Summer 2026 Internship - Software Engineering

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 failsafe microreactor that can be transported anywhere power is needed and run for up to five years without the need to refuel. 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 utilizes modern software engineering to rapidly achieve safe, factory-built microreactors that leverage existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor next year at the Idaho National Laboratory, with initial customer deliveries beginning in 2028.

Software Engineering Internship

Radiant is seeking a motivated

Software Engineering Intern

with a strong computer science foundation to join our team. As an intern, you will work alongside mechanical, electrical, and nuclear engineers to assist in developing software tools that support simulation and analysis for reactor design, development, and safety analysis. This is an excellent opportunity to gain hands-on software development experience in a highly interdisciplinary environment.

Please note: we plan to begin interviewing for Summer 2026 internships in November/December. Responsibilities And Duties

- Assist in creating tooling to support a variety of simulation software packages.

- Contribute to internal software products that support simulation and analysis of simulation results.

Required Qualifications And Skills

- Currently pursuing a degree in computer science, physics, or a related technical discipline.

- Familiarity with Python, C++, C#, or similar object-oriented programming languages.

- Basic knowledge of software development practices and version control tools such as Git.

Desired Qualifications And Skills

- Strong self-motivation and the ability to collaborate effectively in a team environment.

- Interest in contributing to simulation tools or working on software testing.

- Familiarity with distributed software development and common design patterns is a plus.

- A passion for physics, hardware, or electrical engineering is highly encouraged.

Additional Information

- This internship will require working onsite at our El Segundo HQ.

- You may be asked to work extended hours or weekends occasionally to support project goals.

Total Compensation And Benefits

Radiant's new hire compensation package includes base salary, substantial equity grants, and comprehensive benefits. Total compensation and level are determined through a holistic evaluation of your interview performance, experience, education, and qualifications.

Benefits And Perks For Eligible Employees

- Stock: Substantial incentive stock plan for all full-time employees. - Medical: 100% premium coverage for base Silver level plan for employee + 50% premium coverage for dependents. Platinum plans available.

- One Medical: Sponsored memberships for eligible employees and their dependents.

- Vision: 100% premium coverage for top tier plan + 50% for dependents. - Dental: 100% premium coverage for top tier plan (including orthodontia) + 50% for dependents.

- Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.

- 8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.

- Daily catered lunch. Free snacks and drinks.

- Flexible PTO policy. Remote workday allocation.

- Company and team-bonding events, happy hours and in-person camaraderie.

- Beautiful El Segundo headquarters close to the Pacific Ocean.

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.

Unfortunately, we are unable to provide visa sponsorship at this time. 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.