ML24337A158
| ML24337A158 | |
| Person / Time | |
|---|---|
| Site: | HI-STORM 100 |
| Issue date: | 12/09/2024 |
| From: | Melendez-Colon D Storage and Transportation Licensing Branch |
| To: | Elzahri A Holtec |
| Shared Package | |
| ML24337A157 | List: |
| References | |
| EPID L-2023-LLA-0176 | |
| Download: ML24337A158 (1) | |
Text
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 December 9, 2024 Ali Elzahri, Licensing Project Engineer Holtec International Krishna P. Singh Technology Campus 1 Holtec Blvd.
Camden, NJ 08104
SUBJECT:
FOLLOW-UP TO REQUEST FOR ADDITIONAL INFORMATION RESPONSES FOR REVIEW OF THE HOLTEC MODEL NO.
HI-STORM UMAX STORAGE SYSTEM, AMENDMENT 5 - COST ACTIVITY CODE/ENTERPRISE PROJECT IDENTIFICATION NUMBERS 001028/L-2023-LLA-0176
Dear Ali Elzahri:
By letter dated December 14, 2023 (Agencywide Documents Access and Management System
[ADAMS] Accession No. ML23348A302), as supplemented on April 18, 2024 (ML24136A189),
and September 19, 2024 (ML24263A279), Holtec International (Holtec or the applicant) requested the U.S. Nuclear Regulatory Commission (NRC) an amendment to Certificate of Compliance No. 1040 for the Model No. HI-STORM UMAX. The application proposes to add new versions of the UMAX with lid features that will provide protection for colder canisters.
In connection with our review, we need the information identified in the enclosed follow-up to the request for additional information (RAI) responses. To assist us in scheduling the NRC staff review of your response, we request that you provide this information by January 31, 2025.
Inform us at your earliest convenience, but no later than 2 weeks before the response date, if you are not able to provide the information by that time frame. If you are unable to provide a response by the stated date, our review may be delayed.
Please reference Docket No. 72-1040 and Cost Activity Code/Enterprise Project Identification Numbers 001028/L-2023-LLA-0176 in future correspondence related to this review. The NRC staff is available to clarify these questions, and, if necessary, to meet and discuss your proposed responses. transmitted herewith contains proprietary information. When separated from the sensitive conditions in Enclosure 2, this letter and Enclosure 1 are decontrolled.
OFFICIAL USE ONLY - PROPRIETARY INFORMATION A. Elzahri 2
OFFICIAL USE ONLY - PROPRIETARY INFORMATION In accordance with Title 10 of the Code of Federal Regulations Section 2.390, Public inspections, exemptions, requests for withholding, a copy of this letter will be available electronically for public inspection in the NRC Public Document Room (PDR) or from the Publicly Available Records component of the NRCs ADAMS. ADAMS is accessible from the NRC website at http://www.nrc.gov/reading-rm/adams.html. The PDR is open by appointment.
To make an appointment to visit the PDR, please send an email to PDR.Resource@nrc.gov or call 1-800-397-4209 or 301-415-4737, between 8:00 a.m. and 4:00 p.m. eastern time (ET),
Monday through Friday, except Federal holidays.
If you have any questions regarding this communication, please contact me at 301-415-7295, or via email to Daneira.Melendez-Colon@nrc.gov.
Sincerely, Daneira Meléndez Colón, Project Manager Storage and Transportation Licensing Branch Division of Fuel Management Office of Nuclear Material Safety and Safeguards Docket No.: 72-1040 EPID No.: L-2023-LLA-0176
Enclosures:
- 1. Follow-up to RAI Responses (Non-Proprietary)
- 2. Follow-up to RAI Responses (Proprietary)
Signed by Melendez-Colon, Daneira on 12/09/24
ML24337A157(pkg, non-public), ML24337A158(ltr & encl 1),
ML24337A159 (encl 2, non-public)
OFFICE:
NMSS/DFM NMSS/DFM NMSS/DFM NMSS/DFM NMSS/DFM NAME:
DMeléndez Colón WWheatley BPatel TBoyce YDiaz-Sanabria DATE:
12/3/2024 12/4/2024 12/5/2024 12/5/2024 12/9/2024 OFFICE:
NMSS/DFM NAME:
DMeléndez Colón DATE:
12/9/2024
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION Follow-Up to Request for Additional Information Responses Docket No. 72-1040 Certificate of Compliance No. 1040 Amendment No. 5 Model No. HI-STORM UMAX This follow-up request identifies additional information that is needed by the U.S. Nuclear Regulatory Commission (NRC) staff in connection with its review of the application. The NRC staff used NUREG-2215, Standard Review Plan for Spent Fuel Dry Storage Systems and Facilities, in its review of the application.
