ML20086R951
| ML20086R951 | |
| 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 | |
| 8186N, NUDOCS 8403010286 | |
| Download: ML20086R951 (2) | |
Text
c,
) one First Nttionit Plats, Crucago, litmois 7
Address Reply to: Post Office Box 767
(
CNcago, lilinois 60690
.a February 22, 1984 q
,Mr.1 Harold R. Denton, Director Office of Nuclear Reactor Regulation iU.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Byron Generating Station Units 1 and 2 Braidwood Generating Station Units 1 and 2 Effects of Local Intense Precipitation NRC Docket-Nos. 50-454, 50-455, 50-456, and 50-457
Dear Mr. Denton:
This.is to provide additional information regarding the effects nf Lof-local. intense precipitation at Byron and Braidwood stations.
This information is provided to -resolve Confirmatory Issue A.2 identified in the Braidwood SER.
Corresponding revisions to the Byron /Braidwood FSAR 4
Lwillsbe~made at~the. earliest opportunity.-
. Section.2.4.2.3:of.the Byron /Braidwood FSAR documents the analyses of flood levels adjacent-to plant buildings during a probable
. maximum precipitation. event.
For both plants, it is estimated that the l
. water ~ level can reach.an elevation above the grade floor level for short
, periods during these rare evetns.
.o1preventLthis water from directly-entering buildings where T
< essential.equipmenttis located, reinforced concreto-curbs are provided at
. exterior grade floor level doors and hatches.-
Interior grade floor level y*
doors between the turbine building and auxiliary building are generally 5
kept' closed.-. There are no= curbs at the-various turbine building grade i evel doors'. 'Any water entering through the turbine building exterior lidoorways would most likely drain to lower elevations through numerous Jopenings in thesgrade11evel floor. 'Little or no water is expected to 3 reach the interior auxiliary-building doors ~.
16
~
The two grade level interior doorstare. controlled access points
'tolthe; auxiliary; building; They-are'normally closed'and are constantly
""monitoredHas described in our~ security; plans.
At-Byron for_a short jperiod'when UnitL1.is in operationtand Unit:2 is-still under construction, It-
- the Unit 2 door willinot be part'of.the controlled access boundary.
i Lwill,Lhowever', be kept closedLand either an hourly' security patrol will verify thatLit'has not been blocked open or a watchman will bo posted at
'the-door. 'At Braidwood,- the Unit 2 door will be controlled when Unit 1
-:goesfintoroperation, so this interim administrative control is L
' unnecessary.
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H.'R'. Denton February 22, 1984 Please address further questions regarding this matter to this office.
. One. signed original and fifteen copies of this letter and provided for NRC review..
Very truly yours, 77(2, %==
T. R. Tramm
Nuclear Licensing Administrator
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