ML26009A098
| ML26009A098 | |
| Person / Time | |
|---|---|
| Site: | 07109309 |
| Issue date: | 01/22/2026 |
| From: | Storage and Transportation Licensing Branch |
| To: | |
| Shared Package | |
| ML26009A096 | List: |
| References | |
| EPID L-2025-LLA-0067 | |
| Download: ML26009A098 (0) | |
Text
Enclosure UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION REPORT Docket No. 71-9309 Model No. RAJ-II Package Certificate of Compliance No. 9309 Revision No. 14
SUMMARY
By application dated August 4, 2025 (Agencywide Documents Access and Management System Accession No. ML25216A053), Global Nuclear Fuel - Americas, LLC (GNF) requested a Letter Authorization for Model No. RAJ-II (RAJ-II) package, to allow shipment of the GNF 11x11 Lead Use Assembly(LUA) fuel assembly design as LUA using the Certificate of Compliance (CoC) No. 9309, Revision No. 14, to support upcoming business operation.
The U.S. Nuclear Regulatory Commission (NRC) staff reviewed the application using the guidance in NUREG-2216, Standard Review Plan for Transportation Packages for Spent Fuel and Radioactive Material,.(NUREG-2216). Based on the statements and representations in the application and the conditions listed below, the staff concluded that the package meets the requirements of Title 10 of the Code of Federal Regulations (10 CFR) Part 71,Packaging and Transportation of Radioactive Material.
1.0 GENERAL INFORMATION The RAJ-II package is authorized for transport of up to two unirradiated Boiling Water Reactor (BWR) fuel assemblies or individual rods (BWR, generic BWR and Pressurized Water Reactor
[PWR] reactor rods, or uranium carbide rods configured loose), that conform to the American Society for Testing and Materials (ASTM) C996 standard.
The applicant requested that new 11X11 fuel types be authorized for transport using model number RAJ-II transportation package.
The GNF 11x11 (LUA design is an evolution of the GNF3 10x10 design and contains a Type A fissile (AF) material. The GNF 11x11 fuel assembly is comprised of 112 fuel rods in a square array and has a single, centrally located water rod. The GNF 11x11 bundle has 20 Part Length Rods (PLRs), which is greater than the maximum of 16 PLRs specified in the current revision of CoC No. 9309.
The GNF 11x11 LUA fuel assembly average enrichment is less than or equal to 5.0 weight percent (wt.%) Uranium-235 (U-235). The fuel rod maximum enrichment is less than or equal to 5.0 wt.% U-235. The maximum payload weight and the fuel concentrations are within the approved contents of the RAJ-II package.
2 The GNF 11x11 design, while similar to contemporary GNF fuel designs, is not covered by certain fuel assembly parameters in the current revision of Model No. RAJ-II, CoC No. 9309.
The staff evaluated the changes and presents its findings below.
2.0 STRUCTURAL EVALUATION The objective of the structural evaluation is to verify that the applicant has adequately analyzed the structural performance of the new fuel content of the transportation package so that it meets the performance requirements in the regulations of 10 CFR Part 71, Packaging and Transportation of Radioactive Material.
2.1 Structural Evaluation for the Package The RAJ-II package is a certified Type B(U) or Type A fissile material transportation container designed for the transport of unirradiated BWR fuel assemblies. Structurally, it consists of a stainless-steel inner container (IC) and outer container (OC), both equipped with energy-absorbing materials such as balsa wood and aluminum or paper honeycomb. The IC is supported within the OC by a vibration isolation system. The containment of radioactive material is provided by the fuel rod cladding and welded end plugs, and the package is designed to withstand normal and hypothetical accident conditions. The entire package design includes shock absorbers, lifting and tie-down features, and closures are approved and remain unchanged as described in the safety analysis report (SAR). Each package is designed for a maximum of two fuel assemblies.
The structural change introduced in this application is due to the new GNF 11x11 LUAs which is similar to the approved GNF3 10x10 fuel assemblies. The GNF 11x11 LUAs include 112 fuel rods (compared to 96 in GNF3), a central axially varying water rod, and 20 PLRs that exceed the 16 PLR limit in the current CoC. Despite these differences in internal configuration, the overall payload mass remains within the approved limit of 684 kg.
The NRC staff reviewed the impact of the package design due to the introduction of new GNF 11x11 LUAs and found that the maximum gross weight of an RAJ-II package including a maximum payload weight remains unchanged as described in SAR Revision No. 11 section 2.1.3. The staff also found that the center of gravity, the external geometry, and mass distribution are unchanged as shown in SAR Revision No. 11 section 2.1.3. Therefore, the staff concluded that the original approved RAJ-II package design remain applicable, and no further review for the package is performed.
