ML25111A178
| ML25111A178 | |
| Person / Time | |
|---|---|
| Site: | 07109796 |
| Issue date: | 05/16/2025 |
| From: | Yoira Diaz-Sanabria Storage and Transportation Licensing Branch |
| To: | Plate N US Dept of Energy, Naval Reactors |
| Shared Package | |
| ML25111A176 | List: |
| References | |
| EPID L-2024-LLA-0030 | |
| Download: ML25111A178 (1) | |
Text
Nicholas Plate NAVSEA 08G Naval Sea Systems Command 1240 Issac Hull Ave. SE Stop 8021 Washington Navy Yard, DC 20376-8021
SUBJECT:
CERTIFICATE OF COMPLIANCE NO. 9796, REVISION NO. 3, FOR THE MODEL NO. M-290 PACKAGE
Dear Nicholas Plate:
By letter dated February 8, 2024 (Agencywide Documents Access and Management System Accession [ADAMS] No. ML24239A812), as supplemented on May 31, 2024 (ML24233A236),
and December 10, 2024 (ML25092A231), the U.S. Department of Energy, Division of Naval Reactors, (DOE-NR or the applicant) requested renewal and amendment to Certificate of Compliance (CoC) No. 9796 for the Model No. M-290 package. Enclosed is CoC No. 9796, Revision No. 3, for the Model No. M-290 package. The U.S. Nuclear Regulatory Commission staff's safety evaluation report is also enclosed.
The DOE-NR, has been registered as a user of the package under the provisions of Title 49 of the Code of Federal Regulations (CFR) Section 173.471. The approval constitutes authority to use the package for shipment of radioactive material and for the package to be shipped in accordance with the provisions of 49 CFR 173.471.
May 16, 2025
If you have any questions regarding this certificate, please contact me or Nishka Devaser of my staff at (301) 415-5196.
Sincerely, Yoira Diaz Sanabria, Chief Storage and Transportation Licensing Branch Division of Fuel Management Office of Nuclear Material Safety and Safeguards Docket No. 71-9796 EPID No. L-2024-LLA-0030
Enclosures:
1.
Certificate of Compliance 2.
Safety Evaluation Report cc w/encls: Lad Falat, Department of Transportation RVierling, Department of Transportation J. Shuler, DOE c\\o L. T. Gelder Signed by Diaz-Sanabria, Yoira on 05/16/25
SUBJECT:
APPLICATION FOR THE CERTIFICATE OF COMPLIANCE NO. 9796, REVISION NO. 3, FOR THE MODEL NO. M-290 PACKAGE DATED: May 16, 2025 DISTRIBUTION:
Closes EPID No. L-2024-LLA-0030 ADAMS Accession Nos.: ML25111A176 (Pkg), ML25111A178 (Letter & SER),
OFFICE NMSS/DFM NMSS/DFM NMSS/DFM NMSS/DFM NMSS/DFM NAME NDevaser SFigueroa DForsyth GZhao JHuang DATE 4/21/2025 4/23/2025 4/22/2025 4/22/2025 4/22/2025 OFFICE NMSS/DFM NMSS/DFM NMSS/DFM NMSS/DFM NMSS/DFM NAME CStanko DJohnson LRegner TGovan YDiazSanabria DATE 4/23/2025 4/25/2025 4/25/2025 4/30/2025 5/16/2025 SAFETY EVALUATION REPORT Docket No. 71-9796 Model No. M-290 Package Certificate of Compliance No. 9796 Revision No. 3 EVALUATION By letter dated February 8, 2024 (Agencywide Documents Access and Management System Accession [ADAMS] No. ML24239A812), as supplemented on December 10, 2024 (ML25092A231), the U.S. Department of Energy, Division of Naval Reactors, (DOE-NR or the applicant) requested renewal and amendment to Certificate of Compliance (CoC) No. 9796 for the Model No. M-290 package. Enclosed is CoC No. 9796, Revision No. 3, for the Model No. M-290 package. The U.S. Nuclear Regulatory Commission (NRC) staff's safety evaluation report (SER) is also enclosed.
By letter dated May 31, 2024 (ML24233A236), the DOE-NR requested the renewal of CoC No.
9796 for the Model No. M-290 package.
The NRC staff performed its review of the amendment request and associated safety analysis report (SAR) to the M-290 package utilizing the guidance provided in NUREG-2216, Standard Review Plan for Transportation Packages for Spent Fuel and Radioactive Material (SRP).
1.0 GENERAL INFORMATION 1.1 Packaging The M-290 is a right circular cylinder for transporting spent fuel with a package body that is fabricated primarily from stainless steel. The upper inside wall of the package body includes two grooves. One for engagement of an internal retaining ring, and the other for engagement of a closure shear ring system. Between these grooves is a seating ledge for the closure head or canister restraint plate. The package bottom plate is approximately 11.56-inches thick. The thicker lower region of the package body is encircled by a set of 50, equally-spaced, thermal fins welded to the exterior surface. The upper and lower regions of the package body include exterior flanges into which impact mitigating, top and bottom domes are engaged during shipment.
No changes were made to the packaging in this amendment.
