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Radiant is building the world's first mass-produced, portable nuclear microreactors. The Kaleidos reactor is a 1-megawatt, fail-safe design that can be transported and deployed anywhere power is needed, running for up to 5 years without refueling. The company aims to replace diesel generators and provide critical power to hospitals, data centers, remote sites, and military bases. Founded in 2020, Radiant is preparing for its first reactor test at Idaho National Laboratory with initial customer deliveries beginning in 2028.
As Senior Thermofluids Systems Engineer for Power Conversion, you will own system-level thermodynamic modeling of the power conversion architecture that transforms heat from nuclear fission into electricity. You will define operating points balancing system performance and constraints, establish boundary conditions for fluid systems and turbomachinery teams, and serve as the primary technical interface to control systems engineering and reactor modeling teams.
Key responsibilities include: developing and maintaining thermodynamic performance models across startup, shutdown, transients, and off-nominal conditions using tools like MATLAB, Python, and Simulink; establishing interface requirements and boundary conditions (pressures, temperatures, flow rates, control signals) for all subsystems; driving architectural trades across performance, cost, weight, schedule, and safety; providing plant-level dynamic behavior models and operating envelopes to control systems teams; leading root-cause analysis for cycle performance anomalies; performing trade studies to optimize cycle architecture; owning system-level FMEA for fluid subsystems; and communicating clearly across multidisciplinary teams.
Required: Bachelor's degree in Mechanical, Aerospace, Chemical, or Systems Engineering; 5+ years in thermodynamic/power cycle modeling, systems engineering, or performance engineering with requirements development and system-level verification experience; strong working knowledge of thermodynamics and fluid dynamics applied to power generation; proficiency in MATLAB, Simulink, or Python; and strong analytical skills with ability to manage competing priorities.
Desired qualifications include fluid system architecture experience, control scheme development support, familiarity with ASME codes (B31.3, BPVC Section VIII/III), turbomachinery or heat rejection system design experience, hardware build/assembly/test background, FMEA and risk management experience, and nuclear industry background. Must be willing to work extended hours and weekends; 100% on-site at El Segundo headquarters required.
