ML20101G126
| ML20101G126 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 12/14/1984 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | Deyoung R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| Shared Package | |
| ML20101G133 | List: |
| References | |
| 9531N, NUDOCS 8412270428 | |
| Download: ML20101G126 (2) | |
Text
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Address Reply to: Post Offics Box )67
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- December 114, 1984-r
.Mr.
R..C. DeYoung,-Director ~
- Office of' Inspection and : Enforcement F~ Washington,?DC 20055
Subject:
Byron Generating Station U' nits.1 and 2 Independent Design' Inspection
~NRCEInspection-Report No'.' 50-454/83-32
-t ReferenceL(a):
October 19, 1984 letter from T. R.-Tramm C
to R. C. DeYoung 3
Dear:
Mr. DeYoung:-
This letter provides additional information'in response to-the:NRC's' Finding 2-1 which was identified during the Byron
-Integrated Design-Inspection.-
Enclosed.is revision 3 of Sargent and.
-Lundy calculation 3C8-1281-001, " Auxiliary Building Flood ~ Level Calculations".
Review of-this-calculation should enable the NRC to
- the actions taken to address Finding 2-19.
Only minor changes have been.made in revision 3 of this report.
The changes are noted by-change bars in the right margin.
Specifically, the flood level predictions in 4 zones have been-reduced based on more realistic mdeling'of-~the worst; case breaks or cracks.
'The blowdown condenser rooms-(zones S3-3A and S3-3B)'were
-. originally.modeled with both the normal blowdown path and the
' alternate: blowdown path open.
In reality only one path is used and-this-correction led to significantly lower levels.
The positive 1 displacement charging pump rooms (zones S3-9A and S3-98) were Loriginally calculated. assuming a break in a location'which would
.a110w backflow'from the-centrifugal charging pumps.
This location was determined to be a low stress point where no break postulation
'was required.
The calculations for these areas were refined because the floorislab capability was in question with the original levels due to the-combination of floodiload and equipment loads,1and further
' assessment of the effects of slab failure is more difficult than
- "4
' refinement of the flood level calculation.
With the current calculated flood = levels the floor slabs designs contain adequate
~ margin.-
- Please address further questions regarding this matter to p ra m ik "n gg/
JJ-u :
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22-this office..
. One signed original.and' fifteen copies of _this letter are
- provided for.NRC; review.
Very-truly yours, fik f/W T. R. Tramm Nuclear Licensing Administrator cc:'
O. Norkin 9531N P