ML20003G138
| ML20003G138 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 04/24/1981 |
| From: | Delgeorge L COMMONWEALTH EDISON CO. |
| To: | Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8104280349 | |
| Download: ML20003G138 (2) | |
Text
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Commonwealth Edison O One First Natcnal Ptaza. Chicago. t!hnor Accress Repty to: Post Ottee Box 767 Chcago, Ilhnois 6069o A
fyN s April 24, 1981
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[%APR 2 7198]m Mr. A. Schwencer, Chief k Licensing Branch 2 g Division of Licensing ut -
U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
LaSalle County Station Units 1 and 2 Thermal Recombiner Effectiveness NRC Docket Nos. 50-373/374
Dear Mr. Schwencer:
Pursuant to a request maae by the Containment Systems Branch (Mr. F. Eltawila) on April 20, 1981, the following information is submittted.
- 1. Inerting the primary containment has no effect on the efficiency of the LSCS thermal recombiners. These recombiners are guaranteed to recombine all available oxygen and hydrogen present down to one-tenth of one percent by volume of the minority gas available, irrespective of other constituent gases inside containment.
- 2. The design capacity of the thermal recombiners is based upon combining 6 SCFM of hydrogen with 3 SCFM of oxygen. This ba'ss uses an inflow of 150 SCFM total gas composed of up to 4 percent hyorogen and unlimited oxygen (150 SCFM times 4% hydrogen yields 6 SCFM hydrogen). In the inerted atmosphere, the inlet gas mixture is assumed to have up to 5 percent oxygen and unlimited hydrogen. To limit the total recombination to 3 SCFM oxygen with 6 SCFM hydrogen, the in!et gas flow is reduced to 60 SCFM (60 SCFM times 5 percent oxygen yields 3 SCFM oxygen). This reduction to 60 SDFM flow is accomplished remotely from the control room. The design flow of 150 SCFM through the blower-preheater-and reaction chamber is maintained simply by opening a recircLlation valve (from the control room) whenever the inlet flow is reduced to 60 SCFM rate. This recirculation mode of operation is discussed in the manufacturer's report AI-77-55, which the NRC Staff has previously been provided.
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In the event your Staff should have any further questions in this regard, please direct them-to this office.
1 Very truly yours, L. O. DelGeorge Nuclear Licensing Administrator cc: NRC Resident Inspector - LSCS 25498 4
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