Nuclear Startups Most Likely to Build Something Real

Commonwealth Fusion Systems is building SPARC in Massachusetts to test high-field superconducting magnets at reactor scale. A working machine would validate the central premise behind its later power plant.

TerraPower has begun non-nuclear construction for its Natrium project in Wyoming, pairing a sodium-cooled reactor with molten-salt storage. Physical progress places it ahead of many advanced-reactor promises.

Oklo is pursuing compact fast reactors and has assembled agreements with data-center and industrial customers. The commercial interest is credible, though licensing remains the decisive hurdle.

Helion uses pulsed magnetic compression and has promised Microsoft electricity on an unusually aggressive schedule. The contract creates accountability, even if the underlying fusion milestones remain formidable.

Radiant is developing a portable, gas-cooled microreactor for remote sites and defense users. Its Kaleidos design fits the Army’s renewed demand for transportable power unusually well.

Proxima Fusion is designing a stellarator power plant from a strong European research base. Recent funding and partnerships give the technically attractive approach a serious engineering organization.

Antares is building a compact microreactor for remote industrial and defense applications. The constrained initial market is sensible because customers already pay heavily for dependable off-grid power.

Type One Energy is pursuing stellarator fusion and plans to build on existing energy infrastructure in Tennessee. Reusing a real industrial site makes its development path more concrete.

TAE Technologies has spent decades refining beam-driven fusion and aims eventually to use hydrogen-boron fuel. That fuel is exceptionally difficult, but it could reduce neutron-related engineering problems.

Zap Energy uses sheared-flow stabilization to pursue fusion without the huge magnets found in many competitors. A simpler machine would be a major advantage if the plasma remains stable.