ML17037C436
| ML17037C436 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 02/11/1977 |
| From: | Lear G Office of Nuclear Reactor Regulation |
| To: | Rhode G Niagara Mohawk Power Corp |
| References | |
| Download: ML17037C436 (8) | |
Text
FEB' iV Docket No. 50-220 Niagara Mohawk Power Corporation ATTN:
Hr. Gerald K. Rhode Yice President - Engineering 300 Erie Boulevard West
- Syracuse, New York 13202 Gentlemen:
Distribution cket ORB 0'3 Local PDR NRC PDR VStello KRGoller TJCarter
- Attorney, OELD GLear CParrish SNowicki DEisenhut TBAbernathy JRBuchanan ACRS (16)
We have completed a preliminary review of your December 7, 1976 request for Technical Specification changes for Nine f1ile Point Unit No.
1 Spent Fuel Pool Modification.
We have concluded that we need additional information to complete. our review.
Please provide responses to the items of information identified in the enclosure.
If you have any questions, please contact us.
Sincerely,
Enclosure:
Request for Additional Information Original signed by George Lear, Chief Operating Reactors Branch 83 Division of Operating Reactors cc:
Arvin E. Upton, Esquire
- LeBoeuf, Lamb, Leiby 5 NacRae 1757 H Street, N. H.
Washington, D. C.
20036 Anthony Z. Roisman, Esquire
- Roisman, Kessler and Cashdan 1025 15th Street, H.
W.
5th Floor Washington, D. C; 20005 Hr. Eugene G. Saloga, Applicant Coordinator Nine l1ile Point Energy Information Center
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ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION NINE MILE POINT UNIT 1
SPENT FUEL POOL MODIFICATIONS 1.
Provide detailed sketches of the supports and bearing pads for the lateral restraints of the fuel rack assemblies.
In addition, since Figures 5.a and 6 do not show sufficient details of the rack base structure, provide clear sketches of a typical base and its interconnecting structure to other bases.
2.
Provide sketches of the mathematical models of the fuel pool, the fuel storage rack, and the fuel assembly system which were utilized in the analysis.
Illustrate on the sketches the mechanism of shear and load transfer to the fuel pool walls and floor slab.
Discuss the effects of sloshing water.
Also, provide the resulting significant modal frequencies of the fuel racks in air and water, and the corresponding mode shapes and participation factors.
3.
Provide the response spectra utilized for the SSE and the OBE conditions.
Also state the damping values assumed for the fuel l
racks.
I 4.
The maximum vertical seismic acceleration should normally be approximately 2/3 of the maximum horizontal acceleration.
Justify the ratio utilized on page 16 of Attachment "B".
5.
Your reference to Table 1 regarding the loads, load combinations and acceptance criteria utilized in the design of the racks is not sufficient for an adequate review of the design.
Ther efore, provide a summary for these items.
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6.
State clearly the codes which are utilized for the design, fabrication, and installation of the rack structure.
Specify the codes from which the maximum stress limits (at appropriate temperatures) for the materials and welds were obtained.
7.
Compare the most severe temperature distribution considered for the structural design of the fuel pool structure for both the original rack design and the new rack design.
8.
Provide a summary of the highest stresses, the corresponding safety
- margins, the locations where these occur, and the maximum di"placements at the top of the racks for the loading conditions considered in the analysis of the rack structure.
9.
Provide the details of your analysis considering the impact of the fuel assemblies against each other and against the rack walls.
Show how you incorporated the local effect into the total effect on the rack design.
10.
Provide a detailed suranary of the stress margins due to the increased loading of the fuel pool walls and floor for the critical load combinations.
Include a discussion of the possibility of shear failures in the areas of contact of the rack supports with the floor and walls. 'ompare numerically these results to those for the previous rack structure.
11.'.
On page 27 of Attachment "B", provide a numerical compalison of the impact strengths against dropped assemblies of the new and the old rack structures.
12.
In section 7.3, it is stated that there is no thr eat to the integrity of the pool liner if a rack is accidentally dropped into the pool during construction.
State the assumptions regarding the kinetic energy of the dropped rack and the ductility factor of the target in absorbing the energy of impact and provide the results of your analysis.
0 13.
In Attachment "B", the referencesmade on pages 3 and 17 to Table 1'or the codes applicable to the design, fabrication and erection of the rack structures are not clear.
To clarify your'references, the codes utilized for each of these items must be jdentif'jed s paeatel'y.
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