Senior Thermal Modeling Engineer – Onsite, El Segundo

Decisive Point; El Segundo (CA); On-site; USD 130,000 - 190,000; Full time

Benefits offered by this job

Equity

Medical coverage

One Medical membership

Vision coverage

Dental coverage

Parental leave

Lunch provided

Flexible PTO

Remote workday option

On-site HQ

Job summary

Radiant is seeking a driven Senior Thermal Modeling & Analysis Engineer to own high-fidelity CFD and thermal modeling for the Kaleidos microreactor. You will analyze heat generation and transport across reactor systems, cooling, shielding, and surrounding hardware under steady-state, transient, and off-normal conditions.

Your work will directly influence system architecture, component design, material selection, operating limits, test planning, and safety margins.

Qualifications

• Bachelor’s degree in mechanical, aerospace, nuclear engineering, physics, or a related field.
• 5+ years of relevant thermal, CFD, or thermal-fluid analysis experience.
• Extensive experience with STAR-CCM+, Ansys Fluent, or comparable CFD software.
• Strong foundation in heat transfer, fluid mechanics, turbulence modeling, and numerical methods.
• Experience performing steady-state and transient thermal-fluid analyses.
• Experience with model verification, sensitivity studies, and validation or test correlation.
• Ability to prepare and simplify CAD geometry for analysis using Siemens NX or comparable software.
• Experience using Python or another scripting language to automate simulation and post-processing workflows.
• Demonstrated ability to translate analytical results into engineering decisions and communicate effectively across disciplines.

Responsibilities

• Own thermal and CFD analyses from problem definition through model development, execution, validation, documentation, and design recommendation.
• Model turbulent gas flow, conduction, convection, radiation, conjugate heat transfer, and coupled multiphysics behavior across Kaleidos systems.
• Evaluate steady-state, transient, and off-normal operating conditions to identify hotspots, thermal gradients, heat loads, flow distribution, pressure losses, and system margins.
• Define modeling assumptions, boundary conditions, material properties, and appropriate fidelity based on the engineering decision being supported.
• Translate analytical results into actionable design recommendations and collaborate with engineering teams through design iteration.
• Establish and implement simulation best practices, including convergence assessment, mesh and time-step independence, sensitivity studies, uncertainty evaluation, and model verification.
• Correlate analytical models with test data and update modeling assumptions based on measured system behavior.
• Build automated, reproducible workflows for parametric studies, design exploration, post-processing, and simulation efficiency.
• Develop and validate reduced-order models that support system-level analysis and rapid design iteration.
• Clearly communicate assumptions, limitations, risks, margins, and recommendations to cross-functional teams.

Education

Bachelor's degree in mechanical/aerospace/nuclear engineering or physics

Tools

Siemens NX

Python scripting

Job description

Radiant is seeking a driven Senior Thermal Modeling & Analysis Engineer to own high-fidelity CFD and thermal modeling for the Kaleidos microreactor. You will analyze heat generation and transport across reactor systems, cooling, shielding, and surrounding hardware under steady-state, transient, and off-normal conditions.

Your work will directly influence system architecture, component design, material selection, operating limits, test planning, and safety margins.