1.2 Contents The M-290 contents for this amendment request consist of an A1G internal with separate cells, each designed to hold a single, irradiated A1G assembly. A1G assemblies are configured per section 1.2.5 of the A1G SAR. This application changed the assumed operating histories of some cores which in turn yielded changes to the biases, uncertainties, and calculated keff from the prior licensing basis for the cores operated under the new conditions. These proposed loading restrictions apply only to contents covered under this revision. The limits on A1G assemblies authorized for loading in the M-290 under the prior, NRC-approved revision remain unchanged. The design of the A1G assemblies and A1G internals remain the same as the previously approved revision.
1.3 Drawings The packaging is constructed and assembled in accordance with the drawings in appendix 1.3.3 of the M-290 SAR. Internals assemblies and fuel modules for the A1G spent fuel are constructed and assembled in accordance with drawings in appendix 1.3.3 of the A1G SAR.
No changes were made to the drawings for this amendment.
1.4 Conclusion The staff reviewed the general design information. Based on its review, the staff concludes that the information presented in this section of the application provides an adequate basis for the evaluation of the M-290 package against the requirements in Title 10 of the Code of Federal Regulations (10 CFR) Part 71 for each technical discipline.
2.0 STRUCTURAL EVALUATION The objective of the structural review is to verify that the structural and materials performance of revision 2 of the M-290 A1G transportation package is adequately demonstrated to meet the requirements of 10 CFR Part 71, including the tests and conditions specified under normal conditions of transport (NCT) and hypothetical accident conditions (HAC).
2.1 Background and Discussion The M-290 nuclear spent fuel shipping packaging is certified as a Type B package for shipment of fissile and highly radioactive material. The revision 0 of the M-290 application included a core-independent M-290 SAR (M-290 SAR) for features common to all shipments and a core-dependent SAR for the unique aspects to the A1W core (A1W SAR). The approval of the revision 0 of the M-290 application is based on the combination of the M-290 SAR and A1W SAR. Similarly, the approval of revision 1 of the M-290 application based on a core-dependent SAR for the unique aspects to the A1G core (A1G SAR) with the approved M-290 SAR in revision 0 application.
Revision 2 of the A1G M-290 SAR application evaluates a wider subset of A1G core configurations. The SAR revision continues to support selective loading of the A1G spent fuel modules. This application utilized the approved core-independent M-290 SAR with the evaluations for the modifications in the revision 2 of the core-dependent A1G M-290 SAR to demonstrate that the container satisfies the 10 CFR 71 requirements.
The structural review of this application is focused on the modifications in the A1G SAR.
The principal structural components in the A1G M-290 package are the closure head assembly, the internals retaining ring assembly, the internals assembly, and the A1G spent fuel modules.
The closure head assembly is the primary structural component that provides confinement of the A1G spent fuel.
In the structural section of the revision 2 of the A1G SAR, the applicant performed the evaluations for the following modifications: the structural analyses for revised length requirements for leadscrew and tie rod cutting including the effect on control rod withdrawal and load paths, the replacement of the defueling grapple adapter (DGA) by a simplified DGA, a revised residual water threshold, and a revised initial hydrogen concentration.
The applicant described the simplified DGA design in SAR section 1.2.1.2.5.2.5. The summary stated that the safety function and structural design are not changed for the simplified DGA. The NRC staff reviewed the DGA design and finds that the differences in the simplified design have a neglectable impact on the structural safety analysis result. Therefore, the staff determines that additional analyses of the simplified DGA design are not required.
2.1.1 Design Criteria The applicant used a combination of closed-formed, hand calculations, and finite element analysis to evaluate the A1G M-290 package. In general, evaluations for NCT were performed using primarily hand calculations and supplemented by finite element analysis. Conversely, evaluations for HAC were performed primarily with elastic-plastic finite element analyses and supplemented by hand calculations. In addition, brittle fracture, fatigue, and buckling were also evaluated.
The SAR presented the structural design criteria for the A1G M-290 package. The criteria defined the applicable codes and standards, individual loads as related to environmental conditions and natural phenomenon events, load combinations, and allowable stresses for normal, off-normal, and accident-level conditions.
The NRC staffs review did not identify revisions to the structural design criteria including codes, standards, and material specifications, nor proposed deviations in the use of regulatory guidance as compared to the M-290 certificate of compliance. Therefore, the NRC staff did not review the previously approved design criteria.
2.1.2 Weights and Centers of Gravity Tables 2.1-3 through 2.1-6 of the SAR summarize the weights and centers of gravity for the A1G components and spent fuel modules as well as when the M-290 is loaded with the A1G spent fuel.
The staff reviewed the weights and centers of gravity information and found that the information provided in the SAR supply sufficient details to satisfy the package description requirement listed in 10 CFR 71.33. Therefore, the staff determines that the requirements of the 10 CFR 71.33 are satisfied.
2.1.3 Codes and Standards The staff did not identify any revisions to the structural design codes.
2.1.4 Analytical Approach The staff did not identify revisions to the structural design analytical approach. The revision 1 of the A1G M-290 package application used the explicit finite element analysis (FEA) software LS-DYNA for the core-independent A1G M-290 analysis to determine deceleration values and the time-history response at various locations of the A1G M-290 package for the 1-foot drop and the 30-foot drop analyses. The explicit FEA software Abacus was used to evaluate the stresses and strains in key components of the A1G M-290 package based on the output of the LS-DYNA analysis and supplemented these solutions with closed form hand calculations. The applicant used ten models of sub-assemblies to evaluate different components of the A1G M-290 package. The same approach is inherited for this revision 2 of the A1G M-290 package application.
