ML25337A376
| ML25337A376 | |
| Person / Time | |
|---|---|
| Site: | 07109378 |
| Issue date: | 12/11/2025 |
| From: | Storage and Transportation Licensing Branch |
| To: | Holtec |
| Shared Package | |
| ML25337A374 | List: |
| References | |
| EPID L-2024-LLA-0128 | |
| Download: ML25337A376 (0) | |
Text
Enclosure 2 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Request for Supplemental Information and Observation for the Model No. HI-STAR 100MB Package Docket No. 71-9378 Non-Proprietary This request for supplemental information identifies information needed by the staff in connection with its acceptance review of the Holtec International (Holtec or the applicant) Model No. HI-STAR 100MB package.
CHAPTER 3 THERMAL EVALUATION RSI 3-1 Provide bounding thermal analysis files for normal conditions of transport (NCT) and hypothetical accident conditions (HAC).
The bounding thermal analysis files were not provided to support the proposed changes Nos. 1-3 This information is needed to demonstrate compliance with Title 10 of the Code of Federal Regulations (10 CFR) Sections 71.71 and 71.73.
RSI 3-2 Provide tables in Safety Analysis Report (SAR) section 3.I.3 for moderate and high burnup vacuum drying peak cladding temperature (PCT), cyclic drying time limits, and time-to-boil time limits.
There are proposed new fuel package types in this amendment that will undergo moisture removal operations. Tables analogous to SAR tables 3.3.7, Vacuum Drying Threshold Heat Loads (High Burnup Fuel), 3.3.8, Vacuum Drying Threshold Heat Loads (Moderate Burnup Fuel), and 3.3.9, Example Cyclic Drying Time Limits, that provide PCT and cyclic drying time limits have not been provided in the SAR for the proposed fuel package types.
Similarly, tables for each fuel type with time-to-boil time limits that are analogous to SAR table 3.3.5, Example Maximum Permissible Time Limits Under Flooded HI-STAR 100MB Conditions for Several Cask Decay Heat Loads, have not been provided.
This information is needed to demonstrate compliance with 10 CFR 71.33.
Obs. 3-1 Clarify the apparent difference between SAR tables 3.I.2.1, HI-STAR 100MB MSC Materials Temperature Limit, and 3.I.2.3, Basket temperature limits for candidate heat load patterns, basket temperature limits.
SAR table 3.I.2.1 describes two values, one for NCT and one for HAC, for the fuel basket temperature limits. However, SAR table 3.I.2.3 describes many temperature limits as a function of basket type, zone, and basket elevation. It is not clear what
conditions the temperature limits in SAR table 3.I.2.3 apply to (normal, accident, or both). {See proprietary enclosure}
This information is needed to demonstrate compliance with 10 CFR 71.33, 71.71, and 71.73.
Obs. 3-2 Clarify whether there are (or not) other temperatures in addition to the SAR table 3.I.2.3 basket temperature limits used to support the structural analysis.
The use of SAR table 3.I.1.3 has been briefly described in SAR section 3.I.2.2 (SAR table 3.I.1.3 should be editorially changed to SAR table 3.I.2.3 within that section) to indicate that the basket temperature limits that are a function of fuel basket type, basket zone, and basket elevation are used to support the structural stress analysis. However, it is not clear whether other calculated component temperatures based on a candidate heat load pattern are also used to support the structural analysis.
This information is needed to demonstrate compliance with 10 CFR 71.33.
Obs. 3-3 {See proprietary enclosure}
Obs. 3-4 Clarify the validity of the governing fuel basket / multi-purpose canister (MPC) in SAR section 3.I.3.3, Screening calculations to ascertain governing fuel package.
SAR section 3.I.3.3 describes how the bounding fuel basket / MPC is determined.
However, SAR section 3.I.3.3 states, The principal result of the analysis, which are the maximum computed fuel temperatures and cavity pressure, is tabulated in Table 3.I.3.2.
The results support the conclusion that the highest temperatures are obtained in the F-32M-CBS Fuel Package. {See proprietary enclosure}, which doesnt include 3% rods rupture.
This information is needed to demonstrate compliance with 10 CFR 71.33.
Obs. 3-5 {See proprietary enclosure}
Obs. 3-6 Provide an overall framework or break down more clearly the SAR section 3.I.3.9, Evaluation of candidate heat load pattern.
Clearly provide a framework in SAR section 3.I.3.9 that shows the input, thermal methodology, and acceptance criteria.
This information is needed to demonstrate compliance with 10 CFR 71.71(c)(1) and 71.73(c)(4).
Obs. 3-7 Provide justification that the physics modeled in the transportation design, specifically for fluid flow (convective heat transfer), remains valid for any proposed decay heat pattern or total decay heat value.
