Senior Mechanical Engineer

Last Energy is a nuclear energy company that designs, builds, owns, and operates small modular reactors (SMRs) for industrial and commercial customers. The company's flagship product, the PWR-20, is a 20 MWe pressurized water reactor that is fully modular and factory-produced, enabling faster and more cost-effective deployment than traditional nuclear power plants. Last Energy serves as a behind-the-meter independent power producer, supplying reliable baseload electricity to energy-intensive industries including data centers, metals production, food and beverage, pulp and paper, chemicals, and cement manufacturing. The company's mission centers on making nuclear power radically simpler and more accessible by removing the burden of development, financing, and operations from customers through a power purchase agreement model. This approach aligns nuclear energy deployment with the urgent need for resilient, low-carbon power, particularly as demand from AI infrastructure and industrial growth accelerates. Last Energy's use of proven reactor technology combined with proprietary steel containment systems is designed to streamline licensing and reduce construction timelines. Last Energy represents a new generation of nuclear developers focused on decarbonizing hard-to-abate industrial sectors with firm, emissions-free power. By standardizing and modularizing the entire plant through factory manufacturing, the company aims to bring predictable costs and schedules to a sector historically challenged by both, positioning SMRs as a practical climate solution at commercial scale.

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