Senior Test Engineer

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 offers a rare opportunity to bridge engineering, operations, and human factors in a highly technical and fast-paced environment.

Responsibilities

• Perform testing as a Test Conductor/Test Director to gain firsthand experience, ensuring procedures align with real-world execution.
• Partner with design engineers to develop innovative test methods for complex mechanisms and structures.
• Support testing and iterative improvements of fluid, electrical, and structural hardware of the Kaleidos reactor through development, qualification, and acceptance testing.
• Identify and develop appropriate suppliers for component sourcing and fabrication.
• Drive initiatives for continuous improvement in test processes and data delivery quality.
• Support one-off test campaigns in a fast paced, minimum-requirements environment to drive hardware risk reduction.
• Ensure compliance with DOE and NRC standards, maintaining strict formatting, clarity, and usability in procedural documentation.

Requirements

• 5+ years of full-time professional experience in engineering problem-solving, including system design, analysis, or testing.
• Bachelor’s degree from an accredited institution in mechanical, manufacturing, or other related engineering discipline.
• Ability to apply first principles thinking to solve problems and make decisions in uncertain or ambiguous situations.
• Background in highly regulated industries (e.g., nuclear, aerospace, aviation, maritime).
• Demonstrated ability to lead projects and work independently.
• Strong technical fundamentals in fluids and thermodynamics.
• Strong written and verbal communication skills.
• Flexible and adaptable mindset - self-driven with the ability to seek out requirements with minimal direction.

Qualifications

• Prior experience working as an operator in fast-paced test environments (e.g., rocket engine testing, turbopump testing, component level testing), with familiarity in safety protocols, and high-reliability operations, high pressure gases, safety engineering (FMECAs, Keep-out Zone).
• Experience designing, fabricating, or operating fluid systems.
• Knowledge of instrumentation including pressure transducers, thermocouples, resistance temperature detectors, and accelerometers.
• Ability to read and interpret engineering standards, technical requirements, and engineering drawings (ASME 31.3, 31.1, and ASME Boiler Code Section III/VIII).
• Hands-on experience in developing technical procedures.
• Experience reviewing test data and hardware performance analysis.
• Prior operations experience with hands-on work designing and commissioning test ground support equipment (test fixtures, fluid systems, electrical systems).
• Proficiency with Ion, Epsilon3, NX CAD, Teamcenter.
• Experience with Beckhoff PLC Controllers.

Skills

• Ability to apply first principles thinking to solve problems and make decisions in uncertain or ambiguous situations.
• Strong technical fundamentals in fluids and thermodynamics.
• Strong written and verbal communication skills.
• Flexible and adaptable mindset - self-driven with the ability to seek out requirements with minimal direction.
• Prior experience working as an operator in fast-paced test environments (e.g., rocket engine testing, turbopump testing, component level testing), with familiarity in safety protocols, and high-reliability operations, high pressure gases, safety engineering (FMECAs, Keep-out Zone).
• Experience designing, fabricating, or operating fluid systems.
• Knowledge of instrumentation including pressure transducers, thermocouples, resistance temperature detectors, and accelerometers.
• Ability to read and interpret engineering standards, technical requirements, and engineering drawings (ASME 31.3, 31.1, and ASME Boiler Code Section III/VIII).
• Hands-on experience in developing technical procedures.
• Experience reviewing test data and hardware performance analysis.
• Prior operations experience with hands-on work designing and commissioning test ground support equipment (test fixtures, fluid systems, electrical systems).
• Proficiency with Ion, Epsilon3, NX CAD, Teamcenter.
• Experience with Beckhoff PLC Controllers.

Benefits and Perks

• 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.