Commonwealth Fusion Systems
Mechanical Engineer, RF Systems
About this role
Commonwealth Fusion Systems seeks a Mechanical Engineer for RF Systems to design and validate critical components of the SPARC tokamak's RF heating plant, which operates at 25+ MW and 120 MHz. You'll own mechanical architectures for coaxial transmission lines, cooling systems, and high-power electronics enclosures, working hands-on from benchtop to full-scale operation while collaborating across RF, electronics, and process engineering teams.
What you'll do
- Design RF heating plant components including large-diameter coaxial transmission lines, stub tuners, and RF testing loads
- Decompose system requirements into mechanical specifications and own RF heating system mechanical design architectures
- Perform structural loads analysis and thermal analyses to validate mechanical designs
- Develop sheet metal components, mounting hardware for PCB assemblies, cold plates, and precision cooling systems
- Architect thermal management solutions integrating water and air cooling loops into high-power electronics enclosures
- Collaborate with CAD team, providing design guidance, detailed reviews, and manufacturing drawing releases using GD&T standards
What they're looking for
- 3D CAD software proficiency (Siemens NX preferred)
- Structural and thermal analysis
- Heat transfer and fluid dynamics fundamentals
- GD&T and detailed manufacturing drawing creation
- High-power electronics and thermal management design
- Sheet metal fabrication and machining process knowledge
- System requirements decomposition
- Cross-functional technical collaboration
Benefits
- Competitive compensation with equity
- 13 company-wide holidays and flexible vacation
- 10 sick days and generous parental leave
- Health, dental, and vision insurance
- 401(k) with employer matching
- Professional growth opportunities
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Commonwealth Fusion Systems
Commonwealth Fusion Systems develops next-generation fusion power technology, including high-temperature superconducting magnets and the SPARC fusion power demonstrator. The company is hiring R&D engineers, test engineers, mechanical engineers, and metrology specialists to advance fusion energy development through rigorous testing, innovative fluid systems design, manufacturing optimization, and precision measurement of complex reactor components.
View all jobs at Commonwealth Fusion SystemsLikely interview questions
- Describe your experience designing mechanical systems for high-power electronics or RF applications—what were the key thermal or structural challenges you solved?
- Walk us through a time you owned a complete mechanical design architecture from concept to manufacturing release. How did you manage cross-functional dependencies?