ML20276A036
| ML20276A036 | |
| Person / Time | |
|---|---|
| Site: | 07103098 |
| Issue date: | 10/02/2020 |
| From: | Santos N Storage and Transportation Licensing Branch |
| To: | |
| NGSantos NMSS/DFM/STL 301.415.6999 | |
| Shared Package | |
| ML20276A034 | List: |
| References | |
| EPID L-2020-LLA-0107 | |
| Download: ML20276A036 (3) | |
Text
Request for Additional Information U.S. Department of Transportation Japanese Approval Certificate No. J/2009/AF-96, Revision 1 Docket No. 71-3098 Certificate of Compliance No. 3098 Model No. GP-01 By letter dated May 11, 2020 [Agencywide Documents Access and Management System (ADAMS) Accession No. ML20143A100], and as supplemented on August 5, 2020 (ADAMS Package Accession No. ML20231A505), the U.S. Department of Transportation requested that the U.S. Nuclear Regulatory Commission (NRC) staff perform a review of the Japanese Approval Certificate Number J/2009/AF-96, Revision 1, Model No. GP-01 transport package, and make a recommendation concerning the revalidation of the package for import and export use.
This request for additional information (RAI) identifies information needed by the NRC staff (the staff) in connection with its review of the application. The staff used International Atomic Energy Agency (IAEA) Specific Safety Requirements No. 6 (SSR-6), Regulations for the Safe Transport of Radioactive Material, 2012 Edition, in its review of the application.
The RAI describes information needed by the staff to complete its review of the application and to determine whether the applicant has demonstrated compliance with the regulatory requirements of the IAEA SSR-6, 2012 Edition.
CRITICALITY SAFETY (Cr)
RAI-Cr-1 Confirm the properties (compositions) for materials used in the criticality models.
Revise the analyses as needed.
Table II-E-1 of the applications safety analysis provides the compositions of the materials included in the criticality models. These compositions are specified in terms of the individual constituent elements and isotopes (for uranium and boron) and their respective densities in atoms/barn-cm. A review of this table indicates some anomalous features. For example:
- 2. Various atom densities appear to be listed for the incorrect element or nuclide, and in some cases, the density values are not at all correct. For example, the atom density of hydrogen in water should be twice that of oxygen, with the oxygen value being 3.34e-2 (3.34 x 10-2) atom/barn-cm.
- 3. All the atom densities of the stainless steel appear to be shifted by one element (e.g., the atom density for iron should be 5.82e-2 (5.82 x 10-2) atom/barn-cm).
- 4. The atom densities for the borated stainless steel also appear to be shifted by one element with the 1.24e-3 (1.24 x 10-3) atom/barn-cm value not being correct for any of this materials constituents.
This information is needed to confirm compliance with Paragraphs 682 and 684-686 of the IAEA SSR-6, 2012 Edition.
Enclosure 1
2 RAI-Cr-2 Modify the benchmark analysis to:
- a. include evaluation of trends in differences between the calculated k-effective and the experimental k-effective (i.e., the bias and bias uncertainty) for the evaluated critical experiments, and
- b. demonstrate that the benchmark analysis and bias and bias uncertainty calculations are based on only critical experiments that are applicable to the package analysis (e.g., the experiments only contain similar materials).
The benchmark analysis should determine a bias and bias uncertainty for the package analysis that is based on evaluation of critical experiments that are relevant to the package (e.g., experiments that only contain materials that are included in the package analysis in similar arrangements as in the package).
Inclusion of experiments with materials that are not relevant to the package analysis can produce results that hides the true bias and bias uncertainty for the package analysis and may be non-conservative. Furthermore, the applicant should analyze trends to understand the behavior of the bias and bias uncertainty and ensure that an appropriate bias and bias uncertainty have been applied based on the package analyses properties considered in the trending analysis. Trending analysis should include the evaluation of bias and bias uncertainty as a function of parameters such as the following:
- 1. pellet pitch,
- 2. enrichment,
- 3. pellet diameter,
- 4. the ratio of hydrogen to uranium-235 (i.e., H/X),
- 5. the energy of the average lethargy causing fission (i.e., EALF), and
- 6. boron concentrations in absorber materials.
It is not clear from the information provided in the application which LEU-COMP-THERM experiments from the international handbook were considered by the applicant, their similarity to the package, and if trends were evaluated. The staff notes that the current bias and bias uncertainty, if applied to the administrative margin of 0.05, would result in an upper subcritical limit that is exactly the value of the maximum k-effective plus three times the standard deviation reported for the damaged package array.
This information is needed to confirm compliance with Paragraphs 682 and 684-686 of the IAEA SSR-6, 2012 Edition .
RAI-Cr-3 Provide the correct Figure II-E.App-8.
According to the text on page II-E.App1-20 of the application safety analysis, Figure II-E.App.-8 should show the k-effective results for different water amounts between the inner receptacle wall and the outer receptacle inner shell. However, the current figure appears to be for a different analysis.
This information is needed to confirm compliance with Paragraph 682 of the IAEA SSR-6, 2012 Edition.
3 RAI-Cr-4 Clarify the description of the allowable content and provide justification that the criticality analysis is adequate for that content description.
The application states that the contents of the package include solid pellets of the following uranium oxides: UO2, UO3, and U3O8. The criticality analysis only addresses UO2 pellets. It is not clear if the intention of the applicant is that pellets of UO3 and pellets of U3O8 be shipped in the package or these compounds are included to address potential impurities in the UO2 pellets that are composed of these compounds If they are to be considered as separate pellet fuel and not impurities in UO2 fuel, then the criticality analysis should be revised to demonstrate subcriticality for pellets of these oxides. This revision would need to include justification of assumptions on pellet diameters in sensitivity studies and inclusion of a benchmark analysis for each pellet material type that uses the same uranium compounds. The application would also need to describe the behavior of pellets of these materials under routine, normal, and accident conditions with the appropriate justification, ensuring the criticality analysis is consistent with or bounding for that behavior.
This information is needed to confirm compliance with Paragraphs 682 and 684-686 of the IAEA SSR-6, 2012 Edition.
RAI-Cr-5 Confirm whether the package revalidation request includes authorization for air transport, performing the necessary tests and evaluations to demonstrate compliance with the requirements for air transport of fissile material if air transport authorization is requested.
In its review of the package application, the staff did not identify any package evaluations or tests that demonstrate subcriticality for a fissile material package transported by air. Therefore, if authorization of transport by air is part of the requested revalidation, then the application should include the necessary evaluations and tests. These evaluations would include criticality analyses that show the package is subcritical under conditions consistent with the Type C package tests specified in Paragraph 734 of the IAEA SSR-6, 2012 Edition.
Without these evaluations, the staff would recommend that revalidation of the package be conditioned to preclude air transport.
This information is needed to confirm compliance with Paragraph 683 of SSR-6 the IAEA SSR-6, 2012 Edition.