Radiant · 2 weeks ago
Principal Software Engineer - Simulation
El Segundo, CA
Full-time
Onsite
Lead/Staff
8+ years expRadiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. They are seeking an experienced Lead Software Engineer for Simulation to mentor and lead the engineering team responsible for reactor physics modeling, thermal-hydraulics simulations, and Digital Twin development.
Clean EnergyEnergyEnergy EfficiencyRenewable Energy
No H1B
Responsibilities
Lead technical architecture and implementation for simulation systems across thermal, hydraulic, and nuclear reactor physics models
Mentor and provide technical guidance to simulation engineers developing reactor and subsystem physics models
Design and 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 strategies for model tuning as models and frameworks evolve
Drive technical excellence by establishing 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
Own delivery of mission-critical internal simulation products while ensuring sustainable development practices and technical debt management
Contribute to team growth through technical mentorship and promoting a high-performance engineering culture
Qualification
Required
8+ years of professional software engineering experience with significant depth in simulation, scientific computing, or physics-based modeling
Deep technical expertise in programming languages such as Python, Rust, C#, or C/C++, with demonstrated ability to drive architectural decisions
Experience providing technical leadership and mentorship to engineering teams
Strong background in simulation tools, physics-based modeling, numerical methods, or computational science with proven ability to guide technical strategy
Expertise 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 technical leadership and mentorship
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 as a technical lead on 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, AI, or other probabilistic modeling techniques
Benefits
Stock: Substantial incentive stock plan for all full-time employees.
Medical: 100% premium coverage for base Silver level plan for employee + 50% premium coverage for dependents. Platinum plans available.
One Medical: Sponsored memberships for eligible employees and their dependents.
Vision: 100% premium coverage for top tier plan + 50% for dependents.
Dental: 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