In SAR appendix 2.12.13, the applicant updated the lead screw/tie rod minimum and maximum cut requirements due to different fuel material. Though the lead screw/tie rod is not structurally evaluated, they are modeled in the FEA to include their interactions with other structural components.
The staff reviewed this approach and found that the simulation of the lead screw/tie rod correctly reflect the design and capture the design features in the FEA simulation and therefore is acceptable.
2.2 Materials Evaluation The revision 1 of the A1G M-290 package application was previously reviewed and approved by the NRC staff, and that evaluation found the M-290 packaging materials to meet and/or exceed the minimum requirements set forth in 10 CFR Part 71 and was designed and fabricated to meet Type B shipping container criteria. The staff did not identify revisions to the material specifications in revision 2 of the A1G M-290 package application that would call into question the NRC staffs previous findings.
2.3 General Requirements for All Packages In revision 2 of A1G M-290 SAR appendix 2.12.28, the applicant updated the initial hydrogen concentration to a lower percentage value in accordance with the preventative Naval Nuclear Propulsion Program (NNPP) operation. Using this updated hydrogen concentration as input, the time to reach to a total 5 percent hydrogen concentration was recalculated. The result showed that the allowable seal time to maintain a lower than 5 percent concentration of combustible gas is decreased to 53 years. In section 2.4.4.2 of the SAR, the applicant updated that the loaded A1G spend fuel model requirement which only allow a sealed time of no more than 50 years according to the updated results from the hydrogen concentration calculation. The NRC staff reviewed the updates in the calculation of the hydrogen concentration and determined that the changes in the initial hydrogen concentration is correctly reflected in the calculation and the result is reasonable. Detailed evaluation refers to NRC staff thermal evaluation in section 3.0.
The revision 2 A1G M-290 package shares the identical design with the core-independent M-290 package design related to the minimum package size, tamper indicating feature, and the positive closure. The NRC staff determined that the A1G M-290 design is consistent with the previously approved design for requirements of 10 CFR 71.43 for the minimum package size, tamper indicating feature, and the positive closure and therefore is acceptable.
2.4 Lifting and Tie-Down Standards for All Packages The NRC staffs evaluation of the lifting and tie-down device design was provided in the SER for the CoC. The NRC staff found that there were no changes to the lifting and tie-down device design in this current request for revision 2, therefore, the NRC staff concludes that the requirements of 10 CFR 71.45(a) remain satisfied.
2.5 Normal Conditions of Transport (NCT)
The evaluation of the package under the NCT is based on the effects of the tests and conditions specified in 10 CFR 71.71. These tests must not result in a decrease in package effectiveness, as specified in 10 CFR 71.43(f), nor any structural changes resulting in contents dispersal, reducing the effectiveness of components for shielding, heat transfer, containment, or maintaining subcriticality.
2.5.1 Heat The applicant stated that the primary concerns of NCT under hot conditions are thermal stresses due to the applied temperatures distribution, stresses due to the resulting internal pressure and the potential interferences from differential thermal expansion.
2.5.1.1 Summary of Pressures and Temperatures The NRC staff did not identify any revisions to the temperatures, temperatures changes, internal pressures, and stresses due to the cargo decay heat and solar insulation in SAR section 2.6.1.
Because the pressure and temperature loading condition in revision 1 of the SAR has been approved, the staff did not perform any additional reviews of these loading condition and considered that the pressure and the temperatures loading used in the stress design remain consistent with the guidance provided in NUREG-2215.
2.5.1.2 Differential Thermal Expansion The applicant performed multiple thermal expansion and contraction evaluations of the A1G M-290 package internal components in SAR appendix 2.12.2.2. The appendix was updated with a revised analysis for closure head potential interference with the cask. The clearance status was checked for both NCT and HAC. A minimum clearance between the upper cask bore and the closure head was maintained for the worst case of thermal differential expansion on different materials. Thus, the applicant concludes that there will be no interference generated for both NCT and HAC.
In addition, the SAR included a revised analysis for potential lead screw/tie rod interference with the DGA lead screw protector. The applicant stated that the screw/tie rod clearance status was assessed for different thermal contraction for different materials that showed the clearance distance reduced by roughly 4 percent. Thus, the applicant concluded there would not be interference for potential thermal expansion and contraction.
The staff reviewed the applicants analysis and finds that in all situations there are no interference generated as the result of differential thermal expansion and the evaluation is acceptable per the requirements of 10 CFR 71.71(c)(1).
2.5.1.3 Stress Calculations and Results The applicant performed stress calculations for NCT hot conditions for all the A1G M-290 package internal components in SAR appendix 2.12.2. The applicant summarized the calculated combined stress values along with the allowable stress limits and the condition under which the maximum stress occurred for all components in SAR table 2.6-7. For the bounding hot conditions, the calculated stresses were less than the allowable stresses for all but the assembly tie rod shank. In this case, the applicant stated that the plastic strain that may be caused by exceeding the maximum allowed stress under hot conditions could result in a relaxation of the preload and localized plastic strain.
