Senior Software Engineer - Simulation

Senior Software Engineer - Simulation

Radiant is seeking an experienced Senior Software Engineer for Simulation to develop and implement solutions for reactor physics modeling, thermal-hydraulics simulations, and Digital Twin development. In this role, you will serve as a key technical contributor on 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

• Implement and contribute to technical architecture for simulation systems across thermal, hydraulic, and nuclear reactor physics models.
• Collaborate with and support simulation engineers developing reactor and subsystem physics models.
• Build and maintain software infrastructure to support Digital Twin simulation, visualization, and data processing capabilities.
• Contribute to the technical roadmap for thermal and safety analysis simulation. Develop and execute strategies for model tuning as models and frameworks evolve.
• Drive technical excellence by following and reinforcing best practices for simulation software development, code quality, and testing standards.
• Collaborate cross-functionally with Hardware, Nuclear, and Electrical engineering teams to accelerate software-in-the-loop and hardware-in-the-loop testing capabilities.
• Contribute to the delivery of mission-critical internal simulation products while ensuring sustainable development practices and technical debt management.
• Support team growth through knowledge sharing and contributing to a high-performance engineering culture.

Required Qualifications

• Bachelor's degree in physics, mechanical engineering, computer science, or a similar field, or equivalent experience
• 5+ years of professional software engineering experience with significant depth in simulation, scientific computing, or physics-based modeling.
• Strong technical proficiency in programming languages such as Python, Rust, C#, or C/C++, with demonstrated ability to contribute to architectural decisions.
• Experience working effectively within engineering teams in a collaborative technical environment.
• Strong background in simulation tools, physics-based modeling, numerical methods, or computational science with proven ability to execute technical strategy.
• Proficiency 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 deliver high-quality hands-on technical contributions within a collaborative team environment.

Preferred Qualifications:

• Advanced degree (Master's or Ph.D.) in physics, mechanical engineering, computer science, or a similar field.
• Experience contributing to simulation or computational modeling, parallel computing, or high-performance computing projects.
• Background with modern simulation frameworks, finite element analysis, or computational fluid dynamics tools.
• Track record of successful cross-functional collaboration with Hardware, Nuclear, and Electrical engineering teams.
• Strong communication skills with the ability to translate technical complexity for diverse audiences.
• Experience with Machine Learning, Deep Learning, or other probabilistic modeling techniques.

Work Environment

• Must work 100% onsite at El Segundo HQ.
• Must be willing to work extended hours and weekends as necessary to accomplish our mission.