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Advanced Reactors (non-LWR designs)

Advanced Reactor Activities

Non-LWR Vision and Strategy and Implementation Action Plans

The staff has developed a vision and strategy to assure that the NRC is ready to review potential applications for non-light water reactor (non-LWR) technologies effectively and efficiently. The staff described the vision and strategy in "NRC Vision and Strategy: Safely Achieving Effective and Efficient Non-Light Water Reactor Mission Readiness," which was published in the Federal Register on July 21, 2016, for stakeholder input. The NRC updated its Vision and Strategy Document to reflect stakeholder feedback in December 2016.

To achieve the goals and objectives stated in the NRC's vision and strategy, the NRC has developed implementation action plans (IAPs). The IAPs identify the specific activities the NRC will conduct in the near-term (within 5 years), mid-term (5-10 years), and long-term (beyond 10 years) timeframes. The NRC released its draft IAPs to obtain stakeholder feedback during a series of public meetings held between October 2016 and March 2017. The staff also briefed the Advisory Committee on Reactor Safeguards (ACRS) on March 8 and 9, 2017. The staff considered the ACRS comments and stakeholder feedback in the final Near-Term, Mid-Term and Long-Term IAPs which were issued on July 12, 2017.

The staff issued SECY-19-0009, "Advanced Reactor Program Status" on January 17, 2019. This paper provides the status of the NRC staff's activities related to advanced reactors, including the progress and path forward on each of the implementation action plan (IAP) strategies. It also provides an overview of the various external factors influencing the staff's activities to prepare for possible licensing and deployment of advanced reactors.

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Flexible Licensing Processes for Advanced Reactors

The NRC's review and licensing processes are flexible and allow interactions related to a wide variation in design development and deployment strategies. Based on interactions with stakeholders, the NRC determined that guidance would be beneficial to assist non-LWR developers in planning regulatory interactions. To address this need, the NRC developed guidance for its flexible regulatory review processes within the bounds of existing regulations, including the use of conceptual design reviews and staged-review processes in the document, "A Regulatory Review Roadmap for Non-Light Water Reactors." The "roadmap" is also intended to help designers prepare technology- or design-specific regulatory engagement plans. Regulatory engagement plans define desired outcomes from various interactions between the designer and the NRC, considering factors such as the resources available to the designer and the NRC and the coordination of regulatory issues with other aspects of the overall program for developing and deploying non-LWR designs. Regulatory engagement plans also define the timing and scope of regulatory interactions in order to align with stakeholders activities related to plant design, research and development, finance, public policy, and the fuel cycle. The NRC released a draft roadmap document in October of 2016 to support discussions with stakeholders during several public meetings. The staff incorporated stakeholder feedback, and guidance related to standard design approvals and prototype reactors into the final roadmap, which was issued on December 26, 2017.

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Industry-Led Licensing Modernization Project

The NRC has engaged with the Licensing Modernization Project (LMP) being led by Southern Company, coordinated by the NEI, and cost-shared by DOE. The LMP's objective is to develop technology-inclusive, risk-informed, and performance based regulatory guidance for licensing non-LWRs for the NRC's consideration and possible endorsement. The NRC has reviewed four LMP white papers and sent a letter to the LMP on February 21, 2018, concluding its review of the white papers. After a series of public meetings, industry issued its consolidated LMP document (as NEI 18-04) on September 28, 2018. NEI 18-04 outlines an approach for use by reactor developers to select licensing basis events; classify structures, systems, and components; determine special treatments and programmatic controls; and assess the adequacy of a design in terms of providing layers of defense in depth. The staff and industry briefed the ACRS Future Plant Subcommittee on LMP in June and October of 2018, and the ACRS full committee in February 2019. The NRC published draft regulatory (DG) 1353, "Guidance for a Technology-Inclusive, Risk-Informed, and Performance-Based Methodology to Inform the Licensing Basis and Content of Applications for Licenses, Certifications, and Approvals for Non-Light Water Reactors," in the Federal Register on May 3, 2019, for public comment. This proposed new RG endorses, with clarifications, the principles and methodology in NEI-18-04 as one acceptable method for determining the appropriate scope and level of detail for parts of applications for licenses, certifications, and approvals for non-LWRs. The methodology described in NEI 18-04 and the draft RG also provide a general methodology for identifying an appropriate scope and depth of information to be provided in applications to the NRC for licenses, certifications, and approvals for non-LWRs. The NRC plans to issue a final regulatory guide in late 2019.