SAR section 3.I.3.9, Evaluation of candidate heat load patterns, does not include justification for expanding the use of the thermal models to higher total or per assembly decay heats, or in other words, to develop alternate total or per assembly decay heat limits that are higher than those that have been previously approved. Justification should be provided because the proposed total decay heat is greater than some of the total
decay heat values that have been approved. The flow regimes (laminar, transitional turbulent) should remain valid for any selected heat load pattern.
This information is needed to demonstrate compliance with 10 CFR 71.33, 71.71(c)(1) and 71.73(c)(4).
Obs. 3-8 {See proprietary enclosure}
Obs. 3-9 {See proprietary enclosure}
Obs. 3-10 Revise the use of SAR table 1.1.1 throughout SAR section 3.I.
SAR table 1.1.1 is a list of Holtec HI-STAR packages. SAR table 1.1.2 is a list of applicable baskets and MPCs for the HI-STAR 100MB. One example of an occurrence is in SAR section 3.I.1.1, Baskets available for loading fuel are defined in Table 1.1.1. In general, concepts of fuel package configurations in SAR table 1.1.1 throughout SAR section 3.I should be replaced with basket / MPCs in SAR table 1.1.2.
This information is needed to demonstrate compliance with 10 CFR 71.33.
CHAPTER 4 CONTAINMENT EVALUATION RSI 4-1 Provide the appropriately sized dimensions of the port cover plate inner seal [table 8.A-2 (ITEM 12)] that will ensure seal performance.
The applicant stated, in SAR section 8.I.A, that containment boundary seal data for the HI-STAR 100MB MSC package are identical to those in the HI-STAR 100MB as outlined in appendix 8.A. However, table 8.A-2 does not include groove dimensions for the port cover plate inner seal (item 12, metallic seal), which is an important-to-safety (ITS) component.
This information is required to determine compliance with 10 CFR 71.33.
RSI 4-2 (A) Clarify the cask is manufactured with grooves for an elastomeric seal or with grooves for a metallic seal in the application.
The applicant indicated, in Drawing No. 15568 HI-STAR 100MB MSC Cask Assembly, that the inner closure lid inner seal ITS component can be metallic or elastomeric. Likewise, the outer closure lid inner seal ITS component can be metallic or elastomeric. This is different from the original cask Drawing No. 11070 (HI-STAR 100MB Cask) which lists these seals as elastomeric. It should also be clarified that one type of cask is manufactured with grooves for an elastomeric seal and another type of cask is manufactured with grooves for a metallic seal such that seal types are not interchangeable.
(B) Include a procedure in SAR chapter 7 to ensure that the correct O-ring is to be installed (e.g., maintenance, periodic operations) in the HI-STAR 100MB and the HI-STAR 100MB MSC packages that are being transported.
Based on the above, the certificate of compliance (CoC) and SAR chapter 7 should recognize there are (at least) two distinct designs for the HI-STAR 100MB MSC
package. In addition, Drawing No. 11070, HI-STAR 100MB Cask, indicates there are (at least) two distinct designs for the HI-STAR 100MB package. Therefore, recognizing there are at least four distinct packages for one CoC, SAR chapter 7 should include a procedure to ensure that the correct O-ring is to be installed (e.g.,
maintenance, periodic operations) in the HI-STAR 100MB and the HI-STAR 100MB MSC packages that are being transported.
Note: The phrase at least is used because Drawing Nos. 11070 15568 also show that the port cover plate purge plug seal ITS component can be elastomeric or metallic.
Therefore, it is possible there are multiple designs for one CoC because of the permutations of seal types for the different seal locations.
This information is required to determine compliance with 10 CFR 71.33.
RSI 4-3 Provide the required characteristics of containment boundary seals for HI-STAR 100MB MSC to ensure joint seal for containment seals.
It is not certain why the HI-STAR 100MB cask has a number of required characteristics of elastomeric containment boundary seals in SAR table 2.2.11a while the new HI-STAR 100MB MSC does not include the same characteristics in SAR table 2.I.2.4. The important seal characteristics should be relevant for both HI-STAR 100MB cask and HI-STAR 100MB MSC cask.
This information is required to determine compliance with 10 CFR 71.33.
RSI 4-4 Provide the characteristics of the containment O-ring/seal (i.e., vendor and part number) as described below for a spent fuel transportation package (HI-STAR 100MB and HI-STAR 100MB MSC).
A spent fuel package design, to describe materials and for inspection, should include a particular O-ring/seal material (i.e., vendor and part number) along with specifications (the specifications are useful if the applicant must obtain a different seal because of sourcing issues). It appears the HI-STAR 100MB cask mentions a Parker part number for the elastomeric seals (SAR table 2.2.11a), but does not mention something similar for the metallic seals. Likewise, the new HI-STAR 100MB MSC mentions some details of the metallic seal in SAR table 2.I.2.4, but does not provide a vendor and part number.
