ML25071A220

Non-Prop - NRC Staff Review of the Terrestrial Energy USA, Inc. Principal Design Criteria Topical Report for the Integral Molten Salt Reactor - Presentation

ML25071A220
Person / Time
Site:	99902076
Issue date:	03/06/2025
From:	Adams B, Matthew Gordon, Hanh Phan, Kevin Roche NRC/NRR/DANU/UAL2
To:
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Download: ML25071A220 (1)

Text

NRC Staff Review of the Terrestrial Energy USA, Inc.

Principal Design Criteria Topical Report for the Integral Molten Salt Reactor Kevin Roche, Project Manager Hanh Phan, Senior Reliability and Risk Analyst Ben Adams, Nuclear Systems Engineer Matthew Gordon, Materials Engineer Office of Nuclear Reactor Regulation (NRR)

Division of Advanced Reactors and Non-Power Production and Utilization Facilities (DANU)

ACRS Subcommittee Meeting (Open Session)

March 20, 2025

Agenda

• Review chronology

• Topical report (TR) purpose and review strategy

• Safety evaluation (SE) overview

• Conclusions 2

NRC Review Team

• Matthew Gordon, Materials Engineer, NRR/DANU (Technical Lead)

• Christopher Adams, General Engineer, NRR/DANU

• Joseph Ashcraft, Former NRC Staff, NRR

• Hanh Phan, Senior Reliability and Risk Analyst, NRR/DANU (IMSR Project Lead)

• Benjamin Parks, Senior Technical Advisor, NRR/DANU

• Kevin Roche, Project Manager, NRR/DANU (IMSR Project Manager)

• Adrian Muniz, Senior Project Manager, NRR/DANU

• Michelle Vega Rodriguez, Project Manager, NRR/DANU

• Lucieann Vechioli Feliciano, Project Manager, NRR/DANU 3

Review Chronology

• Jun 8, 2020: White Paper containing proposed Principal Design Criteria (PDC) for Integral Molten Salt Reactor (IMSR) submitted (ML20178A457)

• Aug 20, 2020: NRC staff provided comments (ML20304A561)

• Jan 17, 2023: TEUSA IMSR PDC TR, Revision 0 submitted (ML23025A066)

• Feb 17, 2023: TR accepted for review

• Sep 28, 2023: Closed clarification meeting

• Dec 29, 2023: TEUSA IMSR PDC TR, Revision B submitted (ML24053A168)

• Apr 8, 2024: PDC TR audit commenced

• Jul 2, 2024: Audit exited

• Jul 19, 2024: TEUSA IMSR PDC TR, Revision C submitted (ML24204A092)

• Aug 28, 2024: Closed clarification meeting

• Oct 7, 2024: Audit report issued (ML24233A246)

• Nov 4, 2024: Closed clarification meeting

• Feb 20, 2025: NRC staffs draft safety evaluation report issued (ML24339A121) 4

TR Purpose and Review Strategy

• Purpose of TR

• Establish the PDC to support the design/future license applications referencing the IMSR

• Demonstrate compliance with the relevant regulatory requirements of Title 10 of the Code of Federal Regulations (10 CFR) Parts 50 and 52 associated with PDC

• Review strategy

• Ensure compliance with regulatory requirements

• Review conformance with Regulatory Guide (RG) 1.232, Guidance for Developing Principal Design Criteria for Non-Light-Water Reactors

• Evaluate deviations from RG 1.232 in consideration of the key IMSR design features

• Assess applicability of RG 1.232 appendices and guidance to novel IMSR design features 5

Regulations

• In accordance with the provisions of 10 CFR Parts 50 and 52, applicants for a construction permit (CP),

operating license (OL), standard design certification (DC), combined license (COL), standard design approval (SDA), or manufacturing license (ML) must submit PDC for the proposed facility. Specifically, the following regulations pertain to the PDC:

• 10 CFR 50.34(a)(3)(i), which requires, in part, that applications for a CP include PDC for the facility. An OL would reference a CP, which would include PDC

• 10 CFR 52.47(a)(3)(i), which requires, in part, that applications for a standard Design Criteria (DC) include PDC for the facility

• 10 CFR 52.79(a)(4)(i), which requires, in part, that applications for a COL include PDC for the facility

• 10 CFR 52.137(a)(3)(i), which requires, in part, that applications for an SDA include PDC for the facility

• 10 CFR 52.157(a), which requires, in part, that applications for a ML include PDC for the reactor to be manufactured

• 10 CFR Part 50, Appendix A provides requirements on the scope and content of PDC for non-light water reactors (non-LWRs):

• The principal design criteria establish the necessary design, fabrication, construction, testing, and performance requirements for structures, systems, and components important to safety; that is, structures, systems, and components that provide reasonable assurance that the facility can be operated without undue risk to the health and safety of the public.

6

Guidance

• RG 1.232, Guidance for Developing Principal Design Criteria for Non-Light-Water Reactors (ML17325A611)

• Appendices provide example advanced reactor design criteria

• Draft American National Standards Institute (ANSI)/American Nuclear Society (ANS) ANSI/ANS 20.2-2023, Nuclear Safety Design Criteria and Functional Performance Requirements for Liquid-Fuel Molten Salt Reactor Nuclear Power Plants

• The NRC staff is in the process of reviewing ANSI/ANS 20.2-2023 for requested endorsement 7

IMSR PDC Overview

• TEUSA established the IMSR PDC as follows:

• Section I - Overall Requirements (DC 1-5)

• Section II - Multiple Barriers (DC 10-19)

• Section III - Reactivity Control (DC 20-29)

• Section IV - Heat Transport Systems (DC 30-46)

• Section V - Reactor Containment (DC 50-57)

• Section VI - Fuel and Radioactivity Control (DC 60-64)

• Section VII - Additional (DC 70-79) 8

Safety Evaluation Overview

• Regulations and guidance

• IMSR design features (informational)

• IMSR PDC

• PDC with no changes to the design criteria in RG 1.232

• PDC with minor terminology changes

• PDC with substantive technical changes

• Limitations and conditions

• Conclusions 9

Conclusions

• The NRC staff established four Limitations and Conditions (L&Cs)

• TEUSA provided a sufficient set of PDC for the IMSR design, subject to the L&Cs

• The PDC (subject to the L&Cs) establish the necessary design, fabrication, construction, testing, and performance DC for safety significant SSCs to provide reasonable assurance that the IMSR reactor could be operated without undue risk to the health and safety of the public

• The TEUSA PDC TR, Revision C, is suitable for reference in future licensing applications for the IMSR 10

Abbreviations ANSI/ANS - American National Standards Institute/American Nuclear Society CFR - Code of Federal Regulations COL - Combined license CP - Construction permit DANU - Division of Advanced Reactors and Non-power Production Facilities DC - Design criteria IMSR - Integrated Molten Salt Reactor L&C - Limitation and condition LWR - Light water reactor ML - Manufacturing license NRR - Office of Nuclear Reactor Regulation NRC - Nuclear Regulatory Commission OL - Operating license PDC - Principal design criteria RG - Regulatory guide SDA - Standard design approval SSC - Structure, system, or component SE - Safety evaluation TEUSA - Terrestrial USA, Inc.

TR - Topical report 11