Director of Test Engineering

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 Director of Test Engineering to own the design, build, and execution of developmental and qualification test programs that validate our reactor systems and components. This is a hands‑on leadership role: you will build and run a service organization that designs test setups, develops instrumentation and data acquisition systems, executes test campaigns, and delivers high‑quality data and reports to engineering teams.

This role is responsible for establishing standard methods, tooling, and infrastructure that allow Radiant to test hardware at the pace our development schedule demands. The test organization will operate as an internal service to design engineering teams—responsive, fast, and easy to work with.

• Own the end‑to‑end execution of developmental, qualification, and acceptance test campaigns for reactor components and subsystems.
• Design and build test setups—from simple bench‑level fixtures to complex thermal‑hydraulic loop rigs.
• Develop and maintain test plans and procedures that define objectives, instrumentation requirements, success criteria, data deliverables, and safety controls.
• Execute test campaigns, including hands‑on operation of test equipment and supervision of technicians.
• Deliver data packages and test reports to engineering teams with the quality and traceability needed to support design decisions and regulatory documentation.
• Design and build instrumentation systems: sensor selection, signal conditioning, DAQ hardware configuration, and wiring.
• Develop automated data collection, monitoring, and reduction workflows for real‑time insight during test campaigns.
• Establish data management standards: file structures, naming conventions, metadata capture, and archival.
• Establish standard methods for recurring test types: pressure testing, leak checks, thermal cycling, vibration/seismic, environmental exposure, dimensional verification.
• Build reusable test infrastructure and tooling that can be adapted across programs (KDU, KV1, and future production units).
• Create templates and standard operating procedures that lower the barrier for new test campaigns.
• Build and lead a test engineering team (technicians, test engineers, instrumentation specialists).
• Coordinate Responsible Engineers on development test objectives, acceptance test and qualification test execution.

• 10+ years of experience in test engineering, with at least 3 years in a leadership role building or managing test teams or programs.
• Hands‑on experience designing and building test setups for mechanical, thermal, or fluid systems.
• Deep experience with instrumentation and data acquisition systems (sensor selection, DAQ hardware, signal conditioning, automated data collection).
• Experience writing test plans, procedures, and reports with the rigor required for engineering decision‑making.
• Track record of establishing standard test methods and processes for an organization.
• Experience leading teams of technicians and test engineers.
• BS in Mechanical Engineering, Aerospace Engineering, or related discipline.

• Experience in aerospace, defense, or energy test environments with qualification testing per standards like SMC‑S‑016, MIL‑STD‑1540, or equivalent.
• Familiarity with quality…