ML24194A120
| ML24194A120 | |
| Person / Time | |
|---|---|
| Site: | 07109403 |
| Issue date: | 07/16/2024 |
| From: | Storage and Transportation Licensing Branch |
| To: | NAC International |
| Shared Package | |
| ML24194A118 | List: |
| References | |
| EPID L-2023-NEW-0007 | |
| Download: ML24194A120 (1) | |
Text
Enclosure UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Request for Supplemental Information and Observation for the Model No. VOLUNTEER Package Docket No. 71-9403 This request for supplemental information identifies information needed by the staff in connection with its acceptance review of the NAC International (NAC) Model No. OPTIMUS-H package.
CHAPTER 2 STRUCTURAL AND MATERIALS EVALUATION 2-1 Provide the following supporting or reference documents:
(1)
NAC Calculation EA790-2233, Revision 0, Reduction of Redwood and Balsa Test Data Prepared by Navy Warfare Center, NAC International, Atlanta, Georgia (2)
STC-CY Test report, NAC International STC Impact Tests, Sandia National Laboratories, November 13, 2001 (3)
CY-STC Quarter Scale Model Drawings:
a.
423-352, Revision 0, Balsa Impact Limiter, Upper, 1/4 Scale, NAC-STC Cask b.
423-353, Revision 0, Balsa Impact Limiter, Lower, 1/4 Scale, NAC-STC Cask c.
423-354, Revision 2, Drop Test Assembly, 1/4 Scale, NAC-STC Cask d.
423-355, Revision 2, Cask Body-Scale Model 2nd Generation, NAC-STC Cask The safety analysis report (SAR) section 2.13.1.2.1 and Calculation 70000.38-2201, Revision 0 describe benchmarking of the LS-DYNA code for the dynamic drop analysis of the Volunteer package by comparing the results of LS-DYNA computer simulations to the measured response from 1/4-scale-model physical drop tests of the CY-STC package. The applicant submitted the SAR and supporting structural analyses calculations with the application. However, some of the information in the safety and/or supporting analyses rely on or reference information contained in the above listed documents that were not available with the application.
The staff needs to review these documents to verify their relevance in determining that the benchmarking approach is sufficiently robust and capable of producing analytical results for the proposed impact limiter that would be consistent with results produced in a physical test.
This information is required to determine compliance with Title 10 of the Code of Federal Regulations (10 CFR) Section 71.73.
OBSERVATIONS 2-2 Clarify the relevance of using LS-DYNA crushable foam material model for the drop analysis of the cask with Balsa wood as impact material. If not relevant, update the affected licensing documents as necessary.
The SAR, Revision 24A, section 2.13.2 on top of the page 2.13-7 states that the impact limiter balsa wood end and side cores are modeled using the LS-DYNA crushable foam material model. Also, the SAR section 7.4.4 first two paragraphs refers to LS-DYNA crushable foam material model. The calculation 70000.38-2201, Revision 0, LS-DYNA Drop Analysis of Volunteer Balsa Wood Impact Limiter, section 4.7 refers to LS-DYNA crushable foam material model and list acceleration values for LS-DYNA prediction with new and standard foam material in Figure G3-1.
It is unclear to the staff that there is any relevance of an LS-DYNA crushable foam material model with the SAR section 2.13.1.2.1, which describes the benchmark analysis of the LS-DYNA code for the dynamic drop analysis of the Volunteer package by comparing the results of LS-DYNA computer simulations to the measured response from 1/4-scale-model physical drop tests of the CY-STC package.
This information is required to determine compliance with 10 CFR 71.71 and 71.73.
2-3 Provide details of how the stiffness of the crushable impact limiter material properties were derived for the Volunteer and 1/4 scale model of the CY-STC packages.
Table 2.13.-1 of the SAR provides comparison of the Volunteer and CY-STC Impact Limiter Design Parameters, which includes Side Wood Stiffness and End Core Stiffness.
This table documents Side Wood Stiffness derivation formula as (B x C x E) and End Core Stiffness formula as (~H2 x L).
The variables in these formulas are not defined anywhere, and their values are not provided either. The staff needs this information to confirm that the properties of the impact limiter are appropriately captured in the LS-DYNA numerical model for impact simulation.
This information is required to determine compliance with 10 CFR 71.71 and 71.73.
CHAPTER 3 THERMAL EVALUATION 3-1 Provide additional details on the methodology use to numerically connect dissimilar meshes between the impact limiters and the cask top and bottom, and numerically connect the inner surfaces of the cask and the outer diameter of the helium gap, as well as the top and the bottom regions between the loaded basket and the inner surfaces of the cask.
Section 3.3 of the SAR states that constraint equations are used to numerically connect the dissimilar meshes between the impact limiters and the cask top and bottom. Section 3.3 of the SAR also states that constraint equations are used to numerically connect the inner surfaces of the cask and the outer diameter of the helium gap, as well as the top and the bottom regions between the loaded basket and the inner surfaces of the cask.
However, details of the approach are not provided in the application. The approach needs to be clearly explained. Also, justification on the adequacy of the approach needs to be provided as how this would result in realistic or conservative results.
The staff needs this information to have assurance predicted temperatures remain below allowable limits during NCT and HAC conditions.
This information is required to determine compliance with 10 CFR 71. 71 and 71.73.
CHAPTER 4 CONTAINMENT EVALUATION OBSERVATION 4-1 Provide the specifications on the licensing drawing Nos. L115 Rev. 0P, note 3 and L130 Rev. 0P note 5 for, Or equivalent, for the containment boundary elastomeric O-rings.
Licensing drawing Nos. L115 Rev. 0P, note 3 and L130 Rev. 0P note 5 describe the selected containment boundary elastomeric O-rings (port cover and lid respectively), but also includes the words or equivalent.
The containment boundary component specifications for, or equivalent, which are important to safety, category A, have not been provided. Staff suggests removing, or equivalent, from the licensing drawings.
This information is required to determine compliance with 10 CFR 71.33(a)(4) and 71.51(a)(1) and (2).