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.
Last Energy is a pioneering US technology company focused on fleet-wide deployment and operation of next-generation nuclear assets. We are revolutionizing nuclear power delivery for rapid deployment and scalability.
We are seeking a Thermal Engineer to design the pressure-boundary hardware in our micro nuclear power plant, built on proven pressurized water reactor (PWR) technology. That means heat exchangers, piping, pressure vessels, and the primary loop that connects them. This is a hardware role. The engineer in this seat turns thermal performance requirements into components that can be manufactured and deployed, starting from hand calculations and first principles, and saving detailed analysis for detailed design. Working alongside our analysis and structural engineers, this person takes designs from model to physical hardware.
Key Duties & Responsibilities
Lead the conceptual design, analysis, and execution of critical thermal-mechanical components and systems for our advanced power plant
Drive mechanical design of components subject to thermal loading
Own the design of heat exchangers, piping networks, fluid storage tanks, and other pressure-boundary equipment, and partner with our structural engineers on validation, ensuring structural integrity, thermal performance, and design safety across key reactor components
Perform thermal and structural analyses (thermal stress, fatigue, and thermal expansion) to validate component designs against pressure, temperature, and cyclic loading requirements
Contribute directly to the mechanical design and optimization of critical thermal components, translating thermal performance requirements into manufacturable, deployable hardware
Collaborate daily with a multidisciplinary team to integrate thermal-mechanical solutions into cohesive, plant-level designs
Support material selection, tolerancing, and design-for-manufacturing decisions for components operating under high-temperature and high-pressure conditions
Operate autonomously, driving projects from concept to design verification in a startup culture that values speed, ingenuity, and accountability
Qualifications
BS or MS in Mechanical Engineering or related field, with 7+ years of hands-on industry experience designing components under thermal and mechanical loading
Proven experience as a Mechanical, Thermal, or Design Engineer working on thermal systems components within power plant, nuclear, or complex industrial systems
Proficiency in 3D CAD software (e.g., Autodesk Inventor, SolidWorks, Siemens NX, PTC Creo) for mechanical design of thermal-mechanical components and assemblies
Proficiency in analysis software (e.g., ANSYS Mechanical, Abaqus, SolidWorks Simulation) for structural and thermal stress analysis
Solid working knowledge of heat transfer, thermodynamics, and mechanical design principles (fatigue, fracture, thermal expansion, pressure-boundary design)
Experience with pressure vessel or piping design codes a strong plus (ASME BPVC Section III/VIII, B31.1/B31.3)
Practical, hands-on approach to problem-solving with a bias toward manufacturable, deployable designs over purely academic analysis
Excellent communication skills and a willingness to work collaboratively in a cross-functional, startup team environment
