TechCrunch Startup News Nuclear startup Last Energy raises $100M for its steel-encased micro reactor
Dec 17, 2025
Last Energy secures $100 million to launch its innovative steel-encased micro reactor, aiming for a 5 megawatt pilot in Texas next year. The team delves into their unique reactor design inspired by the NS Savannah. They discuss the benefits of steel-encased cores, including efficient operation and a six-year fuel load. There’s also excitement around their strategy to reduce nuclear energy costs by leveraging economies of scale.
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Founder’s Years Of Convincing
- Brett Kugelmas says he spent years convincing people nuclear mattered before public sentiment shifted.
- He now notes that potential customers approach Last Energy expecting nuclear to be part of the solution.
Old Design, New Scale
- Last Energy repurposes a decades-old pressurized water reactor design to build small modular reactors at scale.
- The company aims to mass manufacture units to cut costs and target tens of thousands of deployments.
Investor Momentum In Small Nuclear
- Nuclear startups are attracting large rounds as data centers and other heavy power users seek reliable capacity.
- Last Energy joins peers like X Energy and Halo Atomics in a fundraising wave for reactor startups.