Radiant · 11 hours ago
Senior Software Engineer - Simulation
El Segundo, CA
Full-time
Onsite
Senior Level
5+ years expRadiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. They are seeking a highly driven Senior Software Engineer with a strong background in physics or mechanical engineering to collaborate with teams and improve their simulation and test software stack.
Clean EnergyEnergyEnergy EfficiencyRenewable Energy
No H1B
Responsibilities
Develop thermal, hydraulic, and nuclear models for reactor and reactor subsystem physics
Design and implement technical architecture for simulation systems
Build software infrastructure to support Digital Twin simulation, visualization, and data processing capabilities
Contribute to the technical roadmap for thermal and safety analysis simulation. Implement model tuning strategies as models and frameworks evolve
Establish and champion best practices for simulation software development, code quality, and testing
Collaborate with Hardware, Nuclear, and Electrical engineering teams to develop software-in-the-loop and hardware-in-the-loop testing capabilities
Deliver mission-critical internal simulation products while maintaining code quality and managing technical debt
Mentor junior engineers and contribute to building a high-performance team culture
Qualification
Required
5+ years of professional software engineering experience with significant depth in simulation, scientific computing, or physics-based modeling
Strong proficiency in programming languages such as Python, Rust, C#, or C/C++
Experience with simulation tools, physics-based modeling, numerical methods, or computational science
Hands-on experience 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
Demonstrated ability to drive technical projects independently with minimal oversight
Bachelor's degree in physics, mechanical engineering, computer science, or a similar field, or equivalent experience
Preferred
Advanced degree (Master's or Ph.D.) in physics, mechanical engineering, computer science, or a similar field
Experience with simulation or computational modeling, parallel computing, or high-performance computing
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 explain technical concepts to diverse audiences
Experience with Machine Learning, Deep Learning, AI, or other probabilistic modeling techniques
Benefits
Substantial incentive stock plan for all full-time employees.
100% premium coverage for base Silver level plan for employee + 50% premium coverage for dependents. Platinum plans available.
Sponsored memberships for eligible employees and their dependents.
100% premium coverage for top tier plan + 50% for dependents.
100% premium coverage for top tier plan (including orthodontia) + 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.
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.
Company
Radiant
Radiant develops portable nuclear microreactors designed to generate electricity and heat in a compact, factory-built form.
51-200 employees
Funding
Current Stage
Late StageTotal Funding
$518.82MKey Investors
Andreessen HorowitzUnion Square Ventures
2025-12-17Series D· $300M
2024-11-14Series C· $165M
2023-04-18Series B· $40M
Leadership Team
Doug Bernauer
Chief Executive Officer
Recent News
2026-01-07
The Motley Fool
2026-01-04
Globe and Mail
2026-01-03
Company data provided by crunchbase