Principal Thermal-Hydraulics Engineer
About The Position
Radiant is seeking a Principal Thermal-Hydraulics Engineer to set the technical direction for computational fluid dynamics (CFD) and thermal finite element analysis (FEA) of its Kaleidos high-temperature gas microreactor. The engineer will lead complex, high-consequence modeling, establish methods and validation strategies, and inform decisions across reactor systems, cooling systems, shielding, and other areas. As a technical authority, this person will mentor engineers, influence program-level decisions, and help advance commercialization of Radiant’s transportable nuclear microreactor. The position is based 100% onsite at Radiant’s El Segundo headquarters. The engineer must be willing to work extended hours and weekends as necessary. Compensation includes base salary, equity grants, and health benefits; level and total compensation depend on interview performance, experience, education, and qualifications.
Requirements
- Bachelor’s degree in engineering, physics, or a similar field from an accredited institution.
- 10 or more years of relevant industry experience, with a track record of technical leadership on complex, high-consequence programs.
- Extensive experience with STAR-CCM+, Ansys Fluent, or other commercial CFD codes, including advanced turbulence and conjugate heat transfer modeling.
- Mastery of finite element and computational fluid dynamics principles and methods, with demonstrated experience validating models against test data.
- Proficiency with CAD software, specifically Siemens NX.
- Experience building automated simulation workflows and scripting tools.
- Demonstrated ability to mentor engineers and communicate complex technical results to cross-functional teams and leadership.
- Willingness to work extended hours and weekends as necessary.
- Ability to work 100% onsite at the El Segundo headquarters.
Nice To Haves
- Advanced degree (MS or PhD).
- Experience with radiation heat transport modeling.
- Knowledge of nuclear reactor design, thermal-hydraulics, or safety analysis.
- Experience with multiphysics coupling, such as thermal-structural or neutronics-thermal.
- Experience with reduced-order modeling or system-level thermal-hydraulic codes.
- Experience with regulatory or safety-basis analysis.
- Driven, self-motivated approach and ownership of work end to end.
- Aerospace or automotive industry experience; prior nuclear experience is not required.
Responsibilities
- Serve as the technical authority for thermal CFD and thermal FEA modeling of Kaleidos reactor systems, owning the most complex and highest-risk analyses.
- Define modeling strategy, methodology, and best practices for turbulent flow, heat transfer, and multiphysics interactions, and drive their adoption across the team.
- Lead model verification and validation, correlate simulation results with test data, and establish confidence and uncertainty bounds for design and safety decisions.
- Architect automated simulation workflows and tooling to expand capability, accuracy, and efficiency, and set the roadmap for simulation infrastructure.
- Lead development of reduced-order analysis methods in partnership with design, systems, and test teams.
- Influence reactor, cooling, and shielding design decisions by translating analysis results into clear recommendations for engineering leadership.
- Mentor and develop engineers, set the technical bar through design and analysis reviews, and contribute to hiring.
- Collaborate across disciplines to define analysis requirements, align priorities, and resolve cross-team technical tradeoffs.
Benefits
- Substantial incentive stock plan for all full-time employees.
- Medical coverage up to the base silver-level plan at 100% for employees and 50% for dependents, with plans available up to Platinum.
- Sponsored One Medical memberships for employees and their dependents.
- Vision coverage at 100% for the top-tier plan and 50% for dependents.
- Dental coverage at 100% for the top-tier plan and 50% for dependents; orthodontia is extra.
- Voluntary life, accident, hospital, and critical illness benefits, plus commuter and FSA/HSA options, offered as employee-contributed benefits.
- Eight weeks of paid parental leave for all parents, with additional paid pregnancy leave for California employees.
- Nuclear Engineering Certificate Program with Penn State University, fully covered for eligible employees.
- Daily catered lunch, free snacks, and drinks.
- Flexible PTO policy and remote workday allocation.
- Company and team-bonding events, happy hours, and in-person camaraderie.
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What This Job Offers
Job Type
Full-time
Career Level
Principal
