ML25178C673
| ML25178C673 | |
| Person / Time | |
|---|---|
| Site: | 07109397 |
| Issue date: | 08/01/2025 |
| From: | Storage and Transportation Licensing Branch |
| To: | |
| Shared Package | |
| ML25178C672 | List: |
| References | |
| EPID L-2022-NEW-0002, CAC 001029 | |
| Download: ML25178C673 (1) | |
Text
Enclosure 1 Request for Supplemental Information for HI-STAR 330 Transportation Cask Certificate of Compliance No. 9397 Docket No. 71-9397 Revision 0 This request for supplemental information (RSI) identifies information needed by the staff in connection with its acceptance review of the Holtec International (the applicant) Model No. HI-STAR 330 transportation package.
Chapter 2: Structural Review St-1: Provide center-of-gravity information for the Model No. HI-STAR 330 package for all potential package configurations.
Table 1.1.1 in the safety analysis report (SAR), HI-2210970, Revision 0, provides overall dimensions of the HI-STAR 330 transportation package, and SAR table 7.1.1 provides the weights for two package configurations and the maximum content weights. Drawing 12482, HI-STAR 330 Type B/C Waste Transport Cask, Revision 5, indicates the center-of-gravity location of the empty containment cask outfitted with dose blocker plates. However, component weights and package center-of-gravity information have not been provided. This information is needed to confirm the bounding structural analyses for various transportation package configurations.
This information is required to satisfy the requirements of Title 10 of the Code of Federal Regulations (10 CFR) 71.31(a)(1), 71.31(a)(2), 71.33(a)(5), and 71.35(a).
St-2: Provide the following information in HI-2240470, Revision 0, of Dimensional Limit Summary Report for the HI-STAR 330 Transport Cask:
a) lengths of the Closure Lid Bolt and Impact Absorber Strongback Attachment Bolt to table A-1 b) bolt length, thread specification, and minimum thread engagement length of Liner Tank Bolts to table A-2.
The information requested for the bolts is not indicated on the corresponding licensing drawings in the SAR and is needed in order to verify that the structural evaluations performed for them are accurate. The revision in the note for the Liner Tank Bolts is to provide alignment between the design documents and HI-2240470. Update and submit the documents as necessary.
This information is required to satisfy the requirements of 10 CFR 71.33(a)(5).
Observations The following questions are the staffs Observations in connection with its acceptance review of the applicant Model No. HI-STAR 330 transportation package.
Chapter 2: Structural Review:
Obs-St-1: Clarify which version(s) of the finite element program, LS-DYNA, are being employed to support in this application.
2 The following versions of the LS-DYNA finite element program were noted throughout the application documents:
a) Version R10.1.0 dated 2018 cited in the report HI-2210251, Revision 1, Benchmarking of Material Stress-Strain Curves in LS-DYNA, b) Version 971 dated 2006 cited as SAR Reference 2.6.1, and c)
Version 971 with no date cited in the report HI-2240059, Revision 0, Drop Analysis of the HI-STAR 330 Transport Package.
Staff is concerned that the use of multiple versions of the program for structural analyses may produce inconsistent results. Update and submit the documents as necessary.
This information is required to satisfy the requirements of 10 CFR 71.41(a).
Obs-St-2: Clarify how a secondary impact from the package contents during a package drop is either addressed or mitigated for the existing drop analyses.
Subsection 1.2.2 of the SAR states that segments are not stabilized in the liner tank cassette (LTC) and will move if the Liner Tank is upset. This statement raises concerns with staff that the package contents may be free to change locations during a free drop, which could cause a secondary impact to the containment and/or liner tank. This secondary impact effect would be amplified if the package was partially full with the contents free to shift to the various sides of the package during package drop events of different orientations.
This information is required to satisfy the requirements of 10 CFR 71.41(a), 71.71(c)(7), and 71.73(c)(1).
Obs-St-3: Justify or reconcile the following apparent inconsistencies in the structural evaluations of HI-2210998, Revision 0, Structural Calculation Package of HI-STAR 330 Transport Cask:
1.
