Intern - Nuclear Engineer - Summer 2026

Commonwealth Fusion Systems • Devens, MA

121d

About The Position

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 Nuclear Engineering Intern. We are looking for talented technical interns to join our team! CFS interns are highly valued within the organization and placed into meaningful and challenging roles.

Requirements

• Neutron transport or Neutronics or Reactor Theory course
• Hands-on experience through academic research, project teams, machine shops, hackathons, or industry internships
• Demonstration of exceptional results through a range of different pursuits
• High self-motivation and drive to execute quickly with excellent troubleshooting/problem-solving skills

Responsibilities

• Neutronics analyses such as energy deposition in delicate materials or shielding sensitivity studies for diagnostics design
• Collaborate with engineers on the Nuclear Engineering team to do neutronics calculations (heating, activation, flux, dose, etc) to support the design and operation of SPARC, the scoping of ARC, and any other nuclear engineering needed

Benefits

• 12-16 week internship program
• 40-50 hours per week with set hourly salary based on year in school
• Opportunities vary between onsite in Somerville, MA and Devens, MA

What This Job Offers

• Career Level: Intern
• Industry: Utilities
• Education Level: Bachelor's degree