ML26029A002
| ML26029A002 | |
| Person / Time | |
|---|---|
| Site: | 99902049 |
| Issue date: | 02/02/2026 |
| From: | Victoria Huckabay NRC/NRR/DNRL/NRLB |
| To: | Hayes M NRC/NRR/DNRL/NLIB |
| Shared Package | |
| ML26029A001 | List: |
| References | |
| Download: ML26029A002 (0) | |
Text
MEMORANDUM TO:
Michelle W. Hayes, Chief Licensing and Regulatory Infrastructure Branch Division of New and Renewed Licenses Office of Nuclear Reactor Regulation FROM:
Victoria V. Huckabay, Senior Project Manager Licensing and Regulatory Infrastructure Branch Division of New and Renewed Licenses Office of Nuclear Reactor Regulation
SUBJECT:
AUDIT PLAN FOR THE REGULATORY AUDIT OF SMR-300 TIME-DOMAIN LS-DYNA SOIL STRUCTURE INTERACTION ANALYSIS METHODOLOGY LICENSING TOPICAL REPORT By letter dated November 26, 2025, SMR, LLC, a Holtec International Company (SMR (Holtec)),
submitted Licensing Topical Report (LTR) HI-2251837, Revision 0, SMR-300 Time-Domain LS-DYNA Soil Structure Interaction Analysis Methodology Licensing Topical Report.1,2 The U.S.
Nuclear Regulatory Commission (NRC) staff accepted the LTR for review on January 23, 2026.3 As part of the LTR review, the NRC staff will conduct an audit to better understand the information submitted by SMR (Holtec). The audit will be conducted in SMR (Holtec)s online portal from February 5, 2026, through July 31, 2026 (date approximate). There will be an entrance meeting to discuss the audit process and an exit meeting to summarize the activities and status of each item. In-person meetings may be added to facilitate discussions during the audit, as necessary. The NRC staff will issue an audit summary within approximately 90 days following the exit meeting. The audit plan is provided as Enclosure 1, and detailed information required for the regulatory audit is provided in Enclosure 2 (ML26029A003, proprietary).
CONTACT: Victoria V. Huckabay, NRR/DNRL 301-415-5183 1
Letter from P. Lashley to NRC, SMR-300 Time-Domain LS-DYNA Soil Structure Interaction Analysis Methodology Licensing Topical Report, dated November 26, 2025 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25330A198, part of package ML25330A197).
2 Letter from P. Lashley to NRC, Enclosure 2, SMR-300 Time-Domain LS-DYNA Soil Structure Interaction Analysis Methodology Licensing Topical Report, dated November 26, 2025 (ML25330A200, part of package ML25330A197).
3 Email from NRC to P. Lashley, Topical Report Completeness Determination for Report Number HI-2251837 Revision 0, dated January 23, 2026 (ML26022A028, part of package ML26022A026).
February 2, 2026 Signed by Huckabay on 02/02/26
M. Hayes This audit will be conducted in accordance with the guidance provided in Office Instruction LIC-111, Revision 2, Regulatory Audits.4 Docket No. 99902049
Enclosures:
As stated 4 U.S. NRC, LIC-111, Revision 2, "Regulatory Audits, dated December 19, 2024 (ML24309A281).
Pkg: ML26029A001 Memo: ML26029A002 Encl 2: ML26029A003 (Non-Public) via* e-concurrence NRR-106 OFFICE NRR/DNRL/NLIB:PM NRR/DNRL/NLIB:BC NRR/DNRL/NLIB:PM NAME VHuckabay MHayes VHuckabay DATE 01/30/2026 02/02/2026 UNITED STATES NUCLEAR REGULATORY COMMISSION AUDIT PLAN FOR THE SMR-300 TIME-DOMAIN LS-DYNA SOIL STRUCTURE INTERACTION ANALYSIS METHODOLOGY LICENSING TOPICAL REPORT (CAC/EPID: 002060/L-2025-TOP-0038)
Docket No. 99902049 AUDIT PLAN APPLICANT:
SMR (Holtec)
CONTACTS:
Victoria Huckabay DURATION:
February 5 to July 31, 2026 (Approximate Audit Exit)
AUDIT TEAM:
Michelle Hayes - Branch Chief (Office of Nuclear Reactor Regulation (NRR))
Ian Tseng - Branch Chief (NRR)
Christopher Cook - Branch Chief (NRR)
Victoria Huckabay - Senior Project Manager (NRR)
JS Nie - Technical Reviewer (lead) (Office of Nuclear Regulatory Research)
Si Hwan Park - Technical Reviewer (NRR)
Patrick Koch - Technical Reviewer (NRR)
Sarah Tabatabai - Technical Reviewer (NRR)
Amit Ghosh - Technical Reviewer (NRR)
Additional audit team members may be included as needed.
