Archived Web Page: Draft Regulatory Document RD-364Joint Canada - United States Guide for Approval of Type B(U) and Fissile Material Transportation Packages

2.0 STRUCTURAL EVALUATION

This section of the application should identify, describe, discuss, and analyze the principal structural design of the packaging, components, and systems important to safety. In addition, this section should describe how the package complies with the performance requirements of 10 CFR Part 71 and the PTNS Regulations.

2.1 Description of Structural Design

2.1.1 Discussion

This section should identify the principal structural members and systems (such as the containment vessel, impact limiters, radiation shielding, closure devices, and ports) that are important to the safe operation of the package. The discussion should reference the locations of these items on drawings and discuss their structural design and performance.

The packaging should be described in sufficient detail to provide an adequate basis for its evaluation. The text, sketches, and data describing the structural design features should be consistent with the engineering drawings and the models used in the structural evaluation. Descriptive information important to structures includes the following:

1. Dimensions, tolerances, and materials;
2. Maximum and minimum weights and centers of gravity of packaging and major subassemblies;
3. Maximum and minimum weight of contents if appropriate;
4. Maximum normal operating pressure;
5. Description of closure system;
6. Description of handling requirements; and
7. Fabrication methods as appropriate.

2.1.2 Design Criteria

This section should describe the load combinations and factors that serve as design criteria. For each criterion, this section should state the maximum allowable stresses and strains (as a percentage of the yield or ultimate values for ductile failure) and describe how the other structural failure modes (e.g., brittle fracture, fatigue, buckling) are considered. If different design criteria are to be allowed in various parts of the packaging or for different conditions, this section should indicate the appropriate values for each case. This section should identify the criteria that are used for impact evaluation as well as the codes and standards that are used to determine material properties, design limits, or methods of combining loads and stresses. In the event that the design criteria deviate from those specified by standard codes or if such codes do not cover certain components, this section should provide a detailed description and justification for the use of the design criteria used as substitutes. All assumptions made must be verified. For SNF and high-level waste packages, load combinations and design criteria are defined in NRC Regulatory Guide 7.6, Design Criteria for the Structural Analysis of Shipping Cask Containment Vessels [19], and Regulatory Guide 7.8, Load Combinations for the Structural Analysis of Shipping Casks for Radioactive Material [25].

2.1.3 Weights and Centers of Gravity

This section should list the total weight of the packaging and contents and tabulate the weights of major individual subassemblies such that the sum of the parts equals the total of the package. The discussion should identify the location of the center of gravity of the package and any other centers of gravity referred to in the application. For example, the center of gravity for major sub-assemblies or package configurations that use different shielding configurations or components, should be identified. A sketch or drawing that clearly shows the individual subassembly referred to and the reference point for locating its center of gravity should be included. In general, the discussion need not provide the calculations used to determine the centers of gravity.

2.1.4 Identification of Codes and Standards for Package Design

This section should identify the established codes and standards proposed for use in package design, fabrication, assembly, testing, maintenance, and use. An assessment of the applicability of codes and standards should be included.

This section should identify established codes and standards or justify the basis used for the package design and fabrication. The codes and standards must be appropriate for the intended purpose and must be properly applied. The code or standard should consider the quantity and hazard of the radioactive contents. In specifying a code or standard, it is important to show that the code or standard:

1. Was developed for structures of similar design and material, if not specifically for shipping packages;
2. Was developed for structures with similar loading conditions;
3. Was developed for structures that have similar consequences of failure;
4. Adequately addresses potential failure modes; and
5. Adequately addresses margins of safety.

The American Society of Mechanical Engineers (ASME) has developed a code specifically for the design and construction of the containment systems of a spent fuel cask or high-level radioactive waste transport packaging, known as the ASME Boiler and Pressure Vessel Code, Division 3 [6]. In general, use of this code is acceptable for material specifications, design, fabrication, welding, examination, testing, inspection, and certification of containment systems for spent fuel packaging. Deviations from this code should be explicitly defined and justified for spent fuel, high-level radioactive waste packages, or other packages designed to transport large quantities of radioactive material (e.g., greater than 3000 A₁ for special form or 3000 A₂ for normal form material).

Information regarding design and fabrication criteria and appropriate codes and standards for all types of radioactive material transport packages is provided in references 21 and 27.

