Summer Internship - Thermal Engineer

Summer 2027 Internship - Thermal Engineer

Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid-deploy capability can replace similar-sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases.

Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.

Radiant is seeking a highly motivated Thermal Engineer Internto join the team.

• Develop and execute thermal analysis and CFD to evaluate design and performance of Kaleidos systems.
• Document analysis results to communicate clear and actionable outputs.
• Expand CFD capabilities, accuracy, and efficiencies via methods and workflow development projects.
• Own pipeline for producing analysis geometry from mechanical design CAD
• Develop methods and calculations to support and build confidence in lower-fidelity thermal analysis methods.

• Currently pursuing a BS or MS in Chemical Engineering, Mechanical Engineering, Aerospace Engineering, or related discipline.
• A high level of independence in solving challenging engineering tasks is preferred.
• Ability to seek out resources and proactively ask questions to finish projects through completion effectively, accurately, and timely.
• Ability to work in a fast-paced startup environment with a proactive and collaborative attitude.
• Genuinely excited for our mission to rapidly deploy nuclear microreactors to remote locations requiring abundant, clean energy.
• Knowledge of reactor physics will provide useful context but is not necessary.
• Prior internship experience helpful but not required.

• This internship is based 100% onsite at Radiant’s HQ in El Segundo, CA.

We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law.

This position involves access to technology that is subject to U.S. export controls. Any job offer made will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls.