Principal Power Systems Engineer

About Radiant Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. Rising energy demand is straining the U.S. grid and driving up utility costs, emissions, and interconnection backlogs. Radiant decentralizes energy, producing power close to where it’s used. Its first reactor, Kaleidos, is a factory-built, 1-megawatt, fail-safe microreactor that can be transported by land, sea, or air and runs up to 5 years without refueling.

Deployed locally without a decade-long build or permitting fight, Kaleidos provides independent power for critical infrastructure like military bases, data centers, hospitals, and remote sites. Founded in 2020, Radiant is under contract to deliver power to the U.S. Army, Air Force, Navy, and has pre-order agreements with Equinix, with deployments beginning in 2028.About the Role Radiant is seeking a talented Principal Power Systems Engineer to lead the design, modeling, and validation of electrical power systems supporting our nuclear microreactor platform.

You will play a critical role in defining how power is generated, conditioned, controlled, and delivered to customers across grid-connected, islanded, and rapidly deployable  this role, you will own power system studies from early architecture tradeoffs through detailed modeling, testing, and system validation. You’ll collaborate closely with electrical design, controls, turbo machinery, nuclear, thermal, and software teams to ensure safe, stable, and reliable power delivery under a wide range of operating and contingency conditions.

This role is central to commercializing Earth’s first mass-produced portable nuclear reactors.

Responsibilities & Duties:

Own power system architectural design for microreactor-based power generation systems operating in grid-connected and islanded modes.

Develop single-line diagrams of the power system for single- or multiple-reactor configurations.

Develop FMEAs to identify system behavior during component/system failures and identify redundancy paths.

Evaluate system behavior during disturbances such as load steps, faults, breaker operations, and loss-of-generation events.

Size energy storage systems for reactor cold start and variable load demands.

Own synchronization of multiple reactors in a microgrid and multiple reactors tied to grid.

Collaborate cross-functionally with the power conversion team to understand generator requirements and design power systems that can integrate seamlessly.

Participate in software-in-the-loop (SIL), hardware-in-the-loop (HIL), and system-level testing to validate/verify system performance.

Support system checkouts, commissioning, and testing of all power requirements

Regulatory compliance of power systems, including testing methods to verify power quality.

Required

Qualifications & Skills:

B.S. in Electrical Engineering with an emphasis in power systems or control systems.
5+ years of experience designing power systems for generation, microgrids, or mission-critical power systems.

Experience with sizing and integrating high-voltage battery systems with power electronics.

Strong experience with power system modeling and simulation tools (e.g., PSCAD, ETAP, PSSE, Simulink, or equivalent).Solid understanding of inverters, grid converters, DC/DC converters, rotating generation, and power system control modes (grid-forming, grid-following, droop control).Experience in analyzing system stability, protection behavior, and fault response in complex electrical systems.

Ability to clearly communicate technical concepts and results to cross-functional teams.

Desired

Qualifications & Skills:

M.S. in Electrical Engineering or related discipline.

Experience in power electronics development for high-power,…