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.
Senior Mechanical Engineer
Radiant is seeking a highly motivated Senior Mechanical Engineer to develop new hardware in a fast-paced startup environment. The candidate will be responsible for owning the high-pressure, high-temperature helium circulator through analysis, manufacturing, testing, and integration for the Kaleidos Demonstration Unit (KDU) test reactor. You will develop critical hardware at the center of the reactor Primary Loop while considering performance, reliability, manufacturability, mass, and cost. The ideal candidate has experience building early concept components through production and is excited about our vision to build Earth’s mass-produced nuclear reactors.
Responsibilities & Duties:
- Mechanical Engineering ownership of the high-pressure, high-temperature helium circulator
- Conduct trade studies and develop designs to meet system requirements.
- Perform detailed thermal and mechanical analysis (static strength, durability/fatigue) to determine structural integrity (margins of safety) using both hand calculations and finite element tools.
- Develop and execute hardware testing plans and development campaigns to buy-down technical risk.
- Develop and execute manufacturing/assembly instructions and test plans.
- Create and manage a Bill-Of-Materials (BOM).
- Find and develop suppliers for all components.
- Own subassembly design, manufacturing, and test schedules.
- Own risk analysis and mitigation strategies for hardware.
- Collect requirements, provide expertise and feedback to engineers in other functional areas via clear, constructive communication.
Required Qualifications & Skills
- Bachelor’s degree from an accredited institution in Mechanical, Materials, Aeronautical, Civil or Structural Engineering.
- 5+ years of experience conducting trade studies and design of mechanical components or subsystems.
- 5+ years of experience performing stress analysis (static and fatigue) using both hand calculations and finite element tools (Abaqus, Ansys, or similar).
Desired Qualifications & Skills
- Passionate to learn new skills and apply new concepts, including motor design and operating principles, power electronics integration, and basic turbomachinery concepts.
- 5+ years of experience with design of multi-component assemblies in CAD (SolidWorks or similar).
- 5+ years of professional experience designing hardware that was manufactured, deployed, and iteratively improved.
- Solid understanding and application of GD&T.
- Proficiency with both “hand calc” analytical methods and higher fidelity Finite Element based analysis methods.
- Track record of appropriate fidelity selection, based on engineering questions to be answered.
- Ability to derive free-body diagram and control volume-based models for systems with which one was not previously familiar.
- Experience performing CFD analysis for combined fluid/thermal modeling of systems.
- Self-motivated with strong organizational, written, and oral communication skills.
- Experience with using text-based software development tools.
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.
Top Skills
Radiant El Segundo, California, USA Office
1921 E. Maple Ave., El Segundo, CA, United States, 90245
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