2.2 Materials

This section should describe the materials of construction of the package and address the requirements in 10CFR 71.43(d) or Paragraph 613 of TS-R-1 which is incorporated in Subsection 1(1) of the PTNS Regulations by reference to Paragraph 650 of TS-R-1.

2.2.1 Material Properties and Specifications

This section should list the material mechanical properties used in the structural evaluation. These should include yield stress, ultimate stress, modulus of elasticity, ultimate strain, Poisson’s ratio, density, and coefficient of thermal expansion. If impact limiters are used, this section should include either a compression stress-strain curve for the material or the force-deformation relationship for the limiter as appropriate. For materials that are subjected to elevated temperatures, the appropriate mechanical properties under those conditions should be specified. The source of the information in this section should be identified by publication and page number. Where material properties are determined by testing, this section should describe the test procedures, conditions, and measurements in sufficient detail to enable the staff to evaluate the validity of the results. Materials of construction should be resistant to brittle fracture at all design temperatures.

An appropriate specification should be identified for the control of each material. Materials and their properties should be consistent with the design code or standard selected. If no code or standard is available, the application should provide adequately documented material properties and specifications for the design and fabrication of the packaging.

The materials of structural components should have sufficient fracture toughness to preclude brittle fracture under normal conditions of transport and hypothetical accident conditions. NRC Regulatory Guide 7.11, Fracture Toughness Criteria of Base Material for Ferritic Steel Shipping Cask Containment Vessels with a Maximum Wall Thickness of 4 Inches (0.1 m) [22], and Regulatory Guide 7.12, Fracture Toughness Criteria of Base Material for Ferritic Steel Shipping Cask Containment Vessels with a Wall Thickness Greater than 4 Inches (0.1 m) But Not Exceeding 12 Inches (0.3 m) [23], provide criteria for fracture toughness.

The material properties should be appropriate for the load conditions (e.g., static or dynamic impact loading, hot or cold temperatures, and wet or dry conditions). The temperatures at which allowable stress limits are defined should be consistent with minimum and maximum service temperatures. Force-deformation properties for impact limiters should be based on appropriate test conditions and temperatures.

For packages with impact-limiting devices or features, the methods used to establish their force-deflection characteristics should be provided and should include testing. Testing of the impact limiters may be carried out statically if the effect of strain rates on the material crush properties is accounted for and properly included in the force-deflection relationship for impact analysis. The force-deflection curve of the impact limiter should be provided for all directions analyzed for the packaging.

2.2.2 Chemical, Galvanic, or Other Reactions

This section should describe possible chemical, galvanic, or other reactions in the packaging or between the packaging and the package contents as well as methods used to prevent significant reactions. For each component material of the packaging, this section should list all chemically or galvanically dissimilar materials in contact with it. Coatings used on internal or external package surfaces, any reactions resulting from water in-leakage or cask flooding, and the possible generation of hydrogen or other gases from chemical, radiolytic, or other interactions should be considered. Galvanic interactions and the formation of a eutectic for components that are or may be in physical contact should also be considered. Such interactions may occur with depleted uranium, lead, or aluminum in contact with steel. If appropriate, consider embrittling effects of hydrogen, taking into account the metallurgical state of the packaging materials. Pyrophoricity should also be addressed.

2.2.3 Effects of Radiation on Materials

This section should describe any ageing or damaging effects of radiation on the packaging materials and should cite references for established dose limits for affected materials. These should include degradation of seals, sealing materials, coatings, adhesives, and structural materials.

2.3 Fabrication and Examination

2.3.1 Fabrication

This section should describe the fabrication processes used for the package, such as fitting, aligning, welding and brazing, heat treatment, and foam and lead pouring. For fabrication specifications prescribed by an acceptable code or standard (e.g., those promulgated by ASME or the American Welding Society), the code or standard, edition, date, or addenda should be clearly specified on the engineering drawings. Unless the application justifies otherwise, specifications of the same code or standard used for design should also be used for fabrication. For components for which no code or standard is applicable, the application should identify the specifications on which the evaluation depends and describe the method of control to ensure that these specifications are achieved. This description should reference quality assurance or other appropriate specifications documents, which should be identified on the engineering drawings.

2.3.2 Examination

This section should describe the methods and criteria by which the fabrication is determined to be acceptable. Unless the application justifies otherwise, specifications of the same code or standard used for fabrication should also be used for examination. For components for which no fabrication code or standard is applicable, the application should summarize the examination methods and acceptance criteria in Section 8, Acceptance Tests and Maintenance Program.