Calculation 2 - Structural Qualification of HI-STAR Baseplate, page 2-2: The value of an American Society of Mechanical Engineers (ASME) Level A allowable stress, defined as Smas, is determined to be 96,900 psi, however, the [Withheld per 10 CFR 2.390].
2.
Calculation 2 - Structural Qualification of HI-STAR Baseplate, section 2A.2 of appendix 2A: Compares Containment Baseplate weld stresses resulting from an ASME Level A event to allowable stresses taken from ASME subsection NF, table NF-3324.5(a)-1, however, the applicant has stated that the containment would be designed per ASME subsection NB.
3.
Calculation 4 - Liner Tank and Liner Tank Cassette Evaluation, page 4-2: The Liner Tank Cassette bounding temperature (for Normal Conditions of Transport (NCT)) is stated as [Withheld per 10 CFR 2.390], however, SAR table 3.1.1 reports a temperature of [Withheld per 10 CFR 2.390] for the Liner Tank Cassette side plates.
4.
Calculation 4 - Liner Tank and Liner Tank Cassette Evaluation, pages 4-11 and 4-13:
The Liner Tank weld and bolt stresses resulting from NCT events are compared to Level D allowable stresses taken from ASME subsection NF, which are normally employed for hypothetical accident conditions (HAC). Also, include the citation to the specific section of the code that is the source of the allowable stress equations in the calculation.
3 5.
Calculation 4 - Liner Tank and Liner Tank Cassette Evaluation, page 4-12: [Withheld per 10 CFR 2.390] fillet weld is being evaluated for structural adequacy. The weld throat size is defined to be [Withheld per 10 CFR 2.390]; however, this dimension appears to be the weld leg size.
6.
Calculation 8 - Fire Accident Pressure, page 8-2: Confirm the values chosen as inputs for pressure and temperature as they do not appear to match those published for the containment wall plates in SAR tables 3.1.3 and 3.1.2, respectively. Also, advise where the verification that Level D stress limits per ASME subsection NB are met by the containment structure for this HAC event is documented.
7.
Calculation 9 - Closure Lid Bolts Preload and Containment Fatigue Evaluation, page 9-2:
The net tensile area defined for the [Withheld per 10 CFR 2.390] Containment Lid Closure Bolt employed in the calculation appears to be low, as compared to values published in commercially available handbooks. This bolt area affects the determination of the required torque value.
In order for the correct margins of safety to be determined for each transportation event for which the package is evaluated, it is critical that the correct analysis input parameters and design acceptance criteria are selected to produce a reliable result.
This information is required to satisfy the requirements of 10 CFR 71.41(a).
Obs-St-4: Verify the material properties appearing in SAR table 8.1.5, Critical Material Characteristics for Non-Containment Waste Package Components, for the Liner Tank Cassette Corner Tubes, which list American Society for Testing and Materials (ASTM) A513 or A519 Grade 1026 SRA as the Pre-Evaluated Material.
A review of the ASTM A513 and A519 standards indicate minimum Yield and ultimate material properties lower than those included in SAR table 8.1.5. It appears to staff that if the higher material property values are required for the design application, a different material may need to be specified.
This information is required to satisfy the requirements of 10 CFR 71.41(a).
Obs-St-5: Justify the use of the following material properties in calculation 4 of HI-2210998, which evaluates the Liner Tank and Liner Tank Cassette structural design, versus the minimum values provided in flag notes of licensing drawing 12596, Revision 0, Liner Tanks and Cassettes:
1.
Page 4-2: A material for the Liner Tank and Liner Tank Cassette is chosen with the following properties at [Withheld per 10 CFR 2.390] (vs. flag note minimum properties at room temperature of [Withheld per 10 CFR 2.390].
2.
Page 4-13: A material for the Liner Tank Top Plate Bolts is chosen with the following properties at [Withheld per 10 CFR 2.390] (vs. flag note minimum properties (no temperature specified) of [Withheld per 10 CFR 2.390].
