Last Energy Raises $100M for Compact Steel Micro Reactor
▼ Summary
– Public and investor sentiment toward nuclear energy has shifted positively, with startups no longer needing to justify its importance.
– Last Energy is developing small modular reactors (SMRs) designed to produce 20 megawatts of electricity and has secured $100 million in Series C funding.
– The company’s approach is distinct because it uses an updated, decades-old pressurized water reactor design originally developed for a nuclear-powered ship.
– A key feature of its reactor is a permanent, sealed steel encasement that serves as both the core vessel and the final waste cask, eliminating on-site servicing.
– The company plans to build a 5-megawatt pilot reactor in 2025, aiming for a commercial 20-megawatt unit by 2028, with the goal of driving down costs through mass production.
The nuclear energy sector is witnessing a remarkable resurgence, with startups like Last Energy securing a substantial $100 million in Series C funding to advance its vision of compact, mass-producible power plants. This influx of capital, led by the Astera Institute and supported by a consortium of investors including AE Ventures and Gigafund, signals a strong market belief in small modular reactors as a critical component of the global energy mix. The shift in perception is palpable; where founders once had to evangelize the importance of nuclear power, there is now widespread recognition of its role in meeting surging electricity demands, particularly from data centers.
Last Energy is developing a 20-megawatt small modular reactor, a unit capable of powering approximately 15,000 homes. The company’s strategy involves leveraging a proven, decades-old pressurized water reactor design originally created for the NS Savannah, the world’s first nuclear-powered merchant ship. While the historical design was about a tenth the size, Last Energy’s modern iteration aims for that 20-megawatt output. The journey begins with a smaller-scale pilot: a 5-megawatt reactor at a Texas A&M site, fully funded by this latest investment round. The goal is to activate this pilot next year, paving the way for commercial-scale production by 2028.
A key differentiator for Last Energy is its radical approach to reactor longevity and waste management. The core is permanently encased in a massive 1,000-ton steel chamber, a design choice that forgoes any need for mid-life servicing. CEO Bret Kugelmass notes that while many assume concrete is cheaper, nuclear-grade concrete does not hold that advantage. Each unit arrives on-site pre-fueled with a six-year supply of uranium. The sealed steel vessel has no penetrations beyond essential electrical and control links. Heat from fission warms the steel, and water circulating in external pipes captures this thermal energy to drive a steam turbine.
When the reactor eventually reaches the end of its operational life, the entire steel encasement becomes its own long-term waste storage cask, left in place on-site. This integrated solution aims to simplify decommissioning and eliminate the complex logistics of separate nuclear waste disposal.
This methodology, combined with ambitions for high-volume manufacturing, is central to Last Energy’s goal of drastically reducing the cost of nuclear power. Kugelmass draws parallels to industries where prices halve with every tenfold increase in production volume, though he acknowledges the unique fixed costs associated with nuclear regulations may temper those gains. The company’s mindset is one of scale, thinking not in single units but in the potential for tens of thousands of reactors. This vision places Last Energy among a cohort of well-funded nuclear innovators, such as X-Energy and Aalo Atomics, all racing to transform how the world generates clean, reliable baseload power.
(Source: TechCrunch)
