ML19209A099
| ML19209A099 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 09/25/1979 |
| From: | Peoples D COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7910020352 | |
| Download: ML19209A099 (1) | |
Text
Commonwealth Edison Cre F st Nat<cn.y Pfata Cycago Imnois
.f Address Reply 11 Post Ofhec Box 767 Chicago. lilino 4 60690 September 25, 1979 Dr. Ilarold R.
Denton, Director Of fice of Nuclear Reactor Regulation U.S.
Nuclear Regulatory Commission Washington, D.C.
20555
Subject:
Zion Station Units 1 and 2 Results of Vent Valve Analysis NRC Docket Nos. 50-295 and 50-304 References (a):
July 30, 1979 letter from C.
Reed to H.
R.
Denton (b):
August
.0, 1979 letter from C.
Reed to H.
R.
Denton
Dear Dr. Denton:
Per Reference (a), Commonwealth Edison Company provided the NRC Staff with a schedule for responding to the various staff issue 9 and concerns associated with purging and venting at Zion Station.
Reference (b) indicated that Commonwealth Edison would submit the results of an analysis of 10" vent valve closure capability under accident conditions as soon as it became available.
The results of this analysis follows.
Commonwealth Edison has determined that the 10" vent valves utilized at Zion Station are capable of closure against the 27 psig peak containment pressure.
The 10" vent valve is an air-
- operated, 150 pound gate valve.
The air cyclinder operator provides a closing force sufficient to overcome the maximum friction forces arising at the stem packing and at the disc seat due to the pressure differential.
Based on this information, Commonwealth Edison has concluded that the 10" vent valves will properly close if required during a containment pressurization.
Please address any questions that you may have concerning this matter to this office.
One (1) signed original and thirty-nine (39) copiesof}
this letter are provided for your use.
}
\\\\sD very truly yours,
,4tc31/26,
,t D.
L. Peopl' o
, gg Director of Nuclear Licensing
/
WFN:mae 7910020 35i.&