ML19282C222
| ML19282C222 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 03/19/1979 |
| From: | Naughton W COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7903220242 | |
| Download: ML19282C222 (5) | |
Text
Commonwealth Edison f
( (Q One First National Plaza. Chicago, lilinois t
A7/f Address Reply to: Post Office Box 767 W# Chicago, Illinois 60690 March 19, 1979 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Zion Station Units 1 and 2 Additional Information on Proposed Expansion of Spent Fuel Storage Capacity NRC Docket Nos. 50-295 and 50-304 References (a) :
October 24, 1978 letter from W.
F.
Naughton to Director of Nuclear Reactor Regulation (b):
March 7, 1979 letter from W.
F.
Naughton to H. R. Denton-
Dear Mr. Denton:
Recently, the NRC Staff requested Commonwealth Edison Company to provide additional'information in support of its request to expand the storage capacity of the Zion Unit 1 and 2 spent fuel pool.
Specifically, the NRC Staff requested additional information with regard to Commonwealth Edison's plans to extend the time between refuelings (Question 7 in Reference (a)) and loads to be carried over the storage racks (Question 1 in Reference (b)).
Attachment I to this letter contains Commonwealth Edison's responses to the NRC Staff's requests.
Please address any additional questions that you might have to this office.
One (1) signed original and thirty-nine (39) copies of this letter are provided for your use.
Very truly yours, o202'/[
William F. Naugh n
Nuclear Licensing Administrator Pressurized Water Reactors attachment
ZION STATION UNITS 1 AND 2 NRC DOCKET NOS. 50-295 AND 50-304 ATTACHMENT I Additional Information on Proposed Expansion of Spent Fuel Storage Capacity
Commonwealth Edison NRC Docket Nos. 50-295/304 ATTACHMENT I Question 7
" Discuss any. plans to extend the time between refuelings."
Supplemental Response Commonwealth Edison Company has evaluated longer operating cycles for the Zion units.
These analyses have indicated no net economic advantage for the longer cycles.
However, Commonwealth Edison will continue to update these studies as the various input factors change.
Thus, cycles longer than twelve (12) months may be used in the future.
The number of spent fuel assemblies discharged annually in alternate cycle schemes studied to date is higher than for the twelve (12) month scheme as shown below:
Cycle Length Number of Assemblies Discharged (Months)
Per Cycle Per Year 12 59 59 14 70 60 16 82 61.5 18 94 62.7 Question 1
" Describe in detail the loads to be carried over the storage racks."
Supplemental Response In Reference (b), Commonwealth Edison Company indicated that to keep the ki.netic energy of any dropped tools within the range analyzed movements of tools over spent fuel would be administratively controlled to maintain the tools within two feet of the racks.
Per additional discussions with the NRC Staff, Commonwealth Edison agrees that the aforementioned administrative control can be incorporated into the Zion Station Technical Specifications.
Commonwealth Edison NRC Docket Nos. 50-295/304
. In addition, per discussions with the NRC Staff, Commonwealth Edison discovered a couple of errors in Table 1-1 of Reference (b).
Attached is Revision 1 of Table 1-1.
This revised table includes corrections of those errors and also includes the loaded design factor of the hoisting system.
e
TABLE l-1 SFHT BPT RCC TP Max. Drop of Empty Tool Over Storage Racks (ft) 15.3 14.2 13.2 16.5 Empty Tool Wt. (lbs) 352 800 975 235 Max. Kinetic Energy at Impact (ft-lbs) 5350 11360 12870 3876 Max. Drop Height Loaded Tool Over Racks (ft) 2 2
2 2
Max. Weight Loaded Tool (lbs) 1932 840 1125 275 Max. Kinetic Energy at Impact (ft-lbs) 3864 1680 2250 550 Unloaded Tool Wir( Rope Design Factor 352/43600 800/43600 975/43600 235/43600 Loaded Tool Wire Rope Design Factor 1932/43600 840/43600 1125/43600 275/43600 Design Factor of Tool Connection (loaded) 5:1 5:1 5:1 5:1 Design Factor of Hoisting System (unloaded) 28:1 12.5:1 10.25:1 43:1 Design Factor of Hoisting System (loaded) 5:1 12:1 9:1 36:1 SFHT - Spent Fuel Handling Tool BPT
- Burnable Poison Tool RCC
. Thimble Plug N<~
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