The staff reviewed the applicants evaluation of the package under hot NCT. The staff noted that the resulting stress of the tie rod shank exceeded the maximum allowed stress but remained below the ultimate stress. The tie rod would experience local plastic deformation and preload relaxation but no brittle failure. Because the tie rods shank is not the structural component needed to maintain the package safety, the staff determined that the reduction in preload in the rod shank is acceptable. Based on its evaluation, the NRC staff concludes that the hot conditions specified in 10 CFR 71.71(c)(1) do not substantially reduce the effectiveness of the A1G M-290 package and therefore satisfy the 10 CFR 71.43 requirement.
2.5.2 Cold According to the applicant, the primary concern of the cold test for NCT are the potential interferences due to differential thermal contraction, the potential for brittle fracture, and the effects of freezing of the limited water remaining within the package after draining. Because the cold temperatures and the pressure associated with the low temperature are not changed from revision 1 of the A1G M-290 SAR, the staff focused the review on the potential for brittle fracture, and the effects of freezing which is impacted by the A1G lead screw and in A1G tie rod length changes as required by 10 CFR 71.71(c)(2).
2.5.2.1 Brittle Fracture The applicant stated that brittle fracture was evaluated by categorizing materials as potentially subject to brittle fracture or not subject to brittle fracture. The applicant evaluated the A1G spent fuel materials and components that were classified as potentially subject to brittle fracture. For those components, the applicants assessments demonstrate either brittle fracture will not occur or the consequences of failure due to brittle fracture are acceptable and accounted for in the evaluations for conditions of NCT and HAC.
In SAR appendix 2.12.2.6, both materials used in the A1G lead screw and in A1G tie rod are evaluated in NCT condition. The applicant identified multiple potential load paths for different DGA configurations and tie rod / lead screw cut lengths. A detailed analysis in SAR appendix 2.12.2.7 showed that the lead screw does not buckle during NCT due to a simultaneous 4-g axial shock and 1-g transverse acceleration. In this primarily compression loading condition, the applicant asserts that crack deflect would be the major failure mode, thus brittle facture would not occur under both NCT and HAC conditions.
The SAR appendix 2.12.2.6 also evaluated A1G down stop in NCT. Different situations are evaluated for down stop subject to different loading conditions and orientations. When subject to lateral load, the cracked down stop will potentially have brittle fractures but would still provide the function to carry the compression. Five possible brittle fracture locations on the structural component were assessed by the applicant. The applicant concluded that the structural function of the component can be maintained in all cases. Therefore, the function of carrying the compression force from the control rod remained effective during NCT (appendix 2.12.2.6) and during HAC (appendix 2.12.7).
The staff reviewed the calculation and the discussion about the down stop evaluation and finds that the five possible crack locations would be the only possible locations where the crack could develop. Based on the function and the location of the down stop, the NRC staff determined that the cracks at the possible locations will have no impact to relay the compression force from the control rod through the down stop to the supporting components and therefore will not the reduce the effectiveness of A1G M-290 package. The NRC staff concluded that the A1G M-290 package will satisfy the 10 CFR 71.71(c)(2) requirements.
2.5.2.2 Freezing of Residual or Accumulated Water The applicant stated that the primary concern with the residual water within the M-290 is the potential for freezing of the water against the containment cover seals. The applicant demonstrated that the position of the M-290 package on the railcar causes the residual water in the M-290 package to remain near the bottom of the canister where freezing will not have an effect on the closure seals. With the M-290 package positioned at a small angle tilt on the railcar, the highest extension of the residual water is more than 7 inches below the closure head seals. The applicant showed that the residual water will not enter the A1G fuel cell assemblies; therefore, there is no concern with damage to the fissile contents as a result of any freezing of residual water. Additionally, the applicant asserted that the sealed closure head in the A1G internals protects against water reaching the containment closure head. This water volume provided the input for the hydrogen calculation in SAR appendix 2.12.28 discussed in this SER section 2.3.
The NRC staff reviewed the applicants calculation and the discussion about the freezing of residual or accumulated water and found that the level of residual water will not have direct contact with the cover seals since it is more than 7 inches below the closure head seals.
Therefore, the staff determines that the A1G M-290 package satisfies the 10 CFR 71.71(c)(2) requirements.
2.5.3 Reduced External Pressure The applicant stated that the revision 1 A1G M-290 SAR demonstrated that the M-290 containment boundary remained sealed under reduced external pressure and that no further evaluation was necessary for the M-290 loaded with A1G spent fuel.
The NRC staff found that there were no changes to the evaluation for the reduced external pressure conditions in this revision 2 of A1G M-290 SAR. Therefore, the NRC staff concludes that the requirement of effectiveness of the A1G M-290 package under reduced external pressure conditions as specified in 10 CFR 71.71(c)(3) remain satisfied.
2.5.4 Increased External Pressure The applicant stated that the revision 1 A1G M-290 SAR demonstrated that the M-290 package containment boundary remained sealed under increased external pressure and that no further evaluation was necessary for the M-290 loaded with A1G spent fuel.
The NRC staff found that there were no changes to the evaluation for the increased external pressure conditions in this revision 2 of A1G M-290 SAR. Therefore, the NRC staff concludes that the requirement of effectiveness of the A1G M-290 package under increased external pressure conditions as specified in 10 CFR 71.71(c)(4) remain satisfied.
