ML20211G358
| ML20211G358 | |
| Person / Time | |
|---|---|
| Issue date: | 08/25/1999 |
| From: | Brach E NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Lochbaum D UNION OF CONCERNED SCIENTISTS |
| Shared Package | |
| ML20211G362 | List: |
| References | |
| NUDOCS 9908310240 | |
| Download: ML20211G358 (5) | |
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WASHINGTON, D.C. 30886 0001 August 25, 1999 Mr. David Lochbaum Union of Concerned Scientists -
l 1616 P Street, N.W.
L Suite 310 l
Washington, DC 20036
Dear Mr. Lochbaum:
I am responding to your e-mail message you sent to the Office of Public Affairs conceming a paper entitled, "A Structural Assessment of Candidate Fuel Basket Designs for Storage and Transport of Spent Fuel," written by K. P. Singh and M. DeLong and presented at a Washington, DC, conference in January 1998. Specifically, you asked, "What assurances does the Nuclear Regulatory Commission (NRC) staff have that the fuel basket integrity issues raised by the subject paper have been resolved for the dry cask designs intended for New England nuclear power plants?"
All. licenses for independent spent fuel storage facilities and all transportation and storage certificates of compliance (CoC) must meet the regulatory requirements found in 10 CFR Part 71 (transportation) and 10 CFR Part 72 (storage). These regulations cover a variety of topics, such as criticality, thermal, structural, quality assurance, radiological shielding, and otne areas subject to the review by the staff. Prior to issuance of any license or CoC, the staff will hace made a determination that there is reasonable assurance that the public health and safety will not be endangered by the proposed action.
- The aforementioned paper was presented by one of the vendors applying for a dual-purpose cask design certificate. The simplified analysis presented in the paper of the structural integrity of the storage cask fuel basket neglected many design features that will minimize displacements of the fuel tube (box) in a postulated accident drop event. For instance, the fuel basket assembly design in question has an aluminum disk placed midway between each pair of stainless steel disks for heat transfer enhancement, and the fuel tube also has an over-sleeve which completely encloses the neutron absorber panel. In making a determination with respect to NRC standards, the staff traditionally neglects certain design features, such as these, that would increase the structural integrity of the fuel basket and increase the overall margin of safety. We believe that this approach ensures, in part, a conservative structural analysis. The staff has reexamined the structural analysis of the fuel basket assembly design and found it remains acceptable.
The displacement of the fuel tube shown by the paper is not realistic. Because the fuel tube walIs are very thin (only 0.048 inches), the flexure resistance (i.e., bending) can be neglected.
The staff estimated that with a displacement of less than 0.15 inches at the center span, the fuel
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o tube wall will develop a membrane stress sufficiently large to support the fuel assembly weight amplified by the 60g drop impact. Consequently, the NRC staff continues to believe that the regulations and the subsequent staff review sufficiently assure the public health and safety.
j Sincerely, original /s/ by E. William Brach, Director Spent Fuel Project Office Office of Nuclear Material Safety and Safeguards I
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fuel assembly weight amplified by the 60g drop impact. Consequently, the NRC sta continues to believe that the regulations and the subsequent staff review sufficiently assure t e public health and safety.
Sincerely, E. William Brach, Directo Spent Fuel Project Offi Office of Nuclear Mat ial Safety and Safeguards l
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2 tube wall will develop a membrane stress sufficiently large to support the fuel assembly weight amplified by the 60g drop impact. Consequently, the NRC staff continues to believe that the regulations and the subsequent staff review sufficiently assure the public health and safety.
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E. William Brach, Direct /
Spent Fuel Project OffMe Office of Nuclear Material Safety and Safeguards I
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wall will develop a membrane stress sufficiently large to support the fuel assembly weight amplified by the 60g drop impact. Consequently, the NRC staff continues to believe that the regulations and the subsequent staff review sufficiently assure the public health and safety.
Sincerely, j
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E. William Brach, Director Spent Fuel Proj,ect Office Office of Nuclear Material Safety and Safeguards
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