2.4 General Requirements for All Packages

This section should address the requirements of 10 CFR 71.43(a), (b), and (c) or Paragraphs 634, 635, and 639 of TS-R-1 which are incorporated in Subsection 1(1) of the PTNS Regulations by reference to Paragraph 650 of TS-R-1.

2.4.1 Minimum Package Size

This section should specify the smallest overall dimension of the package, which should not be less than 10 cm (4 in).

2.4.2 Tamper-Indicating Feature

This section should describe the package closure system in sufficient detail to show that it incorporates a protective feature that, while intact, is evidence that unauthorized persons have not tampered with the package. The description should include covers, ports, or any other access that must be closed during normal transportation. Tamper indicators and their locations should be described.

2.4.3 Positive Closure

This section should describe the package closure system in sufficient detail to show that it cannot be inadvertently opened. This description should include covers, valves, or any other access that must be closed during normal transportation.

2.5 Lifting and Tie-Down Standards for All Packages

2.5.1 Lifting Devices

This section should identify all devices and attachments that can be used to lift the package or its lid and show by testing or analysis that these devices comply with the requirements of 10 CFR 71.45(a) or Paragraphs 607 and 608 of TS-R-1 which are incorporated in Subsection 1(1) of the PTNS Regulations by reference to Paragraph 650 of TS-R-1. This includes showing that failure of the lifting devices under excessive load will not impair the ability of the package to meet other requirements. This section should also include drawings or sketches that show the locations and construction of these devices and should show the effects of the forces imposed by lifting devices on other packaging surfaces. Documented values of the yield stresses of the materials should be used as the criteria for demonstrating compliance with 10 CFR 71.45(a), including failure under excessive load. For attachments or other features that could be used to lift the package and that do not meet the lifting criterion, this section should show how they are rendered inoperable for lifting.

2.5.2 Tie-Down Devices

This section should describe the overall tie-down system for the package and show that the system meets the requirements of 10 CFR 71.45(b) and Paragraph 636 of TS-R-1 which is incorporated in Subsection 1(1) of the PTNS Regulations by reference to Paragraph 650 of TS-R-1. Any device that is a structural part of the package and can be used for tie-down should be identified. Drawings or sketches that show the locations and construction of the overall tie-down system and the individual devices should be provided. This section should also discuss the testing or analysis that shows these devices are designed to withstand tie-down forces and should show the effect of the imposed forces on vital package components, including the interfaces between the tie-down devices and other package surfaces. Documented values of the yield stresses of the materials should be used as the criteria for demonstrating the adequacy of the tie-down devices and failure under excessive load. This section should show that failure of the tie-down devices under excessive load will not impair the ability of the package to meet other requirements.

2.6 Normal Conditions of Transport

This section should describe the evaluation that shows the package meets the standards specified in 10 CFR 71.43(f) and 10 CFR 71.51(a)(1) or Paragraphs 646 and 656(a) of TS-R-1 which are incorporated in Subsection 1(1) of the PTNS Regulations by reference to Paragraph 650 of TS-R-1 when subjected to the tests and conditions specified in 10 CFR 71.71, Normal Conditions of Transport, or Paragraphs 719-724 of TS-R-1 which are incorporated in Subsection 1(4) of the PTNS Regulations by reference to Paragraph 716 of TS-R-1 (normal conditions of transport). The package should be evaluated against each condition individually. The evaluation should show that the package satisfies the applicable performance requirements specified in the regulations (e.g., there should be no loss or dispersal of contents; no structural changes that reduce the effectiveness of components required for shielding, heat transfer, criticality control, or containment; and no changes that would affect the ability of the package to withstand the hypothetical accident conditions tests).

The structural evaluation of the package under normal conditions of transport may be performed by analysis or test or a combination of both. In describing the structural evaluation of the package, this section should clearly show that the most limiting initial test conditions and most damaging orientations have been considered and the evaluation methods are appropriate and properly applied. An adequate set of test orientations should be considered since the most damaging orientation for one component may not be the most damaging for another component. The evaluation methods should be appropriate for the loading conditions considered and follow accepted practices and precepts. The results should be correctly interpreted.

