Lead Materials Engineer

About the Company

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.

Radiant is seeking a highly motivated Lead Materials Engineer to lead Radiant’s material team in the development, testing, and qualification of materials and related manufacturing processes used in the Kaleidos 1 MW nuclear microreactor. The ideal candidate is excited to grow an in‑house materials engineering organization, is proficient in materials selection, testing, and analysis, takes great ownership of their work end‑to‑end, and thrives in a highly cross‑functional, fast‑paced environment.

You will be a key contributor to building the world’s first mass‑produced, rapidly‑deployable nuclear reactor.

• Set the technical direction for the materials team, including the definition of project scopes, the guidance of day‑to‑day engineering and support activities, and the development of a materials engineering roadmap to support future reactor designs and builds
• Accountable for materials engineering team’s technical output
• Lead and mentor materials team members technically and professionally
• Communicate project status, issues, and schedules to teammates and executives
• Present to external stakeholders and regulatory bodies (DOE, NRC)
• Review test plans, purchase orders, and analysis
• Provide surge materials engineering support as‑needed
• Manage in‑house materials lab, including the identification, procurement, and operation of materials characterization equipment.
• Create and maintain materials team budget
• Oversee materials database and ensure accuracy and data quality of database content

• Bachelor’s degree from an accredited institution in Materials Science and Engineering, or in Mechanical, Aeronautical, Nuclear, or Chemical Engineering with a materials science and engineering focus
• 5+ years of experience working in the development, testing, and/or analysis of materials for demanding load cases and environments
• Hands‑on experimental or testing experience in laboratory or production environments

• Master’s or PhD degree from an accredited institution in Materials Science and Engineering, or in Mechanical, Aeronautical, Nuclear, or Chemical Engineering with a materials science and engineering focus
• 2+ years of engineering leadership and management experience at a company building and/or testing hardware for nuclear, aerospace, or other extreme environments
• Expert‑level competency in at least one area of materials science, including metallics and structural materials, solid‑state processing and/or joining of materials, composites, ceramics, polymers, and/or nuclear materials such as fuel, neutron poisons, or moderators
• Experience with development and qualification of material systems for high temperature, irradiation, and/or other extreme environments
• Knowledge of standard test methods for materials and experience with development of design allowables
• Self‑motivated with strong organizational, written, and oral communication skills
• Demonstrated ability to work collaboratively with design and operations teams to deliver high‑value results
• Experience with using text‑based software development tools (Python or similar)

• Must be willing to work extended hours and weekends as necessary to accomplish our mission.
• Must work 100% onsite at El Segundo HQ.