Summer 2027 Internship - Mechanical Engineer

Radiant; El Segundo (CA); On-site; USD 30,000 - 41,000; Full time

Job summary

Radiant, an El Segundo, CA-based startup, seeks a Summer 2027 Mechanical Engineer Intern to join the team. You will contribute to design, analysis, and testing of a microreactor project and work closely with senior engineers.

This onsite internship requires pursuing BS or MS in Mechanical or Aerospace Engineering, a solid grasp of thermodynamics, fluid mechanics, and dynamics, and hands-on design experience with CAD and analysis tools.

Qualifications

• Pursuing BS or MS in Mechanical or Aerospace Engineering.
• Strong foundation in thermodynamics, fluid mechanics, statics, dynamics, and strength of materials.
• Hands-on design and build experience through projects, research, labs, or internships.
• Proficiency with CAD, analysis software, and lab instrumentation.

Responsibilities

• Contribute to the design, analysis, and testing of our microreactor.
• Take ownership of deliverables from concept through build and validation with guidance.
• Collaborate across disciplines to integrate designs and resolve technical challenges.
• Support system-level testing, troubleshooting, and design iteration to accelerate development.
• Communicate results through design reviews, technical reports, and presentations to peers and leadership.

Skills

Thermodynamics

Fluid mechanics

Strength of materials

CAD

Education

BS or MS in Mechanical/Aerospace Engineering

Tools

CAD tools

Analysis software

Lab instrumentation

Job description

Summer 2027 Internship - Mechanical 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 Mechanical Engineer Internto join the team.

Responsibilities:

• Contribute to the design, analysis, and testing of our microreactor.

• Take ownership of deliverables from concept through build and validation, with guidance from senior engineers.

• Collaborate across disciplines to integrate designs and resolve technical challenges.

• Support system-level testing, troubleshooting, and design iteration to accelerate KDU development.

• Communicate results through design reviews, technical reports, and presentations to peers and leadership.

Qualifications:

• Pursuing BS or MS in Mechanical Engineering, Aerospace Engineering, or a related discipline.

• Strong foundation in engineering first principles, including but not limited to thermodynamics, fluid mechanics, statics, dynamics, and strength of materials.

• Hands-on experience in design and build through projects, research, labs, or internships.

• Proficiency with engineering tools (e.g., CAD, analysis software, lab instrumentation).

Additional Requirements:

• 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.