This information is required to determine compliance with 10 CFR 71.33.
RSI 4-5 (A) Provide derivations of the containment system cavity free volume and fuel assembly surface area.
The applicant provided the containment system cavity free volume and fuel assembly surface area in table 5-1 and the isotope inventory in table A-1 of the updated Calculation Package HI-2188669, Containment Analysis of HI-STAR 100MB, submitted for Amendment 3. Provide the derivation of the containment system cavity free volume and fuel assembly surface area, as shown in table 5-1, in the application.
(B) Explain changes of the isotopic inventory of nuclides as described below. The applicant needs to provide calculations (i.e., spreadsheet) for verification of the
containment analysis of HI-STAR 100MB as shown in Calculation Package No. HI-2188669 submitted for Amendment 3.
The staff referred to an earlier Calculation Package No. HI-2188669 submitted for the previous Amendment 1 and noted the isotope inventory (Ci/assembly) of the nuclides 3H, 85Kr, 134Cs, 89Sr, and 103Ru is changed/reduced in Calculation Package No. HI-2188669 submitted for this Amendment 3.
Note: the cavity free volume, fuel assembly surface area, and isotopic inventory of nuclides can affect calculations of leakage rates, and more information needs to be provided.
This information is required to determine compliance with 10 CFR 71.35 and 71.51.
Obs. 4-6 Clarify Notes 2a and 2b in SAR table 8.1.1.
The applicant notes in SAR table 8.1.1 that Note 2a: The joint gasket must be reusable (e.g., elastomeric seals). and Note 2b: The gasket was previously installed and the gasketed joint qualified for a leak rate not more than the reference leakage rate (LR) as specified in the table above (i.e. the pre-qualified gasket was never replaced). However, some of the seals can be metallic, which tend not to be reusable. The intent of that statement is not certain.
This information is required to determine compliance with 10 CFR 71.33.
CHAPTER 7 PACKAGE OPERATIONS RSI 7-1 Include a report in chapter 7.I operating procedures that serves to document each candidate heat loading pattern.
The candidate heat loading pattern is the input to the method described in SAR section 3.I.3.9, where the documented temperature and pressure results need to meet the acceptance criteria also in SAR section 3.I.3.9. The candidate heat loading pattern and temperature and pressure results should be documented in a report listed in chapter 7.I.
A response that documents an example of a report (proprietary) for the HI-STORM 100 Amd. 18 was provided in Docket No. 72-1014 by letter dated September 8, 2023 in Agencywide Documents Access Management System (ADAMS) Accession No. ML23251A250.
This information is needed to demonstrate compliance with 10 CFR 71.71(c)(1),
71.73(c)(4), 71.87(a)(f) and (k).
Obs. 7-1 Revise the note numbers in SAR tables 7.I.7.4(a), HI-STAR 100MB MSC with MPC Backfill Requirements, and 7.I.7.4(b), HI-STAR 100MB MSC with Bare Basket Backfill Requirements.
The numbers for the notes within the table are not consistent with the numbers for the notes below the table.
This information is needed to demonstrate compliance with 10 CFR 71.33, 71.71, and 71.73.
Obs. 7-2 Explain or clarify the following regarding SAR table 7.I.7.5:
- a. The MPC-68M-CBS and MPC-32M-CBS are described in the summary of proposed changes (SOPC), proposed change #2 {See proprietary enclosure}, but those MPCs are not specifically included in SAR table 7.I.7.5.
The MPCs in the SOPC that are associated with SAR table 7.I.7.5 should be included in the table.
This information is needed to demonstrate compliance with 10 CFR 71.33, 71.71, and 71.73.
Editorial: Clarify or revise the following in the SAR:
In SAR table 3.I.2.3, Basket Temperature Limits for Candidate Heat Load Patterns, Note1: Zones are defined in Figures 3.I.2.2 through 3.I.2.10 - however, the figures in the SAR go through figure 3.I.2.11.
In SAR table 3.I.2.3 the basket elevation column refers to note 1; however, note 1 refers to zones.
The operating pressure, Pop, is not used in the equations in section 3.I.3.10 of the SAR.
{See proprietary enclosure}
Note 1 for table 3.I.3.1 of the SAR was not provided.
Remove the duplicate time-to-boil scenario in table 3.I.3.5 of the SAR, or clarify the difference between the two scenarios.
In SAR section 3.I.4 for thermal evaluation under HAC, HI-STAR 100MB MSC is evaluated under 10 CFR 71 mandated sequence of hypothetical accidents for a transport package similar.
This information is needed to demonstrate compliance with 10 CFR 71.33.