Senior Mechanical Engineer, Process Equipment

Number of employees

1050

Devens, MA

Posted on: 2026-09-22

Category: renewables

Ready to make this your next chapter?

Let Commonwealth Fusion Systems know you found them on WorkInGreen. It helps more companies post climate jobs here.

Employment type:

Full time

Experience required:

Senior

Salary

$110,000.00 - $185,000.00

About the company:

Commonwealth Fusion Systems (CFS) is on a mission to deliver clean fusion energy to the planet fast enough to matter for humanity’s biggest challenges.

It’s urgent. The gap between the energy we need and the energy we have is widening every day. Fusion is a critical part of the energy transition away from fossil fuels, a new chapter for the world’s energy supply.

We’re committing to delivering fusion power plants and a full-fledged fusion energy industry as we’ve delivered on other promises. Like the world’s strongest high-temperature superconducting magnet, the game-changing technology that’s making commercial fusion energy a reality.

We’ve raised over $2 billion in capital — more than any other fusion energy company — and attracted top talent to design, build, and deliver commercial  fusion power plants. And we’re working with policymakers and suppliers to make fusion energy available globally.

As we push toward the fusion-energy future, we’ll keep setting and meeting milestones, sharing and validating our progress, and encouraging others to do the same.

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 a Senior Mechanical Engineer, Process Equipment
 
The Fuel Cycle and Blanket Development Team is growing to deliver R&D and pilot-scale molten salt (FLiBe) systems to advance fusion. The technology readiness of FLiBe wetted components is modest due to the challenges of the high operating temperature, different corrosion modes, and the chemistry control required to achieve long term goals. The Fuel Cycle and Blanket Development team is looking for a Senior Mechanical Engineer to drive the design and delivery of molten salt process equipment including ASME tanks, heat exchangers, piping systems and gas processing equipment. This engineer will need to work collaboratively with internal teams at CFS as well as with key external partners to reach ARC’s ambitious technical targets.
 
CFS engineering teams have a strong practice of carrying engineering risk where appropriate while attentively and aggressively managing safety risk, and we are looking for an engineer who will actively contribute to this culture.

#LI-Onsite

At CFS, we excel in fast-paced environments, driven by our values of integrity, execution, impact, and self-critique. As we grow, we’re eager to bring on mission-driven folks who offer diverse perspectives and fresh ways to tackle challenges.
 
We value diversity deeply and are proud to be an equal opportunity employer by choice. We consider all qualified applicants equally, regardless of race, color, national origin, ancestry, citizenship status, protected veteran status, religion, physical or mental disability, marital status, sex, sexual orientation, gender identity or expression, age, or any other basis protected by law.
 
This role requires compliance with U.S. laws concerning the export of controlled or protected technologies or information (collectively, “Export Control Laws"). Any offer of employment will be contingent on the need for compliance with such Export Control Laws.

What you'll do:

  • Lead and contribute to the design of fluid process systems for testing at varying scales
  • Develop specifications and designs of high-temperature molten salt process equipment, including vessels, tanks, valves, pumps and piping systems
  • Be the technical lead interfacing with suppliers and construction teams to procure, install and commission process equipment
  • At later project stages, support fixed equipment mechanical reliability
  • Support pipe stress evaluations working with piping stress engineers 
  • Collaborate across CFS teams to incorporate R&D learnings and interfacing system requirements into component designs and specifications
  • Actively engage with suppliers, contactors and CFS teams to put safety first at all project stages
  • Track projects and tasks against milestones and report progress up and across the organization

What we’re looking for:

  • Bachelors degree in Chemical Engineering, Mechanical Engineering, or equivalent
  • 8+ years of work experience
  • Detailed knowledge of ASME BPVC and B31.3 and their use in designing process equipment and piping systems
  • Design of industrial scale fixed equipment
  • Design of higher temperature equipment and components
  • Management of external partners and suppliers 
  • Design for hazardous fluid service
  • Experience at a refinery, chemical plant, or heavy industrial facility preferred
  • Familiarity with design/construction codes and standards such as ASME Section I, ASME Section VIII, ASME B31.3, API 510, API 570 AND API 579 preferred
  • Familiarity with P&IDs, CAD, process flow diagrams, analysis such as heat and mass balances
  • Strong commitment to designing for and working in a safety-prioritized environment.
  • Ability to learn new skills/subject matter quickly
  • Ability to work effectively in a multidisciplinary team of engineers, scientists, technical staff and others
  • Ability to clearly express and critique ideas
  • Great communication and organizational skills 
  • Strong problem solving skills, ability to approach new problems with creativity

  • Bonus points for:

    • Experience with corrosive fluid systems
    • Experience with rotating equipment design, procurement, installation, commissioning and reliability.  
    • Experience with molten salt systems
    • Experience with electro-chemical systems
    • Analysis of pipe stress and support systems
    • Analysis of vessel nozzle loads and stresses
    • CAD software 

    Must-have requirements:

    • Ability to occasionally lift up to 50 lbs
    • Perform activities such as typing, standing or sitting for extended periods of time
    • Willing to occasionally travel to suppliers and support commissioning/test activities
    • Dedication to safety to mitigate industrial hazards that may include heat, cold, noise, fumes, strong magnets, lead (Pb), high voltage, high current, pressure systems, and cryogenics
    •  

    Get job alerts

    Receive new climate job opportunities matching your preferences. We'll email you once to confirm.

    One email per digest. Unsubscribe in one click, any time.

    Not quite the right fit? Keep looking.

    More climate roles that match your skills and values.

    View all jobs
    Form Energy logo
    United States
    Number of employees

    840

    Dollar sign

    $128,662.00 - $160,807.00

    Full time
    Renewables
    Pacific Fusion logo
    United States
    Number of employees

    65

    Dollar sign

    $180,000.00 - $240,000.00

    Full time
    Renewables
    Heliogen logo
    United States
    Commonwealth Fusion Systems logo
    Number of employees

    1050

    Dollar sign

    $110,000.00 - $185,000.00

    Full time
    Renewables

    1551 Renewables jobs at Commonwealth Fusion Systems

    Commonwealth Fusion Systems is hiring Senior Equipment Engineering Project Manager,Power Business Research and Analytics Manager,Staff Mechanical Engineer, and more.

    Hiring at Commonwealth Fusion Systems? Feature these jobs →

    View all jobs at Commonwealth Fusion Systems
    Commonwealth Fusion Systems logo
    Number of employees

    1050

    Dollar sign

    $140,000.00 - $200,000.00

    Full time
    Renewables
    Commonwealth Fusion Systems logo
    Number of employees

    1050

    Dollar sign

    $90,000.00 - $145,000.00

    Full time
    Renewables
    Commonwealth Fusion Systems logo
    Number of employees

    1050

    Dollar sign

    $130,000.00 - $200,000.00

    Full time
    Renewables
    Commonwealth Fusion Systems logo
    Number of employees

    1050

    Dollar sign

    $90,000.00 - $145,000.00

    Full time
    Renewables
    Commonwealth Fusion Systems logo
    Number of employees

    1050

    Dollar sign

    $110,000.00 - $185,000.00

    Full time
    Renewables
    Commonwealth Fusion Systems logo
    Number of employees

    1050

    Dollar sign

    $110,000.00 - $185,000.00

    Full time
    Renewables