3.
Page 4-19: A material for the Liner Tank Cassette Corner Tubes is chosen with the following properties at [Withheld per 10 CFR 2.390]. (vs. flag note minimum properties at room temperature of [Withheld per 10 CFR 2.390].
It appears to staff that employing larger material strength values in the structural adequacy evaluations than those minimum values specified for the materials is a non-conservative design
4 approach. Additionally, specifying the minimum material strength properties at room temperature (or not specifying the temperature associated with the properties) when the component assessment will be performed at an elevated temperature may amplify design non-conservatisms.
This information is required to satisfy the requirements of 10 CFR 71.41(a).
Obs-St-6: Justify or reconcile the following apparent inconsistencies between the licensing drawing 12482, HI-STAR 330 Type B/C Waste Transport Cask, Revision 5 and the SAR content:
1.
SAR sections 1.2.1.2 and 1.2.1.9 indicate that a unique nameplate will be placed on each HI-STAR 330 package that provides at least its maximum gross transport weight. However, the planned location of the nameplate on the package and what information it will include is not indicated on drawing 12482. The following items are recommended for inclusion on the nameplate per NUREG/CR 5502, Engineering Drawings for 10 CFR Part 71 Package Approvals: model number, serial number, gross weight and package identification number.
2.
SAR section 2.3 indicates that the containment cask material is SA-517/A514, whereas drawing 12482 lists [Withheld per 10 CFR 2.390].
3.
SAR section 2.3 indicates that the dose blocker structure material is austenitic steel type 304, whereas drawing 12482 lists [Withheld per 10 CFR 2.390].
4.
SAR table 8.1.4 indicates the Material for the Containment Closure Lid to be SA-203 Grade E, however, drawing 12482 lists [Withheld per 10 CFR 2.390] as an alternative.
5.
SAR table 8.1.4 indicates the Material for the Containment Closure Lid Bolts to be SA-564 Type 630 H1100, however, drawing 12482 lists the material to be
[Withheld per 10 CFR 2.390]. Additionally, SAR table 8.1.4 indicates the Closure Lid Bolt diameter to be [Withheld per 10 CFR 2.390], while the bolt diameter is omitted from drawing 12482.
Accurate material specifications are required to inform the technical analyses submitted in the application for this transportation package.
This information is required to satisfy the requirements of 10 CFR 71.85(c) and 10 CFR 71.33(a)(5).
Obs-St-7: Provide the procurement, design, fabrication, welding, non-destructive examination and testing codes applicable for the important-to-safety (ITS) items of the liner tanks and liner tank cassettes on licensing drawing 12596, Liner Tanks and Cassettes, which is part of SAR section 1.3. Section 1.4 of the SAR indicates that this information is provided on the drawings provided in section 1.3 but is not apparent.
Per NUREG/CR-5502, it is recommended that the design, procurement, fabrication, welding, non-destructive examination and testing codes applicable for the ITS items be indicated on the drawings. Provide this information for the ITS items of the liner tanks and liner tanks cassettes, on the drawing or in the SAR, commensurate to that which is provided in SAR table 8.1.2.
This information is required to satisfy the requirements of 10 CFR 71.31(c).
5 Obs-St-8: Provide the basis of the values of the true stress-strain flow curves for the upper-and lower-bound aluminum impact limiter materials, as presented in Appendix A of calculation report HI-2240059, Revision 0, Drop Analysis of the HI-STAR 330 Transport Package, which are employed in the LS-DYNA HAC event analyses. Also advise and document the temperature at which these values are being reported. Explain inconsistencies between SAR tables 2.2.5 and 8.1.5 and other submitted and referenced documents, as noted below.
The aluminum [Withheld per 10 CFR 2.390] impact limiter flow curves presented in Appendix A of report HI-2240059 indicate that the input parameters are taken from ASME BPVC Section II, Parts A and D, cited as reference A.2. The values for material yield strength, ultimate strength, and modulus of elasticity presented for the lower-and upper-bound do not consistently match those presented in the SAR table 2.2.5, Mechanical Properties of Aluminum (Impact Absorbers), which also cites ASME BPVC Section II, Parts A and D as its source for the properties presented; however the specific aluminum material for which the values are being reported is not identified.
