ML20235D986
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JUN 3 01972 Docket Nos. 50-254 and 50 265 l
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l Commonwealth Edison Company i
ATTN; Mr. Byron Lee, Jr.
J Assistant to the President Post Offica Box 767 Chicago, Illinois 60690 s
Centlemen.
Your responses dated October 22, 1971, and April 17, 1972, to questions regarding the spent fuel cask drop accident have been reviewed by our staff. To complete our evaluation, the following additional information is required.
1.
Provide an outline drawing of the cask which shows its principal dimensions and, the location of its center of gravity.
2.
The analysis apparently is based on the use of an 85-ton cask and to rake the analysis conservative a 100-ton cask was assumed. Discuss the limits of the analysis insofar as tha future changes in the waight, dimensions and locatios of the center of gravity of the cask.
3.
What is tne minimum cask impact area in the uncipped condition?
4.
Discuss the amuf=um possible drop heights of the cask over:
(a) the three-foot crushable mat and (b) the eight-inch crushable mat. Other than administrative concrois, whae provisions have been made to limit the drop bei hts to E
those assumed in the analysest 5.
Discuss what deceleration characteristics have 'oeen assumed for the pool water and how the crush strength value of the mat varies with impact velocity.
6.
Provide tne Hexcel Products Inc. identification numbers or other means of identification for the particular crushable mats utilized it. the eight-inch and three-foot
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8709250436 870921 PDR FOIA MENZ87-111 PDR
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J Commonwealth gdison Company AM 3 01972 7.
Discuss and provide further information which demonstrates that the cask cannot be tipped before being dropped and/or
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that the crushable sist will be adequate even if it is 4
dropped in the cipped condition. Will a single cask trunnion and a single' trunnion yoke support the weight of the caskt 8.
Check and resubmit your analysis which gives consistent.
values of cask weight, drop height, deceleration distance, velocity at instant of impact, and resisting force of the mat for both the eight-inch and three-foot mats.
9.
Are the eight-inch and three-foot dimensions of the crushable mats af ter they have been precrushed as indicated in Figure 1 of SK-720221-17 If so, indicate their heights
'wefore being precrushed.
10.
Does the honeycomb load-deflection curve (resistance function). shown on Figure 1 include the punching effect of the cask finst If not, correct this curve to include the effect of the fins. Also indicate the scale and units of the x and y axis of the curve.
11.
From the information presented, it appears tha'c the crushable structures will be sealed to prevent the entry of water. Discuss how the decelerating characteristics of the crushable'structuras would change if a leak-developed that results in filling the structures with water. What methods will be used to verify that there is no water in the crushable structures. Discuss the possibility of deterioration of the' epoxy adhesive used in the crushable structures and water seals over their lifetime. What inspections or other surveillance will be performed and at what frequency?
12.
Provide a numerical value for the natural period of the structure (T) Figure.2b sketch SK-720221-1.
- 13. Provide the values of stresses in the concrete (compression and shear) and in reinforcing steel (tension) that would exist during normal operation when the pool floor is supporting its maximum anticipated load. Indicate the amount by which these stresses will be increased during cask impact.
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Commonwealth Edison Company !,
- 14.. Explain how the stored spent fuel v111'be protected from a fallen cask if it should tip upon striking the crushable structures. Show the limits of cask movement laterally above' the pool and' the maximum probable movement toward the spent fuel of a dropped cask when tipped.
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. Your responses to the above items are requested by July 21, 1972, to be compatible with our. review schedule. One signed and 39 additional-copies of your submittal are required.
1 Sincerely, i
o W menad by i
D. J. shoed j
Donald J. Skovholt Assistant Director for Operating Rasctors Directorate of Licensing cc.
Mr. Charles Whitmore Distribution President and Chairman Iowa-1111 acts Gas and WDooly, DR R0 (3) i Electric Company 206 East Second Avenue HShapar, OGC JRBuchanan, ORNL Davenport, Iowa 52801 PDR Local PDR f
John W. Rowe, Esquire Docket Files j
Isham, Lincoln & Beale L Reading Counselors at Law One First' National Plaza Branch Reading
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Chicago, Illinois 60670 RBoyd, L RDeYoung, L RTedesco, L j
MRowden, OGC i
MKarman, OGC ASLBP DJSkovholt, L TJCarter, L DLZiemann, L JIRiesland, L RMDiggs, L l
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