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Radiant is building the world's first mass-produced, portable nuclear microreactors. The company's flagship product, Kaleidos, is a 1-megawatt, fail-safe microreactor designed for rapid deployment to hospitals, data centers, remote sites, and military bases. Founded in 2020, Radiant is preparing to test its first reactor at Idaho National Laboratory with initial customer deliveries expected in 2028.
As a Mechanisms Engineer, you will own the design and development of critical mechanisms within Kaleidos, including control blade actuators and air jacket valves. You will be responsible for the complete lifecycle of assigned subsystems: conducting trade studies, performing detailed thermomechanical and kinematic analysis, developing manufacturing and assembly instructions, managing bills of materials, identifying and qualifying suppliers, and executing test plans. You will perform both hand calculations and finite element analysis (using tools like Abaqus, Ansys, or FEMAP) to verify structural integrity and performance margins. Additional responsibilities include risk analysis (FMEA) for subsystems, managing subassembly design and manufacturing schedules, and collaborating with cross-functional teams to collect requirements and provide technical feedback.
This role offers the opportunity to contribute to a transformative technology—the first new commercial reactor design in over 50 years—while working with a team of experienced engineers in a fast-paced startup environment. You will have direct ownership of critical safety and performance systems in a product that will reshape energy infrastructure.
REQUIREMENTS:
- Bachelor's degree in Mechanical or Aeronautical Engineering from an accredited institution
- 3+ years of experience designing mechanisms
- 3+ years of experience performing stress analysis using both hand calculations and finite element tools (Abaqus, Ansys, FEMAP, or similar)
- Must be willing to work extended hours and weekends as necessary
- Must work 100% onsite at El Segundo headquarters
DESIRED QUALIFICATIONS:
- Experience with multi-component assembly design in CAD (NX or similar)
- Experience designing hardware that was manufactured, deployed, and iteratively improved
- Experience designing pneumatic systems
- Experience integrating electromechanical components (motors, encoders)
- Experience working with interdisciplinary teams
- Solid understanding and application of GD&T
- Proficiency with both hand calculation and finite element-based analysis methods
- Ability to derive free-body diagrams for unfamiliar systems
- Self-motivated with strong organizational, written, and oral communication skills
- Experience with text-based software development tools
