ML25140A932
| ML25140A932 | |
| Person / Time | |
|---|---|
| Site: | 07109385 |
| Issue date: | 05/20/2025 |
| From: | Garcia-Santos N Division of Fuel Management |
| To: | Industrial Nuclear Co |
| References | |
| EPID L-2024-NEW-0008, CAC 001029 | |
| Download: ML25140A932 (1) | |
Text
Enclosure Staggered Request for Additional Information Thermal and Structural Evaluations Certificate of Compliance No. 9385 Docket No. 71-9385 Revision No. 0 Model No. IR-100ST This request for additional information (RAI) identifies information needed by the U.S. Nuclear Regulatory Commission (NRC) staff (the staff) in connection with its review of the application.
The staff used NUREG-2216, Standard Review Plan for Transportation Packages for Spent Fuel and Radioactive Material: Final Report, (NUREG-2216) in its review of the application.
Each RAI describes information needed by the staff to complete its review of the application and to determine whether the applicant has demonstrated compliance with the regulatory requirements of 10 CFR Part 71.
THERMAL EVALUATION RAI-Th-1 Provide the following information:
a)
The model inputs such as thermal properties and boundary conditions (e.g., insolation) used in the ANSYS thermal model mentioned in the application.
b)
The version of ANSYS thermal model used to generate the model.
c)
Demonstration that the thermal model was appropriately converged (e.g.,
energy balances, residuals).
d)
Clarification that the thermal model accurately represents the design of the IR-100ST package by modeling package components (stainless steel housing, depleted uranium shielding, polyurethane foam).
e)
Appropriate boundary conditions including the bases for external heat transfer correlations and coefficient values as well as the radiant energy boundary conditions used in the analysis.
f)
Clarify if the design/analysis (e.g., ANSYS model generation and solution methodologies) of the Model No. IR-100ST package is performed under the NRC-approved quality assurance (QA) program.
Section 3.2.1 of the application indicated that thermal properties were not provided because package integrity was established by testing. However, section 3.3 provided package temperatures during normal conditions of transport (NCT) based on an ANSYS thermal model, which would require thermal property inputs and boundary conditions for calculations. Similarly, there was no explicit discussion that the ANSYS thermal model accurately portrayed the Model No.
IR-100ST design. The model inputs (e.g., thermal properties such thermal
2 conductivity, boundary conditions, package components modeled) and quality assurance (QA) discussions are needed in order to make a determination that model results are representative of the package during transport conditions.
In terms of clarifications of the boundary conditions, Section 3.31 of the application only refers to a 12-hour average, but did not specify the insolation value (e.g., 800 watts per square meter (W/m2)) and the package surfaces absorptivity and emissivity. Also, the application did not include a discussion about the bases for external heat transfer correlations and coefficient values and for the radiant energy boundary conditions used in the analysis.
This information is needed to determine compliance with the regulatory requirements in 10 CFR 71.35(a) and 71.41(a).
RAI-Th-2 Describe the behavior of the plastic surround and PM Tag during the fire hypothetical accident conditions (HAC) and address its impact on the fires thermal evaluation.
Section 1.1 of the application mentioned the presence of a urethane surround and plastic PM Tag. However, section 3.4 of the application did not address the behavior of the plastic surround and plastic PM Tag during the fire HAC. In addition, the evaluation did not:
- 1) provide details of potential exothermic reactions (e.g., combustion), such as quantifying its thermal input (e.g., thermal energy release and heat of combustion (joules per kilogram (J/kg)) associated with the plastic PM Tag and surrounds (unspecified) mass relative to the thermal input to the package from the 800 degrees Celsius (°C ) fire;
- 2) discuss the potential impacts on the packages integrity, for example, on:
(i) shielding material (ii) special form source capsule (iii) melted plastic hindering pressure release from the housings openings that keep the package unpressurized, per section 3.1.4 of the application).
This information is needed to determine compliance with the regulatory requirements in 10 CFR 71.43(d), 71.51(a)(2), and 71.73(c)(4).
RAI-Th-3 Provide the packages maximum surface temperature without insolation. As part of your response, explain if the package will meet the nonexclusive use temperature or the exclusive use temperature.
Section 3.3.1 of the application appears to indicate that the maximum outer package temperature (without a personnel barrier) may be 140°F (based on the battery manufacturer data sheet), which is above the 122°F non-exclusive use temperature. However, section 3.3.1 of the application also indicated that the
3 maximum package temperature would be 100°F and, therefore, less than the non-exclusive use temperature.
This information is needed in order to determine compliance with the regulatory requirements in 10 CFR 71.43(g).
RAI-Th-4 Discuss the relevant differences between the Model No. IR-100ST package and the Model No. IR-100 certified test unit package that underwent the fire HAC test and explain the impacts of the differences.
Section 3.4.1 of the application indicated that the fire HAC thermal performance of the Model No. IR-100ST package would be similar to the thermal performance of the Model No. IR100. However, there was no explicit discussion that justified the appropriateness and relevance of the Model No. IR100 package thermal results (e.g., the same construction details), considering there are differences between the two packages (e.g., presence of plastic surround, presence of power cells).
Section 3.1.4 and 3.4.3 of the application stated that gas can move freely from the internal cavity of the depleted uranium shield to the ambient such that there is no pressurization of the package during NCT and HAC. This would indicate there are openings within the package to release internal pressures. A potential pressurization was indicated in section 3.4.2 of the application, which noted that the Model No. IR100 test units polyurethane foam was consumed by the fire, thereby indicating combustion gases were released. In addition, it would appear that gaps would be small since the application noted the Model No. IR100 test units depleted uranium shield was not appreciably oxidized. There should be further information of the package vent mechanisms that ensure the IR-100ST package is not pressurized during NCT and HAC (e.g., expansion of foam and release of polyurethane combustion gases) and that the vent opening sizes are insufficient to cause oxidation of the depleted uranium and there will not be unintended effects by melting of the plastic surround that prevent venting (e.g.,
plugging vent openings).
