ML19323G056
| ML19323G056 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 05/22/1980 |
| From: | Peoples D COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8005300314 | |
| Download: ML19323G056 (2) | |
Text
N Commonwealth Edison k v' )J Address Reply to: Post Othee Box 767 One First National Plaza. Chicago. thinois v Chicago. Illinois 60690 May 22, 1980 9
Mr. Harold R. Denton, Director Of fice of Nuclear Recctor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Zion Station Units 1 and 2 Containment Venting and Purging during Normal Operation NRC Docket Nos. 50-295 and 50-304 Reference (a):
December 14, 1979 letter from D.
L.
Peoples to H.
R. Denton
Dear Mr. Denton:
In Re ference (a), Commonwealth Edison Company' committed to comply with the NRC's " Interim Position for Containment Purge and Vent Valve Operation Pending Resolution of Isolation Valve Operability", as contained in the October 1979 letter to Commonwealth Edison.
In essence, Commonwealth Edison committed to maintain the purge valves in a closed position whenever the reactor was not in a cold shutdown or refueling mode until such time as the purge valves could be shown to close under DBA conditions.
Recently, Nutech Corporation, using torque data supplied by the valve manufacturer (Henry Pratt Company), has performed an analysis to show that:
1.
The valve actuators have sufficient torque capability to stroke the valves from. full open to full closed, within the technical specification time limit, against the design basis LOCA containment pressurizaton; and 2.
The valve structural elements have sufficient stress margins to withstand the concommitant loads imposed while closing, considering torsional shear, shear, bending, tension, compression and seismic loadings.
Based on these results, Commonwealth Edison has concluded that the 42" purge valves will properly close if required during a
-containment pressurization.
Therefore, the restrictions on purging, described above, have been removed for both Zion units.
However, as indicated in Reference (a), Commonwealth Edison continues to limit i
8005300 3lN @
Comm::nwulth Edison 4
1 4
l Mr. H. R. Denton, Director May 22, 1980 1
Page 2 purging to an absolute minimum, not to exceed 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> per year per unit.
In addition, other Administrative Controls currently in ef fect prohibit purging when the reactor is critical.
Commonwealth Edison also reaffirms that venting will be restricted to only those operations required to comply with Technical Specifications that limit containment pressure.
Please address any questions that you might have concerning this matter to this office.
One (1) signed original and thirty-nine (39) copies of this letter are provided for your use.
1 Very truly yours, I
h Y fu d
l D. L. Peop es Director of l
Nuclear Licensing I
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