ML23004A167
| ML23004A167 | |
| Person / Time | |
|---|---|
| Site: | 07103056 |
| Issue date: | 01/11/2023 |
| From: | Storage and Transportation Licensing Branch |
| To: | US Dept of Transportation (DOT) |
| Shared Package | |
| ML23004A165 | List: |
| References | |
| EPID L-2022-DOT-0005 | |
| Download: ML23004A167 (1) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION REPORT Docket No. 71-3056 Model No. 3516A Package United Kingdom Certificate GB/3516A/AF-96 Revision 4
SUMMARY
By letter dated May 12, 2021 (Agencywide Documents Access and Management System
[ADAMS] Accession No. ML23004A150), the U.S. Department of Transportation (DOT) requested that the U.S. Nuclear Regulatory Commission (NRC) staff perform a review of the United Kingdom Certificate of Approval No. GB/3516A/AF-96, Rev 4, for the Model No. 3516A transport package and make a recommendation concerning the revalidation of the package for import and export use.
The NRC staff reviewed the information provided to the DOT by Westinghouse Electric Company LLC in its application for the Model No. 3516A package against the regulatory requirements of the International Atomic Energy Agency (IAEA) Specific Safety Requirements No. SSR-6 (SSR-6), Regulations for the Safe Transport of Radioactive Material, 2012 Edition.
Based upon our review, the statements and representations contained in the application, and for the reasons stated in the enclosed safety evaluation report (SER), we recommend revalidation of the United Kingdom Certificate of Approval No. GB/3516A/AF-96, Rev 4, for the Model No.
3516A transport package for shipment of the contents as described in this SER.
GENERAL INFORMATION The design was most recently reviewed by the NRC on September 10, 2014 (ADAMS Accession No. ML14255A451).
The applicant requested U.S. revalidation of the Certificate of Compliance (CoC) for transportation of unirradiated uranium oxides enriched up to 5.0 weight percent uranium-235 (235U). The only significant change to the package design is the reduction of allowable fissile material contents because of additional criticality analyses performed at the request of the U.K. Competent Authority. There are no changes requested to the previously revalidated packaging design.
CRITICALITY EVALUATION The applicant revised the criticality analysis for the Model No. 3516A from that previously reviewed and approved by the NRC to address several changes in the initial assumptions originally used in the package analysis. These changes include: (1) consideration of additional package orientations in the normal conditions of transport (NCT) array evaluation, including package base-to-base and lid-to-lid orientations which can bring fissile material in adjacent packages closer together; (2) consideration of the effects of temperature changes on system keff; (3) the potential for small amounts of water in-leakage into the package outer container under the NCT water spray test condition; and (4) an increase in water density at low temperatures.
Enclosure
The applicants revised analyses demonstrated that the single package and arrays of packages under the NCT and accident conditions of transport (ACT) remained subcritical with these revised assumptions, provided the per pail and total package allowable fissile mass is slightly reduced. The revised pail and package mass limits as a function of uranium enrichment are shown in Table 1 of Sellafield Ltd. Criticality Design Safety memorandum CDSA/DESM/0518/2368. For up to 4.55 weight percent enriched uranium oxide, the per pail mass limit is 25.0 kilograms (kg), and the total package mass limit is 225.0 kg (previous approval for 25.5 kg per pail and 229.5 kg per package). For up to 5.0 weight percent enriched uranium oxide, the per pail mass limit is 21.5 kg, and the total package mass limit is 193.5 kg (previous approval for 22.0 kg per pail and 198.0 kg per package). Since the applicant demonstrated that the same number of packages in an array under the NCT and ACT are subcritical, the criticality safety index (CSI) is the same as for the previous approval (CSI = 1.66).
The applicant demonstrated that the Model No. 3516A package remains subcritical with the modified initial assumptions and reduced package fissile mass. Since the fissile mass per package is reduced from the previous U.S. revalidation of this package, the staff finds that the package will remain subcritical under the NCT and ACT, in accordance with the fissile material packaging requirements of IAEA SSR-6.
The staff reviewed the CoC for the Model No. 3516A package, as well as the applicants initial assumptions, model configurations, analyses, and results in the safety analysis report (SAR).
The staff finds that the applicant has identified the most reactive configuration of the Model No.
3516A package with the requested contents, and that the criticality results are conservative.
Therefore, the staff finds with reasonable assurance that the package, with the requested contents, will meet the criticality safety requirements of IAEA SSR-6.
CONCLUSION Based on the statements and representations presented in the SAR and supplemental information, the staff agrees that the package meets the standards in the IAEA Safety Standards SSR-6, 2012 Edition. The staff recommends that the DOT revalidate U.K. Certificate of Approval No. GB/3516A/AF-96, Rev 4, for import and export use.
Issued with letter to R. Boyle, U. S. Department of Transportation.
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