This information is needed to determine compliance with the regulatory requirements in 10 CFR 71.35(a) and 71.51.
RAI-Th-5 Clarify that the Model No. IR-100ST package (with functioning power cells) will not be adversely affected by a -40°C ambient temperature or specify an ambient temperature restriction for transport.
Section 2.6.4 of the application mentions that discharging and charging occur during transport, which can include cold ambient conditions (e.g., -29°C, -40°C).
However, the LithiumWerks datasheet (reference noted in section 1.2.1 of the application) for the packages PM Tag power cells mentions a charging temperature range of 0°C to 60°C and a discharging temperature range of -30°C to 60°C.
This information is needed to determine compliance with the regulatory requirements in 10 CFR 71.35(a) and 71.51.
4 Editorial clarification: Clarify the S-tube material(s) in drawing number IR100ST-C, considering it lists titanium, but SAR section 2.2.2 mentions the S-tube can be either titanium or Zircaloy.
STRUCTURAL EVALUATION RAI St-1 Provide the total number of locations where the weld detail applies for attachment of the support saddle (Item No. 5) to the housing base (Item No. 6) shown on the applications drawing No. IR100ST-B, Sheet 3, Revision 1, IR-100ST BODY ASSEMBLY, SAR.
The drawing No. R100ST-B, Section B-B, depicts the near side fillet weld detail for attachment of the support saddle (Item No. 5) to the housing base (Item No.
- 6) with a note in the tail that reads TYP, ITEM 5 to ITEM 6. Since the weld is shown only for the near side of the saddle, and there are two quantities of Item No. 5 (support saddle) specified in the bill of material, it is unclear the total number of locations (i.e., or 4 places) where this weld detail applies. Therefore, the applicant needs to include in the drawing the total number of locations the weld detail is to be applied.
This information is needed to determine compliance with the regulatory requirements in 10 CFR 71.33(a)(5)and 10 CFR 71.107(a).
RAI St-2 Regarding the tie-down test:
a)
Provide the location on the package, on which vertical, horizontal, and transverse loads were applied while the package was tied down with two straps as shown in Figure 2.5-1 of the application.
b)
For the tie-down test, clarify if the vertical, if horizontal and transverse loads were applied simultaneously or not. If not, provide an explanation.
b)
Clarify if the unit was tested by swapping the magnitude of test loads in the horizontal and transverse directions. If not, provide an explanation.
Section 2.5.2 of the application notes that the loads of 583.4 pound-force (lbf),
294.6 lbf, and 120.0 lbf were applied in the longitudinal, lateral, and vertical directions, respectively, as shown in Figure 2.5-1. However, it does not provide the following information of importance for structural evaluation:
- 1) relevant details such as the test loads locations on the package,
- 2) whether the loads were applied in different directions simultaneously or separately, etc.
Since there are no restrictions on how the package is oriented with respect to the direction of travel during the transport, the package evaluation for the tie-down needs to be evaluated for all possible orientations to ensure that the limiting forces applied on the package tie-down are considered in the direction of vehicle travel and in the transverse direction.
5 This information is requested to determine compliance with the regulatory requirements in 10 CFR 71.45(b).
RAI-St-3 Provide the temperature that the stainless steel body of the package was exposed when it was placed on a dry ice environment as noted in the Section 2.6.2 of the application.
Section 2.6.2 of the SAR notes that the IR-100ST stainless steel body was exposed to a dry ice environment (-109ºF [-40ºC]) for an extended period of time in an ice chest without detrimental effects. The staff notes that -109ºF is -78ºC and -40ºC is -40ºF. Also, Sections 2.12.1.7.2.1 and 2.12.1.7.2.2 of the application note that the measured surface temperatures of the CTU-2 package were less than -20ºF and -21ºF, respectively. Clarify what temperatures the IR-100ST body was exposed to during the cold test.
This information is needed to determine compliance with the regulatory requirements in 10 CFR 71.71 and 71.73.
RAI-St-4 Explain why a package orientation to maximize damage at the outlet port end of the package was not considered for the hypothetical accident condition (HAC) free drop and puncture tests.
Section 2.12.1.5 of the application provides the technical basis to select a worst-case package orientation that could potentially compromise depleted uranium (DU) shield integrity and/or the special form source of the package under the free drop and puncture tests. The package drawing Nos. IR100ST-E, Revision 0, and IR100ST-F, Revision 0, depict a configuration and parts for the lock assembly and the outlet port assembly, respectively, that are attached to the package housing at the opposite ends. These drawings do not provide overall dimensions for the lock and outlet port assemblies. However, it appears, from these drawings and the package assembly drawing No. IR100ST-B, that the cantilever dimension from the housing base to the free end is greater for the outlet port assembly than that for the lock assembly, assuming these drawings are drawn to the scale. If the outlet port assembly is longer, the CG-Over-Outlet Port Assembly free end corner orientation may cause overstress conditions at the assembly welded joint to the housing base (i.e., being a weak point) under the free drop and puncture tests. Therefore, the latter conditions need to be evaluated and included in the application, otherwise the applicant needs to provide a justification for not considering this orientation.
Note that the secondary objective of the HAC free drops is to fail the stainless steel body such that a potential air pathway into the interior would form, which could potentially result in a self-sustaining oxidation reaction of the DU and hence, result in a loss of shielding.
This information is needed to determine compliance with the regulatory requirements in 10 CFR 71.73(c)(1) and (3).