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. 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 leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, 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.
Responsibilities & Duties:
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.
Required Qualifications & Skills:
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.
Desired Qualifications & Skills:
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 requirements, particularly as they relate to test documentation and data traceability.
Experience with acceptance testing (workmanship verification) and qualification testing (design margin verification)—understanding the distinction and designing programs accordingly.
Experience with thermal-hydraulic test loops, pressure systems, or high-temperature test environments.
Experience with Turbo machinery and power generation test environments.
Familiarity with FEA/CFD tools for correlating test data with analytical predictions.
Experience building test organizations from scratch at fast-paced companies.
Prior nuclear experience is not required for this role.
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.
This is an exempt salaried role.
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.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
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.