2.5.5 Vibration and Fatigue 2.5.5.1 Vibration The applicant summarized the vibration and shock loads in SAR table 2.12.2.10-1. The applicant stated that vibration of the M-290 transportation packaging, A1G internals, and cargo is driven by the vibration of the M-290 railcar during transportation. In SAR section 2.6.5.1, the applicant discussed the potential for relative motion under the vibratory loads, the component natural frequencies, and any potential for resonance. SAR section 2.6.5.1 also summarized the calculation results in SAR appendix 2.12.2.10 under radial and axial vibratory loads. The applicants comparison of joint clamping capability and the joint vibration loading demand resulting from the finite element analysis shows that no potential for resonance and joint separation will occur in the A1G components due to vibration loads.
The NRC staff found that there were no changes to the evaluation for the vibration induced load in this revision 2 of A1G M-290 SAR. Therefore, the NRC staff concludes that the requirement of effectiveness of the A1G M-290 package under vibration conditions as specified in 10 CFR 71.71(c)(5) remain satisfied.
2.5.5.2 Fatigue The NRC staff found that there were no changes to the fatigue evaluation in this revision 2 of A1G M-290 SAR. Therefore, the NRC staff concludes that the fatigue requirement induced by the vibration load as specified in 10 CFR 71.71(c)(5) remain satisfied 2.5.6 Water Spray In Regulatory Guide (RG) 7.8 section B, the water spray test is considered to have no impact to the structural design when the package is larger than one ton. Because the M-290 package is more than one ton, the NRC staff concluded that it meets the criteria of RG 7.8 and the water spray test of 10 CFR 71.71(c)(6) is not required.
2.5.7 Free Drop The NRC staff found that there were no changes to the free drop test evaluation in this revision 2 of A1G M-290 SAR. Therefore, the staff finds that the requirements of 10 CFR 71.71(c)(7) remain satisfied.
2.5.8 Corner Drop As specified in RG 7.8 section B, the corner drop test applicable to the lightweight package.
Since the A1G M-290 package is a large shipping package, the staff finds that a corner drop test per 10 CFR 71.71(c)(8) is not applicable because it meets the criteria of RG 7.8.
2.5.9 Compression The A1G-configured M-290 transportation package weighs more than 11,000 lbs. Since the compression test of 10 CFR 71.71(c)(9) is applicable only to packages less than 11,000 lbs, this test is not applicable.
2.5.10 Penetration The penetration test was completed as a NCT condition in the SAR accompanying revision 0 of this certificate of compliance. The staff did not identify revisions impacting the penetration test.
Therefore, the requirements of 10 CFR 71.71(c)(10) remain satisfied.
2.6 Hypothetical Accident Conditions (HAC) 2.6.1 Free Drop The applicant used the ten finite element models described in section 2.1.4 of this SER to evaluate the A1G M-290 package for the free drop event in the sequence of tests for the HAC.
The applicant summarized the results of the 30-foot drop in SAR section 2.7.1.8. The free drop test was completed as HAC condition in the SAR accompanying revision 0 of this certificate of compliance. The staff did not identify any updates in this revision 2 of AIG M-290 SAR for the free drop test except the flat top drop.
In SAR appendix 2.12.3, the applicant stated that during the flat top drop test, multiple load paths exist for the translating assembly. The applicant stated that the components of the translating assembly may fail due to local deformation at different assembly lengths but are still acceptable when evaluated using either FEA or closed form evaluations.
In SAR appendix 2.12.7, the applicant stated that during the flat bottom drop test, multiple load paths exist for the translating assembly. The applicant stated that the components of the translating assembly may fail due to local deformation at different assembly lengths but are still acceptable when evaluated using either FEA or closed form evaluations.
In SAR appendix 2.12.2.6, the applicant revised the evaluation for the impact of the shifting load path which results from the revised lead screw/tie rod cut length. The brittle fracture of the translating assembly components was also evaluated and the applicant determined that the down stop is effective at restricting control rod motion during normal and accident conditions.
The applicant investigated the five possible brittle fracture locations on the structural components under the lateral load during HAC. The applicant concluded that the structural function of the components is maintained.
The staff reviewed the applicants analyses for free drop testing under HAC and finds that the calculation assumptions and results are consistent with the expected behavior of the package in drop scenarios. The staff finds that the five possible brittle fracture assessed regions covered all locations where the continuity of the structural component stiffness changed. Based on the function and the location of the down stop, the NRC staff determined that the cracks at the possible locations will have no impact to relay the compression force from the control rod through the down stop to the supporting components and therefore will not the reduce the effectiveness of A1G M-290 package. Therefore, the staff concludes that the outcome of the brittle fracture analyses of the structural members is acceptable and finds that the requirements of 10 CFR 71.73(c)(1) are satisfied.
2.6.2 Crush The weight of the A1G M-290 package is greater than 1100 lbs. Since the crush test of 10 CFR 71.73(c)(2) is required only when the specimen is less than 1100 lbs, this test is not required.
2.6.3 Puncture The 40-inch puncture drop was completed as HAC in the SAR accompanying revision 0 of this CoC. The staff did not identify any revisions for the puncture test in this revision 2 of A1G M-290 SAR. Therefore, the staff finds that the requirements of 10 CFR 71.73(c)(3) remain satisfied.
2.6.4 Thermal The applicant used a combination of closed form calculations and finite element analysis to determine the structural responses (thermal stresses, differential thermal expansion, and stresses due to pressure differentials) of the packaging and contents due to the fire test temperatures of 10 CFR 71.73 (c)(4).