The following table provides reference to the LMP demonstration and pilot activities that have been submitted to date.

Date Design
December 2018 PRISM Sodium Fast Reactor
Licensing Modernization Project Demonstration
September 2018 OKLO's DG-1353 Pilot
August 2018 High Temperature, Gas-Cooled Pebble Bed Reactor
licensing Modernization Project Demonstration

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NRC-DOE Joint Initiative - Non-LWR Design Criteria

In July 2013, the US Department of Energy (DOE) and the NRC established a joint initiative to address a key portion of the licensing framework essential to advanced reactor technologies. The initiative addresses the "General Design Criteria for Nuclear Power Plants," Appendix A to 10 Code of Federal Regulations (CFR) 50, which were developed primarily for LWRs, by adapting them to the needs of advanced reactor design and licensing. The initiative is being accomplished in two phases. Phase 1, completed by DOE, consisted of reviews, analyses and evaluations resulting in a report issued by the DOE in December 2014 titled, "Guidance for Developing Principal Design Criteria for Advanced (Non-Light Water) Reactors." Phase 2 of the initiative, managed by the NRC, involved review of the Phase 1 DOE work products issuance of regulatory guidance resulting from the review.

On April 7, 2016, the NRC issued the, "Draft - Advanced Non-LWR Design Criteria - April 2016," for informal public comment. The informal public comment period closed on June 8, 2016. After consideration of stakeholder input, the NRC issued draft regulatory guide DG-1330, "Guidance for Developing Principal Design Criteria for Non-Light Water Reactors" for formal public comment. DG-1330 was published in the Federal Register on February 3, 2017, for a 60 day public comment period. The public comment period closed on April 4, 2017. The NRC considered the public comments and held a public meeting for further discussion on August 24, 2017. The staff considered the public comments and stakeholder interactions in preparing the final RG 1.232. On April 3, 2018, the NRC issued the, "Final RG 1.232," along with the, "Public Comment Resolution Table." Final RG 1.232 was published in the Federal Register on April 9, 2018.

The issuance of this new NRC regulatory guidance is expected to provide the following benefits:

  • reduced regulatory uncertainty for advanced reactor developers,
  • improved guidance for NRC staff reviewing advanced reactor license applications, and
  • improved timeliness and efficiency of licensing activities for both applicants and NRC staff.

The following table lists the meetings that NRC has conducted with external stakeholders in connection with the initiative:

Date Description

Public Meeting on Non-LWR Design Criteria


Public Meeting on Non-LWR Design Criteria


Non-Public Seminar Modular HTGR Technology and Safety Design Approach


Non-Public Seminar Sodium-Cooled Fast Reactor (SFR) Technology and Safety Overview


Public Meeting to Discuss the DOE Report, "Guidance for Developing Principal Design Criteria for Advanced (Non-Light Water) Reactors."

The following table provides access to documents, and correspondence between the NRC and DOE in connection with the initiative:

Date Description
09/15/15 Response to NRC Staff Second Set of Questions on the U.S. DOE Report, "Guidance for Developing Principal Design Criteria for Advanced Non-Light Water Reactors"
08/17/15 Questions on the U.S. Department of Energy Report, "Guidance for Developing Principal Design Criteria for Advanced (Non-Light Water) Reactors."
07/15/15 Response to NRC Staff Questions on the U.S. Department of Energy Report, "Guidance for Developing Principal Design Criteria for Advanced (Non-Light Water) Reactors."
06/05/15 NRC Staff Questions on the U.S. Department of Energy Report, "Guidance for Developing Principal Design Criteria for Advanced (Non-Light Water) Reactors."
01/15/15 NRC Letter to DOE, "Initiative Regarding U.S. Nuclear Regulatory Commission Licensing Strategy for Advanced Reactor Technologies."
12/08/14 DOE Letter to NRC, "Joint Initiative Regarding U.S. Nuclear Regulatory Commission Licensing Strategy for Advanced (Non-Light Water) Reactor Technologies."
07/09/13 NRC Letter to DOE, "Initiative Regarding U.S. Nuclear Regulatory Commission Licensing Strategy for Advanced Reactor Technologies."