Each follow-up question describes information needed by the NRC staff to complete its review of the application and to determine whether the applicant has demonstrated compliance with the regulatory requirements of Title 10 of the Code of Federal Regulations (10 CFR) Part 72.
Structural Evaluation RAI-St-1F Provide an evaluation for the thermal degradation of concrete subgrade material in space A due to increased temperature for the UMAX storage system.
In response to RAI-St-1 (Agencywide Documents Access and Management System Accession No. ML24263A279), the applicant included the subgrade concrete in the thermal model and provided steady state component temperatures, including the maximum section average temperature of the concrete subgrade from the revised thermal analysis HI-2230586, Revision
- 1. Based on these results, the maximum section average temperature of the concrete subgrade
[Information Withheld Pursuant 10 CFR 2.390]. The applicant compared this temperature to the temperature limit of 350 degrees Fahrenheit (ºF) for the Closure Lid plain concrete per the final safety analysis report (FSAR) FSAR table 2.3.7, stating that the plain concrete used in the Closure Lid is the same material used for the subgrade material in space A for the Version most severe earthquake (MSE) vertical ventilated module (VVM), and therefore satisfies the temperature limit established in table 2.3.7 of the FSAR. The applicant further stated that the plain concrete material in Space A (see figure 3.4.4) is not designed to meet American Concrete Institute (ACI) 349 requirements, and therefore the thermal considerations in appendix A of ACI 349-01 do not apply.
The staff reviewed the request for additional information (RAI) response and considered it to be inadequate due to the following reasons:
The FSAR table 2.3.7, TEMPERATURE LIMITS, does not list and provide a temperature limit for the subgrade concrete material in space A (i.e. the space between underground storage overpacks). The subgrade concrete has a structural function. It is included in the soil structural interaction (SSI) analysis model, used for tornado missile protection during construction, and is also credited for preventing excessive distortion of the storage overpack under the MSE event to permit future retrievability of a multi-purpose canister containing spent fuel. The Closure Lid concrete does not have a significant structural function, and the plain concrete properties are instead used in shielding calculations and analysis of mechanical loadings on the Closure Lid.
OFFICIAL USE ONLY - PROPRIETARY INFORMATION 2
OFFICIAL USE ONLY - PROPRIETARY INFORMATION As a result, the applicant did not provide an adequate basis for the 350 ºF long-term temperature limit for the Closure Lid plain concrete material and its applicability to the subgrade concrete in space A.
Based on statements in FSAR section 8.8.1, it appears to the staff that the temperature limits for the Closure Lid plain concrete in table 2.3.7 are adopted from the HI-STORM 100 FSAR where the bases for the thermal limits are documented. In the HI-STORM 100 FSAR HI-2002444, Revision 24, table 1.D.1, Requirements for Plain Concrete, Note 3 states, The 300 ºF long term temperature limit is specified in accordance with Paragraph A.4.3 of Appendix A to ACI 349 considering the very low maximum stresses calculated and discussed in Section 3.4 of this FSAR for normal conditions. In accordance with this paragraph of the governing code, the specified concrete compressive strength is supported by test data and the concrete is shown not to deteriorate, as evidenced by a lack of reduction in concrete density or durability.