The A1G M-290 package is evaluated for thermal effects from 30 minutes at 1,475 °F for a fire accident. The structural responses of all structural components based on a combination of closed form calculation and the FEA are discussed in SAR appendix 2.12.11. The applicant presented a revised analysis for the cask interference with the internals. In HAC, minimal radial clearances between cask and internals are listed in SAR table 2.12.11-2. The interferences are evaluated using FEA and the resulting pressure is added to the cask internal pressure for HAC and applied to the cask HAC analysis model. The analysis results listed in SAR table 2.12.11-3 show that the expansion of the spacer plates does not significantly affect the cask strain. In SAR appendix 2.12.2.13, the applicant demonstrated that a small interference has a negligible effect on the cask performance, thus the A1G internals and cargo have no plastic deformation resulting from the fire test conditions. The applicant concluded that the pressure on the cask due to thermal expansion of the internals spacer plates does not affect the integrity of the cask.
The staff verified there were no revisions for the thermal evaluation under HAC other than the update evaluations of the cask interference with the internals as described above. The staff reviewed the applicants updated evaluation under the thermal test in according to the condition defined in 10 CFR 71.73(c)(4) and finds that the thermal test conditions do not substantially reduce the effectiveness of the A1G M-290 package. Therefore, the staff finds that the requirements of 10 CFR 71.73(c)(4) are satisfied.
2.6.5 Immersion - Fissile In SAR chapter 6, the applicant determined that the A1G M-290 package remains subcritical under the conservative assumption of an optimally moderated package along with bounding contents and control rod translation; therefore, the staff finds that water exclusion is not necessary to meet criticality requirements, and the test of 10 CFR 71.73(c)(5) has no relevance.
2.6.6 Immersion - All packages The applicant demonstrated that the deep immersion evaluation bounds this required evaluation of 10 CFR 71.73(c)(6). Because the deep immersion per 10 CFR 71.61 imposes a much larger external water pressure than 10 CFR 71.73(c)(6), the staff concludes that this test requirement for 10 CFR 71.73(c)(6) is satisfied.
The staff has reviewed the structural performance of the packaging under the HAC prescribed in 10 CFR 71.73 and concludes that the packaging has adequate structural integrity to satisfy the subcriticality, containment, and shielding requirements of 10 CFR 71.51(a)(2) for a Type B package and 10 CFR 71.55(e) for a fissile material package.
2.7 Special Requirements for Type B Packages Containing More than 105 A2 2.7.1 Deep Immersion The applicant evaluated the M-290 transportation package for deep immersion in the M-290 SAR. The applicant demonstrated that there were no adverse effects including collapse or buckling due to the applied external water pressure. The deep immersion evaluation was completed in the SAR accompanying revision 0 of this certificate of compliance. The staff did not identify any revisions for the deep immersion evaluation in the revision 2 of this A1G M-290 SAR. Therefore, the staff finds that the requirements of 10 CFR 71.61 remain satisfied.
2.8 Evaluation Findings
Based on review of the statements and representations in the application, the NRC staff concludes that the structural design has been adequately described and evaluated and that this revision 2 of A1G M-290 package has adequate structural integrity to meet the requirements of 10 CFR Part 71.
3.0 THERMAL EVALUATION The purpose of this evaluation is to verify that the M-290 transport package provides adequate protection against the thermal tests specified in 10 CFR Part 71 and to verify that the package design meets the thermal performance requirements of 10 CFR Part 71 under NCT and HAC.
The applicant performed a thermal analysis of the M-290 package for NCT and HAC using the Abaqus computer code. The thermal analysis was performed for the A1G fuel modules. The thermal evaluation performed by the applicant assumed that the contents were shipped dry with a maximum decay heat load of 58,484 BTU/hr.
3.1 Description of Thermal Design of Containment The M-290 has been designed as a right circular cylinder with domes on both ends and is shipped in a near-horizontal attitude on its railcar (view figure 1.1-1 of chapter 1 in the M-290 SAR, B-MDP(E)SCD-300). The M-290 is designed to hold either canistered or uncanistered fuel assemblies.
The fueled region of the spent fuel assemblies is located at the bottom half of the packaging (referenced from its vertical loading orientation) in the finned region. The decay heat is transferred to the package inner wall from the canister containing the basket and spent fuel modules by radiation and conduction through internal gas (air or water vapor). Conduction takes place through the package metal wall to the outside diameter and then to the ambient environment through the mechanisms of convection and radiation heat transfer. The lower half of the package enhances the heat transfer by the presence of annular fins welded to the outside of the package. The upper and lower domes, located at both ends of the package protect the package by deforming and absorbing energy during the HAC drop test and protect the lid from direct exposure to the fully engulfing fire.
3.1.1 Maximum Decay Heat The staff reviewed section 3.1.2 of both the M-290 SAR and A1G SAR dealing with decay heat of the contents, and reviewed the calculations, equations, and supplemental documentation provided by the applicant. Based on the staffs review, the staff finds reasonable assurance that the discussion on decay heat and the calculation for maximum decay heat are acceptable.
3.2 Normal Conditions of Transport (NCT)
In analyzing the package for NCT, the applicant assumed a 100 °F ambient temperature, a maximum heat load of 58,484 BTU/hr, and the solar insolation given in the Insolation Data table in 10 CFR 71.71(c)(1). The maximum temperatures calculated for NCT at various locations, and the associated design temperatures, are listed in section 3.3.1.1 of the SAR.
