Fluid Systems Engineer – Heat Exchangers

Fluid Systems Engineer – Heat Exchangers

Radiant is seeking a highly motivated Fluid Systems Engineer to own the design and development of the heat exchangers in the Kaleidos power generation cooling loop. You will develop critical hardware at the heart of the supercritical CO2 heat engine while considering for long-term production requirements related to hardware performance, reliability, mass, cost, and manufacturability. The ideal candidate is experienced in building early concept hardware through production, and is excited about our vision to build Earth’s mass-produced nuclear reactors and provide portable clean power to remote areas globally.   

Responsibilities and Duties:   

• Perform conceptual and detailed design of heat exchangers for the Kaleidos secondary cooling loop, including shell-and-tube, finned tube, and printed circuit heat exchanger (PCHE) technologies. 
• Perform thermal and fluid flow modeling to evaluate heat exchanger performance under a variety of operating scenarios. 
• Work with structural and materials teams to select appropriate alloys and manufacturing processes compatible with high-temperature and irradiated environments. 
• Support FEA and CFD simulations to validate design assumptions and optimize geometry. 
• Collaborate with fabrication partners to develop prototypes and guide manufacturing trials. 
• Ensure designs meet applicable codes, standards (e.g. ASME Section III), and regulatory requirements. 
• Participate in design reviews and contribute to safety case development and risk assessments. 
• Document design processes, specifications, and performance metrics in a traceable and auditable manner. 

Required Qualifications and Skills:  

• B.S. in Mechanical Engineering, Aerospace Engineering, Nuclear Engineering, or related discipline. 
• 3+ years of experience in heat exchanger design or thermal systems in a high-performance hardware environment. 
• Proficiency with thermal/fluid analysis tools (e.g. STAR-CCM, ANSYS, or similar). 
• Familiarity with high-temperature alloys and fabrication techniques such as diffusion bonding and welding. 
• Strong mechanical design skills and CAD proficiency (e.g., NX, SolidWorks, or equivalent). 
• Excellent communication and technical documentation skills. 
• Basic programming knowledge (e.g. Python, C++, or equivalent) 

Desired Qualifications and Skills:   

• Experience designing recuperators or compact heat exchangers in nuclear, aerospace, or high-temperature process industries. 
• Working knowledge of ASME codes relevant to heat exchangers and nuclear components. 
• Experience with design for manufacturability (DFM) and working directly with vendors on prototype development. 

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.