Terrestrial Energy (NASDAQ:IMSR) is positioning its Integral Molten Salt Reactor, or IMSR, around the use of standard low-enriched uranium, a fuel choice Chief Executive Officer Simon Irish said is central to the company’s plans for commercial-scale deployment.
Speaking with TD Cowen’s Esteban Albarracin, Irish said the company’s Generation IV molten salt reactor design can operate using uranium enriched to no more than 5%, and at a level “significantly less” than that threshold. He contrasted the approach with many other advanced reactor concepts, particularly fast-spectrum designs, which he said require high-assay low-enriched uranium, or HALEU.
Fuel Choice and Reactor Design
“We’re not looking to come up with a perfect molten salt reactor,” Irish said. “We’re looking to come up with a commercially successful one.”
He said the use of standard low-enriched uranium is intended to support a scalable supply chain. By comparison, reactor systems operating in a fast spectrum or using smaller cores can require higher-enriched fuel, according to Irish.
Materials Testing and Supply-Chain Qualification
Irish said the challenge for reactor developers extends beyond obtaining materials such as graphite and nuclear-grade steels. Suppliers and materials must be qualified through testing and quality-assurance processes so that supporting data can be accepted by regulators in a licensing application.
For Terrestrial Energy, graphite is a major component because the IMSR is graphite moderated. Irish said graphite qualification requires testing its performance under anticipated reactor-core conditions, a process that cannot be substantially accelerated because it depends on the power of the test reactor.
The company has been testing its graphite for several years in a test reactor in the Netherlands, which Irish described as one of the world’s most powerful test reactors. The work is intended to generate data supporting future licensing applications. Similar testing and qualification work is required for alloys, systems and other components, he said.
Licensing Strategy and Topical Reports
Terrestrial Energy is using topical reports with the U.S. Nuclear Regulatory Commission to seek alignment on individual elements of its future licensing case. Irish said the reports are intended to reduce uncertainty before a broader construction permit or operating-license application is submitted.
The company previously submitted topical reports addressing principal design criteria and postulated initiating events, which Irish described as foundational elements of the reactor’s design and safety analysis. It also submitted a report covering its methodology for qualifying graphite, seeking NRC confirmation that the scope of testing and data collection would be acceptable in a later license application.
Irish said Terrestrial Energy has guided for at least three topical-report submissions in 2026.
The company is also evaluating the NRC’s Part 53 framework as a potential licensing pathway for its first commercial plant and future fleet deployment. Irish said the technology-neutral, risk-informed framework could provide an alternative to earlier approaches that required developers to balance licensing a first-of-a-kind plant with developing a repeatable framework for subsequent units.
Commercial Model and Project Pipeline
Irish said Terrestrial Energy does not intend to build and operate power plants itself. Instead, it plans to play a major role in supplying its reactor design, fuel and replacement components while leaving plant construction and operation to other participants.
He said approximately 20% of the company’s expected future value creation would be associated with its role in construction, while the remaining 80% would come from services and components supplied after a plant is built. Terrestrial Energy expects to provide fuel under long-term contracts during a plant’s roughly 50-year operating life.
The company also expects to supply a replaceable Core-unit every seven years. Irish said those Core-unit supplies could account for 50% to 60% of the company’s value creation in the 2030s.
Terrestrial Energy is working on 10 commercial projects, Irish said, and has publicly discussed three: a project involving Texas A&M, a relationship with Riot Platforms related to future data-center power needs in Texas, and selection of its technology as part of Ameresco’s bid to the U.S. Army for the Aberdeen Proving Ground in Maryland.
Irish did not rank the projects by their stage of commercialization. He said a small modular nuclear project should generally be viewed as requiring more than five years from site selection through site characterization, licensing preparation and construction-permit review, followed by roughly another five years for construction and operating-license work. He added that regulatory reforms could shorten those timelines.
In addition to commercial projects, Terrestrial Energy is pursuing pilot reactor and pilot fuel-plant work with the U.S. Department of Energy. Irish said the projects fit within the company’s existing testing program and are intended to accelerate data collection and establish processes supporting future fuel supply and commercial deployment.
About Terrestrial Energy (NASDAQ:IMSR)
Terrestrial Energy (Nasdaq: IMSR) is a developer of Generation IV nuclear plants that use its proprietary Integral Molten Salt Reactor (IMSR). The IMSR captures the operating benefits of molten salt reactor technology in a plant design that prioritizes capital efficiency, cost reduction, versatility and functionality of nuclear energy supply.
IMSR plants are designed to be small and modular for distributed supply of low-cost, reliable, dispatchable, clean, high-temperature industrial heat and electricity, extending the application of nuclear energy beyond electric power markets to industrial applications such as petrochemical and chemical synthesis and data center operation.
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