The results of the applicant's analysis show that the seal region remained below the acceptable service temperature for ethylene propylene O-rings. The maximum temperature of the fuel modules did not exceed the fuel temperature limit. The calculated temperatures were within the limits for the package materials.
The M-290 package was also analyzed for a 100 °F ambient temperature without insolation.
The maximum temperature at any accessible point on the package surface was determined to be less than 185 °F and therefore meets the requirement in 10 CFR 71.43(g) for maximum temperature for any accessible surface for exclusive use shipments.
Section 2.4.4.2 of the SAR concludes based on the conservative analysis in appendix 2.12.28 therein that the hydrogen concentration will remain below 5 percent by volume for the time that the M-290 containing A1G spent fuel is sealed. There is a loading restriction in place to ensure the package is not sealed for a time greater than a specific period which is less than the time calculated for the hydrogen content to increase to 5 percent by volume.
The staff reviewed the calculations and methods used by the applicant to determine the temperatures and internal environment of the package at NCT for various locations within the M-290 package. Based on the staffs review, the staff finds reasonable assurance that the regulations for NCT were met and that package temperatures do not exceed allowable temperature limits.
3.3 Hypothetical Accident Conditions (HAC)
In analyzing the M-290 package for HAC, the applicant evaluated the package in accordance with 10 CFR 71.73 with the package on the railcar at 100 °F ambient temperature, simulating a 30-minute, 1475 °F fire with insolation and an internal decay heat load of 58,484 BTU/hr. The maximum temperatures calculated for HAC at various locations are listed in section 3.4.3.3 of the SAR.
The thermal analysis for the M-290 transportation package showed that the maximum fuel temperature did not exceed the limit. The results of the applicants analysis showed that the seal region remained below the maximum temperature.
3.4 Evaluation Findings
The staff reviewed the calculations and methods provided by and used by the applicant to determine the temperatures for HAC for various locations within the M-290 package. Based on the staffs review, the staff finds reasonable assurance that the regulations for HAC were met and that package temperatures do not exceed allowable temperature limits.
4.0 CONTAINMENT EVALUATION The DOE-NR did not propose any changes to the M-290 packaging design that impact the containment of the package.
5.0 SHIELDING EVALUATION The applicant submitted a licensing amendment request which includes updated shielding evaluations. The DOE-NR intends these updated evaluations to apply to A1G spent fuel discharged from cores not covered by the previously approved revision. The objective of the staffs evaluation is to verify the proposed change to the M-290 transportation package design continues to meet the radiation safety requirements of 10 CFR 71 under the conditions described in 10 CFR 71.71 and 71.73. The staffs evaluation follows the guidance of SRP.
5.1 Proposed Change No. 1 The only change to the SAR is the assumption described in section 5.3.1 of the application. This change is a small shift in the assumed position of a component. The DOE-NR evaluated the impact on external dose rates with this position change with results shown in figures 5.4-1 through 5.4-6 of the application. The staff noted that this small change will likely have no significant effect on external dose rates, and there is significant margin between the most limiting calculated dose rates and the regulatory limit.
5.2 Evaluation Findings
The proposed change in this license amendment will result in no significant change to maximum external dose rates. Based on the staffs review of the small changes, the margin between maximum dose rates and regulatory limits, and staff review of previous revision, the staff finds reasonable assurance that the shielding requirements of 10 CFR Part 71 will continue to be met with the proposed changes.
6.0 CRITICALITY EVALUATION
The DOE-NR requested an amendment to the certificate for the M-290 transportation package which includes spent fuel discharged from cores not covered by the previously approved revision. In order to ensure the new contents meet the requirements of 10 CFR 71, the DOE-NR has proposed two changes that impact criticality safety: (1) the use of new rod hold-down devices to limit the movement of the control rods; (2) restrictions on loading locations of spent nuclear fuel within the M-290 package depending on irradiation history. The objective of the staffs evaluation is to verify the proposed changes to the M-290 transportation package design continue to meet the criticality safety requirements of 10 CFR 71 under the conditions described in 10 CFR 71.71 and 71.73. The staffs evaluation follows the guidance of SRP.
6.1 Description of Criticality Design 6.1.1 Packaging Design Features The DOE-NR did not propose any changes to the M-290 packaging design that impact criticality safety.
6.1.2 Codes and Standards The DOE-NR did not change any of the codes and standards approved by NRC staff in prior revisions.
6.1.3 Summary Table of Criticality Evaluations The DOE-NR presented the most limiting results of its criticality analyses in table 6.1-1 of the SAR. The staff reviewed the results and noted the calculated reactivity coefficients (keff) all remain below the upper subcritical limit (USL) with all biases and uncertainties applied.
6.1.4 Criticality Safety Index (CSI)
NR showed the maximum number of packages in an array that remained subcritical did not change, and the CSI remains the same.
6.2 Nuclear Contents The M-290 contents for this amendment request consist of an A1G internal with separate cells, each designed to hold a single, irradiated A1G assembly. A1G assemblies are configured per section 1.2.5 of the A1G SAR. The DOE-NR changed some of the assumed operating histories of some cores which in turn yielded changes to the biases, uncertainties, and calculated keff from the prior licensing basis for the cores operated under the new conditions. These proposed loading restrictions apply only to contents covered under this revision. The limits on A1G assemblies authorized for loading in the M-290 under the prior, NRC-approved revision remain unchanged. The design of the A1G assemblies and A1G internals remain the same as the previously approved revision.
