Principal Thermal Modeling Engineer

The posting, as Radiant Industries wrote it

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 a Principal Thermal Modeling Engineer with deep expertise in CFD and thermal FEA to set the technical direction for thermal and fluid simulation of the Kaleidos microreactor. You will lead the most complex and consequential modeling problems for a high-temperature gas reactor, defining the methods, standards, and validation strategy that inform decisions across reactor systems, cooling systems, shielding, and more. As a recognized technical authority, you will mentor engineers, influence program-level decisions, and help drive the milestones that unlock commercialization of the first mass-produced nuclear reactor.

Responsibilities & Duties

• 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 multi-physics interactions, and drive their adoption across the team.
• Lead model verification and validation, correlating simulation results with test data and establishing confidence and uncertainty bounds for design and safety decisions.
• Architect automated simulation workflows and tooling that expand capability, accuracy, and efficiency, and set the roadmap for simulation infrastructure.
• Lead the 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.

Required Qualifications & Skills

• Bachelor’s degree in engineering, physics, or a similar field from an accredited institution; advanced degr

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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: recruiting@radiantnuclear.com.

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.