ML20137D104
| ML20137D104 | |
| Person / Time | |
|---|---|
| Issue date: | 03/19/1997 |
| From: | Haughney C NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Ozer O ELECTRIC POWER RESEARCH INSTITUTE |
| References | |
| NUDOCS 9703260011 | |
| Download: ML20137D104 (2) | |
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March 19, 1997 Mr. Odelli Ozer. Manager Fuel Reliability and S)ent Fuel Disposal Electric Power Researc1 Institute 3412 Hillview Avenue Palo Alto CA 94303 RE:
METHODOLOGY FOR ANALYSIS OF IMPACT DECELERATION OF STORAGE CASK DROP AND TIPOVER ACCIDENTS
Dear Mr. 0zer:
I am responding to your February 18. 1997, letter and the preprint.
" Validation of EPRI Methodology for Analysis of Cask Drop and Tipover Accidents at Spent Fuel Storage Facilities." to be 3 resented at the 5th International Conference on Nuclear Engineering in iay this year.
You contended that "[t]he NRC has been reluctant to approve licensing applications...EPRI methodology.
However, you also indicated interest in using the billet drop and tipover test data obtained by the Lawrence Livermore i
National Laboratory (LLNL) in February 1996 to extend benchmarking of the EPRI methodology.
On the EPRI methodology, although the staff has not been requested to perform a formal evaluation of the method documented in the April 1993 EPRI report NP-7551. " Structural Design of Concrete Storage Pads for Spent Fuel Casks." or its early version. NP-4830. "The Effects of Target Hardness on the Structural l
Design of Concrete Storage Pads for Spent-Fuel Casks." the staff is aware that the reports were based on high-velocity impact test data which may not be totally applicable to a variety of storage pad accident scenarios. Also, the staff notes that, for the cask side drop and tipover, the results based on the EPRI methodology could be very sensitive to the estimated " footprint" size of the cask.
In recognizing the need to use a complete set of low-velocity impact test data appropriate for validating analytical modeling of cask storage pad accidents, the staff tasked the LLNL to conduct a series of side-drop and tipover tests in February 1996.
The effort complemented the three series of end-drop tests documented in the September 1993 Sandia National Laboratories report. " Drop Tests onto Concrete Pads for Benchmarking Response of Interim Spent Fuel Storage Installations."
On the use of LLNL test data, the staff has made available to potential users the measured data in the March 1996 draft LLNL report. " Low-Velocity Impact 99 59 a
Testing of Solid Steel Billet onto Concrete Pads - A Summary of 12 Drop Tests l
Conducted February 1996 at LLNL." A copy of the report was forwarded to Mr.
Y. Rashid of ANATECH on February 24. 1997.
Additionally, the LLNL has been using the test data to validate a finite element analysis approach to model a cask-pad-soil interaction system to calculate cask decelerations.
This approach was used recently in the safety evaluation of a storage cask license application.
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y Mr. Odelli Ozer.
At present, the LLNL is completing the final billet-drop test report.
To validate analytical models, the report will describe the factors essLitial in applying the billet-drop and tipover test data.
It will' also summarize a four-step approach to apply the billet test data to evaluate impact loads for full-size storage casks:
(1) determination of rigid body motion of billet tests.-(2) validation of finite element model representation of billet tests.
(3) finite element simulations of a full-size storage cask for side drop and tipover, and (4) application of the results to quasi-static analysis.of the basket.
My staff has been giving this matter considerable attention over the past several years. since we have clearly recognized its im]ortance to the industry.
Understandably, however, our attention has )een often redirected toward licensing casework needed to support near-term plant operations.
As we finish our efforts. I would appreciate your patience and understanding.
Sincerely.
5 C arles J. Haughney Deputy Director Spent Fuel Project Office Office of Nuclear Material Safety and Safeguards Distribution:
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