ML20210E345
| ML20210E345 | |
| Person / Time | |
|---|---|
| Site: | 07200022 |
| Issue date: | 07/22/1999 |
| From: | Resnikoff M AFFILIATION NOT ASSIGNED |
| To: | |
| Shared Package | |
| ML20210E324 | List: |
| References | |
| 97-732-02-ISFSI, ISFSI, NUDOCS 9907280202 | |
| Download: ML20210E345 (3) | |
Text
o UNITED STATES OF AMERICA BEFORE THE U.S. NUCLEAR REGULATORY COMMISSION ATOMIC SAFETY AND LICENSING BOARD In the Matter of
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PRIVATE FUEL STORAGE, L.L.C.
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(Independent Spent Fuel
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Docket No. 72-22-ISFSI Storage Installation
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1 July 22,1999 DECLARATION OF DR. MARVIN RESNIKOFF IN SUPPORT OF STATE OF UTAH'S AMENDED CONTENTION Q 1, Dr. Marvin Resnikoff, declare under penalty of perjury that:
- 1. I am the Senior Associate at Radioactive Waste Management Associates, a private consulting firm based in New York City. On November 20,1997 and January 16,1998,1 prepared declarations which were submitted to the Licensing Board by the State of Utah in support ofits contentions regarding Private Fuel Storage, L.L.C.'s proposed Independent Fuel Storage Installation. I assisted in the preparation of State of Utah's original Contention Q, which were submitted at that time. A statement of my qualifications was attached to November 1997 declaration.
- 2. I am familiar with Private fuel Storage's ("PFS's") license application and Safety Analysis Report in this proceeding, as well as the applications for the storage and transportation casks PFS plans to use. I am also familiar with NRC regulations, guidance documents, and environmental studies relating to the transportation, storage, and disposal of spent nuclear power plant fuel, and with NRC decommissioning requirements.
- 3. I assisted in the preparation of the State of Utah's Amended Contention Q. The technical facts presented in Amended Contention Q are true and correct to the best of my knowledge, and the conclusions drawn from those facts are based on my best professional judgment.
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- r. Maivin ResnikoF
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July 22,1999 l
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ting ofirradiated Fuel Under Drop Conditions http://www.nrc.gos/OPA/ reports /isgl2.htin kG-12 Buckling ofIrradiated Fuel Under Drop Conditions
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m.,,m Drv Cask Storage l News and Information l NRC Home Page l E-mail Spent Fuel Project Omce Interim StafiGuidance - 12 Issue: Buckling ofIrradiated Fuel Under Bottom End Drop Conditions Discussion:
Fuel rod buckling analyses under bottom end drop conditions have traditionally been performed to demonstrate integrity of the fuel following a cask drop accident. The methodology described by Lawrence Livermore National Laboratory (LLNL) to analyze the buckling ofirradiated spent fuel assembly under a bottom end drop in their repon UCID-21246 is a simplified approach. It assumed that buckling occurred when the fuel rod segment between the bottom two spacer grids reached the Euler buckling limit. The weight of fuel pellets was neglected in the analysis; only the weight of the cladding was considered. Material propedies for unirradiated cladding were used. The buckling analysis also neglected the stiffness of the pellets which could have been fused or locked to the cladding. It assumed the total weight of the cladding to be on top of the fuel rod segment between the bottom two spacer grids. In addition, it also assumed that the fuel rod segment between the bottom two spacer grids was pin-connected. The restraint and lateral support of the fuel basket structure to the fuel assemblies were ignored in the analysis.
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The weight of pellets and irradiated material properties should be included in any end drop analysis. With these changes, the simplistic method ofUCID-21246 may not yield acceptable results. For example, the staff conducted calculations using the same methodology as LLNL repon UCID-21246 except irradiated material properties for the clad, and the weight of fuel pellets are included in the calculations. The most vulnerable fuel assembly in the LLNL report, a 17x17 Westinghouse fuel assembly, was chosen for this exercise. Euler buckling loads for the clad were calculated using the following formula:
P.=2El/L2 j
a where i
6 Eclad = 10.47 x 10 psi Iclad"I/4X(T - r; ) = 1/4 x (0.187 - 0.1645 ) = 3.85 x 10 in4 4
4 4
4 o
L = 24 inches The results indicate that Iof2 7/2/9910.55 AM
http /www.nrc. gov /oPNreports/isgl2.htm lso-t? @ucbing ofIrndirted Fuel Ur.d:r Drop Conditions
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P = 69 lb c7 Since the weight of cladding and pellets for the 144 inch-long fuel rod is about 4.98 lb, the buckling load in terms of gravitational acceleration (g) is P /W = 69/4.98 = 13.86 g er This is considerably smaller than the 82 g reported in the LLNL report UCID-21246. However, there are several bounding assumptions in this approach which make the results unrealistically low for predicting cladding failure, j
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Conclusion:==
j Analyses of fuel rod buckling performed to demonstrate fuel integrity following a cask drop accident yield results which contain a large margin to actual failure. The calculated onset of buckling does not imply fuel or cladding failure. Where such analyses yield unacceptable res'ilts, more realistic analyses of dynamic fuel behavior are appropriate and acceptable. If the cladding stress remains below yield strength, the fuel integrity is assured.
Recommendation:
If the analytical approach described in the LLNL report UCID-21246 for axial buckling is used to assess fuel integrity for the cask drop accident, the analysis should use the irradiated material properties and should include the weight of fuel pellets.
Alternately, an analysis of fuel integrity which considers the dynamic nature of the drop accident and any restraints on fuel movement resulting from cask design is acceptable ifit demonstrates that the cladding stress remains below yield. If a finite element analysis is performed, the analysis model may consider the entire fuel rod length with intermediate supports at each grid support (spacer). Irradiated material properties and weight of fuel pellets should be included in the analysis.
The appropriate section of Standard Review Plan, NUREG-1536, should be revised to - sy Reflect analytical approach for fuel rod bucking analyses.
Approved E. William Brach Date
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