Senior Software 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 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 Software Engineer

Radiant is seeking a driven Senior Software Engineer to work on a variety of internal tools and platforms. In this role, you will design, build, maintain, and scale the internal systems and platforms that support simulation, hardware testing, data processing, and analysis. You will have an opportunity to work in an interdisciplinary environment with a high degree of ownership and drive milestones forward to unlock commercialization of the first mass-produced nuclear reactor.

Responsibilities and Duties:

• Architect, build, and maintain a variety of internal tools and platforms


• Help define and build our simulation and analysis stack to support the development of Digital Twins


• Collaborate across teams to integrate new and existing software with a variety of software and hardware platforms


• Mentor and be a technical leader: review code and provide feedback, establish best practices (documentation, testing, deployment automation)

Required Qualifications and Skills:

• Bachelor’s degree in computer science or engineering


• 5-8+ years of professional experience in Python, C++, C#, or similar object-oriented programming languages


• Familiarity with Git, Docker, and common CI/CD frameworks

Desired Qualifications and Skills:

• Highly self-motivated with strong communication skills


• Experience testing software and hardware systems


• Experience with embedded and distributed software development and familiarity with common design patterns


• Interest in physics, hardware and electrical engineering

Additional Requirements:

• Must be willing to work extended hours and weekends as necessary to accomplish our mission.


• Must work 100% onsite at El Segundo HQ.

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% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.


• One Medical: Sponsored memberships for employees and their dependents.


• Vision: 100% top tier plan coverage + 50% for dependents.


• Dental: 100% top tier plan coverage, orthodontia extra, 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.