Lead Test Engineer, Power Generation

Radiant•El Segundo, CA

5h•Onsite

About The Position

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 Lead Test Engineer, Power Generation to own the strategy, execution, and team leadership for testing the power generation system including turbomachinery, heat exchangers, controls, and primary cooling systems. This role is ideal for a hands-on technical leader who enjoys building test infrastructure, running complex hardware, and mentoring engineers and technicians while remaining deeply involved in day-to-day testing. You will lead testing development for our high-speed machinery and own creating our test site from the ground up. This test infrastructure will be used to iterate quickly on our designs evaluating vibration, performance, thermal behavior, and system reliability in development and transition into acceptance testing for production units. This role works closely with mechanical design, analysis, manufacturing, and operations teams to ensure turbomachinery designs are validated, robust, and production-ready.

Requirements

Bachelor’s or Master’s degree in Mechanical Engineering or a related field, or equivalent experience
8+ years of experience in testing, development, or validation of turbomachinery, rotating equipment, or complex mechanical systems
Hands-on experience testing high-speed rotating machinery and high-temperature hardware
Strong understanding of rotordynamics, vibration, and bearing behavior as applied to real hardware testing
Experience correlating test results with analytical predictions and design intent
Demonstrated technical leadership and ability to drive complex test efforts to completion
Strong written, verbal, and organizational skills
Willingness to work extended hours or weekends as necessary to accomplish program objectives
Must work 100% onsite at Radiant’s El Segundo headquarters
This is an exempt salaried role.

Nice To Haves

Prior experience leading or mentoring test engineers or technicians
Experience with power generation or other high-reliability power generation systems
Familiarity with rotordynamic analysis tools (e.g., XLrotor, Dyrobes, or equivalent) from a test correlation or validation perspective
Knowledge of bearing selection and performance in high-speed, high-temperature applications
Familiarity with relevant industry standards (API, ASME, ISO)
Startup or fast-paced hardware development experience
Prior nuclear experience is not required

Responsibilities

Test Site & Infrastructure Development
Lead requirements definition, design, and implementation of Radiant’s test site
Design, build, commission, and maintain test rigs, fixtures, instrumentation, and support systems for turbomachinery, heat exchangers, controls, and primary cooling systems
Establish operating procedures, safety controls, and facility readiness for high-speed, high-energy, and high-temperature test environments
Test Strategy, Planning & Technical Ownership
Own and lead the turbomachinery test strategy across development, qualification, and production acceptance phases
Define test objectives, plans, success criteria, instrumentation strategies, and data requirements for high-speed rotating machinery and supporting thermal-fluid systems
Serve as the technical authority for vibration, rotordynamic, and bearing-related testing
Translate analytical predictions (critical speeds, stability margins, transient response) into targeted test campaigns that validate design assumptions and retire risk.
Balance test coverage, technical risk, schedule, and hardware availability to enable rapid iteration while maintaining safety and rigor
Test Execution & Data Analysis
Plan and execute development, qualification, and acceptance tests including startup/shutdown, transient, off-design, and endurance testing
Operate test hardware hands-on with a strong emphasis on repeatability, data quality, and safety
Analyze test data to assess vibration behavior, rotordynamic stability, bearing performance, thermal response, and overall system performance
Compare test results against analytical predictions and work with design teams to resolve discrepancies
Lead root cause investigations for anomalies or failures and drive corrective actions based on test evidence
Technical Leadership & Team Development
Provide technical leadership and mentorship to test engineers and technicians
Act as a player-coach: remain hands-on while scaling testing capability, throughput, and organizational maturity
Support hiring, onboarding, and technical development of turbomachinery test personnel
Develop work estimates, test schedules, and status updates for program leadership
Review and approve test procedures, reports, and data packages
Establish standards for test documentation, data management, and knowledge capture
Help mature Radiant’s turbomachinery test processes, labs, and safety culture over time
Cross-Functional Collaboration
Partner closely with turbomachinery mechanical engineers to ensure designs are testable and adequately validated
Review component and system-level design documentation with an eye toward test coverage, instrumentation, and risk
Collaborate with thermal, manufacturing, quality, and operations teams to support prototype, first-article, and production hardware testing
Represent testing in design reviews, test readiness reviews, and technical leadership discussions

Benefits

Stock: Substantial incentive stock plan for all full-time employees.
Medical: 100% premium coverage for base Silver level plan for employee + 50% premium coverage for dependents. Platinum plans available.
One Medical: Sponsored memberships for eligible employees and their dependents.
Vision: 100% premium coverage for top tier plan + 50% for dependents.
Dental: 100% premium coverage for top tier plan (including orthodontia) + 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.
Burgeoning satellite offices in Oak Ridge, TN and Washington, D.C., near Capitol Hill.