Principal Embedded Software Engineer

• Radiant is seeking a Principal Embedded Software Engineer to set the technical direction for embedded software across instrumentation and control (I&C) systems
• You will define architecture, establish engineering standards, and personally drive the development of mission-critical, highly performant embedded systems that interface with sensors and actuators at the heart of a first-of-its-kind reactor design
• You will have the opportunity to shape the embedded software foundation of the first commercialized portable nuclear microreactor, technology that will redefine how the world accesses clean, reliable power
• Define and own the embedded software architecture for I&C systems, establishing patterns and standards that scale across the full program lifecycle
• Lead design and development of reliable, fault-tolerant embedded software for production hardware operating in demanding environments
• Develop and bring up new drivers for I&C hardware across a range of sensing and actuation subsystems
• Serve as the senior technical voice in design reviews, setting the bar for rigor, surfacing systemic risks, and driving decisions that span multiple subsystems and teams
• Own the full engineering lifecycle, from architecture through test, build, and field implementation, and set expectations for how the team executes that lifecycle
• Establish robust hardware and software testing frameworks, validation methodology, and documentation standards that meet rigorous safety requirements
• Mentor and grow embedded engineers across the team; model technical excellence and engineering judgment
• Partner with electrical, controls, and hardware engineering leadership to align on cross-disciplinary interfaces and constraints

Benefits

• Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans
• Equity: Substantial incentive stock plan for all salaried employees
• Dental: 100% coverage, orthodontia extra, 50% for dependent
• Flexible PTO policy
• Vision: 100% coverage + 50% for dependents
• Voluntary Life, Accident, Hospital, Critical Illness, Commuter and FSA are offered as employee contributed benefits
• Beautiful El Segundo headquarters close to the Pacific Ocean
• Team-bonding company outings, happy hours and in-person camaraderie

• The ideal candidate thrives in ambiguous early-stage environments, can make high-consequence technical decisions with incomplete information, and leaves a lasting organizational imprint through the systems and culture they build
• Hands-on experience with an RTOS (Zephyr, NuttX, ThreadX, etc.), including low-level bring-up and porting
• Track record of influencing technical direction beyond your immediate team, through documentation, standards, or cross-functional alignment
• Demonstrated experience driving architecture across complex, multi-subsystem embedded programs, not just feature ownership
• Bachelor’s degree in computer engineering, computer science, electrical engineering, or a related field
• Strong communicator capable of driving consensus across engineering, program, and leadership stakeholders
• Deep proficiency in embedded C/C++
• 8+ years of industry experience in embedded software, including significant ownership of system-level architecture decisions
• Must work 100% onsite at El Segundo HQ
• Must be willing to work extended hours and weekends as necessary to accomplish our mission
• Experience with Zephyr RTOS at an architectural or maintainer level
• Experience with CMake in large, multi-target embedded builds
• Experience working with Simulink Autocode C++ export in a production context
• Proficiency in reading and interpreting hardware schematics; ability to debug at the hardware/software boundary
• Experience in safety-critical or high-reliability domains (aerospace, defense, medical, nuclear, or industrial)