Updates relative to the Phase 2 portion of the initiative are also available by subscribing to the NRC GovDelivery Subscription service.

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Advanced Reactor Training Materials

The NRC contracted with the Oak Ridge National Laboratory (ORNL) to develop a 12-module training course on molten-salt reactors (MSRs). The course provides background on various MSR concepts presently under development, including a history of earlier MSR projects, descriptions of conceptual designs, and expected technical and regulatory challenges. The training materials are publicly available.

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Testing Needs and Prototype Plants

On June 16, 2017, the NRC issued a preliminary draft document, "Nuclear Power Reactor Testing Needs and Prototype Plants for Advanced Reactor Designs." This document described the relevant regulations governing the testing requirements for advanced reactors, described the process for determining testing needs to meet the NRC's regulatory requirements, clarified when a prototype plant might be needed and how it might differ from the proposed standard plant design, and described licensing strategies and options that include the use of a prototype plant to meet the NRC's testing requirements. The document was discussed during periodic public meetings on advanced reactor topics. The staff considered stakeholder feedback and issued the final paper as part of the regulatory review roadmap in December 2017.

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Advanced Reactor Workshops

In 2015, the NRC and the U.S. Department of Energy (DOE) began co-hosting a series of Advanced Reactor Workshops. The first workshop was held on September 1-2, 2015, 2015 and included presentations and discussions on roles and responsibilities of the NRC and DOE, previous experience licensing non-LWR designs, critical gaps and needs in research and development that need to be addressed, and suggestions for improvements in the licensing of non-LWR designs. The second workshop was held on June 7-8, 2016 and focused on exchanging information from NRC, DOE, industry and included presentations and discussions on strategies for advanced reactor development and deployment, recent initiatives; and advanced reactor fuel development, qualification, and challenges. The Third workshop in this series was held on April 25 and 26, 2017. The NRC has now transitioned from this workshop format to more frequent periodic stakeholder meetings to focus on specific topics of interest as discussed below.

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Advanced Reactor Reference Materials

Date Issued Topic Author Affiliation
06/28/19 Metal Fuel Fabrication Safety and Hazards Final Report Pacific Northwest National Laboratory
06/19/19 Advanced Reactor Siting Policy Considerations Oak Ridge National Laboratory
03/31/19 Advanced Non-Light-Water Reactors Materials and Operational Experience NUMARK Associates
03/31/19 Technical Gap Assessment for Materials and Component Integrity Issues for Molten Salt Reactors Oak Ridge National Laboratory
11/30/18 Molten Salt Reactor Fuel Qualification Considerations and Challenges Oak Ridge National Laboratory
08/21/18 Phenomena Important in Liquid Metal Reactor Simulations Brookhaven National Laboratory
05/09/18 Phenomena Important in Modeling and Simulation of Molten Salt Reactors Brookhaven National Laboratory

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Periodic Stakeholder Meetings

The NRC holds periodic stakeholder meetings to discuss non-LWR topics of interest. The following table lists the meetings that NRC has conducted to date in connection with this initiative:

Date Description

Tentative Dates for Future Meetings


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Pre-Application Activities

Below is a summary of non-LWR reactor designers that have formally notified the NRC of their intent to engage in regulatory interactions. There are several more potential pre-applicants that participate in various industry activities that could be added to this list once they formally engage with the NRC.

Developer Pre-application information RIS response Technology
Oklo Inc. OKLO 10/6/2016 Compact Fast Reactor
X-Energy LLC XE-100 1/16/2018 Modular High Temperature Gas-Cooled Reactor
Kairos Power LLC Kairos Power Fluoride Salt-Cooled, High Temperature Reactor (KP-FHR) 3/14/2018 Molten Salt Reactor
Terrestrial Energy USA Ltd Integral Molten Salt Reactor (IMSR) 1/25/2019 Molten Salt Reactor
TerraPower, LLC Molten Chloride Fast Reactor (MCFR) 6/4/2017 Molten Salt Reactor

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Related Documents

Over the years, a number of Commission papers and Commission Policy statements have been written on various topics related to licensing of advanced reactors. The staff has assembled a collection of these documents spanning from 2001 to the present. The staff has also assembled a list of stakeholder position papers identifying stakeholder documents that communicate opinions to the staff on technical or policy issues.

Page Last Reviewed/Updated Friday, July 12, 2019