Terrestrial Energy
🇺🇸 Charlotte, US · Founded 2013 · Active
Terrestrial Energy is a reactor developer founded in Canada in 2013 and now headquartered in Charlotte, North Carolina. It is designing the Integral Molten Salt Reactor (IMSR), in which a fluoride salt containing uranium serves as both fuel and coolant, rated at 822 MW of heat or 390 MW of electricity and delivering heat at 585°C. The design completed phase 2 of the Canadian Nuclear Safety Commission's pre-licensing vendor design review in April 2023, and in 2025 the US Nuclear Regulatory Commission approved its principal design criteria. The company merged with HCM II Acquisition Corp., a listed shell company, and began trading on Nasdaq under the ticker IMSR at the end of October 2025.
- Sector
- Fission
- Technology
- Molten salt reactor
- Fuel
- Low-enriched uranium
- Role
- Reactor developer
Terms
- Molten salt reactor
- Fuel DISSOLVED in the salt, which in most designs is fuel carrier and coolant at once. Distinct from a salt-cooled reactor with solid fuel; the two are often confused. Moderator, where one is used at all, is a separate design choice from the salt: thermal-spectrum MSRs are typically graphite-moderated, fast-spectrum MSRs carry no moderator.
- Low-enriched uranium
- Uranium enriched to 5% uranium-235 or less, typically 3 to 5%: the range almost all power reactors use. Formally, anything below 20% is low-enriched; this site holds the band from 5% to just under 20% separately as HALEU, with its 5 to 10% part also tagged as LEU+. A fuel above 5% uranium-235 belongs in one of those, never here, whatever a developer's own materials call it.
Designs
| Design | Developer | Approach | Electrical output per unit | Size class | Licensing stage |
|---|---|---|---|---|---|
| Integral Molten Salt Reactor (IMSR) IMSR, IMSR400 | Terrestrial Energy | Molten salt reactor | 195 MWe planned | Small modular reactor | No milestone recorded |