ML20212P961
| ML20212P961 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 01/14/1987 |
| From: | Ainger K COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 2630K, NUDOCS 8702020099 | |
| Download: ML20212P961 (2) | |
Text
=_ - _
/m} Commonwealth Edison One First National Plaza Chicago, Illinois
<2 Address Fleply to: Post Office Box 767 e
3
'^%/ Chicago, lilinois 60690 - 0767 January 14, 1987 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC.
20555
Subject:
Byron Station Units 1 and 2 Essential Service Water System Cooling Towers NRC Docket Nos. 50-454 and 50-455
Reference:
(a) November 3, 1986 letter from K.A. Ainger to H.R. Denton
Dear Mr. Denton:
This is to provide additional information regarding the essential service water system cooling towers. Reference (a) described the predicted heat removal ccpability of the cooling towers based on available preoperational testing data. As stated in reference (a), data collected and analyzed on the cooling towers supports two unit operation with four cells available and no tornado warning in effect while the outdoor wet bulb is less than or equal to 77.5'F.
If a tornado warning were in effect such that only three cells were postulated to be available during an accident, two unit operation would be justified if the outdoor wet bulb temperature is less than 67.8'F.
For conservatism, one unit will be placed in Id shutdown if the wet bulb temperature exceeds 75*F with no tornado warning
. effect and one unit will be placed in cold shutdown if the wet bulb temperature exceeds 65'F with a tornado warning in effect.
Although reference (a) states that four fans are required to be
)
available for 78'F operation, we are not intending to relax the requirement in i
the Technical Specifications for six fans to be available for two unit operation.
A performance test program for the essential service water cooling i
towers is being planned for the time period between April and August of 1987.
The earliest time that we expect to collect operating data from the towers is late April or early May.
Data collection will probably continue through the i
summer to refine the tower performance estimate. A report containing the results of the test program is expected to be issued in September, 1987.
If 1
data collection has not been initiated in the late April /early May time frame, we will notify the NRC by letter regarding the reason for the delay.
l 1
J Apf 8702020099 870114 ff PDR ADOCK 05000454 gL P
- f0 i
I a
., Any revisions to the testing schedule outlined above will not 'oe made without prior NRC approval.
Please direct any questions regarding this matter to'this office.
Very truly yours,
[
K. A. Ainger Nuclear Licensing Administrator
/klj cc: Byron Resident Inspector Region III Office 2630K i
1 4
i e
-