Software Engineering Leader - Simulation

 About Radiant

Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid-deploy capability can replace similar-sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.

About the Role

Radiant is seeking a Software Engineering Leader for Simulation to build and lead the engineering team responsible for reactor physics modeling, thermal-hydraulics simulations, and Digital Twin development. In this role, you will scale a high-performing team while maintaining technical depth, ensuring our simulation infrastructure enables Radiant to design, test, and validate reactor systems—accelerating our path to commercialization.

Responsibilities and Duties:

• Build, lead, and mentor a team of simulation engineers developing thermal, hydraulic, and nuclear models for reactor and reactor subsystem physics.

• Guide technical architecture and implementation for simulation systems.

• Scale software infrastructure to support Digital Twin simulation, visualization, and data processing capabilities.

• Define and own the technical roadmap for thermal and safety analysis simulation. Develop and execute a strategy for model tuning as models and model frameworks change.

• Foster a culture of technical excellence by establishing best practices for simulation software development, code quality, and testing.

• Collaborate cross-functionally with Hardware, Nuclear, and Electrical engineering teams to accelerate software-in-the-loop and hardware-in-the-loop testing capabilities.

• Own team delivery of mission-critical internal simulation products while ensuring sustainable development practices and technical debt management.

• Recruit, develop, and retain top engineering talent and build a high-performance team culture.

Required Qualifications:

• 7+ years of professional software engineering experience with significant depth in simulation, scientific computing, or physics-based modeling.

• 4+ years of people management experience leading engineering teams.

• Strong technical background in programming languages such as Python, Rust, C#, or C/C++, with the ability to review code and guide architectural decisions.

• Experience building and scaling highly technical engineering teams.

• Familiarity with simulation tools, physics-based modeling, numerical methods, or computational science sufficient to guide technical strategy.

• Familiarity with numerical solvers, visualization frameworks, and automated testing approaches for scientific software.

• Strong foundation in software engineering best practices, including version control, code review, and CI/CD pipelines.

• Proven ability to balance hands-on technical contributions with team leadership and people development.

• Bachelor's degree in physics, mechanical engineering, computer science, or a similar field, or equivalent experience

Preferred Qualifications:

• Advanced degree (Master's or Ph.D.) in physics, mechanical engineering, computer science, or a similar field.

• 9+ years of professional software engineering experience with significant depth in simulation, scientific computing, or physics-based modeling.

• 6+ years of people management experience lead