ML20087K366
| ML20087K366 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 02/22/1984 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 8185N, NUDOCS 8403260132 | |
| Download: ML20087K366 (2) | |
Text
_- -.
[; ] oni First Nttional Plata. Chictgo. Ilknps Commonwealth Edison (O
Adoress Reply to. Post Office Box 767 Chicago. Illinois 60690 February 22, 1984 Mr. Harold R. Denton, Directai Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Byron Generating Station Units 1 and 2 Braidwood Generating Station Units 1 and 2 Hydrogren Recombiners NRC Docket Nos. 50-454, 50-455, 50-456, and 50-457
Dear Mr. Denton:
This letter provides additional information regarding the design of hydrogen recombiners at Byron and Braidwood stations as described in Section 6.2.5 of the Byron SER.
As indicated on the attached diagram, there are two hydrogen rccombiners permanently installed at each station.
Though cross-ties, 01ther recombiner may be used on either unit.
The suction and discharge valve operators are powered from opposite division Class 1E power supplies.
They are not powered from a common power supply because cortain single failures in that configuration could compromise recombiner system effectiveness.
The present electrical division assignments prevent backflow through a failed recombiner.
As presently arranged, both hydrogen recombiners operate in parallel, utilizing the same suction and exhaust piping for each containment.
With a Class 1E power supply failure, sufficient redundancy exists to operate at least one recombiner at design ctpacity.
If.each recombiner and its suction and discharge valves were powered from the same supply, a single failure of either Class lE power supply could prevent isolation of the associated recombiner piping circuit.
Flow from the redundant recombiner would follow the path of least resistance and backflow through the failed recombiner.
The design flow rate of air from the containment would not be achieved.
Please address further questions regarding this matter to this office.
One signed original and fifteen copies of this letter and the diagrams are provided for NRC review.
Very truly yours, fr W
~
T.
R.
Tramm Nuclear Licensing Administrator
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DIAGRAM OF OFF-GAS SYSTEM - HYDROGEN RECOMBINERS i