Senior Mechanical Engineer

Last Energy is a pioneering US technology company deploying next-generation modular nuclear power plants. With projects underway in the US and UK, we’re transforming how nuclear energy is designed, built, and delivered—through high-throughput manufacturing, efficient supply chains, and rapid deployment strategies. As a Senior Mechanical Engineer at Last Energy, you’ll work directly with the CEO and core leadership team to drive forward the most critical mechanical and system-level challenges shaping our fleet-wide product. This is a role for builders, doers, and innovators who thrive in a fast-paced, hands-on environment where decisions are made quickly and your ideas directly shape the product. Key Duties & Responsibilities • Lead design and execution of critical mechanical systems and components that enable scalable, manufacturable nuclear power plants • Collaborate daily with the CEO and executive team on the company’s most urgent engineering priorities—your technical insights will directly inform product strategy and deployment timelines • Drive concept development, detailed CAD modeling, and rapid prototyping of novel industrial systems • Perform structural, thermal, and fluid analyses using advanced simulation tools (FEA, CFD) to validate and optimize designs • Design and analyze complex mechanical assemblies • Integrate mechanical, electrical, and control systems into cohesive plant-level solutions • Oversee prototype fabrication, assembly, and testing, both in-house and with external partners • Develop fixtures, tooling, and manufacturing aids to streamline build and test operations • Continuously optimize designs for manufacturability and deployment speed, balancing performance with cost and scalability • Operate autonomously, driving projects from concept to reality in a startup culture that values speed, ingenuity, and accountability Qualifications • Bachelor’s degree in Mechanical Engineering or a related field (advanced degree a plus) • 4+ years of hands-on mechanical design and analysis experience in high-growth, high-urgency environments (startup or advanced manufacturing preferred) • Deep proficiency with CAD tools (SolidWorks, AutoCAD, or equivalent) • Demonstrated expertise in FEA and CFD using software such as ANSYS, LS-DYNA, Nastran, or similar. • Strong foundation in materials science, stress analysis, and thermal/fluid systems • Proven ability to turn concepts into tested prototypes quickly, with minimal oversight • Exceptional communication and collaboration skills, especially when interfacing with executives and cross-functional teams • A bias toward action, creative problem solving, and the drive to own complex problems end-to-end Last Energy provides decarbonized, reliable, affordable nuclear energy at scale by innovating on the delivery model, not the reactor. By significantly reducing the time and cost of deployment, we are decarbonizing global energy production, increasing access to 24/7 baseload power, and creating a scalable clean energy future for humanity.