2.2 Structural Evaluation for the GNF 11x11 Fuel The applicant performed the structural evaluation of the GNF 11x11 fuel type for the RAJ-II package under both normal conditions of transport (NCT) and hypothetical accident conditions (HAC). The applicant used a manual calculation to evaluate the thermal performance of the GNF 11x11 fuel under both NCT and HAC. The applicant also performed a finite element analysis using LS-DYNA to simulate the mechanical response of the package and the new GNF 11x11 fuel under drop scenarios. These included vertical end drops, side drops, and corner drops that were chosen based on the drop analysis result in SAR Revision No. 11. The applicant also used simulations to benchmark against physical drop test data from full-scale
3 Certification Test Units (CTUs) to validate the model. The results were compared with the structural design criteria defined in the SAR Revision No. 11 section 2.1.2.
2.2.1 New Fuel Evaluation for Thermal and Differential Expansion under NCT and HAC The applicant performed thermal evaluations to assess the behavior of the GNF 11x11 fuel under temperature extremes ranging from the coldest temperature at -40 °C under NCT to the highest temperature the fuel is subject to under HAC at 800 °C in the SAR, section 2.6.1.2. The evaluation focused on the differential thermal expansion between the fuel pellets and the cladding. The result shows that, at the highest evaluated temperature of 800 °C, a radial gap remains between the pellet and cladding. This was validated for both standard uranium dioxide (UO) pellets and those with increased silicon concentration.
The staff reviewed the thermal performance analysis and found that the radial gap between the pellet and cladding is still maintained under both NCT and HAC conditions. Therefore, the staff concludes that the package satisfies the regulatory requirements of 10 CFR 71.71(c)(2) and 71.73(c)(4).
2.2.2 New Fuel Evaluation for Drop Performance under HAC The applicant performed vertical end drops, side drops, and corner drop simulations using LS-DYNA. The entire package with the new GNF 11X11 fuel assembly mass was modeled during the drop test. A detailed fuel bundle model is used to conduct the analysis for the new GNF 11X11 performance under HAC impact. The analysis results are checked for the integrity of the containment boundary and the geometry of the contents for criticality analysis.
In SAR section 2.12.2.1, the applicant described the RAJ-II container model which was developed from licensing drawings and included solid elements representing the IC, OC, and energy-absorbing components such as balsa wood and honeycomb structures. The impact surface was modeled as a rigid, unyielding plane, and the initial velocity for drop scenarios was calculated based on a 9-meter free fall. The RAJ-II container model was benchmarked against physical drop test data from GNF-J CTUs. Simulated deceleration values closely matched measured data, confirming the accuracy of the model. The validated container model was used to generate acceleration time histories for use in evaluating the fuel bundle response. These were developed for both nominal (77 °C) and worst-case (-40 °C) conditions, incorporating assumptions regarding material stiffness, moisture content, and temperature effects.
In SAR section 2.12.2.2, the applicant described the detailed fuel bundle simulations used to assess the mechanical behavior of the GNF 11x11 fuel under HAC drop conditions. A total of six simulations were performed, covering three drop orientationsvertical end, side, and cornereach evaluated at two temperatures (-40 °C and 77 °C). The detailed fuel bundle models included elastic-plastic material behavior for zirconium alloy cladding, stainless-steel lower tie plates, and Inconel spacers, with strain-rate effects considered to simulate realistic impact conditions. In the simulation, fuel pellets were modeled properly to avoid overestimating structural support. The cladding strain analysis showed a maximum total strain below the allowable limit in the corner drop scenario at -40 °C. Additionally, a lattice expansion model was developed using an axial quarter-slice of the fuel bundle due to symmetry to evaluate the maximum increase in rod-to-rod pitch spacing, which is crucial for the criticality safety assessment. Using the worst-case acceleration inputs and simplified mass distribution, the maximum average pitch expansion was calculated and further used as a bounding input in the criticality evaluation presented in chapter 6.0 of the SAR.
4 The staff reviewed the analysis steps and found that the evaluation methodology is reasonable, the fuel rods integrity as the containment boundary can be maintained under HAC drop scenarios, and the calculation of the cladding pitch is conservative. Therefore, the staff concludes that the package satisfies the regulatory requirement of 10 CFR 71.73(c)(1).