If the bases for the temperature limits of the Closure Lid plain concrete in HI-STORM UMAX SAR table 2.3.7 are adopted from the HI-STORM 100 FSAR, the 350 ºF temperature limit used for the HI-STORM UMAX Closure Lid and therefore MSE subgrade concrete in space A does not align with the 300 ºF long term temperature limit specified in the HI-STORM 100 FSAR, table 1.D.1, for the plain concrete. Also, the applicant stated in the RAI response that the thermal considerations in appendix A of ACI 349-01 do not apply to the subgrade concrete in space A, which is inconsistent with the bases used for setting the plain concrete long term temperature limit in the HI-STORM 100 FSAR. Considering the above, it is not clear to the staff the bases for acceptance of the long-term temperature limit of the concrete in subgrade space A for the UMAX system. The staff requests the following information:
a) If the temperature limits in table 2.3.7 for the plain concrete are adopted from the HI-STORM 100 FSAR, resolve the temperature limit discrepancy between the two HI-STORM systems FSARs and; i) provide bases for the applicability of the long term temperature limit for the Closure Lid concrete to the concrete used for the subgrade in space A; ii) demonstrate the plain concrete used for the subgrade in space A meets the critical requirements for the concrete constituent materials specified in the HI-STORM 100 FSAR, table 1.D.1 and; iii) demonstrate low stresses in subgrade concrete under normal conditions similar to that shown for the Closure Lid concrete in Note 3 of table 1.D.1 of the HI-STORM 100 FSAR.
b) If the temperature limits in table 2.3.7 for the plain concrete are not adopted from the HI-STORM 100 FSAR, provide bases for the 350 ºF, the long-term temperature limit for the UMAX system Closure Lid concrete and its applicability to the subgrade concrete in space A, based on the applicable industry codes, standards and/or tests. Also, update the UMAX system FSAR, section 8.8.1 as appropriate to resolve any discrepancy.
c)
As a result of the long-term temperature increase under this amendment and due to the significant differences in the plain concrete functions and locations between the Closure Lid and the subgrade space A, FSAR table 2.3.7 should be updated to list the plain concrete in Space A with its temperature limits, and the associated bases for the temperature limits should be provided.
The staff notes that in the RAI response, table 1, the numbers listed for the margins for Fuel Cladding and Concrete Subgrade do not match the differences between the calculated
OFFICIAL USE ONLY - PROPRIETARY INFORMATION 3
OFFICIAL USE ONLY - PROPRIETARY INFORMATION temperature and the temperature limit. Example for Concrete Subgrade: [Information Withheld Pursuant 10 CFR 2.390]
The staff needs this information to determine compliance with 10 CFR 72.236(b), (c), (d) and (l).
RAI-St-2F Provide detailed justification for not reanalyzing the SSI analyses due to the increased long-term temperatures for the UMAX storage system components and subgrade in space A.
The applicant responded that from the thermal model, the maximum surface temperature of the concrete in space A is well below the previously approved temperature limit of 350 ºF for the plain concrete in the Closure Lid per FSAR table 2.3.7. The applicant further stated that the plain concrete used in the Closure Lid is the same material used for the subgrade material in space A for the Version MSE VVM. Since the concrete temperature remains below the established FSAR limit, there is no reason to degrade the concrete strength properties and re-perform the SSI analysis contained in calculation/supplement 7A/3 of Holtec Report HI-2125228, Revision 17. Based on the lower temperatures, the elastic modulus values used to characterize steel components are minimally affected (i.e., less than 3 percent for cavity enclosure container shell and less than 1 percent for Divider Shell). Therefore, a full re-analysis of the SSI model is not warranted.
The staff agrees with the applicants response that a full re-analysis of the SSI model is not warranted, if the applicant provided the requested information in this RAI and accepted by the staff. In the RAI, the staff requested a detailed justification by providing sensitivities of the changes in the input parameters (such as relevant steel and concrete properties) due to temperature increases on the responses from the MSE SSI analyses (seismic demands) and a comparison to the design margin available in the affected UMAX overpack and other component acceptance limits. The response to the RAI did not provide the requested information. Also, as stated in the staff follow-up for the RAI-St-1 response, the applicant did not adequately demonstrate: the bases for acceptance of the concrete long-term temperature limit in the subgrade space A, and the impact of long-term temperature increases on the relevant concrete design parameters. The staff needs this information to determine the impact on the safety and retrievability of the package under an MSE event.
The staff needs this information to determine compliance with 10 CFR 72.236(b), (c), (d) and (l).