Staff notes that ASME Section II Part A does not contain material specifications for aluminum, but ASME Section II Part B does. For ASTM B209 5083 specifically, elongation values (engineering strain/failure strains) are reported to be [Withheld per 10 CFR 2.390], for plates that are between 2 inches and 8 inches thick, respectively. The true [Withheld per 10 CFR 2.390], by the applicant was determined based on an uncited area reduction value q in report HI-2240059, for both upper-and lower-bound aluminum material values. Moreover, SAR table 2.2.5 values for aluminum would not fit within the specifications of SAR table 8.1.5, as the maximum yield strength is [Withheld per 10 CFR 2.390], which the reported value [Withheld per 10 CFR 2.390], from table 2.2.5 would exceed. In addition, the minimum yield strength of aluminum used in LS-DYNA drop simulations is reported to be [Withheld per 10 CFR 2.390],
which does not fall within the range of parameters in table 8.1.5. The licensing drawings indicate that impact limiters may be made of plates that are as thick as [Withheld per 10 CFR 2.390],
which is a value that is outside the bounds of the specification in ASME Section II Part B, thus material properties are unspecified for plates that exceed 8 inches in thickness.
Additionally, report HI-2210251, Revision 1, Benchmarking of Material Stress-Strain Curves in LS-DYNA, was updated and submitted to include material testing results of aluminum alloy ASTM B221 5083 (Ellcast 5), noted by the applicant as being intended for use in the HI-STAR 330 cask impact limiters; the values for material yield strength, ultimate strength, and modulus of elasticity intended for LS-DYNA input in Appendix A do not consistently match those presented in this report.
Furthermore, the value for reduction in area, defined as q, cited in HI-2240059 is much larger than that presented in the material testing results of HI-2210251. As this value is employed to determine the fracture strain of the material, employing a larger value in the model would make the material more ductile than the actual, resulting in nonconservative outputs.
The staff notes that SAR table 8.1.5 lists ASTM B209 5083 as the pre-evaluated material for the aluminum impact absorbers and provides minimum and maximum values for material yield and ultimate strengths as well as a minimum area reduction percentage value, all of which match those employed in HI-2240059. Staff also notes that in Note 4 of the table, the material properties correspond to a room temperature, while Note 5 indicates that the minimum area reduction percentage value is based on the testing results of HI-2210251, which does not appear to be the case.
6 Finally, it appears that the values of the lower-bound true stress-strain flow curves presented in Appendix A of HI-2240059 were not correctly translated into the LS-DYNA model.
As accurate aluminum material impact absorber properties are critical to the packages evaluation for all drop tests, the applicant is asked to:
a) verify the exact aluminum material being employed for the impact absorbers (e.g., ASTM B209 5083, B221 5083, or other),
b) advise at what temperature the impact absorbers are being evaluated, c) provide the exact citations for each material input value employed in for the impact absorber flow curves in HI-2240059, d) provide a justification for a minimum area reduction percentage requirement that is much larger than the results of those from the testing program in HI-2210251, and, e) update all documentation, including SAR tables 2.2.5, 8.1.5, report HI-2240059, and LS-DYNA models and analyses, as appropriate.
This information is required to satisfy the requirements of 10 CFR 71.41(a).
Obs-St-9: Explain the method employed in determining the area reduction value for several materials included in Appendix A of report HI-2240059, where their associated true stress-strain flow curves are incorporated in the LS-DYNA dynamic analysis models.