2.3 Evaluation Findings The NRC staff reviewed and evaluated the applicants statements and representations in the application. Based on the review and evaluations, the NRC staff finds that the changes introduced in this application due to the new GNF 11x11 LUAs, have been adequately evaluated and do not impact the original RAJ-II package design approved in the previous application. Therefore, the structural design and integrity of the package including the new fuel type, the meet the regulatory requirements in 10 CFR Part 71.
3.0 THERMAL EVALUATION 3.1 Review Objectives The objective of the thermal evaluation is to ensure that the design of RAJ-II packages meeting the regulatory requirements in 10 CFR Part 71 and to adequately evaluate the thermal performance of the package for the tests specified under NCT and HAC, in accordance with 10 CFR Part 71.
The application seeks approval of the new unchanneled GNF 11x11 LUA.
3.2 Description of the Thermal Design There are no changes to this section with the introduction of new contents. Therefore, section 3.1 of the current approved SAR (Global Nuclear Fuel, GNF RAJ-II Safety Analysis Report, NEDE-33869P, Revision 11, September 2022, as amended.) remains applicable. The SAR includes an adequate description of the thermal design. There are no changes to the packaging materials of construction, the inner and outer containers, or the thermal insulation of the inner container. The contents are unirradiated fuel. Therefore, the decay heat of the contents is negligible.
3.3 Material Properties and Component Specifications There are no changes to material properties and component specifications. Therefore, the current approved SAR remains applicable.
3.4 Thermal Evaluation under Normal Conditions of Transport There are no changes to this section with the introduction of new contents. Therefore, section 3.3.1 of the currently approved SAR remains applicable. Section 3.5.3 of the approved SAR contains details applicable to NCT thermal analysis.
5 3.5 Thermal Evaluation under Hypothetical Accident Conditions There is no change to the RAJ-II package thermal design. Therefore, only the differences in behavior of the new package contents are addressed. Because the RAJ-II HAC thermal model is unchanged with the addition of new contents, the maximum HAC temperature is unchanged and the maximum internal pressure calculations in section 3.4.3.2 of the currently approved SAR remain applicable.
3.6 Accident Conditions for Fissile Material Packages for Air Transport The RAJ-II transportation package is not designed for air transport. Therefore, HAC analysis is not applicable.
3.7 Thermal Tests The applicant stated in the SAR that no acceptance or periodic thermal test is required, since the thermal analysis provided in SAR chapter 3 is based on bounding evaluations and no significant material degradation is expected during the package operation.
3.8 Findings
The staff reviewed the RAJ-II transportation package design, construction, and preparations for shipment and found reasonable assurance that the package material and component temperatures will not exceed the specified allowable short-time limits during HACs, consistent with the tests specified in 10 CFR Part 71.
4.0 CONTAINMENT EVALUATION 4.1 Review Objective The objective of the containment evaluation is to verify that the performance of the RAJ-II transportation package design has been adequately evaluated to meet the test requirements specified under NCT and HAC, in accordance with 10 CFR Part 71.
The application seeks approval of the new unchanneled GNF 11x11 LUA.
4.2 Description of the Containment System There are no changes to this section with the introduction of new contents. Therefore, section 4 of the currently approved SAR (which includes an adequate description of the containment system), remains applicable. There is no change to the package materials. The evaluations in chapters 2.0 and 3.0 of the SAR and the corresponding evaluations included in the application demonstrate that the package with GNF 11x11 LUA contents do not rupture under HAC scenarios, which bound the NCT requirements for a package containing a Type A quantity of fissile material.
6 4.3 Containment Evaluation under Normal Condition of Transport There are no changes to this section with the introduction of new contents because the GNF 11x11 LUA shipments contain only Type A fissile material quantities.
4.4 Containment Evaluation under Hypothetical Accident Conditions There are no changes to this section with the introduction of new contents because the GNF 11x11 LUA shipments contain only Type A fissile material quantities.
4.5 Evaluation Findings The staff reviewed the RAJ-II transportation package design, construction, and preparations for shipment. Based on review of the statements and representations in the application, the NRC staff finds that the RAJ-II transportation package has been adequately described and evaluated to demonstrate that it satisfies the containment requirements of 10 CFR Part 71.
5.0 SHIELDING EVALUATION There were no changes to the shielding evaluation as written in RAJ-II in the currently approved SAR Revision No. 11.
6.0 CRITICALITY EVALUATION
6.1 Review Objectives The objective of the criticality evaluation is to verify that the RAJ-II package design meets the nuclear criticality safety requirements in 10 CFR Part 71.
