SECTION I · THE BRIEF
Brief #71576Updated 08 SEP 2026DEVENS, MALeverKHOSLA VENTURES
Employbl Company Profile

Senior R&D Test Engineer - Fluid Systems

Commonwealth Fusion Systems (CFS) is an American company founded in 2018 aiming to build a compact nuclear fusion power plant based on the ARC tokamak reactor concept. The company is based in Cambridge, Massachusetts,…

Location
Devens, MA
Company size
500–2,000
Posted
5d ago
Via
Lever
Section II · Full ProfileFree with an account
  • 01Comp band & equity packageLocked
  • 02Seniority & experience requirementsLocked
  • 03Interview process & rubricLocked
  • 04Hiring manager & team contextLocked
  • 05Growth trajectory in this roleLocked
  • 06Offer & decision timelineLocked

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Senior R&D Test Engineer - Fluid Systems

Commonwealth Fusion Systems· Devens, MAView company profile


Job title
Senior R&D Test Engineer - Fluid Systems
Job location
Devens, MA
Job description
About Commonwealth Fusion Systems:
Commonwealth Fusion Systems is on a mission to deliver the urgent transition to fusion energy.
Combining decades of research, top talent, and new technologies, we’re designing and building commercially viable fusion power plants. And we're working with policymakers, suppliers, and many others to build the energy industry of the future.
We’re in the best position to make it happen. Since 2018, we’ve raised $4 billion of capital, making us the largest and leading fusion company in the world.
Now we’re looking for more thinkers, doers, builders, and makers to join us. People who’ll bring new perspectives, solve tough problems, and thrive as part of a team.
If that’s you and this role fits, we want to hear from you.

Join the power movement as an Senior R&D Test Engineer

The role of an Senior R&D Test Engineer is to develop novel fluid systems for R&D test stands, with a major focus on supporting magnet testing. The range of process fluids is broad (liquid, gaseous, cryogenic, supercritical, molten salt, etc.), requiring strong mechanical and chemical engineering fundamentals. The ideal candidate will be resourceful—combining industry best practices, off-the-shelf and customized hardware, and creativity to deliver these fluid systems on tight timelines.

Projects will be on varying scales, from smaller-scale test stands and deep system analysis to larger, complex projects as needed for SPARC and ARC. In addition to designing and building, the engineer will actively operate as a test engineer to commission systems and design automation alongside a team of test/software engineers and operators. You must work collaboratively across production, R&D, procurement, and the SPARC team. Various projects will also require flexing outside of traditional fluids engineering into other disciplines, such as structures and materials engineering, to successfully retire risks for SPARC and ARC.

What you'll do:
  • Design fluid systems for test stands that meet test objectives/requirements, soliciting feedback from interfacing teams as necessary
  • Challenge requirements as necessary to achieve simplicity in design and develop efficient de-risking strategies and plans
  • Perform hand calculations and system level analyses demonstrating sufficient margin for fluid system requirements; build and run Ansys structural and thermal simulations on components and assemblies
  • Procure off-the-shelf process fluid components, manage relationships with vendors, draft specifications for speciality parts and design custom fluid system components as needed
  • Manage the build and commissioning of fluid systems, coordinating engineers and technicians to safely bring systems to operational status
  • Design system instrumentation and automation for safe operations
  • What we're looking for:
  • Bachelor’s degree in mechanical, chemical, process engineering, or a closely related field
  • 7+ years of experience in the engineering of integrated fluid/mechanical systems (experience with both small-scale rapid R&D and large-scale systems is highly desired)
  • Full-lifecycle fluid systems:
    • Hands-on experience executing the entire lifecycle of large-scale thermofluid systems
    • Component expertise:
      • Experience developing specifications, sizing and working with tanks, process piping, pumps, valves, compressors, purification stages, circulators, heat exchangers, etc.
      • Design documentation:
        • Strong background in establishing system requirements, generating process flow diagrams (PFDs), and developing piping and instrumentation diagrams (P&IDs)
        • Instrumentation:
          • Experience in the design, integration, and troubleshooting of system instrumentation
          • Software and analysis tools:
            • Experience utilizing engineering tools such as ANSYS, COMSOL, 1D compressible flow codes, Python and MATLAB
            • Extreme environments:
              • Practical experience designing, building, and commissioning fluid systems for specialized pressurized, cryogenic, vacuum, and/or elevated-temperature applications
              • Vendor relations:
                • Experience sourcing complex components, drafting technical specifications, and managing relationships with specialized vendors and suppliers
                • Cross-functional communication:
                  • Strong ability to distill complex fluid system details and effectively communicate to non-experts and interfacing teams across R&D, production, and procurement
                  • Problem solving:
                  • Highly driven to challenge assumptions, make efficient technical decisions, and develop innovative solutions on tight timelines
  • Bonus points for:
  • Adaptability:
    • Ability to flex into adjacent engineering disciplines, such as structures or materials, when required to help retire risks for SPARC and ARC
    • Process optimization:
      • Strong aptitude for identifying bottlenecks and improving throughput during system designs, builds, and commissioning operations
  • Must-have requirements:
  • Ability to occasionally lift up to 50 lbs
  • Perform activities such as stooping, climbing, typing, standing, or sitting for extended periods of time
  • Dedication to safety to mitigate industrial hazards that may include heat, cold, noise, fumes, strong magnets, lead (Pb), high voltage, and cryogenics
  • Willingness to travel or work required nights/weekends/on-call occasionally
  • View job listing ↗
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    Commonwealth Fusion Systems headquarters

    Cambridge, MA

    Company size

    5002,000 employees

    Founded

    2018

    Total raised

    $3,877,000,000

    View company profile ↗

    Funding rounds