In addressing the sections listed below, the following general information should be considered and included as appropriate:

1. For evaluation by test, this section should describe the test method, procedures, equipment, and facilities that were used. For example, the drop test surface should be described sufficiently to show that it represents an essentially unyielding surface. The steel puncture bar should be described with respect to its material of construction, dimensions, including showing that the length is sufficient to cause maximum damage to the package, and the method used to secure the bar to the unyielding surface. The test methods and instruments should be adequate for the measurements needed, and the measurements should be sufficient for describing the structural response or damage. The pass/fail criteria for evaluating the package performance in the tests should be provided and justified.
2. The package orientations evaluated for the tests should be clearly identified and justified as being most damaging. Where sequential tests are required, the damage from one test should be considered when performing subsequent tests.
3. If the package tested is not identical in all respects to the package described in the application, the differences should be identified, and justification should be given to show that the differences would not affect the test results.
4. The materials used as substitutes for the radioactive contents during the tests should be described, and justification should be given that shows that this substitution would not affect the results, including an assessment of the effects of internal decay heat and pressure build up if appropriate.
5. A detailed and quantitative description of the damage caused by the tests should be provided along with the results of any measurements that were made, including both interior and exterior damage as well as photographs of the damaged packaging. Videos of the tests should be provided if available. The test results should be thoroughly evaluated. The test conclusions should be valid and defensible. Unexpected or unexplainable test results, indicating possible testing problems or non-reproducible specimen behaviour, should be discussed and evaluated. The tests should demonstrate an adequate margin of safety. The test results should clearly show that the effects of the tests can be reliably reproduced. Effects of uncertainties in mechanical properties, test conditions, and diagnostics should be described.
6. For prototype and model testing, this section should provide a complete description of the test specimen, including detailed drawings that show its dimensions and materials of construction and dimensional tolerances to which the prototype or model was fabricated. The fabrication tolerances of the test specimen should be compared to those that will be used for the package. The test specimen should be fabricated using the same materials, methods, and quality assurance as specified in the design. For scale models, this section should identify the scale factor that was used and should provide a detailed description of the laws of similitude that were used for testing, considering time scale, material density, velocity at impact, and kinetic energy. Information should be provided to show that the model test will give conservative results for peak g-force, maximum deformation, and dissipated energy. In addition, the damage done to the model should be correlated to the damage to the package. In general, scale models do not provide reliable quantitative data regarding the leakage rate of the package.
7. For evaluation by analysis, this section should describe the methods and calculations used in the package evaluation in sufficient detail to enable the staff to verify the results. In so doing, this section should clearly describe and justify all assumptions used in the analysis and include adequate narration, sketches, and free body force diagrams. In addition, for equations used in the analysis, this section should either cite the source or include the derivation.
8. The computer programs should be identified and described and should be shown to be well benchmarked, widely used for structural analyses, and applicable to the evaluation.
9. Computer models and related details should be well described and justified. For example, the number of discrete finite elements used in the model should reflect the type of analysis performed and should be appropriate, considering such factors as stress or displacement.
10. Sensitivity studies used to determine the appropriate number of nodes or elements for a particular model should be provided.
11. A detailed description of the modeling of bolted connections, including element types, modeling technique, and material properties, should be included.
12. For impact analysis, information should be provided that shows how all of the kinetic energy will be dissipated and what local deformation and dynamic forces would occur during impact, the package response in terms of stress and strain to components and structural members, the structural stability of individual members, stresses attributable to impact combined with those stresses caused by temperature gradients, differential thermal expansions, pressure, and other loads. Load combinations and acceptance criteria are provided in references 19 and 25. The evaluation should compare the maximum stresses or strains with design code allowables. The analysis should provide information that shows the critical combinations of environmental and loading conditions were evaluated.
13. The analytical results should be directly compared with the acceptance criteria. The response of the package to loads, in terms of stress and strain to components and structural members, should be shown. The structural stability of individual members should be evaluated as applicable.
14. Analytical methods should consider impact at any angle, rigid-body rotation, and secondary impact (slapdown). Dynamic amplification factors should be appropriately applied if a quasi-static analysis technique has been used.
15. The models and material properties should be appropriate for the load combinations considered, and the evaluation should include all appropriate initial conditions and load combinations. Material properties (e.g., elastic, plastic) should be consistent with the analysis methods. The strain rate at which the properties were determined should be justified. The analysis should consider true stress-strain or engineering stress-strain as applicable.
16. An assessment should be included that shows that the normal conditions do not reduce the effectiveness of the package.