6.2 Description of the Criticality Evaluation The applicant submitted a letter authorization request to support shipment of GNF 11x11 LUAs using the RAJ-II package. The RAJ-II package design remains unchanged from the configuration described in the approved SAR and continues to accommodate unirradiated fuel assemblies with zirconium alloy cladding. While the GNF 11x11 LUA shares design characteristics with previously evaluated GNF BWR fuel types (e.g., 10x10 assemblies), certain parameters exceed the bounding values in the SAR. As a result, the applicant performed a focused analysis to assess the impact of these differences on criticality safety.
The applicant used the KENO-VI code within the SCALE 6.1 package, applying the continuous-energy ENDF/B-VII cross-section library. Validation was supported by representative critical experiments, and no changes to the previously approved methodology were proposed. The staff reviewed the approach and found it consistent with the current approved RAJ-II SAR Revision No. 11.
To identify the most reactive configuration for GNF 11x11 LUAs in the RAJ-II package, the applicant conducted a series of sensitivity studies consistent with the methodology in the RAJ-II SAR Revision No. 11. These studies evaluated the impact of fuel rod pitch, pellet diameter,
7 cladding thickness, moderator density, and material distribution on system reactivity.
Conservative modeling assumptions were applied, including full-density moderator within the inner container, void conditions in the outer container and inter-package spacing, and optimal polyethylene placement. The analyses confirmed that the selected HAC package array configuration represents the bounding condition for criticality safety, with all evaluated parameters contributing to a maximized reactivity scenario.
For single package evaluations, the applicant demonstrated that the bounding HAC configuration remains subcritical and conservatively bounds the NCT case. The reported effective neutron multiplication factors were:
NCT Single Package: keff = 0.67386 +/- 0.00030 HAC Single Package: keff = 0.78289 +/- 0.00031 HAC Package Array (2N = 9): keff = 0.89650 +/- 0.00028 The staff reviewed these results and confirmed that the HAC package array bounds both the HAC and NCT single package configurations and remains below the subcritical limit.
The applicant did not perform a separate evaluation of package arrays under NCT, citing that the HAC array provides a more reactive configuration. The staff agrees with this justification, as the physical changes and moderation conditions under HAC are expected to yield higher reactivity. To evaluate the HAC array, the applicant modeled a 3x1x3 (2N = 9) array of RAJ-II packages loaded with the bounding GNF 11x11 LUA fuel design at 5.0 wt.% U-235 enrichment.
Moderator density studies confirmed that full-density moderator within the inner container yields the most reactive configuration, with keff values ranging from 0.44177 at 0.0 g/cm³ to a peak of 0.89706 at 1.0 g/cm³.
The Criticality Safety Index (CSI) was calculated in accordance with 10 CFR 71.59, resulting in a value of 11.2 for the bounding HAC array configuration. The staff finds the CSI determination acceptable and consistent with regulatory guidance.
GNF 11x11 LUAs will be shipped unchanneled, are limited to Type A fissile material, and are restricted to a maximum enrichment of 5.0 wt.% U-235. Gadolinia rods are not required, and additive fuel may be included as previously approved. These conditions, combined with the bounding analysis and validated methodology, support the criticality safety basis for the proposed configuration.
6.3 Evaluation Findings Based on review of the statements and representations in the application, the staff concludes that the nuclear criticality safety design has been adequately described and evaluated and that the package meets the criticality safety requirements of 10 CFR Part 71.
7.0 OPERATING PROCEDURES EVALUATION There are no changes to this section with the introduction of new RAJ-II 11X11 fuel type.
8 8.0 ACCEPTANCE TESTS AND MAINTENANCE PROGRAM EVALUATION There are no changes to this section with the introduction of new RAJ-II 11X11 fuel type.
CONDITIONS The following conditions are included under this letter authorization:
(1) Transporting a limited number of shipments of 11X11 LUA fuel assemblies.
(2) The LUA shipments will be restricted based on a Criticality Safety Index of 11.2.
(3) The fuel assemblies will contain only Uranium dioxide (UO2) and gadolinium, with an additional allowance for trace amounts of silicon.
(4) The fuel assemblies will contain commercial grade uranium enriched up through 5.0 weight percent (wt.%) of uranium-235 (U-235) and meet Type A fissile material contents.
(5) The fuel assemblies will be shipped unchanneled.
(6) All other conditions of CoC No. 9309 shall remain the same.
(7) This authorization shall expire on October 31, 2027.
CONCLUSION Based on the statements and representations contained in the application, and the conditions listed above, the staff concludes that the package meets the requirements of 10 CFR Part 71.