For several materials, a value for Syr is defined by the applicant, however this variable is not identified. This variable is then employed in a subsequent calculation for area reduction, q, as a ratio to the material yield stress, multiplied by an unidentified fraction. The applicant is asked to provide a definition and references for the Syr variable as well as the equation for determination of q. This information is required for the following materials in Appendix A:
[Withheld per 10 CFR 2.390], Containment Plates
[Withheld per 10 CFR 2.390], Dose Blocker Plates
[Withheld per 10 CFR 2.390], Trunnions For the [Withheld per 10 CFR 2.390] material for Closure Lid Bolts, a value for reduction in area, q, is defined by the applicant, providing the ASME BPVC Section II as a reference.
However, the exact citation within Section II must be provided, as this value is critical to properly model the seal area dynamic behavior.
This information is required to satisfy the requirements of 10 CFR 71.41(a).
Obs-St-10: Justify the application of the strain rate curves provided in ASME BPVC Section I Appendix EE for stainless steel to all ITS package materials other than the aluminum impact absorbers in the LS-DYNA dynamic event analyses.
Section 5.3 of calculation report HI-2240059 indicates that the ASME BPVC Appendix EE strain rate amplification is applied for all materials in the LS-DYNA model, except for the aluminum impact absorber material. The strain rate factors presented in Table EE-1250-1 of the appendix for various temperature and strain rates are clearly labeled as being applicable to type
[Withheld per 10 CFR 2.390] stainless steel materials. As the HI-STAR 330 does not employ this material for any of the ITS components of its package, use of these strain rates for all non-impact absorber components in the dynamic evaluations does not appear to be appropriate.
7 This information is required to satisfy the requirements of 10 CFR 71.41(a).
Obs-St-11: Provide an explanation as to why the following HAC event cases are not included in the scope of dynamic evaluations for the HI-STAR 330 package, as well as responses to the trunnion-related questions:
30-foot free drop with optional bottom trunnions installed Puncture with bar that strikes either the side or bottom trunnion, which drives the trunnion directly into the containment boundary, whichever produces the more severe results One of these HAC events was requested to be evaluated for the HI-STAR ATB 1T package, and appears to be a challenge to the HI-STAR 330 package as well. Likewise, the new optional bottom surface trunnions present another opportunity to directly challenge the containment boundary.
Additionally, the exact dimensions of the trunnion and its interface with the dose blocker and containment plates is not clearly communicated on drawing 12482, Sh. 3 of 6, Detail 3E-3E, which shows the side trunnion:
a.
There are two different diameters of the solid trunnion shaft depicted in this Detail, with [Withheld per 10 CFR 2.390], being the smaller one, inserted within the dose blocker plate. However, the dimensional report, HI-2240470, lists the maximum diameter trunnion diameter as [Withheld per 10 CFR 2.390].
b.
The only shown attachment of the trunnion to the package is the all-around fillet weld between the trunnion circumference and the dose blocker plate. This connection is not translated properly into the LS-DYNA model, where tied contacts between the trunnion and surrounding dose blocker plates essentially fuse both parts together as a full penetration weld would between the parts. Also, the structural evaluation for this fillet weld does not appear to be included in calculation #1 of report HI-2210998.
c.
It is not clear whether the trunnion end/retainer plate, categorized as NITS, is relied upon for keeping the lifting sling on the trunnion during lifting operations and/or resisting lateral loads from the tie-down strut during tie-down conditions. Provide justification for its apparent lack of material information and/or structural evaluation.
This information is required to satisfy the requirements of 10 CFR 71.41(a).
Obs-St-12: Explain why, in the LS-DYNA model, the material properties for the seal area seating flange weld overlay are input as elastic when they are exceeding the material yield strength as a result of a HAC drop event. Also, identify where material properties for the weld overlay cited in SAR table 8.1.5 were obtained.
During a review of the resulting stresses from the LS-DYNA Bottom End Drop of the HI-STAR 330 package analysis, several locations within the grooved areas of the seal bottom flanges were observed to have stress magnitudes exceeding that of the material yield strength. This was observed in both the inner (ITS) and outer (NITS) seal grooves. When the assigned material properties were verified, it was discovered that the materials for the ER 360 listed in SAR table 8.1.5 weld overlay were input as ELASTIC. Identify where the material properties for the AWS ER360 weld overlay presented in SAR table 8.1.5 were obtained.
