Intern - Materials Test Engineer - Fall Co-op 2026

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 working with policymakers and suppliers to build the energy industry of the future.

We’re in the best position to make it happen. Since 2018, we’ve raised nearly $3 billion in capital, making us the largest and leading private 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 Materials Test Engineering Intern

The CFS Materials Team is seeking a motivated Materials Test Engineering Intern to join our cutting-edge team. In this role, you will support the development and testing of advanced materials critical to key tokamak systems such as plasma-facing components, the vacuum vessel, and high field magnets. This is a unique opportunity to work at the forefront of sustainable energy innovation in a collaborative, fast-paced R&D environment.

Program Details:

• 26 week internship
• 40-50 hours per week with set hourly salary based on year in school
• Opportunities onsite in Devens, MA. If an intern is going to be on site, you will be responsible for your own transportation and housing
• Specific project assignments and required technical skillset will vary based on the team’s existing need
• Opportunities available for currently enrolled college students in all levels of schooling from bachelor’s degree to PhD
• Interns must be authorized to work in the United States for any employer

What you'll do:

• Support day-to-day operations and test development work in the Materials Test Lab, including sample preparation, test execution, data collection, and analysis
• Work alongside engineers and technicians to enable material performance evaluation for critical fusion components
• Contribute to custom test development projects
• Example projects may include: Assisting with the design and build of high-temperature outgassing test stand, commissioning and calibration of new test equipment, improving lab workflows for repeatability and turnaround time, development of capabilities for mechanical testing of composite materials using existing Instron test frames

What we’re looking for:

• Interest or experience with materials science, metallurgy, mechanical engineering, mechanical testing, electrical engineering, physics, chemistry, nanoscience, microscopy, engineering lab work, or instrumentation
• Hands-on or engineering project experience or hands-on experience with materials testing and characterization equipment and testing procedures is preferred
• Demonstration of exceptional results through a range of different pursuits
• High self-motivation and drive to execute quickly with excellent troubleshooting/problem-solving skills

Must-have Requirements:

• Willingness to travel or work required nights/weekends/on-call occasionally
• Perform activities such as 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

$23 - $35 an hour

Rates are aligned to your current year in school, ensuring equitable and consistent pay across our intern program.

For BS interns, the hourly rate is $23–$29

F or MS/PhD interns, the rate is $32–$35

Benefits included for full-time interns:

• 40 hours of sick time

• Health, dental, and vision insurance

• 401(k) with employer matching (must be 21 years of age to enroll)

• Professional growth opportunities

• Team-building activities

#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.