2.6.1 Heat

The thermal evaluation for the heat test should be described and reported in Section 3, Thermal Evaluation. The results of the thermal evaluation should be used as input to the following sections.

2.6.1.1 Summary of Pressures and Temperatures

This section should summarize all pressures and temperatures derived in Section 3 that will be used to perform the calculations needed for Sections 2.6.1.2-2.6.1.4, as described below.

2.6.1.2 Differential Thermal Expansion

This section should present calculations of the circumferential and axial deformations and stresses (if any) that result from differential thermal expansion. The evaluation should consider possible interferences resulting from a reduction in gap sizes. Steady-state and transient conditions should be considered. These calculations should be sufficiently comprehensive to demonstrate package integrity under normal transport conditions and should consider appropriate load combinations, such as maximum normal operating pressure and decay heat and fabrication stresses.

2.6.1.3 Stress Calculations

This section should present calculations of the stresses that are attributable to the combined effects of thermal gradients, pressure, and mechanical loads (including fabrication stresses from lead pour and lead cooldown). Sketches that show the configuration and dimensions of the members or systems being analyzed and the points at which the stresses are calculated should be provided. The analysis should consider whether repeated cycles of thermal loadings, together with other loadings, will cause fatigue failure or extensive accumulations of deformation.

2.6.1.4 Comparison with Allowable Stresses

This section should present the appropriate stress combinations and compare the resulting stresses with the design criteria specified in the application and should show that all relevant performance requirements have been satisfied as specified in the regulations. Stresses should be within the limits for normal condition loads.

2.6.2 Cold

The thermal evaluation under normal cold conditions should be described and reported in Section 3, Thermal Evaluation. Using the results from the thermal evaluation, this section should assess the effects that the cold condition has on the package, including material properties and possible liquid freezing and lead shrinkage. The resulting temperatures and their effects on package components and operation of the package should be reported. Brittle fracture should be evaluated. The evaluation should consider the minimum internal pressure with the minimum internal heat load (typically assumed to be no decay heat) and any residual fabrication stresses. Differential thermal expansions and possible geometric interferences should be considered. Stresses should be within the limits for normal condition loads.

2.6.3 Reduced External Pressure

This section should describe the evaluation of the package for the effects of reduced external pressure, as specified in 10 CFR 71.71(c)(3) and Paragraphs 643 and 619 of TS-R-1 which are incorporated in Subsection 1(1) of the PTNS Regulations by reference to Paragraph 650 of TS-R-1. The evaluation should include the greatest pressure difference between the inside and outside of the package, as well as the inside and outside of the containment system, and evaluate this condition in combination with the maximum normal operating pressure.

2.6.4 Increased External Pressure

This section should describe the evaluation of the package for the effects of increased external pressure, as specified in 10 CFR 71.71(c)(4) and Paragraph 615 of TS-R-1 which is incorporated in Subsection 1(1) of the PTNS Regulations by reference to Paragraph 650 of TS-R-1. The evaluation should include the greatest pressure difference between the inside and outside of the package, as well as the inside and outside of the containment system, and evaluate this condition in combination with the minimum internal pressure. This section should include a buckling evaluation.

2.6.5 Vibration

This section should describe the evaluation of the package for the effects of vibrations that are normally incident to transport, as specified in 10 CFR 71.71(c)(5) or Paragraph 612 of TS-R-1 which is incorporated in Subsection 1(1) of the PTNS Regulations by reference to Paragraph 650. The combined stresses attributable to vibration, temperature, and pressure loads should be considered, and a fatigue analysis should be included if applicable. If closure bolts are reused, the bolt preload should be considered in the fatigue evaluation. Packaging components, including internals, should be evaluated for resonant vibration conditions that can cause rapid fatigue damage.

2.6.6 Water Spray

This section should show that the water spray test has no significant effect on the package.

2.6.7 Free Drop

This section should describe the package evaluation for the effects of a free drop. The general comments in Section 2.7.1 of this document may also apply to this condition. Note that the free drop test follows the water spray test. This section should also address such factors as drop orientation; effects of free drop in combination with pressure, heat, and cold temperatures; and other factors discussed in Section 2.6.

