Lead, Fluid Systems Engineering

About Radiant Radiant is an El Segundo, CA-based company building the world's only mass-produced, transportable nuclear microreactors. The U.S. grid is under growing strain, with power demand accelerating, driving higher utility costs, rising carbon emissions, and interconnection backlogs. Radiant has a solution, transportable, on-site power. Our first reactor, Kaleidos, is 1 megawatt: small enough to be factory-built, transported by land, sea, or air, and deployed wherever power is needed. 1 MW can power 1000 homes for five years. Ship it back and we refuel for a 20 year operating life. We made energy a product that can be used for critical infrastructure like military bases, data centers, hospitals, and remote sites, as well as the commercial main street businesses that keep America running. Founded in 2020, Radiant is under contract to deliver power to the U.S. Army, Navy and Air Force and has signed pre-order agreements with Equinix, with deployments beginning in 2028. About the Role Radiant is seeking an impactful Lead, Fluid Systems Engineering to build and lead the team that owns critical Kaleidos fluid systems from preliminary design through build and production. These systems include the primary loop subsystems and the power conversion loop, which convert heat from the reactor core into electrical power. As a player-coach, you will set technical direction at a staff level, stay hands-on in the hardest design and analysis problems, and hire, develop, and lead a team of fluid systems engineers. You will have an instrumental impact on fueling the first new commercial reactor design in over 50 years. Leadership

• Lead, mentor, and grow a team of fluid systems engineers; set clear goals, give regular feedback, and support career development.

• Recruit and hire top engineering talent, and build a team culture of ownership, rigor, and constructive communication.

• Own team planning, prioritization, and resourcing, including subassembly design, manufacturing, and test schedules.

• Partner with leadership and other functional areas to collect requirements, align priorities, and resolve cross-team tradeoffs.

Technical Ownership

• Own the architecture and end-to-end engineering of fluid systems and components, including compressors, valves, and heat exchangers, and set the technical bar for the team.

• Personally tackle the most complex thermal and fluids analysis, using first-principles hand calculations and finite element tools to drive design decisions, verify performance, and ensure structural integrity.

• Lead trade studies to optimize the system and meet program requirements.

• Establish and review manufacturing/assembly instructions, test plans, and BOM management.

• Drive supplier identification, selection, and development for all components.

• Own subsystem risk analysis (FMEA) and ensure design reviews are rigorous.

• Provide expertise and clear, constructive feedback to engineers in other functions.

Required Qualifications & Skills

• Bachelor’s degree from an accredited institution in Mechanical, Materials, Aeronautical, Civil, or Structural Engineering.

• 8+ years of experience designing, building, and testing fluid systems, with demonstrated technical leadership at a senior or staff level.

• Experience leading or mentoring engineers, formally or informally, and a desire to grow as a people manager.

• Experience with fluid system architecture design.

• Proficient knowledge of fluid dynamics and thermodynamics.

• Proficient knowledge of heat exchanger design and analysis methods.

Desired Qualifications & Skills

• Prior experience managing engineers, including hiring and performance feedback.

• Knowledge of thermodynamic power cycles.

• Experience designing piping systems for thermal growth using hand calculations and FEA tools.

• Experience with process piping design and testing codes, such as ASME B31.3 and ASME PCC-2.

• Experience with fluid system modeling via MATLAB/Python.

• Experience with design for manufacturability and ramping up hardware builds in a production environment.

• Experience designing and operating test stands.

• Extreme ownership of work and a high degree of responsibility.

• Excellent communication across multidisciplinary teams.

• Prior nuclear experience is not required.

Additional Requirements

• Willingness to work extended hours and weekends as necessary to accomplish our mission.

• Must work 100% onsite at El Segundo HQ.

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.

• Nuclear Engineering Certificate Program: 100% covered educational program with Penn State University, for eligible employees, to rapidly upscale into nuclear.

• 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 full-time 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: [email protected].

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. 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.