. R. Butler, Chief Licensing Branch No. 2 Division of Licensing U.S. Nuclear Regulatory Commission Washington, DC 20555 Subj ect: Clinton Power Station Unit 1 Deviation Request Concerning Internal Sealing of Conduits
Dear Mr. Butler:
The Branch Technical Position CMEB 9.5.1, Section C.5.a(3),
recommends that:
" Openings inside conduit larger than 4 inches in diameter should be scaled at the fire barrier penetration."
Illinois Power (IP) intends to deviate from the above recommendation.
It is IP's position to seal openings inside conduits larger than four inches in diameter at their first accessible points on both sides of the fire barrier. This would provide an adequate fire stop to maintain the fire resistance of the fire barrier and prevent the passage of smoke and hot gases. The following are justifications for IP's position based on a review performed by Sargent and Lundy. The results of this review are documented in letter SLMI-Y6287, dated June 21, 1985, R. A. Parson to H. R. Victor.
1.
A conduit, although it will act as a thermal conductor through a fire barrier, will not be in contact with combustibles outside the conduit.
A fire will not propagate through the fire barrier since the outside of the conduit will be sealed at its penetration through the barrier.
2.
The propagation of fire from hot gases and pyrolysis of cable insulation within the conduit cannot occur because the ends of the conduit where it opens to the rooms on either side of the fire barrier will be scaled.
3.
Conduits scaled in this manner will be easily accccsible for surveillance. Conduit seals at a fire barrier will either bc inaccessible or extremely difficult to access for surveillance purposes.
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U-600182' L30-85 ( 07-16)-L B51-85 ( 07-16)-L 1A.120 4.
The structural integrity of the conduit in the event of a fire is assured since the peak temperature of the ASTM E-119 standard time-temperature curve for a 3-hour fire endurance test (1925'F) is well below the melting point of the steel conduit (>2500'F) used at the Clinton Power Station Unit 1.
For the reasons listed above, IP requests your approval of this deviation by August 2, 1985.
Sincere 4 yours J
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pan nber Director - uclear Licensing and Configuration Nuclear Station Engineering DWW/ lab cc:
B. L. Siegel, NRC Clinton Licensing Project Manager NRC Resident Office Regional Administrator, Region III USNRC Illinois Department of Nuclear Safety m