Mechanical Designer

We are a next-generation nuclear technology startup pioneering the commercialization of High-Temperature Gas-cooled Reactors (HTGRs) — a proven, safe, and transformative technology for delivering ultra-high-temperature heat and enabling a carbon-neutral future.

Our mission is to deploy the world’s first global fleet of Advanced Modular Reactors, redefining how clean energy powers industries, communities, and economies.

As a fast-growing company in its early stage, every team member — whether in engineering, program management, partnerships, operations, or business development — plays a direct role in shaping our technology, culture, and impact. You’ll join a collaborative, mission-driven team of internationally recognized experts and innovators working together to bring advanced nuclear energy to the world.

The Mechanical Designer will be a key contributor to Zetta Joule’s reactor design activities, responsible for developing the 3D CAD models, assemblies, and detailed drawings that define the mechanical design of our High-Temperature Gas-cooled Reactor (HTGR). Working at the intersection of design engineering, analysis, materials, and manufacturing, this role translates engineering requirements and design concepts into buildable, maintainable, and inspectable components using 3D CAD tools.

The Mechanical Designer maintains configuration-controlled CAD data, manages assembly-level interfaces across systems, and supports design reviews, fabrication vendors, and the technical baseline as the design matures from concept through detailed design.

• Develop 3D models, assemblies, and 2D fabrication drawings for HTGR primary system components — reactor vessel, core internals, heat exchangers, hot gas ducting, and supporting structures.
• Apply GD&T and drafting standards to produce clear, complete, manufacturable drawing packages, including weld details, tolerancing, and inspection requirements.
• Design components with consideration for high-temperature service, including thermal expansion, differential growth, clearances, and support and restraint arrangements.
• Collaborate with Stress Analysis, Materials, Thermal Hydraulics, and Systems Engineering to incorporate analysis results, material constraints, and design loadings into the CAD design.
• Build and maintain large, multi-level assembly models and manage interfaces between systems and components, including interference checks, envelope and space allocation, and constructability and maintainability reviews.
• Prepare and maintain CAD models in a form suitable for simulation, such as simplified geometry, defeaturing, and mid-surface extraction, in support of finite element and CFD analyses.
• Create and manage bills of materials, part numbering, and revision control within a PDM/PLM environment (e.g., Solid Works PDM) in coordination with Systems Engineering configuration management.
• Support design reviews, change control, and the design baseline by documenting design changes, and by generating visualizations and layout drawings for technical and stakeholder communication.
• Work with fabrication vendors and suppliers to resolve manufacturability questions, review shop drawings, and support fabrication, inspection, and assembly planning.
• Contribute to development of CAD standards, templates, and modeling best practices for the engineering team.

• BS in Mechanical Engineering, Mechanical Engineering Technology, or a related field required; equivalent design experience considered.
• Minimum 5 years of experience as a mechanical designer or design engineer in an engineering or manufacturing environment.
• Advanced proficiency in Solid Works, Autodesk Fusion, or other 3D CAD tools, including part, assembly, sheet metal,…