Skip to main content

Alert

The NRC is shutdown due to the lapse in appropriations. Exempted activities to maintain critical health and safety activities and progress on critical activities, including activities outlined in Executive Order 14300, as described in the OMB Approved NRC Lapse Plan will continue.

Navigation

Spotlight

Terra Innovatum SOLO

Rendering of Terra Innovatum SOLO plaza

Project Overview

The U.S. Nuclear Regulatory Commission (NRC) is currently engaged in pre-application activities with Terra Innovatum as of January 2025. Terra Innovatum is developing its SOLO micro modular reactor design, intended to form the basis for a scalable modular energy platform from MWe to GWe-class. A SOLO unit is designed to deliver approximately 1MWe. The design features a solid heterogeneous composite moderator and is intended to accommodate both traditional zircaloy-clad low-enriched uranium (LEU) fuel or, when available, LEU+ and high-assay low-enriched uranium (HALEU) fuels. Heat removal is accomplished by helium gas which eliminates the need for water from the reactor coolant system. The reactor is intended to feature autonomous operation, on-line safeguards-by-design, and a defense-in-depth structure of radiological barriers with the intent to minimize or eliminate emergency planning zone (EPZ) requirements beyond the operational boundary.

For more information, please see the Terra Innovatum SOLO pre-application documents (NRC Docket 99902138). 

To subscribe to the Terra Innovatum SOLO email service, select Terra Innovatum SOLO from the Advanced Reactors list after entering your email into the GovDelivery system.

Pre-Application Activities

Product Type Reference  Status
SOLO Micro Modular Nuclear Reactor Regulatory Engagement Plan, Rev 0 Regulatory Engagement Plan ML25017A401 No review requested
SOLO Micro Modular Nuclear Reactor Regulatory Engagement Plan, Rev 1 Regulatory Engagement Plan ML25159A006 No review requested
Design Considerations on Reactor Core (Fuel) at Nominal Conditions White Paper ML25159A010 Under review
Proposed Preliminary Safety Analysis Report Content and Exceptions White Paper ML25159A011 Under review
Transportation and Logistics for SOLO Research and Test Reactor Deployment White Paper ML25159A008 Under review
SOLO Micro Modular Nuclear Reactor Principal Design Criteria Topical Report ML25159A013 Under review

Page Last Reviewed/Updated Monday, August 11, 2025

Page Last Reviewed/Updated Monday, August 11, 2025