Closure lid bolts should be evaluated for the combined effects of free drop impact force, internal pressures, thermal stress, O-ring compression force, and bolt preload. Port covers, port cover plates, and shielding enclosures should also be evaluated for the combined effects.

2.6.8 Corner Drop

If applicable, this section should describe the effects of corner drops on the package. The applicability of the corner drop is defined in 10 CFR 71.71(c)(8) and Paragraph 722 of TS-R-1 which is incorporated in Subsection 1(4) of the PTNS Regulations by reference to Paragraph 716 of TS-R-1.

2.6.9 Compression or Stacking

This section should describe the effects of the compression or stacking test. The package must be subjected for a period of 24 hours to a compressive load equal to the greater of the following:

1. The equivalent of 5 times the weight of the package; and

2. The equivalent of 13 kPa (2 pounds per square inch (psi)) multiplied by the vertically projected area of the package.

The load shall be applied uniformly to the top and bottom of the package in the position in which the package would normally be transported.

2.6.10 Penetration

This section should describe the effects of penetration on the package and should identify the most vulnerable location on the package surface.

2.7 Hypothetical Accident Conditions

This section should describe the structural performance of the package when subjected to the tests specified in 10 CFR 71.73, Hypothetical Accident Conditions, or tests described in Paragraphs 726-729 of TS-R-1 which are incorporated in Subsection 1(4) of the PTNS Regulations by reference to Paragraph 716 of TS-R-1.

The structural evaluation should consider the accident conditions in the indicated sequence to determine their cumulative effect on a package. Damage caused by each test is cumulative, and the evaluation of the ability of a package to withstand any one test must consider the damage that resulted from the previous tests. This section should confirm that the package effectiveness has not been reduced as a result of the normal conditions of transport, as included in Section 2.6. Brittle fracture should also be considered. This section should include applicable information regarding tests and analyses, as described in Section 2.6 above. In general, inelastic deformation of the containment system closure (e.g., bolts, flanges, seal regions) is not acceptable for Type B packages. Deformation of other parts of the containment vessel may be acceptable if the containment boundary is not compromised. Deformation of shielding components, components required for heat transfer and insulation, and components required for subcriticality should be defined and evaluated in Sections: 3,Thermal Evaluation; 4, Containment; 5, Shielding Evaluation; and 6, Criticality Evaluation; of the application.

With respect to initial conditions for the tests (except for the water immersion tests), ambient temperature and internal pressure should be specified and should be shown to be the most unfavourable. For physical tests that are not performed at the most unfavourable pressure or at the temperature extremes, the application should include an evaluation to show that the pressure and temperature would not affect the ability of the package to meet the other performance requirements. For example, the evaluation may include information regarding combined loads and material properties.

Paragraph 664 of TS-R-1 which is incorporated in Subsection 1(1) of the PTNS Regulations by reference to Paragraph 650 of TS-R-1 requires that a Type B package be designed for an ambient temperature range from -40 °C to +38 °C. Initial conditions in 10 CFR 71.73(b) specify that the ambient temperature preceding and following the tests must be between -29°C (-20°F) and +38 °C (+100°F).

2.7.1 Free Drop

This section should evaluate the package under the free drop test. The performance and structural integrity of the package should be evaluated for the drop orientation that causes the most severe damage, including center-of-gravity-over-corner, oblique orientation with secondary impact (slapdown), side drop, and drop onto the closure. Orientations for which the center of gravity is directly over the point of impact should also be considered. An orientation that results in the most damage to one system or component may not be the most damaging for other systems and components. If a feature such as a tie-down component is a structural part of the package, it should be considered in selecting the drop test configurations and drop orientation. For these reasons, it is usually necessary to consider several drop orientations.

The following items should be addressed, if applicable:

1. For packages with lead shielding, the package should be evaluated for the effects of lead slump. The lead slump determined should be consistent with that used in the shielding evaluation.
2. The closure lid bolt design should be assessed for the combined effects of free drop impact force, internal pressures, thermal stress, O-ring compression force, and bolt preload.
3. The buckling of package components should be evaluated.
4. Other package components, such as port covers, port cover plates, and shield enclosures, should be evaluated for the combined effects of package drop impact force, puncture, internal pressures, and thermal stress.

2.7.1.1 End Drop

This section should describe the effects of the end drop test on the package.

2.7.1.2 Side Drop

This section should describe the effects of the side drop test on the package.

