ML26006A205
| ML26006A205 | |
| Person / Time | |
|---|---|
| Site: | 99902049 |
| Issue date: | 01/06/2026 |
| From: | Holtec, SMR |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML26006A202 | List: |
| References | |
| 300-USNRC-26001 | |
| Download: ML26006A205 (0) | |
Text
www.holtec.com www.smrllc.com Combined Post-Submittal Meeting:
Concrete-Strengthened Steel Structures Design and Analysis Methodology LTR Time-Domain LS-DYNA Soil Structure Interaction Analysis Methodology LTR (Open Session) January 12, 2026 Holtecs SMR-300 Technology Safe, Secure, Reliable, Flexible, Economical Clean Energy to Support the Worlds Energy Needs Holtec International Krishna P. Singh Technology Campus One Holtec Boulevard Camden, NJ 08104, USA
[Not Export Controlled]
holtec.com l smrllc.com l Page 2 Agenda Overview Concrete Strengthened Steel (CSS) Structures Design and Analysis Methodology Licensing Topical Report (LTR) (CSS Structures LTR)
Time-Domain LS-DYNA Soil Structure Interaction (SSI) Analysis Methodology LTR (SSI Analysis LTR)
Q&A Closed Session
holtec.com l smrllc.com l Page 3 Overview Holtec International plans to build a dual-unit SMR-300 plant located at Palisades Energy Center in Covert, MI Individually named Pioneer Unit 1 and Pioneer Unit 2 Additional future SMR-300 power plants at other locations are contemplated LTRs are applicable to any SMR-300 site
holtec.com l smrllc.com l Page 4 Overview Dual-unit SMR-300 Nuclear Island structures include Two Reactor Buildings, each with a Containment Enclosure Structure above grade (CES)
Containment Structure below grade (CS)
Steel Containment Vessel above grade (SCV)
One common Reactor Auxiliary Building (RAB)
Two Intermediate Buildings (IBs)
holtec.com l smrllc.com l Page 5 Presents Methodology and Acceptance Criteria for CSS structural design Describes:
Use of Concrete Strengthened Steel Modules (CSSMs)
General requirements for CSSMs Structural modeling details Design and analysis approaches Fabrication and inspection requirements Test plan used to confirm design and analysis methodologies Applies to containment and non-containment structures Submittal Date: December 2, 2025 Overview - SMR-300 CSS Structures LTR
holtec.com l smrllc.com l Page 6 LTR Objectives Request NRC review and approval of:
Design and Analysis Methods Acceptance Criteria Requirements for material selection, fabrication and construction, inspection and examination Future applicant can use LTR as an acceptable approach to meet applicable regulatory requirements and guidance Overview - SMR-300 CSS Structures LTR
holtec.com l smrllc.com l Page 7 Overview - SMR-300 CSS Structures LTR Background & Timeline Date Description September 23, 2024 Public meeting to introduce the use of modularity for the SMR-300 nuclear island structures August 12, 2025 Public meeting to provide an overview of the structural modularity approach to SMR-300 design, discussing testing of concrete strengthened steel modules and planned content of a future structural modularity licensing LTR December 2, 2025 Submittal of the Concrete Strengthened Steel Structures Design and Analysis Methodology Licensing Topical Report
holtec.com l smrllc.com l Page 8 RAB Overview - SMR-300 CSS Structures LTR General Layout - Use of Modular Construction RB RB IB IB Reactor Auxiliary Building Reactor Building Intermediate Building
holtec.com l smrllc.com l Page 9 Overview - SMR-300 CSS Structures LTR Outline Introduction Regulatory Requirements and Guidance General Requirements Loads and Load Combinations Modeling Approach Design Capacities Connection Design Analysis, Design & Detailing for Openings Impactive & Impulsive Loadings Performance Under Fire QA & QC Requirements Corrosion Protection/Mitigation Requirements Experimental Evaluations References Appendix A: Design Example for Application of CSSMs to SMR 300 SCCV Appendix B: Design Example for Application of CSSMs to SMR-300 RAB Walls
holtec.com l smrllc.com l Page 10 Overview - SSI Analysis LTR
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Description:==
Time-domain seismic system or SSI analysis methodology Uses LS-DYNA finite element code More realistic alternative to traditional frequency-domain approaches such as SASSI by better capturing:
Nonlinear soil behavior Soil-structure interface effects, and Fluid-structure interaction Submittal Date: November 26, 2025
holtec.com l smrllc.com l Page 11 Overview - SSI Analysis LTR LTR Objectives Request NRC approval of proposed method for:
Conducting SSI analysis Generating seismic input parameters for qualification of safety-related SSCs (e.g., in-structure response spectra (ISRS))
Future applicant can use LTR as an acceptable approach to meet applicable regulations
holtec.com l smrllc.com l Page 12 Overview - SSI Analysis LTR Date Description September 27, 2022 Public meeting to introduce time-domain nonlinear SSI analysis approach November 8, 2023 Public meeting and submittal of preliminary SMR-160 SSI analysis results white paper December 18, 2023 Submittal of updated SMR-300 white paper and responses to NRC questions March 3, 2024 NRC provided the review assessment of the white paper November 26, 2025 Submittal of SMR-300 Time-Domain LS-DYNA Soil Structure Interaction Methodology Licensing Topical Report Background and Timeline
holtec.com l smrllc.com l Page 13 Overview - SSI Analysis LTR Table of Contents Introduction
Background
Assumptions and Software Solution Strategy Regulatory Compliance
Input of Ground Motions
Modeling of Supporting Soil
Modeling of Structures
Modeling of Fluids
Soil Structure Interaction
Development of In-Structure Response Spectra
Effects of Inclined Waves Validation of SMR-300 SSI Analysis Methodology Conclusion References
holtec.com l smrllc.com l Page 14 Questions