Build Engineer, Turbomachinery

About the role

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. This role is hands-on, ideal for new graduates or early-career engineers who want to learn by building, assembling, and integrating complex turbomachinery systems.

Responsibilities

• Hands-On Builds & Assembly
• Responsible for assembly and integration of prototype and first-article turbomachinery. hardware, including compressors, turbines, rotors, electric motors, bearings, seals, and housings.
• Develop precise assembly instructions, alignment procedures, and torque specifications.
• Support rotor stacking, bearing installation, balancing, and alignment operations.
• Document assembly activities, as-built observations, and lessons learned.
• Process & Tooling Support
• Help develop and maintain build tools, fixtures, and work-holding solutions.
• Support creation of work instructions and standard operating procedures for assembly processes.
• Provide feedback to design and manufacturing teams to improve hardware assembly and integration.
• Cross-Functional Collaboration
• Work closely with design engineers, test engineers, and technicians to prepare hardware for testing and validation.
• Participate in troubleshooting assembly issues and contribute to iterative improvements.
• Receive mentorship from senior build engineers while gradually taking on more responsibility.

Qualifications

• Bachelor’s degree in Mechanical Engineering or a related field (or expected graduation within 6 months).
• Strong interest in hands-on mechanical assembly, rotating machinery, or turbomachinery systems.
• Basic understanding of GD&T, fits, torque, and alignment principles.
• Comfort reading and interpreting mechanical drawings and CAD models.
• Willingness to learn, take initiative, and work safely with precision hardware.

Desired Qualifications

• Prior hands-on experience from internships, co-ops, class projects, or design competitions (SAE, Formula SAE, robotics, etc.).
• Familiarity with mechanical assembly, rotor balancing, or bearing handling.
• Interest in turbomachinery, power generation, or high-speed rotating systems.
• Excited to work in a fast-paced, innovative startup environment.
• Prior nuclear experience is not required.

Additional Requirements

• Must be willing to work extended hours and occasional weekends to support build schedules.
• Must work 100% onsite at Radiant’s El Segundo headquarters.