2.7.1.3 Corner Drop

This section should describe the effects of the corner drop test on the package.

2.7.1.4 Oblique Drops

This section should describe the effects of oblique drops or should provide information that shows that the end, side, and corner drops are more damaging to all systems and components that are vital to safety.

2.7.1.5 Summary of Results

This section should describe the condition of the package after each drop test and describe the damage for each orientation.

2.7.2 Crush

If applicable, this section should describe the effects of the dynamic crush test on the package.

2.7.3 Puncture

This section should describe the effects of puncture on the package and identify and justify that the orientations for which maximum damage would be expected have been evaluated. This description should consider any damage resulting from the free drop and crush tests as well as both local damage near the point of impact of the puncture bar and the overall effect on the package. Containment system valves and fittings should be addressed. Punctures at oblique angles, near a support valve, at the package closure, and at a penetration should be considered as appropriate. General comments provided in Sections 2.6 and 2.7.1 of this document may also apply to this test condition.

Although analytical methods are available for predicting puncture, empirical formulas, derived from puncture test results of laminated panels, are usually used for package design. Nelms’ formula, developed specifically for package design, provides the minimum thickness needed for preventing the puncture of the steel surface layer of a typical steel-lead-steel laminated cask wall.

2.7.4 Thermal

The thermal test should follow the free drop and puncture tests and should be reported in Section 3, Thermal Evaluation, of the application. This section should evaluate the structural design for the effects of a fully engulfing fire as specified in 10 CFR 71.73(c)(4) or Paragraph 728 of TS-R-1 which is incorporated in Subsection 1(4) of the PTNS Regulations by reference to Paragraph 716 of TS-R-1. Any damage resulting from the free drop, crush, and puncture conditions should be incorporated into the initial condition of the package for the fire test. The temperatures resulting from the fire and any increase in gas inventory caused by combustion or decomposition processes should be considered when determining the maximum pressure in the package during or after the test. The maximum thermal stresses that can occur either during or after the fire should be addressed.

2.7.4.1 Summary of Pressures and Temperatures

This section should summarize all of the temperatures and pressures as determined in Section 3, Thermal Evaluation, of the application.

2.7.4.2 Differential Thermal Expansion

This section should include calculations of the circumferential and axial deformations and stresses (if any) that result from differential thermal expansion. Peak conditions, steady-state conditions, and all transient conditions should be considered.

2.7.4.3 Stress Calculations

This section should include calculations of the stresses caused by thermal gradients, differential expansion, pressure, and other mechanical loads. Sketches showing configuration and dimensions of the members of systems under investigation and locations of the points at which the stresses are being calculated should be included.

2.7.4.4 Comparison with Allowable Stresses

This section should describe the appropriate stress combinations and compare the resulting stresses with the design criteria in Section 2.1.2 of the application. This section should show that all the performance requirements specified in the regulations have been satisfied.

2.7.5 Immersion—Fissile Material

If the contents include fissile material subject to the requirements of 10 CFR 71.55, General Requirements for Fissile Material Packages, or Paragraph 671 of TS-R-1 which is incorporated in Paragraph 7(1)(a) of the PTNS Regulations by reference to Paragraph 813 of TS-R-1 (unless excepted by Paragraph 671) and if water leakage has not been assumed for the criticality analysis, this section should assess the effects and consequences of the water immersion test condition in accordance with10 CFR 71.73(c)(5) or Paragraphs 731-733 of TS-R-1 which are incorporated in Subsection 1(4) of the PTNS Regulations by reference to Paragraph 716 of TS-R-1. The test should consider immersion of a damaged specimen under a head of water of at least 0.9 meter (m) (3 feet (ft)) in the orientation for which maximum leakage is expected.

2.7.6 Immersion—All Packages

This section should evaluate, as required in 10 CFR 71.73(c)(6) or Paragraph 729 of TS-R-1 which is incorporated in Subsection 1(4) of the PTNS Regulations by reference to Paragraph 716 of TS-R-1, an undamaged package for water pressure equivalent to immersion under a head of water of at least 15 m (50 ft). Paragraph 729 of TS-R-1 specifies that the test period be not less than 8 hours, whereas 10 CFR 71.73(c)(6) does not specify a test duration. For test purposes, an external water pressure of 150 kPa (21.7 (psi)) gauge is considered to meet these conditions.