8 This information is required to satisfy the requirements of 10 CFR 71.41(a).
Chapter 7: Materials Review:
Obs-M-1: Provide material specifications (e.g., ASME SA 516 Grade 70, ASTM B209 Alloy 6061-T651) for package components that are designed and constructed in accordance with a code or standard and/or components that provide a structural, thermal, shielding, or containment function. The staff observed that drawing 12482, identifies materials as Steel and Aluminum but material specifications and grades are not identified.
This information is requested by the staff to demonstrate compliance with 10 CFR 71.33(a).
Obs-M-2: Explain the basis for excluding the impact absorbers from the baseline drop simulations which use true stress-strain relationships developed using minimum material properties. In SAR section 2.6.1, Description of the Finite Element Model, the staff observed that the applicant used LS-DYNA drop simulations to assess the behavior of the package dynamic response including a safety determination of the closure lid join connections. This benchmark study included physical testing of multiple tensile test specimens for separate material used in the HI-STAR 330 package followed by LS-DYNA simulations using identical input conditions, including specimen geometry, boundary conditions and material inputs, but did not include the impact absorbers.
This information is requested by the staff to demonstrate compliance with 10 CFR 71.31(c).
Obs-M-3: Clarify the ASME Boiler & Pressure Vessel (BPV) code edition used for the package design and construction. In SAR chapter 3 References, it mentions ASME BPV Code section II, Part D, 2023 Edition being used, but 2023 is not referenced elsewhere in the application.
This information is requested by the staff to demonstrate compliance with 10 CFR 71.31(c)
Obs-M-4: In SAR Drawing No. 12482, Sheet 1 of 6, Note 5 states, Unless otherwise specified, cask surfaces may be painted or coated with evaluated and pre-qualified preservatives (or equivalent products with acceptable critical characteristics) for corrosion prevention purposes.
Although four surface treatments/coatings appear to be described in SAR section 2.2.4, the applicant should clarify whether the coating is relied on to prevent loss of material that could affect a safety function such as shielding or structural performance.
This information is requested by the staff to demonstrate compliance with 10 CFR 71.31(c) and 10 CFR 71.43(d).
Obs-M-5: Identify the material(s) for the Weld Metal for NB Welds in SAR table 8.1.4, Fracture Toughness Test Criteria: Containment System. The applicant identified the line item for weld metal for NB Welds but no material(s) were specified in the table.
This information is requested by the staff to demonstrate compliance with 10 CFR 71.31(c)
Obs-M-6: In SAR table 8.1.3, ASME Code Requirements and Alternatives for the HI-STAR 330 package, for the alternative concerning NB-4243, the applicant stated, the structural acceptability of this weld join for all normal and accident conditions has been demonstrated by
- analysis,
9 The staff requests the applicant to clarify if there were considerations for stress reduction factors due to the alternative NDE chosen (PT), the procedure for the weld material deposited, how acceptable fracture toughness is ensured, and how is hydrogen cracking minimized for the weld materials.
For the code alternative in SAR table 8.1.3, provide the following information:
1.
Identify whether weld stress reduction factors and fatigue reduction factors are applied to the welds examined by progressive penetrant testing (PT).
2.
Describe how the progressive PT will be conducted with respect to the weld material deposited.
3.
Explain how the progressive PT examinations consider the fracture toughness of the weld.
4.
Describe is ensured controls to detect and minimize hydrogen cracking of the weld materials.
This information is requested by the staff to demonstrate compliance with 10 CFR 71.31(c).
Editorial:
Obs-E-1: Clarify HI-STAR 330 only accepts HI-STAR waste package types B and C as specified in table 1.2.1 and 7.1.2. For example, the first paragraph of section 1.2.1.4 concludes:
The attenuation of gamma radiation occurs through three sequential metal masses in the body of the HI-STAR package for waste package Types A through D. In addition, section 1.2.1.1.b states that four waste packages (Types A, B, C, and D) are analyzed for HI-STAR 330 package.