Principal Electrical Engineer, Electronics

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 Principal or Staff Electrical Engineer to define and lead the electrical architecture for Kaleidos, our commercial microreactor targeted for customer deployment in 2028.

The work spans full-stack PCB development, mixed-signal design, high-speed interfaces, power distribution, and signal integrity to support the data acquisition, signal conditioning, and real-time processing that reactor control depends on.

You will serve as the technical lead for custom hardware, setting design standards, driving architecture decisions, and owning high-reliability, low-noise board development from requirements definition and schematic capture through layout, bring-up, validation, and field deployment. You will shape the hardware roadmap and guide the electrical team's technical direction as we scale toward first commercial deployments in 2028.Responsibilities & Duties:

Own the boards that control a fission reactor: multilayer mixed-signal designs for reactor control and instrumentation, terrestrial today with space applications ahead.

Define and own the electrical architecture strategy for mixed-signal systems: power distribution, analog front ends, and digital control interfaces.

Design low-noise analog front-end circuits and integrate them with ADC/DAC and digital subsystems.

Own schematic capture, component selection, and layout, including high-speed and precision routing for sensor interfaces, data acquisition paths, and communication buses, with focus on signal integrity, power integrity, grounding, and EMI/EMC mitigation.

Bring up, debug, and validate hardware hands-on through board-level testing, instrumentation, and root-cause analysis.

Write and execute the validation and qualification plans that prove performance, reliability, and environmental margin.

Work directly with firmware, FPGA, DSP, and responsible engineers at the hardware-software boundary.

Provide technical leadership and mentorship across the electrical team, lead design reviews, and own hardware risk identification and mitigation.

Required

Qualifications & Skills:

Bachelor’s degree in Electrical Engineering or a related field.
8+ years designing custom PCBs, including multilayer and mixed-signal boards.

Prior experience shipping hardware you designed, carried from requirements through layout, bring-up, and qualification into production or field deployment.

Demonstrated experience setting electrical architecture direction and driving decisions across complex, multi-disciplinary programs.

Strong experience with schematic capture and PCB layout tools (Altium, Cadence, or similar).Solid command of signal integrity, power integrity, grounding strategies, and EMI/EMC mitigation.

Analog and mixed-signal design experience, including sensor interfaces, ADC/DAC integration, and low-noise practices.

Familiarity with high-speed interfaces (SPI, I2C, UART, Ethernet) and their…