2.7.7 Deep Water Immersion Test (for Type B Packages Containing More than 10⁵ A₂)

If applicable, this section should evaluate the package for an external water pressure of 2 megapascals (MPa) (290 psi) for a period of no less than 1 hour, as specified in 10 CFR 71.61, Special Requirements for Type B Packages Containing more than 10⁵ A₂, or Paragraph 670 of TS-R-1, which is incorporated in Subsection 1(1) of the PTNS Regulations by reference to Paragraph 667 of TS-R-1, and Paragraph 730 of TS-R-1, which is incorporated in Subsection 1(4) of the PTNS Regulations by reference to Paragraph 716 of TS-R-1. NRC regulations in 10 CFR 71.61 state: “A Type B package containing more than 10⁵ A₂ must be designed so that its undamaged containment system can withstand an external water pressure of 2 MPa (290 psi) for a period of not less than 1 hour without collapse, buckling, or in-leakage of water.”

Paragraph 730 of TS-R-1 states: “Enhanced water immersion test: The specimen shall be immersed under a head of water of at least 200 m for a period of not less than one hour. For demonstration purposes, an external gauge pressure of at least 2 MPa shall be considered to meet these conditions.”

2.7.8 Summary of Damage

This section should summarize the condition of the package after the accident test sequence. The description should address the extent to which safety systems and components have been damaged and relate the package condition to the acceptance standards.

2.8 Hypothetical Accident Conditions for Air Transport of Plutonium or Packages with Large Quantities of Radioactivity

This section should show that the contents of the package when transported by air will be limited such that both NRC and CNSC regulations are met. This section should specifically address the following limits:

1. Packages containing radioactive material in special form that exceeds 3000 A₁ or 100,000 A₂ may not be transported by air.
2. Packages containing radioactive material in normal form that exceeds 3000 A₂ may not be transported by air.
3. Packages that contain plutonium in excess of an A₂ quantity (except for material with very low concentration) may not be transported by air.

2.9 Hypothetical Accident Conditions for Fissile Material Packages for Air Transport

If applicable, this section should address the hypothetical accident conditions specified in 10 CFR 71.55(f) or Paragraph 680 of TS-R-1 which is incorporated in Subsection 1(1) of the PTNS Regulations by reference to Paragraph 672 of TS-R-1.

2.10 Special Form

For packages designed to transport radioactive material only in special form, this section should state that the contents meet the requirements in 10 CFR 71.75, Qualification of Special Form Radioactive Material, or Paragraphs 603 of TS-R-1 as referenced in Subsection 1(1) of the PTNS Regulations when subjected to the applicable test conditions of 10 CFR 71.75 or Paragraphs 704-711 of TS-R-1 which are incorporated in Subsection 1(1) of the PTNS Regulations by reference to Paragraphs 602-604 of TS-R-1. The chemical and physical form should be specified. In addition, this section should include a detailed drawing of the encapsulation showing its dimensions, materials, manner of construction, and method of non-destructive examination.

2.11 Fuel Rods

The structural integrity of fuel rods and cladding integrity should be addressed for packages used to transport fresh or irradiated nuclear fuel. Where fuel structural components and cladding are considered to provide containment of radioactive material or confinement or geometry control of fissile material under normal or accident test conditions, this section should provide an analysis or test results showing that the components will maintain sufficient mechanical integrity to provide the degree of containment or confinement assumed.

For SNF, the application should specifically address whether damaged or high-burnup fuel is to be transported. High burnup fuel for light-water reactors is defined as fuel with greater than 45,000 megawatt days per metric tonne of uranium (MWD/MTU) burnup. Damaged fuel should be defined and assessed with respect to the containment, shielding, and criticality evaluations. Guidance with respect to the definition of damaged fuel is provided in reference 2. Damage may include known or suspected cladding defects, greater than hairline cracks or pinhole leaks, or damage to the structural components of a fuel assembly, such as spacer grids. Any special provisions for transporting damaged fuel (e.g., use of a canister) should be addressed.

2.12 Appendix

The appendix should include a list of references, with chapter, section, or page numbers if appropriate; applicable pages from referenced documents if not generally available; computer code descriptions; input and output files; test results; test reports; descriptions of test facilities; and instrumentation, photographs, and other appropriate supplemental information. This appendix should also include materials and manufacturing specifications for items that are significant with respect to safety but are not produced to generally recognized standards.