6.3 General Considerations for Criticality Evaluations 6.3.1 Model Configuration The DOE-NR did not make any changes to its criticality model aside from the irradiation history of the contents discussed in section 6.2 above.
6.3.2 Material Properties The DOE-NR did not make any changes to the material properties used in its criticality evaluations.
6.3.3 Analysis Methods and Nuclear Data The DOE-NR did not make any changes to the codes or cross-section libraries used in its criticality evaluations.
6.3.4 Demonstration of Maximum Reactivity The DOE-NR expresses burnup as core age in the CoC and set two effective burnup limits with associated loading restrictions for the proposed new contents. The staff reviewed the DOE-NRs evaluation of reactivity as a function of burnup and finds reasonable assurance that the minimum limits chosen by the DOE-NR are within a region of decreasing reactivity with additional operation. However, the lower end of the burnup range yields configurations above the USL under the old assumptions. The DOE-NR has proposed two solutions based on burnup and irradiation history limits. One solution uses rod hold-down devices to restrict the movement of the control rods under HAC which will reduce the calculated keff of the most reactive configuration. Another option limits assemblies with lower burnup in quantity and location, which also reduces the calculated keff of the most reactive configuration. A combination of these two solutions may also be used in the same M-290 package. Control rod shifting and loading limits on A1G assemblies less than the minimum burnup remain unchanged from the previous revision.
The DOE-NR evaluated the effect of burnup, moderator temperature, fuel assembly rotation, and fuel assembly shifting independently. The DOE-NR evaluated several combinations of loadings to determine most reactive loading that meets the burnup location restrictions. The results of the combinations of assembly types, loading locations, and burnup are shown in table 6.3-4 of the SAR. The most reactive configuration is shown in figure 6.3-17 of the SAR.
Staff reviewed the DOE-NRs evaluations and finds they adequately cover the range of configurations and conditions that can reasonably be expected. As a result, staff finds reasonable assurance that the DOE-NRs analyses show the most reactive configuration will remain subcritical.
6.3.5 Moderator Exclusion Under HAC The DOE-NR evaluated the M-290 configuration under HAC as flooded and does not rely on moderator exclusion for criticality safety.
6.4 Single Package Evaluations The DOE-NR made small changes to the single package evaluation under flooding conditions and NCT. For flooding conditions, NR updated the distance control rods can shift within the M-290 and changed the amount of water assumed to be present after draining. Both changes are small in magnitude, and these configurations maintain a large margin between the maximum calculated keff and the package USL.
For a single package under HAC, the DOE-NR proposed no changes to the assumed configuration aside from the contents and the shifting of control rods.
6.5 Evaluations of Package Arrays Aside from the contents changes described in section 6.4 above, the DOE-NR made no changes to the assumed configuration of arrays of M-290 packages.
6.6 Benchmark Evaluations The DOE-NR did not make any changes to the benchmarks or methodology used to determine the total bias and uncertainty, expressed as a single k value. The DOE-NR subtracted this value from the administrative USL to determine the package USL. The staff reviewed the new evaluation and noted that the new bias and uncertainty with the proposed changes yield a USL that is bounded by the previous USL. As a result, staff finds the DOE-NR continued use of the previously approved biases and uncertainties acceptable since they conservatively minimize the USL.
6.7 Evaluation Findings
Based on staff review of the methods, analyses, information presented in the amendment request, and prior staff review, the staff finds reasonable assurance that the proposed contents will maintain sufficient margin of subcriticality and meet the requirements of 10 CFR Part 71.
7.0 OPERATING PROCEDURES In the application, the DOE-NR provided procedures that are specific to the A1G fuel assemblies for preparing the package for loading, loading the contents, and unloading the M-290 package, and preparing an empty package for transport. The A1G-specific procedures, along with those in the M-290 core-independent SAR, provide the full set of operating procedures for operating the M-290 package containing proposed changes to the contents.
The staff reviewed the Operating Procedures in chapter 7 of the application to verify that the package will be operated in a manner that is consistent with its design evaluation. On the basis of its evaluation, the staff concludes that the combination of the engineered safety features and the operating procedures provide adequate measures and reasonable assurance for safe operation of the proposed design basis fuel in accordance with 10 CFR Part 71.
8.0 ACCEPTANCE TESTS AND MAINTENANCE PROGRAM The A1G SAR provides acceptance tests for M-290 packaging components specific to the A1G fuel modules. The specific acceptance tests include visual inspections and measurements; weld inspections; a pressure and leakage tests on the A1G closure head; and component and material tests. Based on the statements and representations in the application, the staff concludes that the acceptance tests for the packaging meet the requirements of 10 CFR Part 71.
CONDITIONS The following conditions were revised in the CoC:
Condition 7 was revised to reflect changes to provide clarity of the A1G fuel content limitations.
Condition 12 was revised to renew the CoC for an additional 5 years.
The REFERENCES section was revised to include this amendment request.
CONCLUSIONS Based on our review, the statements and representations contained in the application, as supplemented, and the conditions listed above, we conclude that the Model No. M-290 package meets the requirements of 10 CFR Part 71 and has been renewed for a 5-year term.
Issued with Certificate of Compliance No. 9796, Revision No. 3.