Observers from the United Kingdom Office for Nuclear Regulation may be invited to observe audit activities.
I.
BACKGROUND AND AUDIT BASIS By letter dated November 26, 2025, SMR, LLC, a Holtec International Company (SMR (Holtec)),
submitted Licensing Topical Report (LTR) HI-2251837, Revision 0, SMR-300 Time-Domain LS-DYNA Soil Structure Interaction Analysis Methodology Licensing Topical Report. The NRC staff accepted the LTR for review on January 23, 2026.
This audit will be conducted in accordance with the guidance provided in the Office Instruction LIC-111, Revision 2, Regulatory Audits.
II.
OBJECTIVES The NRC staff will seek clarification, gain understanding, and verify information related to the subject LTR. The audit will identify if information is needed to support a regulatory finding so it can be placed on the docket. Additionally, review and discussion of the audit material will help focus on any subsequent requests for additional information.
III.
REGULATORY AUDIT SCOPE The audit team will examine supporting documentation provided by SMR (Holtec) in the online portal and will hold discussions during audit meetings. Audit topics include the initial information needs described below and any additional items identified during the audit.
IV.
INFORMATION AND OTHER MATERIAL NECESSARY FOR THE REGULATORY AUDIT The initial audit information needs include the issues/topics below. The audit team may identify additional questions and/or information needs that will be communicated to SMR (Holtec) throughout the audit. Refer to Enclosure 2 (ML26029A003, proprietary) for additional information regarding the issues/topics listed below.
1.
Modeling of Soil-Structure-Fluid Interactions (SSFI)
Provide information related to consideration of sloshing during a high seismic event and modeling of SSFI. Also see Item 4 in this list, Verification and Validation of the Proposed Modeling Approach.
2.
Interface Modeling Provide additional information on the SSI model, including the formulation of the interface model; identification of the model parameters; experimental testing to determine the model parameters; and verification and validation of the model.
3.
Modeling of Radiation Damping For NRC staffs requests on this issue, see Enclosure 2.
4.
Verification and Validation of the Proposed Modeling Approach Provide additional information to verify and validate the FSI and SSI analyses: 1) using test cases that cover a range of structural configurations and seismic excitation levels consistent with the SMR-300 and its design basis to verify that the proposed FSI modeling methodology can accurately predict key response parameters, including sloshing effects, base shear, overturning moment, and hydrodynamic pressure; and
- 2) using test cases that include a variety of structural and soil configurations and properties, as well as multiple seismic excitations to verify that the proposed time-domain LS-DYNA methodology for SSI analysis can accurately reproduce the results obtained from equivalent SASSI analyses.
V.
SPECIAL REQUESTS The NRC staffs requests that SMR (Holtec) provide subject matter expert(s), if necessary, to discuss the details of the audit material.
VI.
LOGISTICS AND DELIVERABLES Entrance Meeting:
February 5, 2026 Exit Meeting:
July 31, 2026 (date approximate)
The audit team will hold audit calls and/or meetings with SMR (Holtec), as necessary, to understand audit material. The team will inform SMR (Holtec) of any emerging information needs.
An audit report will be issued within 90 days following the exit meeting. The NRC point of contact for this audit is Victoria Huckabay at Victoria.Huckabay@nrc.gov.